27. Costelli P, Muscaritoli M, Bonetto A, Penna F, Reffo P, et al. (2008) Muscle myostatin signalling is enhanced in experimental cancer cachexia. Eur J Clin Invest 38: 531–538. 28. Patel K, Amthor H (2005) The function of myostatin and strategies of myostatin blockade - new hope for therapies aimed at promoting growth of skeletal muscle. Neuromuscul Disord 15: 117–126. 29. Tobin JF, Celeste AJ (2005) Myostatin, a negative regulator of muscle mass: implications for muscle degenerative diseases. Curr Opin Pharmacol 5: 328–332. 30. Askanas V, Engel WK (2008) Inclusion-body myositis: muscle fiber molecular pathology and possible pathogenic significance of its similarity to Alzheimer’s and Parkinson’s disease brains. Acta Neuropathol 116: 583–595. 31. Wojcik S, Engel WK, McFerrin J, Askanas V (2005) Myostatin is increased and complexes with amyloid-b within sporadic inclusion-body myositis muscle fibers. Acta Neuropathol 110: 173–177. 32. Vattemi G, Engel WK, McFerrin J, Askanas V (2004) Endoplasmic reticulum stress and unfolded protein response in inclusion body myositis muscle. Am J Pathol 164: 1–7. 33. Karpati G, O’Ferrall EK (2009) Sporadic inclusion body myositis: pathogenic considerations. Ann Neurol 65: 7–11. 34. Meredith SC (2005) Protein denaturation and aggregation. Cellular responses to denatured and aggregated proteins. Ann NY Acad Sci 1066: 181–221. 35. Stefani M, Dobson CM (2003) Protein aggregation and aggregate toxicity: new insights into protein folding, misfolding diseases and biological evolution. J Mol Med 81: 678–699. 36. Abedini A, Raleigh DP (2009) A role for helical intermediates in amyloid formation by natively unfolded ploypeptides? Phys Biol 6: 15005. 37. Kumar S, Mohanty SK, Udgaonkar JB (2007) Mechanism of formation of amyloid protofibrils of barstar from soluble oligomers: evidence for multiple steps and lateral association coupled to conformational conversion. J Mol Biol 367: 1186–1204. 38. Svane AS, Jahn K, Deva T, Malmendal A, Otzen DE, et al. (2008) Early stages of amyloid fibril formation studied by liquid-state NMR: the peptide hormone glucagon. Biophys J 95: 366–377. 39. Jansen R, Dzwolak W, Winter R (2005) Amyloidogenic self-assembly of insulin aggregates probed by high resolution atomic force microscopy. Biophys J 88: 1344–1353. 40. Jua´rez J, Taboada P, Mosquera V (2009) Existence of different structural intermediates on the fibrillation pathway of human serum albumin. Biophys J 96: 2353–2370. 41. Bucciantini M, Calloni G, Chiti F, Formigli L, Nosi D, et al. (2004) Prefibrillar amyloid protein aggregates share common features of cytotoxicity. J Biol Chem 279: 31374–31382. 42. Bucciantini M, Giannoni E, Chiti F, Baroni F, Formigli L, et al. (2002) Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases. Nature 416: 507–511. 43. Glabe CG (2006) Common mechanisms of amyloid oligomer pathogenesis in degenerative disease. Neurobiology of Aging 27: 570–575. 44. Vattemi G, Nogalska A, Engel WK, D’Agostino C, Checler F, et al. (2009) Amyloid-b42 is preferentially accumulated in muscle fibers of patients with sporadic inclusion body myositis. Acta Neuropathol 117: 569–574. 45. Nogalska A, Wojcik S, Engel WK, McFerrin J, Askanas V (2007) Endoplasmic reticulum stress induces myostatin precursor protein and NF-kB in cultured human muscle fibers: relevance to inclusion body myositis. Exp Neurol 240: 610–618. 46. Wojcik S, Nogalska A, McFerrin J, Engel WK, Oledzka G, et al. (2007) Myostatin precursor protein is increased and associates with amyloid-b precursor protein in inclusion body myositis model. Neuropath Appl Neuro 33: 238–242. 47. Lin W, Popko B (2009) Endoplasmic reticulum stress in disorders of myelinating cells. Nat Neurosci 12: 379–385. 48. Schroder M (2008) Endoplasmic reticulum stress responses. Cell Mol Life Sci 65: 862–894. 49. Garlepp MJ, Mastaglia FL (2007) Inclusion body myositis: new insights into pathogenesis. Curr Opin Rheumatol 20: 662–668. 50. Badtke MP, Hammer ND, Chapman MR (2009) Functional amyloids signal their arrival. Sci Signal 2: pe43. 51. Maji SK, Perrin MH, Sawaya MR, Jessberger S, Vadodaria K, et al. (2009) Functional amyloids as natural storage of peptide hormones in pituitary secretory granules. Science 325: 328–332. 52. Fernandez-Escamilla A-M, Rousseau F, Schymkowitz J, Serrano L (2004) Prediction of sequence-dependent and mutational effects on the aggregation of peptides and proteins. Nat Biotechnol 22: 1302–1306. 53. Trovato A, Chiti F, Maritan A, Seno F (2006) Insight into the structure of amyloid fibrils from the analysis of globular proteins. PLoS Comput Biol 2: e170. 54. Trovato A, Seno F, Tosatto SCE (2007) The PASTA server for protein aggregation prediction. Protein Eng Des Sel 20: 521–523. Myostatin Amyloid Formation 55. Reumers J, Schymkowitz J, Rousseau F (2009) Using structural bioinformatics to investigate the impact of non synonymous SNPs and disease mutations: scope and limitations. BMC Bioinformatics 10: S9. 56. Mittl PRE, Priestle JP, Cox DA, Mcmaster G, Cerletti N, et al. (1996) The crystal structure of TGF-b3 and comparison to TGF-b2: implications for receptor binding. Protein Sci 5: 1261–1271. 57. Schreuder H, Liesum A, Pohl J, Kruse M, Koyama M (2005) Crystal structure of recombinant human growth and differentiation factor 5: evidence for interaction of the type I and type II receptor-binding sites. Biochem Biophys Res Comm 329: 1076–1086. 58. Tsumoto K, Ejima D, Kumagai I, Arakawa T (2003) Practical considerations in refolding proteins from inclusion bodies. Protein Expr Purif 28: 1–8. 59. Goda S, Takano K, Yamagata Y, Nagata R, Akutsu H, et al. (2000) Amyloid protofilament formation of hen egg lysozyme in highly concentrated ethanol solution. Protein Sci 9: 369–375. 60. Malisauskas M, Ostman J, Darinskas A, Zamotin V, Liutkevicius E, et al. (2005) Does the cytotoxic effect of transient amyloid oligomers from common equine lysozyme in vitro imply innate amyloid toxicity? J Biol Chem 280: 6269–6275. 61. Calloni G, Lendel C, Campioni S, Giannini S, Gliozzi A, et al. (2008) Structure and dynamics of a partially folded protein are decoupled from its mechanism of aggregation. J Am Chem Soc 130: 13040–13050. 62. Mauro M, Craparo EF, Podesta A, Bulone D, Carrotta R, et al. (2007) Kinetics of different processes in human insulin amyloid formation. J Mol Biol 366: 258–274. 63. Groenning M, Norrman M, Flink JM, Weert Mvd, Bukrinsky JT, et al. (2007) Binding mode of Thioflavin T in insulin amyloid fibrils. J Struct Biol 159: 483–497. 64. Bourhim M, Kruzel M, Srikrishnan T, Nicotera T (2007) Linear quantitation of Ab aggregation using Thioflavin T: reduction in fibril formation by colostrinin. J Neurosci Methods 160: 264–268. 65. Walsh DM, Hartley DM, Kusumoto Y, Fezoui Y, Condron MM, et al. (1999) Amyloid b-protein fibrillogenesis. Structure and biological activity of proto- fibrillar intermediates. J Biol Chem 274: 25945–25952. 66. Levine-III H (1993) Thioflavine T interaction with synthetic Alzheimer’s disease b-amyloid peptides: detection of amyloid aggregation in solution. Protein Sci 2: 404–410. 67. Sabate´ R, Lascu I, Saupe SJ (2008) On the binding of Thioflavin-T to HET-s amyloid fibrils assembled at pH 2. J Struct Biol 162: 387–396. 68. Marshall KE, Serpell LC (2009) Structural integrity of b-sheet assembly. Biochem Soc T 37: 671–676. 69. Kelly SM, Jess TJ, Price NC (2005) How to study proteins by circular dichroism. Biochim Biophys Acta 1751: 119–139. 70. Receveur-Brechot V, Bourhis JM, Uversky VN, Canard B, Longhi S (2006) Assessing protein disorder and induced folding. Proteins Struct Funct Bioinform 62: 24–45. 71. Rezaei-Ghaleh N, Zweckstetter M, Morshedi D, Ebrahim-Habibi A, Nemat- Gorgani M (2009) Amyloidogenic potential of a-chymotrypsin in different conformational states. Biopolymers 91: 28–36. 72. Picotti P, Franceschi GD, Frare E, Spolaore B, Zambonin M, et al. (2007) Amyloid fibril formation and disaggregation of fragment 1–29 of apomyoglobin: insights into the effect of pH on protein fibrillogenesis. J Mol Biol 367: 1237–1245. 73. Bocharova OV, Breydo L, Parfenov AS, Salnikov VV, Baskakov IV (2005) In vitro conversion of full-length mammalian prion protein produces amyloid form with physical properties of PrPSc. J Mol Biol 346: 645–659. 74. Hartley DM, Zhao C, Speier AC, Woodard GA, Li S, et al. (2008) Transglutaminase induces protofibril-like amyloid-b protein assemblies that are protease-resistant and inhibit long-tem potentiation. J Biol Chem 283: 16790–16800. 75. Soto C, Casta n˜o EM, Frangione B, Inestrosa NC (1995) The a-helical to b- strand transition in the amino-terminal fragment of the amyloid b-peptide modulates amyloid formation. J Biol Chem 270: 3063–3067. 76. Frieden C (2007) Protein aggregation processes: In search of the mechanism. Protein Sci 16: 2334–2344. 77. Makin OS, Serpell LC (2005) Structures for amyloid fibrils. FEBS J 272: 5950–5961. 78. Heiring C, Muller YA (2001) Folding screening assayed by proteolysis: application to various cystine deletion mutants of vascular endothelial growth factor. Protein Eng 14: 183–188. 79. Pratico D (2008) Evidence of oxidative stress in Alzheimer’s disease brain and antioxidant therapy. Ann NY Acad Sci 1147: 70–78. 80. Lai E, Teodoro T, Volchuk A (2007) Endoplasmic reticulum stress: signaling the unfolded protein response. Physiology 22: 193–201. 81. Paschen W (2003) Endoplasmic reticulum: a primary target in various acute disorders and degenerative diseases of the brain. Cell Calcium 34: 365–383. 82. Francoeur AM, Assalian A (1996) MICROCAT: A novel cell proliferation and cytotoxicity assay based on WST-1. Biochemica 3: 19–25. PLoS ONE | www.plosone.org 12 February 2010 | Volume 5 | Issue 2 | e9170