Plays an important role in caveolar biogenesis and morphology. Regulates caveolae morphology by inducing membrane curvature within caveolae. Plays a role in caveola formation in a tissue-specific manner. Required for the formation of caveolae in the lung and fat endothelia but not in the heart endothelia. Negatively regulates the size or stability of CAVIN complexes in the lung endothelial cells (By similarity). May play a role in targeting PRKCA to caveolae (PubMed:9566962). Component of the CAVIN complex composed of CAVIN1, CAVIN2, CAVIN3 and CAVIN. Interacts with CAVIN4; this augments the transactivation of NPPA by CAVIN4 (By similarity). Binds to PRKCA in the presence of phosphatidylserine (PubMed:9566962). Interacts with CAVIN1 and CAV3 (By similarity). Localizes in the caveolae in a caveolin-dependent manner. The leucine-zipper domain is essential for its localization in the caveolae. The N-terminus is blocked. Phosphorylated on Ser residues. Binds phosphatidylserine (PS) in a calcium-independent manner. PS-binding is inhibited by phosphotidic acid and phosphatidylinositol. Does not bind phosphatidylcholine (By similarity). Belongs to the CAVIN family.