Myozenin-2, also referred to as Calsarcin-1, is a protein that in humans is encoded by the MYOZ2gene.[1][2][3] The Calsarcin-1 isoform is a muscle protein expressed in cardiac muscle and slow-twitch skeletal muscle, which functions to tether calcineurin to alpha-actinin at Z-discs, and inhibit the pathological cardiac hypertrophic response. This differs from the fast-skeletal muscle isoform, calsarcin-2.
The function of calsarcin-1 in cardiac and slow-skeletal muscle has been illuminated through studies in transgenic animals. Mice lacking the MYOZ2 gene (MYOZ2-/-) are generally sensitized to calcineurin signaling in both muscle types.[8] In slow-skeletal muscle, MYOZ2-/- show increased slow-twitch muscle fibers. In cardiac, MYOZ2-/- show induction of the fetal gene program typical of pathologic hypertrophy, however there was no evidence of hypertrophied morphometry at baseline. However, upon calcineurin activation or pressure overload-induced pathologic hypertrophy, MYOZ2-/- exhibited exaggerated cardiac hypertrophy, demonstrating that calsarcin-1 negatively modulates the function of calcineurin during pathologic hypertrophic remodeling.[8] Additional studies supported these findings in demonstrating that adenoviral overexpression of calsarcin-1 attenuated Gq alpha subunit-stimuated hypertrophy and ANP induction, by Angiotensin II, phenylephrine and endothelin-1 agonists in neonatal cardiomyocytes.[9] Overexpression of calsarcin-1 in mice (CS1Tg) was protective against Angiotensin II-induced pathologic cardiac hypertrophy, evidenced by preserved fractional shortening and contractility, as well as a blunted induction of the fetal hypertrophic gene program and significantly reduced expression of calcineurin-stimulated MCIP1.4 gene expression.[9] Taken together, these studies strongly support a role for calsarcin-1 in suppressing pathologic cardiac hypertrophy.
↑ 7.07.17.2Frey N, Barrientos T, Shelton JM, Frank D, Rütten H, Gehring D, Kuhn C, Lutz M, Rothermel B, Bassel-Duby R, Richardson JA, Katus HA, Hill JA, Olson EN (December 2004). "Mice lacking calsarcin-1 are sensitized to calcineurin signaling and show accelerated cardiomyopathy in response to pathological biomechanical stress". Nature Medicine. 10 (12): 1336–43. doi:10.1038/nm1132. PMID15543153.
↑ 8.08.1Frey N, Barrientos T, Shelton JM, Frank D, Rütten H, Gehring D, Kuhn C, Lutz M, Rothermel B, Bassel-Duby R, Richardson JA, Katus HA, Hill JA, Olson EN (December 2004). "Mice lacking calsarcin-1 are sensitized to calcineurin signaling and show accelerated cardiomyopathy in response to pathological biomechanical stress". Nature Medicine. 10 (12): 1336–43. doi:10.1038/nm1132. PMID15543153.
↑ 9.09.1Frank D, Kuhn C, van Eickels M, Gehring D, Hanselmann C, Lippl S, Will R, Katus HA, Frey N (November 2007). "Calsarcin-1 protects against angiotensin-II induced cardiac hypertrophy". Circulation. 116 (22): 2587–96. doi:10.1161/CIRCULATIONAHA.107.711317. PMID18025526.
Ahmad F, Gonzalez O, Ramagli L, Xu J, Siciliano MJ, Bachinski LL, Roberts R (December 2000). "Identification and characterization of a novel gene (C4orf5) located on human chromosome 4q with specific expression in cardiac and skeletal muscle". Genomics. 70 (3): 347–53. doi:10.1006/geno.2000.6399. PMID11161785.
Frey N, Olson EN (April 2002). "Calsarcin-3, a novel skeletal muscle-specific member of the calsarcin family, interacts with multiple Z-disc proteins". The Journal of Biological Chemistry. 277 (16): 13998–4004. doi:10.1074/jbc.M200712200. PMID11842093.
Gontier Y, Taivainen A, Fontao L, Sonnenberg A, van der Flier A, Carpen O, Faulkner G, Borradori L (August 2005). "The Z-disc proteins myotilin and FATZ-1 interact with each other and are connected to the sarcolemma via muscle-specific filamins". Journal of Cell Science. 118 (Pt 16): 3739–49. doi:10.1242/jcs.02484. PMID16076904.
Rual JF, Venkatesan K, Hao T, Hirozane-Kishikawa T, Dricot A, Li N, Berriz GF, Gibbons FD, Dreze M, Ayivi-Guedehoussou N, Klitgord N, Simon C, Boxem M, Milstein S, Rosenberg J, Goldberg DS, Zhang LV, Wong SL, Franklin G, Li S, Albala JS, Lim J, Fraughton C, Llamosas E, Cevik S, Bex C, Lamesch P, Sikorski RS, Vandenhaute J, Zoghbi HY, Smolyar A, Bosak S, Sequerra R, Doucette-Stamm L, Cusick ME, Hill DE, Roth FP, Vidal M (October 2005). "Towards a proteome-scale map of the human protein-protein interaction network". Nature. 437 (7062): 1173–8. doi:10.1038/nature04209. PMID16189514.