Modulates the morphology of formed caveolae in cardiomyocytes, but is not required for caveolar formation. Facilitates the recruitment of MAPK1/3 to caveolae within cardiomyocytes and regulates alpha-1 adrenergic receptor-induced hypertrophic responses in cardiomyocytes through MAPK1/3 activation. Contributes to proper membrane localization and stabilization of caveolin-3 (CAV3) in cardiomyocytes (By similarity). Induces RHOA activation and activates NPPA transcription and myofibrillar organization through the Rho/ROCK signaling pathway (PubMed:18332105). Component of the CAVIN complex composed of CAVIN1, CAVIN2, CAVIN3 and CAVIN4 (By similarity). Interacts with CAVIN1, ADRA1A and ADRA1B (PubMed:24567387). Interacts with CAVIN2; this augments the transactivation of NPPA (PubMed:18332105, PubMed:24567387). Interacts with CAV3 (PubMed:26497963, PubMed:24567387). Interacts with MAPK1 and MAPK3 (By similarity). In cardiomyocytes, accumulates in the Z-line of the sarcomere. In vascular smooth muscle cells, detected diffusely throughout the cytoplasm. Localizes in the caveolae in a caveolin-dependent manner. The coiled coil domain (residues 44-77) is essential for membrane-targeting in cardiomyocytes. Belongs to the CAVIN family.