May act as a scaffolding protein within caveolar membranes. Interacts directly with G-protein alpha subunits and can functionally regulate their activity. Acts as an accessory protein in conjunction with CAV1 in targeting to lipid rafts and driving caveolae formation. The Ser-36 phosphorylated form has a role in modulating mitosis in endothelial cells. Positive regulator of cellular mitogenesis of the MAPK signaling pathway. Required for the insulin-stimulated nuclear translocation and activation of MAPK1 and STAT3, and the subsequent regulation of cell cycle progression (By similarity). Monomer or homodimer. Interacts with CAV1; the interaction forms a stable heterooligomeric complex that is required for targeting to lipid rafts and for caveolae formation. Tyrosine phosphorylated forms do not form heterooligomers with the Tyr-19-phosphorylated form existing as a monomer or dimer, and the Tyr-27-form as a monomer only. Interacts (tyrosine phosphorylated form) with the SH2 domain-containing proteins, RASA1, NCK1 and SRC. Interacts (tyrosine phosphorylated form) with INSR, the interaction (Tyr-27-phosphorylated form) is increased on insulin stimulation. Interacts (Tyr-19 phosphorylated form) with MAPK1 (phosphorylated form); the interaction, promoted by insulin, leads to nuclear location and MAPK1 activation. Interacts with STAT3; the interaction is increased on insulin-induced tyrosine phosphorylation leading to STAT activation (By similarity). Potential hairpin-like structure in the membrane. Membrane protein of caveolae. Tyr-19-phosphorylated form is enriched at sites of cell-cell contact and is translocated to the nucleus in complex with MAPK1 in response to insulin. Tyr-27-phosphorylated form is located both in the cytoplasm and plasma membrane. CAV1-mediated Ser-23-phosphorylated form locates to the plasma membrane. Ser-36-phosphorylated form resides in intracellular compartments (By similarity). Phosphorylated on serine and tyrosine residues. CAV1 promotes phosphorylation on Ser-23 which then targets the complex to the plasma membrane, lipid rafts and caveolae. Phosphorylation on Ser-36 appears to modulate mitosis in endothelial cells. Phosphorylation on both Tyr-19 and Tyr-27 is required for insulin-induced 'Ser-727' phosphorylation of STAT3 and its activation. Phosphorylation on Tyr-19 is required for insulin-induced phosphorylation of MAPK1 and DNA binding of STAT3. Tyrosine phosphorylation is induced by both EGF and insulin (By similarity). Belongs to the caveolin family.