May function as an adapter in striated muscle to couple protein kinase C-mediated signaling via its LIM domains to the cytoskeleton. Interacts via its LIM domains with various PKC isoforms. Interacts via its PDZ domain with the ACTN2 C-terminal region. Interacts with MYOZ1, MYOZ2 and MYOZ3. Localized to the cytoplasm around nuclei and pseudopodia of undifferentiated cells and detected throughout the myotubes of differentiated cells. Colocalizes with ACTN2 at the Z-lines. Expressed primarily in adult heart and skeletal muscle, and detected at lower levels in lung. Isoforms are expressed in a tissue-specific manner. Isoform 1, isoform 3 and isoform 5 are expressed in heart, whereas isoform 2, isoform 4 and isoform 6 are expressed in skeletal muscle. Initially expressed in a myocardium-specific manner at 8.5-9 dpc and remains cardiac-restricted until day 12. Strongly expressed throughout heart in all stages examined. At 12.5 dpc expressed at low levels in non-cardiac striated muscles. By 14.5 dpc expressed at high levels in both cardiac and skeletal muscle, and also strongly expressed in striated muscles of tongue, thoracic and abdominal muscles, leg and diaphragm. The various isoforms are developmentally regulated in both skeletal and cardiac muscle. Isoform 5 and isoform 6, which are barely detectable during embryogenesis are up-regulated postnatally. In heart, isoform 3 is up-regulated developmentally, whereas the predominant isoform 1 is expressed throughout development and into adulthood. In skeletal muscle, the predominant isoform 2 is gradually replaced by isoform 4 postnatally. Sequencing errors.