ASSAY

Abstract: This invention relates to truncated Tec kinase polypeptides and their use in screening for compounds which modulate the activity of Tec kinase polypeptides. Also described are nucleotide sequences encoding truncated Tec kinase polypeptides, vectors and host cells containing said nucleotides.

Description: Assay Field of invention The present invention relates to truncated Tec kinase polypeptides, nucleotide sequences encoding truncated Tec kinase polypeptides, vectors and host cells containing said nucleotides, methods of screening for compounds which modulate the activity of Tec kinase polypeptides, and the use of compounds identifiable by said method in therapy Background to the invention Antigen receptors on T, B and mast cells are multimolecular complexes that are activated by interactions with external signals These signals are then transmitted to regulate gene expression and posttranscnptional modifications A family of non-receptor tyrosine kinases known as the "Tec kinase family", including Itk, Tec, Btk, Bmx and Txk tyrosine kinases, is involved in the signal transduction in T, B and mast cells The members of the Tec kinase family share a similar domain structure, having an N-terminal pleckstnn-homology (PH) domain, a Tec homology domain (TH), which includes one (Itk, Bmx, Txk, and Tec29) or two (Btk and Tec) proline-nch regions (PR), Src homology 3 (SH3) and Src homology 2 (SH2) domains, and a catalytic kinase domain (SH1 ), see for example Yang et al (2000) Immunity 12 373-382 A need exists to identify modulators of Tec kinase polypeptides in order to provide compounds for use in therapy At present, there are no methods available for screening Tec kinase polypeptides Accordingly, the object of the present invention is to provide a screen for compounds which modulate the activity of Tec kinase polypeptides and thereby provide compounds for use in therapy Summary of Invention The present invention is based on the finding that a truncated- Tec kinase polypeptide can be used in an assay to screen for compounds which modulate the activity of Tec kinase polypeptides. Accordingly, the invention provides a truncated Tec kinase polypeptide having a Tec kinase amino acid sequence truncated by a minimum of the amino acids constituting the PH domain and a portion of the TH domain including at least one proline rich region up to but not including the amino acids constituting the kinase domain. Another aspect of the invention is an isolated poiynucleotide which (a) encodes a truncated Tec kinase polypeptide of the invention; (b) is complementary to poiynucleotide (a); (c) selectively hybridises to poiynucleotide (a) or (b); or (d) is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c). Further aspects of the invention are: - an expression vector which comprises a poiynucleotide of the invention and which is capable of expressing a polypeptide of the invention; - a host cell comprising an expression vector of the invention; - a primer which is capable of generating a poiynucleotide of the invention; - a method of producing a polypeptide of the invention which method comprises introducing into an appropriate cell line a vector comprising a poiynucleotide of the invention under conditions suitable for obtaining expression of the polypeptide; - a method for the identification of a compound which modulates the activity of a Tec kinase polypeptide, comprising contacting a polypeptide of the invention with a test compound and detecting any enhancement or inhibition in the activity of the polypeptide, compared to the activity that would occur in the absence of said test compound, - a compound which modulates Tec kinase activity and is identifiable by the method referred to above, - use of a compound which modulates Tec kinase activity and is identifiable by the method referred to above for the manufacture of a medicament for the treatment or prophylaxis of a disorder that is responsive to modulation of Tec kinase activity, and a method of treating a subject having a disorder that is responsive to modulation of Tec kinase activity which method comprises administering to said subject an effective amount of a compound identifiable by the method referred to above Detailed Description of the Invention We have surprisingly found that a truncated Tec kinase polypeptide, which is truncated by a minimum of the ammo acids constituting the PH domain and at least one of the proline rich region of the TH domain, up to but not including the ammo acids constituting the kinase domain, is suitable for screening for compounds which modulate the activity of Tec kinase polypeptides The truncated Tec kinase polypeptides of the present invention are constitutively active despite truncation of a large portion of the protein The polypeptides of the invention have been found to be particularly suitable for screening as they do not need to be pre-activated by phosphorylation In vivo, Tec kinases need to be phosphorylated by other kinases in order to activate the enzyme (Gibson et al (1996) J Immunology 156 2716-2722) Whilst pre- activation by phosphorylation is commonly required in assays, for example, LCK assays include a phosphorylation step (Trevillyan, et al (1999) Arch Biochem Biophys 364, 19-29) the removal of the need to preactivate the polypeptides of the present invention offers a simplification for the assay A further advantage of the present invention is the provision of an assay that is "robust". The present inventors have found that the assay is robust in two respects. Firstly, it is possible to generate large amounts of truncated enzyme which are stable over a long time. Secondly, the assay gives a high frequency of comparable results upon repeat testing. The polypeptides of the invention may therefore provide useful screening targets for the identification and development of novel pharmaceutical agents, including agonists and antagonists of Tec kinases, which may be useful in the treatment and/or prophylaxis of disorders such as inflammation. Truncated Tec Kinase Polypeptides The invention provides a truncated Tec kinase polypeptide having a Tec kinase amino acid sequence truncated by a minimum of the amino acids constituting the PH domain and a portion of the TH domain including at least one proline rich region up to but not including the amino acids constituting the kinase domain. In other words, the point of truncation can occur anywhere after the first proline rich region of the TH domain (i.e. the proline rich region closest to the PH domain) and before the kinase domain. Preferably, the Tec kinase amino acid sequence is truncated by a minimum of the amino acids constituting the PH domain and a portion of the TH domain including at least one proline rich region up to but not including the amino acids constituting the SH2 and kinase domain, i.e. the point of truncation can occur anywhere after the first proline rich region of the TH domain and before the SH2 domain. More preferably, the Tec kinase amino acid sequence is truncated by the amino acids constituting PH domain and a portion of the TH domain including at least one proline rich region up to but not including the amino acids constituting the SH3, SH2 and kinase domain, i.e. the point of truncation can occur anywhere after the first proline rich region of the TH domain and before the SH3 domain. In a preferred aspect of the invention, when the Tec kinase polypeptide contains more than one proline rich region, the truncated Tec kinase polypeptide does not contain any proline rich regions, I e the point of truncation occurs after all the proline rich regions of the TH domain The domains of the Tec kinase polypeptides referred to above are defined in Figures 5 and 6 Figure 6 shows a schematic representation of the domain structure of Tec kinases The "PH domain" as described herein is the N-terminal domain of the Tec kinase polypeptide It comprises β sheet structure The "TH domain" as described herein is the domain situated between the PH and SH3 domains of the Tec kinase polypeptide It comprises a globular core and either one (Itk, Bmx, Txk, Tec29) or two (Tec, Btk) proline rich (PR) regions The "proline rich regions" as described herein are the proline rich regions in the TH domain Preferably, a proline rich region comprises at least two proline residues within six consecutive ammo acids, preferably at least three proline residues within six consecutive ammo acids, more preferably at least four proline residues within six consecutive ammo acids The "SH3 domain" as described herein is the domain situated between the TH and SH2 domains of the Tec kinase polypeptide It comprises two β sheets positioned at approximately right angles to each other The "SH2 domain ' as described herein is the domain situated between the SH3 and kinase domain of the Tec kinase polypeptide The "kinase domain ' as described herein is the C-terminal domain of the Tec kinase polypeptide The "kinase domain may alternatively be known as the "SH1 ' domain A 'Tec kinase polypeptide as described herein is a polypeptide of the Tec kinase family, including Itk, Tec, Btk, Bmx and Txk tyrosine kinases Figure 5 shows an alignment of the polypeptide sequences of Tec family kinases showing the PH, TH, SH3 and SH2 domains The ClustalX analysis program was used to align the sequences (Thompson, J D , Gibson, T J , Plewniak, F , Jeanmougm, F and Higgins, D G (1997) The ClustalX windows interface flexible strategies for multiple sequence alignment aided by quality analysis tools Nucleic Acids Research, 24 4876-4882) The default settings were used Accordingly, in a preferred aspect of the invention, the Tec kinase polypeptide is truncated at a position between ammo acid 199 (last ammo acid of the first proline rich region of the TH domain, when the sequence is aligned as shown in Figure 5) and am o acid 451 (first ammo acid of the kinase domain, when the sequence is aligned as shown in Figure 5) More preferably the Tec kinase polypeptide is truncated at a position between am o acid 199 (last ammo acid of the first proline rich region of the TH domain, when the sequence is aligned as shown in Figure 5) and am o acid 417 (last ammo acid of the SH2 domain, when the sequence is aligned as shown in Figure 5) More preferably the Tec kinase polypeptide is truncated at a position between ammo acid 199 (last ammo acid of the first proline rich region of the TH domain, when the sequence is aligned as shown in Figure 5) and ammo acid 333 (first ammo acid of the SH2 domain, when the sequence is aligned as shown in Figure 5) Even more preferably the Tec kinase polypeptide is truncated at a position between ammo acid 199 (last ammo acid of the first proline rich region of the TH domain, when the sequence is aligned as shown in Figure 5) and am o acid 224 (first ammo acid of the SH3 domain, when the sequence is aligned as shown in Figure 5) In a more preferred aspect of the invention, when the Tec kinase polypeptide has more than one proline rich region, the Tec kinase polypeptide is truncated at a position between amino acid 213 (last ammo acid of the second proline rich region of the TH domain, when the sequence is aligned as shown in Figure 5) and am o acid 451 (first ammo acid of the kinase domain, when the sequence is aligned as shown in Figure 5) More preferably the Tec kinase polypeptide is truncated at a position between ammo acid 213 (last ammo acid of the second proline rich region of the TH domain, when the sequence is aligned as shown in Figure 5) and ammo acid 417 (last ammo acid of the SH2 domain, when the sequence is aligned as shown in Figure 5) More preferably the Tec kinase polypeptide is truncated at a position between ammo acid 213 (last ammo acid of the second proline rich region of the TH domain, when the sequence is aligned as shown in Figure 5) and ammo acid 333 (first ammo acid of the SH2 domain, when the sequence is aligned as shown in Figure 5) Even more preferably the Tec kinase polypeptide is truncated at a position between am o acid 213 (last am o acid of the second proline rich region of the TH domain, when the sequence is aligned as shown in Figure 5) and ammo acid 224 (first am o acid of the SH3 domain, when the sequence is aligned as shown in Figure 5) In a particular aspect of the invention, the start of the SH3 domain is defined by the ammo acid sequence *X-X-V-[VIK]-A-[LM]-Y-D-[YF], the start of the SH2 domain is defined by the ammo acid sequence [IL]-[ED]-X-Y-E-*W-Y, and the start of the kinase domain is defined by the ammo acid sequence G-[LF]-[GRSJ- Y-[GDE]-[SK]-W-*, where, the letters denote ammo acids in one letter code, the square brackets denote a single ammo acid, the ammo acids within the square brackets are alternatives, X is any one ammo acid residue, and "*" indicates the start of the domain For example, the Tec kinase polpeptide sequences to be truncated may be selected from Btk (human) - Accession no Q06187 (SwissProt), Btk (mouse) - Accession no P35991 (SwissProt), Itk (human) - Accession no Q08881 (SwissProt), Itk (mouse) - Accession no Q03526 (SwissProt), Tec (human) - Accession no P42680 (SwissProt), Tec (mouse) - Accession no P24604 (SwissProt), Bmx (human) - Accession no P51813 (SwissProt), Bmx (mouse) - Accession no P97504 (TREMBL), Txk (human) - Accession no P42681 (SwissProt), and Txk (mouse) - Accession no P42682 (SwissProt) Preferably the truncated Tec kinase polypeptide is a truncated Itk polypeptide or a truncated Btk polypeptide Preferably the Itk polypeptide to be truncated has a sequence as set forth in Figure 4 ("ITK" sequence) or a homolog or variant thereof Preferably the truncated Itk polypeptide has the polypeptide sequence set forth in Figure 3 or a homolog or variant thereof More preferably, the truncated Itk polypeptide has a sequence encoded by the poiynucleotide sequence set forth in Figure 2 Preferably the Btk polypeptide to be truncated has a sequence Btk (human) Accession no Q06187 (Swiss prot Database) or a homolog or variant thereof Preferably, the truncated Btk polypeptide has the polypeptide sequence set forth in Figure 8 or a homolog or variant thereof More preferably the truncated Btk polypeptide has a sequence encoded by the poiynucleotide sequence set forth in Figure 9 The polypeptides of the present invention are provided in an isolated form The term "isolated" is intended to convey that the material is not in its native state Thus, the naturally-occurring polypeptide present in a living animal is in its native state and is not isolated, but the same polypeptide, separated from some or all of the materials it co-exists with in the natural system, is isolated The polypeptides may be mixed with carriers or diluents which will not interfere With their intended use and still be regarded as isolated Similarly, a polypeptide which has been produced by synthetic means, for example, by recombmant methods is "isolated ' The polypeptides of the present invention are also preferably provided in purified form, and preferably are purified to at least 50% purity more preferably about 75% purity, most preferably 90% purity or greater, such as 95%, 98% pure Routine methods can be employed to purify and/or synthesize the polypeptides according to the invention Such methods are well understood by persons skilled in the art, and include techniques such as those disclosed in Sambrook et al, Molecular Cloning a Laboratory Manual, 2 nd Edition, CSH Laboratory Press, 1989 the disclosure of which is included herein in its entirety by way of reference The polypeptide of the present invention may be a recombmant or a synthetic polypeptide The polypeptide of the invention is a human or animal sequence (or homologous to such sequence) Such an animal is typically a mammal, such as a rodent (e g a mouse) or a primate Preferably the polypeptide is a human sequence Homologues of polypeptide sequences are referred to above Such homologues typically have at least 70% homology, preferably at least 80%, 90%, 95%, 97% or 99% homology, for example over a region of at least 15, 20, 30, 100 or more contiguous ammo acids The homology may be calculated on the basis of ammo acid identity (sometime referred to as "hard homology ) Identity is calculated using the widely used GCG (University of Wisconsin) suite of programs and preferably using the distances software (correction method) The term "variant" refers to a polypeptide which has a same essential character or basic biological functionality as the truncated Tec kinase polypeptide in question Preferably a variant polypeptide is one which binds to the same ligand as the truncated Tec kinase polypeptide Such variants may include allelic variants and the deletion, modification or addition of single ammo acids or groups of amino acids within the polypeptide sequence Ammo acid substitutions may be made, for example from 1 2 or 3 to 10 15, 20 or 30 substitutions The modified polypeptide retains activity as a truncated Tec kinase polypeptide Changes in ammo acid sequence of peptides can be guided by known similarities among ammo acids and other molecules or substituents in physical features such as charge density, hydrophobicity, hydrophilicity, size and configuration etc. For example, the amino acid Thr may be replaced by Ser and vice versa, and Leu may be replaced by lie and vice versa, For example, a polar amino acid such as glycine or serine may be substituted for another polar amino acid; a basic amino acid may be substituted for another basic amino acid; an acidic amino acid may be substituted for another acidic amino acid; or a non- polar amino acid may be substituted for another non-polar amino acid. Groups of amino acids normally considered to be equivalent are: (a) Ala (A), Ser (S), Thr (T), Pro (P), Gly (G); (b) Asn (N), Asp (D), Glu (E), Gin (Q); (c) His (H), Arg (R) Glu (E), Gin (Q); (d) Met (M), Leu (L), He (I ), Val (V); and (e) Phe (F), Tyr (Y), Trp (W). Polypeptides of the invention may be chemically modified, e.g. post- translationally modified. For example, they may be glycosylated or comprise modified amino acid residues. They may also be modified by the addition of histidine residues to assist their purification, or other suitable protein tags, see for example, Nilsson et al. (1997) Protein Expression and Purification 1 1 :1 -16. Such modified polypeptides fall within the scope of the term "polypeptide" of the invention. Polynucleotides and primers A further aspect of the invention is an isolated poiynucleotide which (a) encodes a truncated Tec kinase polypeptide of the invention; (b) is complementary to poiynucleotide (a); (c) selectively hybridises to poiynucleotide (a) or (b); or (d) is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c). A preferred aspect is an isolated polynucelotide which: (a) encodes the truncated Itk polypeptide set forth in Figure 3; (b) is complementary to poiynucleotide (a); (c) selectively hybridises to poiynucleotide (a) or (b), or (d) is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c) A more preferred aspect of the invention is an isolated poiynucleotide having (a) the sequence set forth in Figure 2 (b) a sequence complementary to poiynucleotide (a), (c) a sequence which selectively hybridises to poiynucleotide (a) or (b), or (d) a sequence that is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c) A further aspect of the invention, is an isolated polynucelotide which (a) encodes the truncated Btk polypeptide set forth in Figure 8, (b) is complementary to poiynucleotide (a), (c) selectively hybridises to poiynucleotide (a) or (b), or (d) is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c) A more preferred aspect of the invention is an isolated poiynucleotide having (a) the sequence set forth in Figure 9, (b) a sequence complementary to poiynucleotide (a), (c) a sequence which selectively hybridises to poiynucleotide (a) or (b), or (d) a sequence that is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c) The poiynucleotide sequences of the present invention may be in the form of RNA or in the form of DNA, for example cDNA, genomic DNA, and synthetic DNA Preferably the poiynucleotide sequence of the invention is cDNA The DNA may be double-stranded or single-stranded, and if single stranded may be the coding strand or non-coding (anti-sense) strand As used herein the term poiynucleotide includes nucleic acids that contain one or more modified (e g , tπtylated) or unusual (e g , mosine) bases Thus, DNAs or RNAs with backbones modified for stability or for other reasons are polynucleotides as that term is intended herein The poiynucleotide of the invention is a human or animal sequence (or homologous to such sequence) Such an animal is typically a mammal, such as a rodent (e g a mouse) or a primate Preferably the poiynucleotide is a human sequence Homologues of poiynucleotide sequences typically have at least 70% sequence identity, preferably at least 80%, 90%, 95%, 97% or 99% sequence identity, for example over a region of at least 15, 20, 30, 100 or more contiguous nucleotides. Methods of measuring nucleic acid homology are well known in the art. For example, the UWGCG Package provides the BESTFIT program which can be used to calculate homology (Devereux et al 1984). Similarly the PILEUP and BLAST algorithms can be used to line up sequences (for example are described in Altschul 1993, and Altschul et al 1990). In accordance with the invention, the default settings may be used. As used herein, "selective hybridisation" means that generally the poiynucleotide can hybridize to the gene region sequence at a level significantly above background. The signal level generated by the interaction between a poiynucleotide of the invention and the gene region sequence is typically at least 10 fold, preferably at least 100 fold, as intense as interactions between other polynucleotides and the gene region sequence. The intensity of interaction may be measured, for example, by radiolabelling the poiynucleotide, e.g. with 32 P. Selective hybridisation may typically be achieved using conditions of low stringency (0.3M sodium chloride and 0.03M sodium citrate at about 40°C), medium stringency (for example, 0.3M sodium chloride and 0.03M sodium citrate at about 50°C) or high stringency (for example, 0.03M sodium chloride and 0.003M sodium citrate at about 60°C). The coding sequence of polynucleotides of the present invention may be modified by nucleotide substitutions, for example from 1 , 2 or 3 to 10, 15, 25, 50 or 100 substitutions. The poiynucleotide may alternatively or additionally be modified by one or more insertions and/or deletions and/or by an extension at either or both ends. The modified poiynucleotide encodes a polypeptide which has the activity associated with a truncated Tec kinase polypeptide. Degenerate substitutions may be made and/or substitutions may be made which would result in a conservative amino acid substitution when the modified sequence is translated, for example as shown above. Generation of a Tec kinase oligonucleotide may be performed by methodologies known in the art such as polymerase chain reaction (PCR) for example on genomic DNA or cDNA with appropriate oligonucleotide primers derived from or designed based on a knowledge of the sequence of the Tec kinase of interest. For example, the poiynucleotide sequences of Tec kinases may be selected from: Btk (human) - Accession no. X58957 (EMBL/GenBank), Btk (mouse) - Accession no. L08967 (EMBL/GenBank), Itk (human) - Accession no. D13720 (EMBL/GenBank), Itk (mouse) - Accession no. L00619 (EMBL/GenBank), Tec (human) - Accession no. D29767 (EMBL/GenBank), Tec (mouse) - Accession no. S53716 (EMBL/GenBank), Bmx (human) - Accession no. X83107 (EMBL/GenBank), Bmx (mouse) - Accession no. U88091 (EMBL/GenBank), Txk (human) - Accession no. L27071 (EMBL/GenBank), and Txk (mouse) - Accession no. U 16145 (EMBL/GenBank). According to a further aspect of the invention, there is provided a primer which is capable of generating a Tec kinase poiynucleotide which encodes a truncated Tec kinase polypeptide of the invention. An allele specific primer is used, generally together with a constant primer, in an amplification reaction such as a PCR reaction, which provides discrimination between alleles through selective amplification of one allele at a particular sequence position. The allele specific primer is preferably at least 10, preferably at least 1 5 or at least 20, for example at least 25, at least 30 nucleotides in length. For example, in the generation of a truncated Itk polypeptide, the primers shown in Figure 1 may be used to generate the corresponding poiynucleotide. In the generation of a truncated Btk polypeptide, the primers shown in Figure 7 may be used to generate the corresponding poiynucleotide. The poiynucleotide sequences of the present invention are provided in an isolated form The term "isolated' is intended to convey that the material is not in its native state Thus, the naturally-occurring poiynucleotide sequence present in a living animal is in its native state and is not isolated, but the same poiynucleotide sequence, separated from some or all of the materials it co-exists with in the natural system, is isolated They may be mixed with carriers or diluents which will not interfere with their intended use and still be regarded as isolated Such poiynucleotide sequence could be part of a vector Such poiynucleotide sequence could be part of a composition, and still be isolated in that such vector or composition is not part of its natural environment The poiynucleotide sequences of the present invention are also preferably provided in purified form, and preferably are purified to at least 50% purity, more preferably about 75% purity, most preferably 90% purity or greater, such as 95%, 98% pure Production of Tec kinase polypeptides The poiynucleotide sequences of the present invention may be employed for producing a polypeptide of the invention by recombmant techniques Thus, for example the nucleotide sequence may be included in any one of a variety of expression vehicles or cloning vehicles, in particular vectors or plasmids for expressing a protein A further aspect of the invention is therefore a vector comprising a poiynucleotide of the invention Appropriate cloning and expression vectors for use with prokaryotic and eukaryotic hosts include mammalian expression vectors insect expression vectors yeast expression vectors, bacterial expression vectors and viral expression vectors, see Sambrook et al Molecular Cloning A Laboratory Manual, Second Edition, Cold Spring Harbor NY , (1989) Examples of suitable vectors include derivatives of bacterial plasmids, phage DNA, yeast plasmids, vectors derived from combinations of plasmids and phage DNA and viral DNA and baculoviruses A preferred vector is a baculovirus In a preferred aspect, the vector further comprises one or more regulatory sequences to direct mRNA synthesis, including, for example, a promoter, operably linked to the sequence Suitable promoters include insect cell promotors, polyhed n promotor, p10 and other promoters known to control expression of genes in prokaryotic or eukaryotic cells or their viruses The vector may contain an enhancer and a πbosome binding site for translation initiation and a transcription terminator Large numbers of suitable vectors and promoters/enhancers, will be known to those of skill in the art, but any plasmid or vector, promoter/enhancer may be used as long as it is replicable and functional in the host The vector may also include appropriate sequences for selection and/or amplification of expression For this the vector will comprise one or more phenotypic selectable/amp fiable markers Such markers are also well known to those skilled in the art In a further aspect, the present invention provides host cells comprising a vector of the invention, and capable of expressing a nucleotide sequence of the invention The host cells can be, for example, a higher eukaryotic cell, such as a mammalian cell or a lower eukaryotic cell, such as a yeast cell or a prokaryotic cell such as a bacterial cell Suitable prokaryotic hosts for transformation include E-coli Suitable eukaryotic hosts include insect cells, e g SF9 cells, Tni cells, Hι5 cells, and mammalian cells, e g HEK HeLa, COS, CHO, NSO 3T3 (fibroblast cell line) Cells expressing a nucleotide sequence of the invention can be lysed to obtain the polypeptide of the invention, which may optionally be purified Cell free translation systems can also be employed to produce such proteins Using RNAs derived from the DNA constructs of the present invention A further aspect of the invention is a method of producing a polypeptide of the invention, which method comprises introducing into an appropriate cell line a vector comprising a poiynucleotide as defined herein under conditions suitable for obtaining expression of the polypeptide Methods of scieening The present invention further provides a method for identification of a compound which modulates Tec kinase activity Compounds which modulate Tec kinase activity are those which inhibit or enhance the function of the Tec kinase polypeptides (e g to act as antagonists or agonists of the Tec kinase protein function) In general terms, the screen for such compounds will comprise contacting a polypeptide of the invention with a test compound, and then detecting any enhancement or inhibition of polypeptide activity that results (compared to the activity that would occur in the absence of the test compound) By contacting, it is meant that the test compound and the polypeptide of the invention are in such proximity that they are able to interact biologically The polypeptides of the invention may be used in high throughput screens, thus enabling large numbers of compounds to be studied The activity that is detected is preferably phospho-transfer activity Phospho- transfer involves the transfer of a phosphate from ATP to a tyrosine residue contained within the substrate Phospho-transfer activity may be detected by the inclusion of a target polypeptide in the assay More particularly, polypeptides of the invention may be used in any suitable tyrosine kinase assay, for example, by a time-resolved fluorescence assay, such as homogenous time-resolved fluorescence (HTRF®, Packard Instrument Company) Kolb et al , DDT Vol. 3, 333-342, in-plate binding assays including coloπmetπc and luminescent readouts and time-resolved fluorescence, see for example Farley et al , Anal Biochem (1992) 203, 151 -157, Lehel et al , (1997) Anal Biochem 244, 340-346 and Braunwalder et al , (1996) Anal Biochem 238, 340-346, or radiometπc assays, for example, using 33 P or 2 P, such as scintillation proximity assay (SPA, Amersham International) Examples of time-resolved fluorescence assays are in-plate time-resolved fluorescence (trf) assay (Delfia®, Wallac Oy) Preferably a time-resolved fluorescence assay is used, most preferably homogenous time- resolved fluorescence In a preferred aspect, the method of screening is carried out using cells expressing a polypeptide of the invention and incubating such cells with the test compound, optionally in the presence of a Tec kinase ligand Methods of treatment A further aspect of the present invention is a compound which modulates Tec kinase activity and is identifiable by screening techniques referred to above Preferably, the compound has been identified using the above screening techniques The compounds may be agonists or antagonists of the Tec kinase polypeptide, but preferably are antagonists The compounds include, for example, aptamers, polypeptides, antibodies and small molecules The compounds may be useful in the treatment and/or prophylaxis of disorders that are responsive to modulation of Tec kinase activity For example, it has been demonstrated in vivo that Itk-deficient mice are unable to establish TH2 cells suggesting that Itk has a role in mediating the development of IL-4 producing TH2 cells (Fowell et al (1999) Immunity 1 1 399-409) The absence of this cytokme in Itk-deficient mice suggests that compounds which modulate Tec kinases may be useful in the treatment of inflammatory diseases such as, for example, asthma One particular aspect of the invention is the use of a compound which modulates Tec kinase activity and is identifiable by the screening techniques of the invention, for the manufacture of a medicament for the treatment or prophylaxis of disorders that are responsive to modulation of the activity of Tec kinase activity, such as inflammation Another aspect of the invention is a method of treating a subject having a disorder which is responsive to modulation of Tec kinase activity, such as inflammation, which method comprises administering to a subject an effective amount of a compound identifiable by the screening techniques of the invention Examples of inflammatory conditions include asthma, allergic rhinitis, URID (upper respiratory inflammatory disease), adult respiratory distress syndrome, arthritic conditions such as rheumatoid arthritis, rheumatoid spondylitis, and osteoarthπtis, inflammatory eye conditions such as uveitis (including iritis) and conjunctivitis, inflammatory bowel conditions such as Crohn's disease, ulcerative colitis and distal proctitis, peπodontal disease, esophagitis, inflammatory skin conditions such as psoriasis, eczema and dermatitis Preferred inflammatory conditions are asthma, allergic rhinitis and URID (upper respiratory inflammatory disease) Where the Tec kinase is Btk, preferably the disorder is selected from inflammatory conditions (described above), diseases with a B cell component such as B cell leukaemias and SLE (Systemic Lupus erythematosis), and diseases associated with platelet function Substances identified according to the screening methods outlined above may be formulated with standard pharmaceutically acceptable carriers and/or excipients as is routine in the pharmaceutical art The exact nature of a formulation will depend upon several factors including the particular substance to be administered and the desired route of administration The substances may be administered by enteral or parenteral routes such as via oral, buccal, anal, pulmonary, intravenous, intra-arteπal, intramuscular, intrapentoneal, topical or other appropriate administration routes Therapeutically effective amounts of such compounds can be readily determined by those skilled in the art using, e g dose-response studies The dose of agent may be determined according to various parameters, especially according to the substance used, the age, weight and condition of the patient to be treated, the route of administration and the required regime A suitable dose may however be from 0 01 to 50mg/kg body weight such as 1 to 40 mg/kg body weight A physician will be able to determine the required route of administration and dosage for any particular patient Brief Description of the Figures: Figure 1 shows the oligonucleotide sequences used to generate the truncated Itk construct shown in Figure 2 Figure 2 shows the poiynucleotide sequence of the truncated Itk construct (including cloning sites, underlined) Figure 3 shows the poiynucleotide and translated polypeptide sequence of the truncated Itk construct Figure 4 shows an alignment of the polypeptide sequences of Itk (as in Swissprot data base accession number Q08881 ) and the truncated construct showing PH, SH3, SH2 and kinase domains The domain boundaries are as defined by Swissprot entry Q08881 PH 4-1 1 1 , SH3 171 -23, SH2 239-338, Kinase 363-615 Note tlTK = truncated ITK Figure 5 shows an alignment of the polypeptide sequences of Tec family kinases (SwissProt database) Btk (human) - Accession no Q06187, Btk (mouse) - Accession no P35991 , Itk (human) - Accession no Q08881 , Itk (mouse) - Accession no Q03526, Tec (human) - Accession no P42680, Tec (mouse) - Accession no P24604, Bmx (human) - Accession no P51813, Txk (human) - P42681 /Q14220, and Txk (mouse) - Accession no P42682, showing the PH domain (Bold, italic and boxed) Tec homology domain (Italic and boxed), SH3 domain (Bold and boxed) and SH2 domain (Boxed) Figure 6 shows a schematic representation of the domain structure of Tec kinases Figure 7 shows the oligonucleotide sequences used to generate the truncated Btk construct shown in Figure 9 Figure 8 shows the translated polypeptide sequence of the truncated Btk construct Figure 9 shows the poiynucleotide sequence of the truncated Btk construct Note the full length sequence is available on the genembl database accession number X58957 Examples Example 1 A Generation of the truncated Itk construct To generate an active form of Itk oligonucleotide, PCR primers were designed to amplify, from cDNA, a single region of Itk corresponding to the combined SH3, SH2 and kinase domains and to incorporate a start ethionine and restriction endonuclease sites for cloning the construct The Oligonucleotide sequences used to generate the truncated Itk construct are shown in Figure 1 A T cell cDNA library was used as a source of template DNA (generation of library described in Biotechniques (1998) 25 85-92) A PCR product was cloned (Figure 2) sequenced and used to generate a recombmant baculovirus for infection of SF9 insect cells using standard molecular biological techniques (see for example, Sambrook et al, Molecular Cloning a Laboratory Manual, 2 nd Edition, CSH Laboratory Press, 1 ! Example 1 B Protein expression and assay formation Insect cell pellets infected with the recombmant baculovirus described in Example 1 A were homogenised in 40 mM HEPES (pH 7 4), 100 mM NaCI 2 mM EDTA, 10% glycerol, 0 1 mM vanadate and protease inhibitors The 100 000 g supernatant was stored at -85°C Stored lysates were thawed on ice, ATP and MgCI 2 (0 1 mM and 10 mM) were added Following incubation on ice the kinase was diluted in 40 mM HEPES (pH 7 4) The kinase reaction mixture contained 40 mM HEPES (pH 7 4), 10 mM MgCI 2 , 0 05 mM ATP, 0 0005 mM peptide (Biot -AAAEEIYGEI) The reaction was stopped by the addition of EDTA (25 mM) The amount of phosphopeptide was quantitated by homogeneous time resolved fluorescence as described in Kolb et al (1998) Drug Discovery Today 3 333-342 An increase in the level of fluorescence indicates an increase in kinase activity The Km for ATP and peptide was determined to be 0 039 +/- 0 01 1 mM and 0 480 +/- 0 1 83 uM respectively Example 1 C Screening compounds for modulation of Itk activity The table below shows inhibitors of Itk activity identified using the screen described in Example 1 B above Compound testing in kinase assay Order of additions: Compound to well Enzyme to well 15 min pre-incubation Substrates (ATP, src-peptide) added 30 min incubation Reaction stopped with EDTA HTRF reagents (APC, Eu labelled antibody (antiPY antibody)) added Stand for 20 mins Read signal on plate reader UK: ITK Note; PIC 5 0 is -Iog10 IC 50 in molar, a higher PIC 50 indicates greater potency. Example 1 D: Performance of Itk Screen The following data demonstrate the robustness of the Itk assay. Repetition of the assay described above over a period between 12/8/99 and 24/2/00 (Batch 1 ) and 22/3/00 and 25/5/00 (Batch 2) demonstrates: (i) it is possible to generate large amounts of truncated enzyme which are stable over a long time, and (ii) the assay gives a high frequency of comparable results upon repeat testing. The results are expressed as the mean + SD (n > 80). Example 2A: Generation of the truncated Btk construct To generate an active form of Btk oligonucleotide, PCR primers were designed to amplify, from cDNA, a single region of Btk corresponding to the combined SH3, SH2 and kinase domains and to incorporate a start methionine and restriction endonuclease sites for cloning the construct. The Oligonucleotide sequences used to generate the truncated Btk construct are shown in Figure 7. A PCR product was cloned, sequenced and used to generate a recombinant baculovirus for infection of SF9 insect cells using standard molecular biological techniques (see for example, Sambrook et al, Molecular Cloning: a Laboratory Manual, 2 nd Edition, CSH Laboratory Press, 1 989). Example 2B Protein expression and assay formation Insect cell pellets infected with the recombinant baculovirus described in Example 2A were homogenised in 40 mM HEPES (pH 7 4), 100 mM NaCI 2 mM EDTA, 10% glycerol, 0 1 mM vanadate and protease inhibitors The 100 000 g supernatant was stored at -85°C Stored lysates were thawed on ice and diluted in 40 mM HEPES (pH 7 4) The kinase reaction mixture contained 40mM HEPES pH7 4, 80mM MgCt 2 , 1300uM ATP, 500nM peptide (Biotin- AAAEEIYGEI-NH2) The reaction was stopped by the addition of EDTA (0 16 M) The amount of phosphopeptide was quantitated by homogeneous time resolved fluorescence as described in Kolb et al (1998) Drug Discovery Today 3 333-342 An increase in the level of fluorescence indicates an increase in kinase activity The Km for ATP was determined to be 1 69 +/- 0 36mM Example 2C Screening compounds for modulation of Btk activity The table below shows an inhibitor of Btk activity identified using the screen described in Example 2B above Compound testing in kinase assay Order of additions Compound to well Enzyme to well 1 5 mm pre-incubation Substrates (ATP, src-peptide) added 30 mm incubation Reaction stopped with EDTA HTRF reagents (APC Eu labelled antibody (antiPY antibody)) added Stand for 20 mms Read signal on plate reader Compound: Staurosporin Note: PIC 50 is -Iog10 IC 50 in molar, a higher PIC 50 indicates greater potency.

Claims: CLAIMS 1 A truncated Tec kinase polypeptide having a Tec kinase ammo acid sequence truncated by a minimum of the ammo acids constituting the PH domain and a portion of the TH domain including at least one proline rich region up to but not including the ammo acids constituting the kinase domain 2 A truncated Tec kinase polypeptide as claimed in claim 1 wherein the Tec kinase ammo acid sequence is truncated by a minimum of the ammo acids constituting the PH domain and a portion of the TH domain including at least one proline rich region up to but not including the amino acids constituting the SH2 and kinase domain 3 A truncated Tec kinase polypeptide as claimed in claim 1 wherein the Tec kinase ammo acid sequence is truncated by a minimum of the amino acids constituting the PH domain and a portion of the TH domain including at least one proline rich region up to but not including the ammo acids constituting the SH3 SH2 and kinase domain 4 A truncated Tec kinase polypeptide as claimed in any one of claims 1 -3 which does not contain any proline rich regions 5 A truncated Tec kinase polypeptide as claimed in any one of claims 1 -4 wherein the Tec kinase polypeptide is Itk 6 A truncated Tec kinase polypeptide as claimed in claim 5 having the ammo acid sequence set forth in Figure 3 or at least 70% homology thereto 7 A truncated Tec kinase polypeptide as claimed in any one of claims 1 -4 wherein the Tec kinase polypeptide is Btk 8. A truncated Tec kinase polypeptide as claimed in claim 7 having the amino acid sequence set forth in Figure 8 or at least 70% homology thereto. 9. An isolated poiynucleotide which: (a) encodes a truncated Tec kinase polypeptide as claimed in any one of claims 1 -8; (b) is complementary to poiynucleotide (a); (c) selectively hybridises to poiynucleotide (a) or (b); or (d) is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c), 10. An isolated polynucelotide as claimed in claim 9 which: (a) encodes the truncated Itk polypeptide set forth in Figure 3; (b) is complementary to poiynucleotide (a); (c) selectively hybridises to poiynucleotide (a) or (b); or (d) is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c). 1 1. An isolated poiynucleotide as claimed in claim 10 having: (a) the sequence set forth in Figure 2; (b) a sequence complementary to poiynucleotide (a); (c) a sequence which selectively hybridises to poiynucleotide (a) or (b); or (d) a sequence that is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c). 12. An isolated polynucelotide as claimed in claim 9 which: (a) encodes the truncated Btk polypeptide set forth in Figure 8; (b) is complementary to poiynucleotide (a); (c) selectively hybridises to poiynucleotide (a) or (b); or (d) is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c). 13 An isolated poiynucleotide as claimed in claim 12 having (a) the sequence set forth in Figure 9, (b) a sequence complementary to poiynucleotide (a), (c) a sequence which selectively hybridises to poiynucleotide (a) or (b), or (d) a sequence that is degenerate as a result of the genetic code from poiynucleotide (a), (b) or (c) 14 A vector comprising a poiynucleotide as claimed in any one of claims 9-13 1 5 A host cell comprising a vector as claimed in claim 14 16 A primer which is capable of generating a truncated Tec kinase poiynucleotide as claimed in any one of claims 9-13 1 7 A method of producing a polypeptide as claimed in any one of claims 1 -8, which method comprises introducing into an appropriate cell line a vector comprising a poiynucleotide as claimed in any one of claims 9-13 under conditions suitable for obtaining expression of the polypeptide 18 A method for the identification of a compound which modulates the activity of a Tec kinase polypeptide, comprising contacting a polypeptide as claimed in any one of claims 1 -8 with a test compound and detecting any enhancement or inhibition in the activity of the polypeptide, compared to the activity that would occur in the absence of said test compound 19 A method for the identification of a compound as claimed in claim 18, comprising contacting a compound of interest with a polypeptide as claimed in any one of claims 1 -8 in the presence of a target polypeptide and observing phosphorylation of the target polypeptide A method according to claims 18 or 19 wherein a cell line expressing a polypeptide as claimed in any one of claims 1 -8 is contacted with the compound of interest A compound which modulates Tec kinase activity and is identifiable by the method according to any one of claims 18-20 A compound identifiable by the method according to any one of claims 18-20 for use in therapy Use of a compound which modulates Tec kinase activity and is identifiable by the method of any one of claims 18-20 for the manufacture of a medicament for the treatment or prophylaxis of a disorder that is responsive to modulation of Tec kinase activity Use according to claim 23 wherein the disorder is inflammation A method of treating a subject having a disorder that is responsive to modulation of Tec kinase activity, which method comprises administering to a patient an effective amount of a compound identifiable by a method according to any one of claims 18-20 The method according to claim 25 wherein the disorder is inflammation

Inventors: HAYES DAVID JOHN, SIMS MARTIN JOHN, HAYES, DAVID, JOHN, SIMS, MARTIN, JOHN
Applicants: GLAXO GROUP LTD, HAYES DAVID JOHN, SIMS MARTIN JOHN, GLAXO GROUP LIMITED, HAYES, DAVID, JOHN, SIMS, MARTIN, JOHN
Application year: 2001
Main classification: C12N9
IPC codes: A61K38, A61K45, A61P29, A61P43, C12N1, C12N5, C12N9, C12N15, C12Q1, G01N33