Xin Actin Binding Repeat Containing Protein 2 (XIRP2)

XIRP2contains 28 Xin repeats within a region spanning about 1,000 amino acids. EST database analysis indicated that XIRP2 is expressed in heart, tongue, and skeletal muscle.

The deduced protein contains 3,283 amino acids. Northern blot analysis detected myomaxin expression in heart and skeletal muscle only. Western blot analysis confirmed myomaxin expression in striated muscle. Immunohistochemical analysis showed robust myomaxin expression in a striated pattern in mouse heart, and myomaxin colocalized with alpha-actinin-2 (ACTN2) at Z discs.Myomaxin expression was upregulated upon differentiation in cultured mouse myoblasts and by hypertrophic stimuli in neonatal rat cardiomyocytes.