MYOTILIN, AN ACTIN-ORGANIZING PROTEIN

Abstract: The present invention concerns a novel cytoskeletal protein, myotilin, which contains Ig-like domains homologous to a giant sarcomeric structural protein titin. Myotilin is expressed in skeletal and cardiac muscles, it colocalizes with alpha -actinin in the sarcomeric I-bands and directly interacts with alpha -actinin. Expression of myotilin in mammalian non-muscle cells and in yeast causes reorganization of actin into thick F-actin bundles and inhibits growth of yeast cells.

Description: MYOTILIN, A NOVEL ACTIN-ORGANIZING PROTEIN Field of the invention The present invention concerns a novel cytoskeletal protein, myotilin, which contains Ig-like domains homologous to a giant sarcomeric structural protein titin. Myotilin is expressed in skeletal and cardiac muscles, it colocalizes with α-actinin in the sarcomeric I-bands and directly interacts with α-actinin. Expression of myotilin in mammalian non-muscle cells and in yeast causes reorganization of actin into thick F-actin bundles and inhibits growth of yeast cells. Background of the invention Among the various cell types in the higher organisms, the striated muscle cells have differentiated to carry out the task of force generation and transduction. To serve this very specialized function, the muscle cells express many gene products or mRNA splice variants that are not found in other cells of the body. Many of the muscle specific genes encode cytoskeletal proteins by which a highly organized sarcomeric architecture is created [1, 2]. The major components of thin and thick filaments, actin and myosin, are linked to a variety of molecules regulating the assembly, structural integrity and function of the striated muscle. For instance, the giant protein titin that spans from the M-line of the thick filament to the Z-line of the thin filament, functions as a spring and a ruler of the sarcomere, and α-actinin, an actin-binding protein, crosslinks thin filaments into antiparallel bundles in the Z-lines [2-8]. The force generated by cytoskeletal components of the contracting subunits is transduced through the plasma (sarcolemma) membrane to the extracellular matrix via a connecting multi-subunit dystrophin-glycoprotein complex [9, 10]. The importance of the individual components of the sarcomeric and sarcolemmal structures is highlighted by recent findings demonstrating that mutations in several different structural proteins result in muscular diseases such as muscular dystrophies and cardiomyopathies [9-12]. Many of the identified muscle disease genes encode proteins of dystrophin-associated sarcolemmal complex, but recently also other types of molecules, including regulators of the sarcomeric architecture, have been indicated to participate in pathogenesis of certain disease forms. A mutation in α-tropomyosin gene, TPM3, was shown to cause an autosomal dominant nemaline myopathy (NEM1) [13]. The nebulin gene is a candidate for another form of nemaline myopathy (NEM2) [14] and the titin gene is a candidate for autosomal dominant tibial muscular dystrophy [15]. In spite of recent advances, several clinically distinguishable forms of muscular dystrophy with unidentified disease genes exist. Two forms of muscular dystrophy, a dominant form of limb-girdle muscular dystrophy (LGMDIA) and a dominant form of distal myopathy with vocal cord and pharyngeal weakness (VCPMD) have been mapped to an overlapping locus in 5q31 [16,17]. Several studies have shown that actin cytoskeleton is substantially modified in transfor- med cells [reviewed in 18, 19 and 20]. In cells, actin molecules undergo dynamic reorganization, i.e. polymer formation from actin monomers and disruption or modulation of existing polymers. These events are controlled by a variety of actin-binding proteins with versatile activities. The complex dynamic regulation of cytoskeletal filaments depends on the expression and activity of various components within cells. Interestingly, a large fraction of actin exist in most cell types as monomers, whereas in muscle cells more than 99% of actin is in filaments. This suggests that muscle cells express protein(s), some of which may be unknown, whose function is to preserve the actin molecule equilibrium in a polymerized state. Taken the important role of actin cytoskeleton in functions related to abnormal cell growth and the changes in actin organization in transformed cells, factors regulating actin organization serve as attractive targets for cancer chemotherapy. Such an idea has been recently supported by experimental data indicating that two novel actin-stabilizing components, jasplakinolide and chondramides inhibit growth of transformed cells [20, 21]. Summary of the invention Here we describe the cDNA sequence and structure of myotilin gene, which encodes a novel component of the striated and cardiac muscle cytoskeleton. Myotilin protein contains two C2-type Ig-like domains with considerable homology to certain Ig- domains of titin. Myotilin resides both in the sarcomere, where it localizes within the I-bands and is bound to α-actinin, and along the sarcolemmal membrane. The myotilin gene locates in chromosome 5q31 inside a 2Mb region, which contains the LGMDIA disease gene [16], and thus is a candidate for LGMDIA. Transfection of myotilin into mammalian cells and yeast cells induces formation of thick actin bundles and reduces growth of yeast indicating a role for myotilin in organization of the actin-containing cytoskeleton. The designation "myotilin" comes from myofibrillar protein with litin— like Ig-domains. It should be noted that the designation "myofilin" which was used earlier, was amended due to the fact that a muscle-specific gene of Echinococcus granulosus was previously termed "myophilin" [22]. Although the terms are spelled differently, a similar pronunciation creates possibility for confusion and therefore the designation "myofilin" was changed to "myotilin". Expression of myotilin in mammalian cells and yeast causes reorganization of actin into thick filaments. The expression of myotilin or its C-terminal fragment (amino acids 215-498) changes yeast morphology and reduces growth rate. The actin-organizing and growth inhibiting properties suggest that myotilin or its fragments may be used in development of substances to control cell growth in various pathological conditions including treatment of cancer or microbial infections. Description of the drawings Fig. 1A. Deduced amino acid sequence of myotilin. The inferred 498 residue myotilin polypeptide is shown. Said sequence is also given in the appended Sequence listing as SEQ ID NO:2. The regions containing Ig-like domains are boxed. Dashed line indicates the 17 residue peptide used for production of rabbit antiserum. The nucleotide sequence of cDNA for myotilin has been deposited to Genbank database (accession number AF144477). The nucleotide sequence is given as SEQ ID NO:l. Fig. IB. Schematic structure of myotilin. Schematic diagram of the protein structure shows the serine-rich region (grey box) containing a hydrophobic stretch (black box) and the two Ig-domains (loops). The approximate positions of various regions are shown below. Fig. 1C. Myotilin sequence comparison with titin. Two paired Ig-domains and flanking regions of human myotilin and titin (Ig-domains 7 and 8) were aligned using the Clustal W method. Residues belonging to the Ig-like domains are boxed. Black boxes indicate conserved residues and grey boxes indicate conservative substitutions. GeneBank accession number for titin is 138344. Fig. 2. Organization of the myotilin gene Exons (vertical black boxes) numbered with Roman numerals and introns are shown in scale. The position of translation initiation signal in exon II and the translation stop codon in exon X is indicated. The sizes of introns are in kb. Fig. 3. Integrated map of chromosome 5 in the myotilin gene region. Distances between markers are based on combined genetic and physical mapping information (http://www.genome.wi.mit.edu/). The myotilin gene is located in chromosome 5q31, 141 cM from top of chromosome 5 linkage group [24] and maps within the 2 Mb limb- girdle muscular dystrophy (LGMDIA) critical region [16] thus being a positional candidate gene for the disease. IL9, the interleukin-9 gene. The orientation of the chromosome is indicated (centromere to the left). Fig. 4. Northern blot analysis of myotilin. A commercial multiple tissue mRNA filter was probed with a 32 P-labeled 320 bp fragment of myotilin cDNA. The filter was exposed for 20 h. The probe hybridizes strongly with skeletal muscle RNA and weakly with cardiac muscle RNA, whereas other indicated tissues are negative. The right lane shows a 6h exposure of the skeletal muscle mRNA, in order to demonstrate two different transcript sizes (2.2 and 2.5 kb). Fig. 5A. In vitro translation of myotilin. The myotilin cDNA was in vitro translated using a coupled reticulocyte lysate kit. A 57 kDa protein band representing the full-size protein is detected. The smaller 45 kDa band in the translation of full length cDNA is apparently due to aberrant translational starting point in the sequence. Myotilin 2 i 5 _ 498 is a deletion construct used in two-hybrid experiments. Mw = molecular weight markers. Fig. 5B. Western blot analysis of myotilin. Lysates from the indicated tissues were used for immunoblotting with affinity purified myotilin antibody. Western blotting of human skeletal muscle reveals a strong 57 kDa band and a fainter 110 kDa band (arrowheads), whereas the non-muscular tissues show no reactivity. Preabsoφtion of the myotilin antibody with 5-fold molar excess of the antigenic peptide results in loss of immunoreactivity from skeletal muscle lysate (right lane). Fig. 6. Immunolocalization of myotilin in purified myofibrils. Bundles of bovine myofibrils were isolated as described in Materials and methods and stained with antibodies against myotilin, α-actinin, actin, titin and a rabbit preimmune IgG. All analyzed proteins localize to I-bands in sarcomeres but the staining patterns differ. Myotilin and α-actinin decorate the middle of I-bands, whereas actin staining is more diffuse. Titin is detected as a doublet staining the junctions of A- and I-bands. The phase contrast image demonstrates the sarcomeric structure, where the light bands are thin filaments (I-bands) and the dark ones are thick filaments (A-bands). Bar = 5 μm. Figs 7A to 7D. Immunohistochemical staining of myotilin in frozen sections of human skeletal muscle. Frozen sections of skeletal muscle were analyzed by immunoperoxidase technique using an affinity purified myotilin antibody (A-C) or a control antiserum (D). Myotilin staining is detected in the I-bands of sarcomeres (A), and in transverse sections, also along the sarcolemma of muscle fibers (B). Positive reactivity is also detected in muscular nerves (C). (D) A control staining with preimmune serum. Figs 8A to 8E. Homotypic interaction of myotilin and association with α-actinin. (A) Domain structure of α-actinin and myotilin and the constructs used in yeast two- hybrid and in vitro binding assays. ABD = actin-binding domain, R = spectrin-like repeat, EF = EF-hand region. The grey box in myotilin indicates the serine-rich region and the loops indicate Ig-like domains. (B) A photomicrograph of the yeast two-hybrid interactions. On the left are the expressed bait fusion proteins and on the top are the prey fusion proteins. EG202 = empty bait vector and JG4-5 = prey vector. Color reaction is an indicator of an interaction. (C) Quantitation of β-galactoside values. The bait and prey fusion proteins are as in B. The β-galactosidase values are categorized as follows: - = <20; + = 21-150; ++ = 151-300; +++ = 301-450. (D) Affinity precipitation analysis of myotilin - α-actinin interaction. The NH 2 - terminal and COOH-terminal parts of α-actinin were expressed as GST-fusion proteins, purified and bound to glutathione-Agarose beads. 35 S-labeled in vitro translated myotilin was allowed to bind GST-α-actinin fusion protein-containing beads. Bound material was separated in SDS-PAGE and autoradiographed. Myotilin binds the R3/R4/EF construct, whereas the ABD/R1/R2 and the GST control are not binding. (E) Coomassie stained SDS-PAGE demonstrating the constructs used in the binding assay. Figs 9A to 9F. Effect of myotilin in the organization of actin-containing cytoskeleton in COS cells. On the left, COS cells transiently transfected with myotilin cDNA (mt 1- 498); in the middle cells transfected with a COOH-terminal construct, myotilin 215 _ 498 (mt 215-498); on the right, a transfection control β-galactosidase cDNA (β-gal). (A- B) show staining of myotilin, (C) shows β-galactosidase staining. (D-F) is double staining of the same cells for F-actin. Note thick F-actin and myotilin containing bundles in (A) and (D). Myotilin 2 , 5 _ 498 colocalizes with F-actin, but organization of actin does not differ from control cells, β-galactosidase control does not show any specific localization. Bar = 20 μm. Fig. 10. Confocal analysis of COS cells expressing myotilin. COS cells transfected with myotilin cDNA were fixed, double-stained for F-actin (ph) and myotilin (my) and analyzed by a confocal microscope. Images on the top right and middle right are composites of corresponding phailoidin (red) and myotilin (green) staining. Areas of overlapping distribution are in yellow. Note the thick cytoplasmic F-actin and myoti- lin-containing structures in top panel and the submembraneous cortical structures in the middle panel. On the bottom are shown composite images of phailoidin- (red) and myotilin-staining (green) of one transfected cell shown at 2 μm (left) and 6 μm (middle) above the growth substratum demonstrate a haphazard arrangement of the F- actin and myotilin-containing structures. On the bottom right, an overlay of myotilin- staining of sections at 1 μm interval through the entire cell is shown. The color coding indicates distance (μm) from the substratum. Note lack of staining at the ventral surface of the cell. Bar = 10 μm. Figs HA to 11F. The effect of myotilin on yeast cell cytoskeleton and growth. Yeast cells expressing myotilin (A and B) and control cells (C and D) were stained with rhodamine-phalloidin to decorate F-actin (A and C) or with calcofluor to stain cell wall carbohydrates (B and D). Note that the myotilin expressing cells are elongated, grow in rows and are connected with thick actin-bundles suggesting a defective cell separation event. E. Growth rate of cells expressing various myotilin fragments. The numbers indicate amino acids of myotilin included in the constructs. Full-length myotilin and myotilin 215 _ 498 reduce cell growth. JG4-5 = an empty vector. F. Growth rate of cells expressing myotilin and/or control proteins in two different expression vectors. The strongest growth inhibitory effect is caused by expression of myotilin or its COOH-terminal fragment in both vectors. The growth rate of cells expressing ezrin, a control actin-organizing protein, does not differ from growth of cells transfected with empty vectors, α-actinin = spectrin-like repeats of chicken gizzard α-actinin, EG202 and JG4-5 = empty vectors. Detailed description of the invention Characterization of myotilin cDNA A partial cDNA encoding myotilin was initially discovered based on a yeast two-hybrid screen for novel cytoskeletal components. Using this sequence as a probe, we cloned a 2244 bp cDNA from a human skeletal muscle library. The cDNA contains a 1494 bp open reading frame (nucleotides 281 to 1774) encoding a 498 amino acid polypeptide (SEQ ID NO:2), which we have termed myotilin (Fig. 1A). The methionine start codon is in partial agreement with the Kozak consensus sequence. The NH 2 -terminal sequence is particularly rich in serine residues often arranged in a paired fashion, and contains a 23 amino acid hydrophobic stretch (residues 57-79). Upon database searches, the NH 2 - terminal sequence is unique and does not contain known structural domains. The COOH-terminus of the protein is predicted to form two Ig-like domains with conserved key residues (Fig. IB) [23]. Several cytoskeletal proteins involved in organization of the muscle sarcomere have recently been shown to contain such structural units. By sequence comparison, the highest homology is detected between myotilin and the region of human striated muscle titin, which contains the Z-disk associated Ig- domains 7 and 8 (Fig. 1C) (residues 1406-1621 of titin)[4]. The sequences within the compared regions are 31 % identical and 53 % conserved without any introduced gaps. A similarity comparison using the Clustal method indicates a 38.3 % similarity between this region of myotilin and titin. The sequence similarity between myotilin and titin is restricted to the Ig-domains of myotilin. Other characteristic structural features of titin, the fn(III)-type domains, the specific sequences of Z-disk, I-band and M-band, or the repeating KSP phosphorylation motif [4] are not present in myotilin. However, the sequence prediction of myotilin reveals several other possible sites for phosphorylation, three of them in the serine-rich region. Organization of myotilin gene The organization of myotilin gene was determined by comparing the myotilin cDNA with the genomic sequence from chromosome 5 Pac clone 9cl3 (Genbank accession number AC006084). All splice junction sequences are in agreement with the GT-AG consensus (Table 1). The exon/intron boundaries were further confirmed by amplification of each exon from a commercial PI clone with intron specific primers (not shown). The gene is composed of ten exons, and the translation initiation signal is in exon II (Fig. 2). Thus the small 69 bp first exon is not translated. The size of the entire gene is under 20 000 bp without the promoter region. The sequences coding for the Ig- domains are located in exons VI and VII (first Ig-domain) and in exons VIII and IX (second Ig-domain). Table 1. Exon-intron structure and splicejunction sites of the human myotilin gene. Exon Sequence at exon-intron junction No. Size 5 'splice donor Intron size 5 'splice acceptor (bp) (kb) I 69 GGAACTACGGgtaagtccct 2.5 ccttttgaagGAACAATATT II 567 TGGATTCCAAgtaagtgaat 4.8 ctttttaaagCTATCAACAG III 175 TGGAAATCAAgtgggcaaga 1.5 ttctctaaagCGTCTAACAT IV 102 AGACTCGCAGgtaagttaaa 3.2 taatttcaagCAACACAACT V 50 CACAAGTAAGgtaaaaaa11 1.1 attcttgtagAAGTAGATCA VI 133 GGACTTCAAAgtaagagaag 1.3 ttctttctagGTGAGTGGAC VII 208 GATGTCCTTGgtaagcctcc 2.5 taatatatagCAAAAGAACA VIII 166 ACCGAATAAGgtaggatatg 0.7 tttatttcagCTTATATCAA IX 134 GACGTTACGGgtatgtcata 0.2 tctatttcagCACGTCCAAA X 641 Chromosomal localization of myotilin The chromosomal localization of myotilin gene was determined by radiation hybrid mapping. The myotilin gene was mapped to chromosome 5q31 between the markers AFM350ybl and D5S500 (Fig. 3). The gene causing an autosomal, dominantly inherited limb-girdle muscular dystrophy (LGMD) 1A has been mapped to chromosome 5q31 between the markers D5S479 and D5S594 [16]. The myotilin gene is inside this reported area. Taken all the data together, myotilin is a candidate gene for LGMDIA. Expression pattern of myotilin By Northern blot analysis we detected two different transcripts (2.2 and 2.5 kb) strongly expressed in skeletal muscle and weakly in the heart (Fig. 4). The two transcripts in the heart are only seen after a prolonged exposure (not shown). Smooth muscle and several non-muscular tissues, including brain, placenta, lung, liver, kidney and pancreas, did not contain detectable mRNA. In vitro translation of the full-length cDNA yielded a 57 kDa polypeptide, which is in agreement with the mass of myotilin estimated from the cDNA sequence (Fig. 5A). We raised an antibody against myotilin by immunizing rabbits with a synthetic branched 17 amino acid peptide encompassing residues 352-368 (see Fig. 1A). In Western blotting this antibody revealed a 57 kDa protein band and a fainter band near 110 kDa from skeletal muscle but not from smooth muscle or non-muscular tissues (Fig. 5B). The reactivity could be blocked by incubating the antibody with 5-fold molar excess of the corresponding peptide (Fig. 5B). Both the mRNA and immunoblotting data thus indicate that myotilin is a muscular protein with a clearly restricted expression pattern. The identity of the 110 kDa band is unclear. As it migrates at a region twice the size of a myotilin monomer and as myotilin is able to form intermolecular interactions (see below), the band possibly represents a myotilin dimer. Upon treatment of tissues with 1% Triton X-100 or with 1M KC1, myotilin was retained in the insoluble fraction suggesting a cytoskeletal association (data not shown). Subcellular localization of myotilin in skeletal muscle To characterize the subcellular localization of myotilin we isolated bundles of striated muscle myofibrils and stained them using the affinity purified peptide antiserum. The immunostaining pattern was compared to several characterized components of the sarcomere (Fig. 6). Myotilin staining was detected in the I-bands. The staining pattern was reminiscent of α-actinin, which is known to decorate the Z-lines of the I-bands. Actin, the major component of thin filaments, gave a more diffuse staining pattern along the entire I-bands. A titin mAb, which recognizes an epitope at junctions of thin and thick filaments revealed a staining pattern of a doublet band at each sarcomere. The immunolocalization data demonstrates that myotilin is an integral component of striated muscle sarcomeres. To further study the localization of myotilin in the striated muscle we performed immunohistochemical analyses of frozen tissue sections with the myotilin antibody. In peφendicular sections, where the organization of sarcomeres was visible, we could detect a periodical cross-striated staining of myotilin (Fig. 7A), which was consistent with the pattern in isolated myofibrils. Especially in transverse sections (Fig. 7B) the myotilin staining was also localized at the plasma membrane indicating that myotilin is also present at the sarcolemma. In addition to these findings, myotilin antibody stained intramuscular nerve fibers (Fig. 7C). The preimmune serum gave no reactivity (Fig. 7D). Myotilin forms intermolecular interactions and directly binds α-actinin in vitro We used the yeast two-hybrid method to study protein interactions of myotilin. Among the tested partners, the strongest interactions were seen between myotilin and α-actinin (a construct containing spectrin-like repeats R1-R4) and between myotilin molecules (Fig. 8A-C). α-actinin is known to form dimers via spectrin-like repeats [25, 26] and this could be verified also in our two-hybrid analysis (Fig. 8B). However, quantitation of the β-galactosidase values indicate that the intensity of the reaction was weaker than the interaction between α-actinin and myotilin and between two myotilin molecules (Fig. 8C). An NH 2 -terminal deletion construct containing the Ig-domains, myotilin 215 _ 498 bound full-length myotilin, but did not bind α-actinin (R1-R4). We were unable to express myotilin 215 _ 498 as a bait to test whether the intermolecular interaction of myotilin is mediated by the COOH-terminal Ig-domain containing region or by NH 2 -terminal association to the COOH-terminal part. The interaction between myotilin and α-actinin was further tested by an affinity precipitation assay, using in vitro translated 35 S- labelled myotilin and GST-α-actinin constructs bound to glutathione-Agarose. Myotilin bound the COOH-terminal half of α-actinin (R3/R4/EF-hand), but not the NH 2 -terminal half (ABD/R1/R2) or GST alone (Fig. 8D-E). Based on the two-hybrid and affinity precipitation results, residues important for α-actinin binding reside in the first 215 NH 2 -terminal residues of myotilin and the myotilin binding site in α-actinin apparently locates within spectrin-like repeats 3 and 4. Effect of transfected myotilin on actin-cytoskeleton and cell growth The cellular localization and function of myotilin was further analyzed by transiently transfecting HA-epitope tagged full length myotilin and a COOH-terminal myotilin construct (myotilin 215 _ 498 ) into COS-1 cells that do not express endogenous protein. The myotilin 215 _ 498 construct was confirmed by in vitro translation to yield a proper size polypeptide (Fig. 5A). β-galactosidase DNA was used as a transfection control. After 72 hours the cells were fixed and double stained for myotilin or β-galactosidase and actin. Myotilin 215 _ 498 showed partly a diffuse cytoplasmic staining pattern but also submembraneous accumulation which colocalized with cortical actin visualized by phailoidin staining (Fig. 9B,E). In contrast, full length myotilin localized within the filament network of the cell body and phailoidin staining revealed a strict colocalization with F-actin in these filaments. Remarkably, we could notice formation of thick F- actin containing bundles in COS-1 cells (Fig. 9A,D), whose actin-containing skeleton is poorly organized under these culture conditions, β-galactosidase showed a diffuse cytoplasmic distribution and did not colocalize with F-actin (Fig. 9C,F). The myotilin-induced actin-containing structures were further characterized by confocal microscopy (Fig. 10). Typically, the actin bundles were present in the cell body, although in some cells they were located subcortically in the cell periphery (Fig. 10, middle row). Sectioning of the cells revealed that the F-actin and myotilin-containing structures were often haphazardly arranged at different levels in the cytoplasm. This is visualized in the bottom panel of Fig. 10, in which images on the left and in the middle are composites of F-actin and myotilin staining at two different planes of the same cells and the image on the right is an overlay of the myotilin labelling in the entire cell. Importantly, the structures were not present at the ventral surface of the transfected cells indicating that they are not stress fibers. The effect of myotilin on actin organization is not reminiscent of changes induced by overexpression of previously characterized actin- organizing proteins and suggests a unique mechanism of action. Effect of myotilin on yeast cell actin and cell growth The biological functions of myotilin were also studied by expressing myotilin in Saccharomyces cerevisiae. Induction of myotilin expression resulted in reorganization of actin into thick filaments not detected in control cells (Fig. 11A and C). The myotilin expressing cells grew in rows and the filaments continued from one cell to another (Fig. 11A). This result indicates that the actin organizing property of myotilin is conserved within different organisms. Expression of myotilin or its COOH-terminal part resulted in inhibition of cell growth, whereas expression of NH 2 -terminal constructs (1-150 and 1-250) or a shorter COOH-terminal construct (270-472) did not have a similar effect (Fig. HE). This growth-inhibitory function parallelled with moφhogenic changes in yeast cells. When myotilin was expressed simultaneously in two different expression vectors, the growth inhibiting effect was stronger than the effect produced by a single vector indicating that the effect is dependent on the level of protein expression (Fig. 11F). In this experiment, expression of an irrelevant cytoskeletal actin-binding protein, ezrin, did not affect cell growth, further demonstrating the specificity of the effect of myotilin. Experimental Abbreviations ABD actin-binding domain CH calponin homology EST expressed sequence tag F-actin filamentous actin fa fibronectin ig Immunoglobulin LGMD Limb Girdle Muscular Dystrophy MBP Myosin Binding Protein MLCK Myosin Light Chain Kinase R repeat Materials and methods cDNA cloning of myotilin and sequence analysis A partial cDNA was used for screening of the full-length myotilin cDNA from a skeletal muscle library (Stratagene, La Jolla, CA). Positive clones were sequenced with an ABI 310 Genetic Analyzer (Perkin-Elmer, Foster City, CA). Protein database searches were done with BLAST program (http://www.ncbi.nlm.nih.gov). Sequence alignments between Ig-domains of myotilin and other cytoskeletal proteins were performed with the MegAlign software (DNASTAR). The domain predictions were obtained from Pfam server (http://genome.wustl.edu/Pfam/). Protein motif predictions were done with Protein Family alignment Pfam2.1 (http://pfam.wustl.edu/) and with Motif (http://www.motif.genome.ad.jp/). Genomic structure of myotilin gene The organization of myotilin gene was determined by comparing the myotilin cDNA with the genomic sequence from chromosome 5 Pac clone 9cl3 (Genbank accession number AC006084). A commercial PI clone (GenomeSystems Inc., St. Louis, ML, searched by PCR with myotilin primers) was used for amplification and sequencing of exon-intron boundaries. Chromosomal localization of myotilin The chromosomal localization of myotilin gene was determined by radiation hybrid mapping using the Genebridge II panel. PCR assays were performed as duplicates and the resulting data vector was analyzed using the Whitehead Genome Center server (http:/www-genome. wi.mit.edu). Production of myotilin antibody A polyclonal antibody was raised in rabbits using a synthetic branched, lysine-cored 17 amino acid peptide of myotilin (marked in Fig. 1 with a scattered line) as the antigen. After five immunizations, rabbits were bled. The specific antibody was purified in an affinity column using a corresponding single chain peptide coupled to CNBr-activated Sepharose 4B (Pharmacia, Uppsala, Sweden) as the ligand. The specificity of the rabbit antibody was verified by reactivity with appropriate GST-fusion protein constructs in Western blot analysis (data not shown) and by cross-blocking experiments, in which five-fold molar excess of the specific peptide but not an irrelevant myotilin peptide (residues 199-217) absorbed the reactivity. mRNA and protein studies Northern blot analysis was performed with a multiple tissue mRNA filter (Clontech Laboratories, Inc., Palo Alto, CA) using a 32 P-labeled 320 bp myotilin cDNA fragment, which encodes amino acids 369-471, as a probe. In vitro translations were performed with a coupled reticulocyte lysate kit (Promega, Madison, WI) using 35 S- labeled methionine for detection. The templates were full-length myotilin and a construct containing amino acids 215-498 (myotilin 215 _ 498 ) in Bluescript plasmid vector (Stratagene). For Western blotting, fresh tissues were homogenized in reducing Laemmli buffer. Equal amounts of protein, as estimated by Coomassie blue staining, were separated in 8 % SDS-PAGE and transferred to nitrocellulose filters (Schleicher & Schuell GmbH, Dassel, Germany). The filters were probed with the myotilin antibody or with a control preimmune serum, followed by peroxidase conjugated goat anti-rabbit IgG (Dako A/S, Copenhagen, Denmark) and ECL detection (Pierce, Rockford, IL). Localization of myotilin in myofibrils Bundles of bovine and human myofibrils were isolated as described [27] cytocent- rifuged onto objective slides, fixed in -20°C methanol, and reacted with mAb against actin (AC 40, Sigma Chemical Co., St. Louis, MO), titin (Til, Sigma), α-actinin (67CB11) [28] and a control mAb X63 (ATCC, Maryland, USA) or with affinity purified anti-myotilin antibody or the corresponding preimmune IgG. Secondary antibodies were FITC-conjugated goat anti-mouse IgG (Cappel Research Products, Durham, NC) and TRITC-conjugated goat anti-rabbit F(ab)2 fragment (Jackson ImrnunoResearch Laboratories, Inc., West Grove, PA). Staining of bovine and human myofibrils yielded identical results. Immunohistochemistry Frozen 2 μm sections of human skeletal muscle were immobilized on poly-L-lysine- coated glass slides, fixed with cold acetone and immediately air-dried. For im- munohistochemical staining the sections were reacted with 1:100 dilution of affinity- purified myotilin Ab or rabbit pre-immune IgG at similar concentration. The antibody was detected with Elite Vectastain ABC kit (Vector Laboratories, Inc., Burlingame, CA) according to manufacturer's instructions. The slides were briefly counterstained with hematoxylin-eosin. Yeast two-hybrid analysis and in vitro binding assay Full length myotilin, myotilin 215 _ 498 and spectrin-like repeats R1-R4 (residues 267-749) of chicken smooth muscle α-actinin (kindly provided by Dr. D. Critchley, University of Leicester, UK) were subcloned into EG202 and JG4-5 plasmids for two-hybrid analysis [29]. The COOH-terminal construct of myotilin was subcloned from a partial cDNA sequence obtained from the skeletal muscle library screen. The authentity of the constructs was verified by sequencing. The genotype of the S. cerevisiae strain BOYl, kindly provided by P. Ljungdahl, Ludwig Institute for Cancer Research, Stockholm, Sweden, is MAT ahis3 trpl leu2::6LexAop-LEU2 URA3: :8LexAop-Gall -LacZ ' . BOYl mating type a was made using the YCpHO CUT4 plasmid [30]. Yeast strains were grown at 30°C in rich medium or in synthetic minimal medium with appropriate amino acid supplements. Bait and prey constructs were transformed into BOYl -yeast of both a and α mating type using the TRAFO protocol (www.manitoba.ca/faculties/medicine/ human-genetics/gietz/trafo.html.) and plated on selection plates. Clones were grown to late logarithmic phase in selective medium. For analysis of fusion protein expression, yeast cells from 1 ml of overnight culture were lysed in reducing Laemmli sample buffer, the samples were boiled and analyzed by SDS-PAGE and immunoblotting. Baits and preys were grown on selection plates, replica plated together on rich media plates for mating overnight and replica plated on double (tryptophane and histidine) or triple (tryptophane, histidine and leucine) selection with or without 5-bromo-4-chloro-3- indolyl-β-D-galactopyranoside (X-gal) (Boehringer) for selection of interactions. For the in vitro binding assay, GST-α-actinin fusion proteins, ABD/R1/R2, R3/R4/EF [25] or GST alone were produced in E. coli and purified with glutathione-Agarose beads (Pharmacia). 2 μg of fusion proteins on glutathione beads were reacted with 20 μl of in vitro translated, 35 S-labeled myotilin in 10 mM Tris-HCl, pH 7.5, 5 mM EDTA, 130 mM KC1, 0.05% Tween 20. After washes with the same buffer, bound material was eluted by boiling in Laemmli buffer, subjected to SDS-PAGE and detected by autoradiography. Localization of myotilin in transfected COS-1 cells In transfection studies full length myotilin and myotilin 215 _ 498 construct in an HA-tagged pAHP plasmid (a derivative of pcDNA3, Invitrogen, San Diego, CA) and a control SV- β-galactosidase vector (Clontech) were used. COS-1 cells plated on 6 cm tissue culture dishes were transfected with 5 μg of appropriate plasmid cDNA using Superfect (Qiagen GmbH, Hilden, Germany) and grown on glass coverslips. After 72 hours, cells were fixed in 3.5 % paraformaldehyde at +4°C for 10 min. and permeabilized in 0.1 % Triton X-100. Transfected protein was immunoreacted with anti-HA mAb (12CA5, Boehringer GmbH, Mannheim, Germany) or anti-β-galactosidase mAb (Boehringer) followed by FITC-conjugated goat anti-mouse IgG. F-actin was simultaneously visualized with rhodamine-labelled phailoidin (Molecular Probes, Eugene, OR). The specimens were viewed with a Zeiss Axiophot II epifluorescence microscope (Carl Zeiss, Oberkochen, Germany) or alternatively, with a confocal 410 Invert Laser Scan microscope (Carl Zeiss). Effect of myotilin on yeast actin and cell growth The effect of myotilin on yeast actin cytoskeleton and growth rate was studied as follows. For actin staining, cells expressing myotilin or cells transfected with an empty vector were fixed in 4% paraformaldehyde. F-actin was visualized with rhodamine- labelled phailoidin (Molecular Probes, Eugene, OR) and the cell wall with calcofluor (1 mg/ml) (Sigma). After washings the cells were resuspended in DABCO mounting solution. For analysis of the effect of myotilin in cell growth, haploid cells transfected with myotilin in JG4-5 vector were grown in glucose, washed and an equal amount of cells with different myotilin constructs were added into galactose-containing growth medium for induction of protein expression. Diploid cells expressing two different proteins from the JG4-5 and EG202 vectors were grown in galactose from the initiation of the experiment. At indicated time points a small aliquot of cells was sonicated and OD,^ was measured using a spectrophotometer. References 1. Furst, D.O. and Gautel, M. (1995) The anatomy of a molecular giant: How the sarcomere cytoskeleton is assembled from immunoglobulin superfamily molecules. J. Mol. Cardiol. 27:951-959. 2. Keller, T.C. 3rd. (1995) Structure and function of titin and nebulin. Curr. Opin. Cell Biol. 7:32-38. 3. Blanchard, A., Ohanian, V. and Critchley, D. (1989) The structure and function of α-actinin. J. Muscle Res. Cell Motil. 10:280-289. 4. Labeit, S. and Kolmerer, B. (1995) Titins: giant proteins in charge of muscle ultrastructure and elasticity. Science 270:293-296. 5. Fowler, V.M. (1996) Regulation of actin filament length in erythrocytes and striated muscle. Curr. Opin. Cell Biol. 8:86-96. 6. Gautel, M., Goulding, D., Bullard, B., Weber, K. and Furst, O. (1996) The central Z- disk region of titin is assembled from a novel repeat in variable copy numbers. J. Cell Sci. 109:2747-2754. 7. Maruyama, K. (1997) Connectin / titin, giant elastic protein of muscle. Faseb J. 11:341-345. 8. Young, P., Ferguson, C, Banuelos, S. and Gautel, M. (1998) Molecular structure of the sarcomeric Z- disk: two types of titin interaction lead to an asymmetrical sorting of α-actinin. EMBO J. 17:1614-1624 9. Brown, R.H. Jr. (1996) Dystrophin-associated proteins and the muscular dystrophies: A glossary. Brain Pathol. 6: 19-24. 10. Ozawa, E., Noguchi, S., Mizuno, Y., Hagiwara, Y. and Yoshida, M. (1998) From dystrophinopathy to sarcoglycanopathy: evolution of a concept of muscular dystrophy. Muscle Nerve 21: 421-438 11. Olson, T.M., Michels, V.V., Thibodeau, S.N., Tai, Y-S. and Keating, M.T. (1998) Actin mutations in dilated cardiomyopathy, a heritable form of heart failure. Science 280:750-752. 12. Towbin, J.A. (1998) The role of cytoskeletal proteins in cardiomyopathies. Curr. Opin. Cell Biol. 10: 131 - 139. 13. Laing, N.G., Wilton, S.D., Akkari, P.A., Dorosz, S., Boundy, K, Kneebone, C, Blumbergs, P., White, S., Watkins, H., Love, D.R. and Haan, E. (1995) A mutation in the a-tropomyosin gene TPM3 associated with autosomal dominant nemaline myopathy. Nat. Genet. 9:75-79 14. Pelin, K., Ridanpaa, M., Donner, K.. Wilton. S.. Krishnarajah, J., Laing, N.G., Kolmerer, B., Labeit, S., de la Chapelle, A. and Wallgren-Petterson, C. (1997) Refined localization of the genes for nebulin and titin on chromosome 2q allows the assignment of nebulin as a candidate gene for autosomal recessive nemaline myopathy. Eur. J. Hum. Genet. 65:620-626 15. Haravuori, H., Makela-Bengs, P., Udd, B., Partanen, J., Pulkkinen, L., Somer, H. and Peltonen, L. (1998) Assignment of the tibial muscular dystrophy locus to chromosome 2q31. Am. J. Hum. Genet. 62:620-626 16. Bartoloni, L, Horrigan, S.K., Viles, K.D., Gilchrist, J.M., Stajich, J.M., Vance, J.M., Yamaoka, L.H., Pericak- Vance, M., Westbrook, CA. and Speer, M.C. (1998) Use of CEPH meiotic breakpoint panel to refine the locus of limb-girdle muscular dystrophy type 1A (LGMDIA) to a 2-Mb interval on 5q31. Genomics 54:250-255. 17. Feit, H., Silbergleit, A., Schneider, L.B., Gutierrez, J.A., Fitoussi, R.-P., Reyes, C, Rouleau, G.A., Brais, B., Jackson, C.E., Beckmann, J.S. and Seboun, E. (1998) Vocal cord and pharyngeal weakness with autosomal dominant distal myopathy: clinical description and gene localization to Soβl. Am. J. Hum. Genet. 63:1732-1742. 18. Janmey, P.A. and Chaponnier, C. (1995) Medical aspects of the actin cytoskeleton. Curr. Opin. Cell Biol. 7:111-117. 19. Assoian, R.K. and Zhu, X. (1997) Cell anchorage and the cytoskeleton as partners in growth factor dependent cell cycle progression. Curr. Opin. Cell Biol. 9:86-92. 20. Jordan, M.A. and Wilson, L (1998). Microtubules and actin filaments: dynamic targets for cancer chemotherapy. Curr. Opin. Cell Biol. 10:123-130. 21. Sasse, F., Kunze, B., Gronewold, M. and Reichenbach, H. (1998). The chondrami- des: Cytostatic agents from myxobacteria acting on the actin cytoskeleton. J. Natl. Cancer fast. 90: 1559-1563. 22. Martin, R.M., Gasser, R.B., Jones, M.K. and Lightowlers, M.W. (1995) Identification and characterization of myophilin, a muscle-specific antigen of Echinococcus granulosus. Molecular & Biochemical Parasitology. 70:139-48 23. Williams, A.F. and Barclay, A.N. (1988) The immunoglobulin superfamily-domains for cell surface recozinition. Annu. Rev. Immunol. 6:381-405. 24. Laitinen, T, Kauppi, P., Ignatius, J., Ruotsalainen, T., Daly, M.J., Kaariainen, H., Kruglyak, L, Laitinen, H., de la Chapelle, A., Lander, E.S., Laitinen, LA. and Kere, J. (1997) Genetic control of serum IgE levels and asthma: linkage and linkage disequili- brium studies in an isolated population. Hum. Mol. Genet. 6:2069-2076. 25. Kahana, E. and Gratzer, W.B. (1991) Properties of the spectrin-like structural element of smooth-muscle α-actinin. Cell Motil. Cytoskel. 20:242-248. 26. Flood, G., Kahana, E., Gilmore, A.P., Rowe, A.J., Gratzer, W.B. and Critchley, D.R. (1995) Association of structural repeats in the α-actinin rod domain. Alignment of inter-subunit interactions. J. Mol. Biol. 252: 227-234. 27. Knight, P.J., and Trinick, J.A. (1982) Preparation of myofibrils. Methods Enzymol. 85 Pt B:9-12. 28. Narvanen, O., Narvanen, A., Wasenius, V-M., Partanen, P. and Virtanen, I. (1987) A monoclonal antibody against a synthetic peptide reveals common structures among spectrins and α-actinin. FEBS Lett. 224:156- 160. 29. Guyris, J.E., Golemis, E., Chertkov, H. and Brent, R. (1993) Cdi 1, a human Gl and S phase protein phosphatase that associates with Cdk2. Cell 75:791-803. 30. Raghuraman, M., Brewer, B. and Fangman, W. (1994) Activation of a yeast replication origin near a double-stranded DNA break. Genes & Development 8:554- -562. SEQUENCE LISTING <110> Carpen, Olli Salmi angas, Paula <120> Myotilin, a novel actin-organizing protein <130> 31262 <140> <141> <150> 60/093,169 <151> 1998-07-17 <160> 2 <170> Patentln Ver. 2.1 <210> 1 <211> 2244 <212> DNA <213> human skeletal muscle library <220> <221> CDS <222> (281) .. (1774) <400> 1 gggaaggaga tgcctcttcc ttcccttcaa tagtgggtta aacccagctg gcaccctctg 60 gaactacggg aacaatattc ttcaagagaa ggtcactcta ccaaagccag gagcacagta 120 ttctcaggat ctcaacaagg aagagcagac caaggttgct tctgattcct tacaaccttc 180 cgtaattcca ggcttgtggc cccaaattca gggccccacc cttccaggaa caaatcatta 240 tagtaataat ttgccttcat cttccatata ccaactaagc atg ttt aac tac gaa 295 Met Phe Asn Tyr Glu 1 5 cgt cca aaa cac ttc ate cag tec caa aac cca tgt ggc tec aga ttg 343 Arg Pro Lys His Phe lie Gin Ser Gin Asn Pro Cys Gly Ser Arg Leu 10 15 20 cag cct cct gga cca gaa ace tec age ttc tct age cag ace aaa cag 391 Gin Pro Pro Gly Pro Glu Thr Ser Ser Phe Ser Ser Gin Thr Lys Gin 25 30 35 tct tec att ate ate cag ccc cgc cag tgt aca gag caa aga ttt tct 439 Ser Ser lie lie lie Gin Pro Arg Gin Cys Thr Glu Gin Arg Phe Ser 40 45 50 gcc tec tea aca ctg age tct cac ate ace atg tec tec tct get ttc 487 Ala Ser Ser Thr Leu Ser Ser His lie Thr Met Ser Ser Ser Ala Phe 55 60 65 cct get tct ccc cag cag cat get ggc tec aac cca ggc caa agg gtt 535 Pro Ala Ser Pro Gin Gin His Ala Gly Ser Asn Pro Gly Gin Arg Val 70 75 80 85 aca ace ace tat aac cag tec cca gcc age ttc etc age tec ata tta 583 Thr Thr Thr Tyr Asn Gin Ser Pro Ala Ser Phe Leu Ser Ser lie Leu 90 95 100 cca tea cag cct gat tac aat age agt aaa ate cct tec get atg gat 631 Pro Ser Gin Pro Asp Tyr Asn Ser Ser Lys lie Pro Ser Ala Met Asp 105 110 115 tec aac tat caa cag tec tea get ggc caa cct ata aat gca aag cca 679 Ser Asn Tyr Gin Gin Ser Ser Ala Gly Gin Pro lie Asn Ala Lys Pro 120 125 130 tec caa act gca aat get aag ccc ata cca aga act cct gat cat gaa 727 Ser Gin Thr Ala Asn Ala Lys Pro lie Pro Arg Thr Pro Asp His Glu 135 140 145 ata caa gga tea aaa gaa get ttg att caa gat ttg gaa aga aag ctg 775 lie Gin Gly Ser Lys Glu Ala Leu lie Gin Asp Leu Glu Arg Lys Leu 150 155 160 165 aaa tgc aag gac ace ctt ctt cat aat gga aat caa cgt eta aca tat 823 Lys Cys Lys Asp Thr Leu Leu His Asn Gly Asn Gin Arg Leu Thr Tyr 170 175 180 gaa gag aag atg get cgc aga ttg eta gga cca cag aat gca get get 871 Glu Glu Lys Met Ala Arg Arg Leu Leu Gly Pro Gin Asn Ala Ala Ala 185 190 195 gtg ttt caa get cag gat gac agt ggt gca caa gac teg cag caa cac 919 Val Phe Gin Ala Gin Asp Asp Ser Gly Ala Gin Asp Ser Gin Gin His 200 205 210 aac tea gaa cat gcg cga ctg caa gtt cct aca tea caa gta aga agt 967 Asn Ser Glu His Ala Arg Leu Gin Val Pro Thr Ser Gin Val Arg Ser 215 220 225 aga tea ace tea agg gga gat gtg aat gat cag gat gca ate cag gag 1015 Arg Ser Thr Ser Arg Gly Asp Val Asn Asp Gin Asp Ala lie Gin Glu 230 235 240 245 aaa ttt tac cca cca cgt ttc att caa gtg cca gag aac atg teg att 1063 Lys Phe Tyr Pro Pro Arg Phe lie Gin Val Pro Glu Asn Met Ser lie 250 255 260 gat gaa gga aga ttc tgc aga atg gac ttc aaa gtg agt gga ctg cca 1111 Asp Glu Gly Arg Phe Cys Arg Met Asp Phe Lys Val Ser Gly Leu Pro 265 270 275 get cct gat gtg tea tgg tat eta aat gga aga aca gtt caa tea gat 1159 Ala Pro Asp Val Ser Trp Tyr Leu Asn Gly Arg Thr Val Gin Ser Asp 280 285 290 gat ttg cac aaa atg ata gtg tct gag aag ggt ctt cat tea etc ate 1207 Asp Leu His Lys Met lie Val Ser Glu Lys Gly Leu His Ser Leu lie 295 300 305 ttt gaa gta gtc aga get tea gat gca ggg get tat gca tgt gtt gcc 1255 Phe Glu Val Val Arg Ala Ser Asp Ala Gly Ala Tyr Ala Cys Val Ala 310 315 320 325 aag aat aga gca gga gaa gcc ace ttc act gtg cag ctg gat gtc ctt 1303 Lys Asn Arg Ala Gly Glu Ala Thr Phe Thr Val Gin Leu Asp Val Leu 330 335 340 gca aaa gaa cat aaa aga gca cca atg ttt ate tac aaa cca cag age 1351 Ala Lys Glu His Lys Arg Ala Pro Met Phe lie Tyr Lys Pro Gin Ser 345 350 355 aaa aaa gtt tta gag gga gat tea gtg aaa eta gaa tgc cag ate teg 1399 Lys Lys Val Leu Glu Gly Asp Ser Val Lys Leu Glu Cys Gin lie Ser 360 365 370 get ata cct cca cca aag ctt ttc tgg aaa aga aat aat gaa atg gta 1447 Ala lie Pro Pro Pro Lys Leu Phe Trp Lys Arg Asn Asn Glu Met Val 375 380 385 caa ttc aac act gac cga ata age tta tat caa gat aac act gga aga 1495 Gin Phe Asn Thr Asp Arg lie Ser Leu Tyr Gin Asp Asn Thr Gly Arg 390 395 400 405 gtt act tta ctg ata aaa gat gta aac aag aaa gat get ggg tgg tat 1543 Val Thr Leu Leu lie Lys Asp Val Asn Lys Lys Asp Ala Gly Trp Tyr 410 415 420 act gtg tea gca gtt aat gaa get gga gtg act aca tgt aac aca aga 1591 Thr Val Ser Ala Val Asn Glu Ala Gly Val Thr Thr Cys Asn Thr Arg 425 430 435 tta gac gtt acg gca cgt cca aac caa act ctt cca get cct aag cag 1639 Leu Asp Val Thr Ala Arg Pro Asn Gin Thr Leu Pro Ala Pro Lys Gin 440 445 450 tta egg gtt cga cca aca ttc age aaa tat tta gca ctt aat ggg aaa 1687 Leu Arg Val Arg Pro Thr Phe Ser Lys Tyr Leu Ala Leu Asn Gly Lys 455 460 465 ggt ttg aat gta aaa caa get ttt aac cca gaa gga gaa ttt cag cgt 1735 Gly Leu Asn Val Lys Gin Ala Phe Asn Pro Glu Gly Glu Phe Gin Arg 470 475 480 485 ttg gca get caa tct gga etc tat gaa agt gaa gaa ctt taataacttt 1784 Leu Ala Ala Gin Ser Gly Leu Tyr Glu Ser Glu Glu Leu 490 495 accaacattg gaaaacagcc aactacacca ttagtaatat atttgattac atttttttga 1844 aattaatcca tagctgtatt aacagattat ggttttaatt aggtaatata gttaatatat 1904 atttataata ttatttatcc tttgactctt gcacattcta tgtacccctc cgatttgtga 1964 agcctacagg aaatctgggt atatggattt gtaactgcag aagactatct taaaatacag 2024 gattttaaea tttaagtcat gcaeatttaa caattaeagg ttataaatta gtatcaaett 2084 tttaaacaca tctaatgctt gtaataaegt ttaetggtac tgctttctaa ataetgtttt 2144 aeecgttttc tcttgtagga ataetaaeat ggtatagatt atetgagtgt tccaeagttg 2204 tatgtcaaaa gaaaataaaa ttcaaatatt taaaacggac 2244 <210> 2 <211> 498 <212> PRT <213> human skeletal muscle library <400> 2 Met Phe Asn Tyr Glu Arg Pro Lys His Phe lie Gin Ser Gin Asn Pro 1 5 10 15 Cys Gly Ser Arg Leu Gin Pro Pro Gly Pro Glu Thr Ser Ser Phe Ser 20 25 30 Ser Gin Thr Lys Gin Ser Ser lie lie He Gin Pro Arg Gin Cys Thr 35 40 45 Glu Gin Arg Phe Ser Ala Ser Ser Thr Leu Ser Ser His He Thr Met 50 55 60 Ser Ser Ser Ala Phe Pro Ala Ser Pro Gin Gin His Ala Gly Ser Asn 65 70 75 80 Pro Gly Gin Arg Val Thr Thr Thr Tyr Asn Gin Ser Pro Ala Ser Phe 85 90 95 Leu Ser Ser He Leu Pro Ser Gin Pro Asp Tyr Asn Ser Ser Lys He 100 105 110 Pro Ser Ala Met Asp Ser Asn Tyr Gin Gin Ser Ser Ala Gly Gin Pro 115 120 125 He Asn Ala Lys Pro Ser Gin Thr Ala Asn Ala Lys Pro He Pro Arg 130 135 140 Thr Pro Asp His Glu He Gin Gly Ser Lys Glu Ala Leu He Gin Asp 145 150 155 160 Leu Glu Arg Lys Leu Lys Cys Lys Asp Thr Leu Leu His Asn Gly Asn 165 170 175 Gin Arg Leu Thr Tyr Glu Glu Lys Met Ala Arg Arg Leu Leu Gly Pro 180 185 190 Gin Asn Ala Ala Ala Val Phe Gin Ala Gin Asp Asp Ser Gly Ala Gin 195 200 205 Asp Ser Gin Gin His Asn Ser Glu His Ala Arg Leu Gin Val Pro Thr 210 215 220 Ser Gin Val Arg Ser Arg Ser Thr Ser Arg Gly Asp Val Asn Asp Gin 225 230 235 240 Asp Ala He Gin Glu Lys Phe Tyr Pro Pro Arg Phe He Gin Val Pro 245 250 255 Glu Asn Met Ser He Asp Glu Gly Arg Phe Cys Arg Met Asp Phe Lys 260 265 270 Val Ser Gly Leu Pro Ala Pro Asp Val Ser Trp Tyr Leu Asn Gly Arg 275 280 285 Thr Val Gin Ser Asp Asp Leu His Lys Met He Val Ser Glu Lys Gly 290 295 300 Leu His Ser Leu He Phe Glu Val Val Arg Ala Ser Asp Ala Gly Ala 305 310 315 320 Tyr Ala Cys Val Ala Lys Asn Arg Ala Gly Glu Ala Thr Phe Thr Val 325 330 335 Gin Leu Asp Val Leu Ala Lys Glu His Lys Arg Ala Pro Met Phe He 340 345 350 Tyr Lys Pro Gin Ser Lys Lys Val Leu Glu Gly Asp Ser Val Lys Leu 355 360 365 Glu Cys Gin He Ser Ala He Pro Pro Pro Lys Leu Phe Trp Lys Arg 370 375 380 Asn Asn Glu Met Val Gin Phe Asn Thr Asp Arg He Ser Leu Tyr Gin 385 390 395 400 Asp Asn Thr Gly Arg Val Thr Leu Leu He Lys Asp Val Asn Lys Lys 405 410 415 Asp Ala Gly Trp Tyr Thr Val Ser Ala Val Asn Glu Ala Gly Val Thr 420 425 430 Thr Cys Asn Thr Arg Leu Asp Val Thr Ala Arg Pro Asn Gin Thr Leu 435 440 445 Pro Ala Pro Lys Gin Leu Arg Val Arg Pro Thr Phe Ser Lys Tyr Leu 450 455 460 Ala Leu Asn Gly Lys Gly Leu Asn Val Lys Gin Ala Phe Asn Pro Glu 465 470 475 480 Gly Glu Phe Gin Arg Leu Ala Ala Gin Ser Gly Leu Tyr Glu Ser Glu 485 490 495 Glu Leu

Claims: Claims 1. An isolated and purified myotilin protein comprising the amino acid sequence shown in SEQ ID NO:2, or a functional fragment thereof. 2. An isolated DNA encoding the myotilin protein or fragment thereof according to claim 1. 3. An antibody which is specifically reactive with the protein or fragment thereof according to claim 1. 4. A method for diagnosing muscular dystrophies or cardiomyopathies, comprising the steps of - obtaining a sample from a patient by muscular biopsy, - preparing a microscopic section from said sample, - effecting immunohistochemical staining of myotilin in said microscopic section, and - comparing the staining pattern obtained to a normal myotilin staining pattern. 5. A method for diagnosing muscular dystrophies or cardiomyopathies, comprising the steps of - obtaining a sample from a patient by muscular biopsy, - isolating myotilin nucleic acids from said sample and - detecting mutations in the myotilin gene. 6. Use of myotilin protein or a fragment thereof in preparation of compounds that regulate actin-cytoskeleton. 7. Use of myotilin protein or a fragment thereof in preparation of compounds that regulate cell growth. 8. Use of myotilin protein or a fragment thereof in preparation of a medicament for treating cancer. 9. Use of myotilin protein or a fragment thereof in preparation of an antimicrobial medicament. 10. A method for treating cancer, comprising the step of administering to a subject in need of such treatment, an effective cancer cell growth regulating amount of a substance having the actin-cytoskeleton regulating activity of myotilin protein. 11. A method for treating microbial infections, comprising the step of administering to a subject in need of such treatment, an effective microbial cell growth regulating amount of a substance having the cell growth regulating activity of myotilin protein. 12. A pharmaceutical composition for use in inhibiting cancer cell growth, comprising at least one compound having the cell growth regulating activity of myotilin protein, and a pharmaceutically acceptable carrier. 13. A pharmaceutical composition for use in regulating actin-cytoskeleton, comprising at least one compound having the actin-cytoskeleton regulating activity of myotilin protein, and a pharmaceutically acceptable carrier.

Inventors: CARPEN OLLI, GROENHOLM MIKAELA, HEISKA LEENA, MYKKAENEN OLLI-MATTI, SALMIKANGAS PAULA, CARPEN, OLLI, GROENHOLM, MIKAELA, HEISKA, LEENA, MYKKAENEN, OLLI-MATTI, SALMIKANGAS, PAULA
Applicants: CARPEN OLLI, GROENHOLM MIKAELA, HEISKA LEENA, MYKKAENEN OLLI MATTI, SALMIKANGAS PAULA, CARPEN, OLLI, GROENHOLM, MIKAELA, HEISKA, LEENA, MYKKAENEN, OLLI-MATTI, SALMIKANGAS, PAULA
Application year: 1999
Main classification: C12N15
IPC codes: A61K38, C07K14, C12N15