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. Induces RHOA activation and activates NPPA transcription and myofibrillar organization through the Rho/ROCK signaling pathway. Component of the CAVIN complex composed of CAVIN1, CAVIN2, CAVIN3 and CAVIN4. Interacts with CAVIN1, ADRA1A, ADRA1B, MAPK1 and MAPK3. Interacts with CAVIN2; this augments the transactivation of NPPA. 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. Belongs to the CAVIN family. Truncated N-terminus.