Interactions with M-band titin and calpain 3 link myospryn (CMYA5) to tibial and limb-girdle muscular dystrophies.
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Sarparanta J, Blandin G, Charton K, Vihola A, Marchand S, Milic A, Hackman P, Ehler E, Richard I, Udd B
Interactions with M-band titin and calpain 3 link myospryn (CMYA5) to tibial and limb-girdle muscular dystrophies.
J Biol Chem. 2010 Sep 24;285(39):30304-15. doi: 10.1074/jbc.M110.108720. Epub 2010 Jul 15.
- PubMed ID
- 20634290 [ View in PubMed]
- Abstract
Mutations in the C terminus of titin, situated at the M-band of the striated muscle sarcomere, cause tibial muscular dystrophy (TMD) and limb-girdle muscular dystrophy (LGMD) type 2J. Mutations in the protease calpain 3 (CAPN3), in turn, lead to LGMD2A, and secondary CAPN3 deficiency in LGMD2J suggests that the pathomechanisms of the diseases are linked. Yeast two-hybrid screens carried out to elucidate the molecular pathways of TMD/LGMD2J and LGMD2A resulted in the identification of myospryn (CMYA5, cardiomyopathy-associated 5) as a binding partner for both M-band titin and CAPN3. Additional yeast two-hybrid and coimmunoprecipitation studies confirmed both interactions. The interaction of myospryn and M-band titin was supported by localization of endogenous and transfected myospryn at the M-band level. Coexpression studies showed that myospryn is a proteolytic substrate for CAPN3 and suggested that myospryn may protect CAPN3 from autolysis. Myospryn is a muscle-specific protein of the tripartite motif superfamily, reported to function in vesicular trafficking and protein kinase A signaling and implicated in the pathogenesis of Duchenne muscular dystrophy. The novel interactions indicate a role for myospryn in the sarcomeric M-band and may be relevant for the molecular pathomechanisms of TMD/LGMD2J and LGMD2A.