May serve as an anchoring protein that mediates the subcellular compartmentation of protein kinase A (PKA) via binding to PRKAR2A. May attenuate calcineurin ability to induce slow-fiber gene program in muscle and may negatively modulate skeletal muscle regeneration. Plays a role in the assembly of ryanodine receptor (RYR2) clusters in striated muscle. Interacts with PRKAR2A. Interacts with ACTN2, DES and DTNBP1/dysbindin. Interacts with DMD/dystrophin. Interacts with the calcineurin catalytic subunit PPP3CA. Interacts with TTN (By similarity). Interacts with CAPN3; this interaction, which results in CMYA5 proteolysis, may protect CAPN3 from autolysis (By similarity). Interacts with FSD2 (PubMed:28740084). In cardiac muscles, identified in a complex composed of FSD2, CMYA5 and RYR2 (PubMed:28740084). Found predominantly at the periphery of the nucleus but also throughout the cell. Localized in lysosomes. In skeletal muscles, localizes along myofiber periphery, at costameres. Predominantly flanks Z-disks (By similarity). Occasionally present at the M-band level. In the mdx mouse model for Duchenne muscular dystrophy, exhibits a discontinuous localization at the myofiber periphery with extensive regions devoid of CMYA5. This highly irregular pattern is associated with an increased cytoplasmic localization, particularly in discrete foci within myofibers. Colocalized with RYR2 in the sarcoplasmic reticulum (By similarity). Expressed in skin as well as in cardiac muscle. Expressed in skeletal muscle (at protein level). At 10.5 dpc, strong expression is observed in the atria and ventricles of the heart. The signal is localized predominantly to the trabecular zone but not the compact zone of the ventricles. Weaker expression is detected in the developing somites at this time point. At 12.5 dpc the intense hybridization signal is maintained in the heart with stronger expression in the atria compared with the ventricles. At 15.5 dpc, continues to be expressed in the heart with lower levels in the atria compared with the ventricles. In contrast, skeletal muscle displays high levels of transcripts. A sagittal section of an isolated heart from an 17.5 dpc mouse embryo shows abundant expression in myocardial cells with a more robust signal in the trabecular region. Expression in the cardiac valves is completely absent at this time point. Up-regulated in response to mechanical stretch of skeletal muscle (hypertrophy mechanically-induced). May be up-regulated by the PKA-CREB signaling pathway. Amphipathic helix regions act as an anchoring domain for PKA, and appear to be responsible of the interaction between myospryn and PRKAR2A. Phosphorylated by PKA.