SYNPO2

Myopodin is a 117.4 kDa protein composed of 1093 amino acids,[8] although four alternatively-spliced isoforms have been described.

Myopodin contains a novel actin binding site (between amino acids 410 and 563) in the center of the protein.

[5] During myotube differentiation, myopodin interacts with stress fibers prior to co-localizing with alpha actinin-2 at Z-discs in mature striated muscle cells.

[6] Importin binding and nuclear import of myopodin appears to be mediated by serine/threonine phosphorylation-dependent binding of myopodin to 14-3-3 beta[10] Myopodin appears to regulate compartmentalized, intracellular signal transduction between the Z-disc and nucleus in cardiac muscle cells, by forming a Z-disc signaling complex with alpha actinin-2, calcineurin, CaMKII, muscle-specific A-kinase anchoring protein, and myomegalin.

[11] Specifically, phosphorylation by protein kinase A or CaMKII, and dephosphorylation by calcineurin facilitates the binding or release, respectively, of 14-3-3-beta, and the corresponding nuclear or cytoplasmic localization, respectively, of myopodin.