Figure 1.

Caveolae are invaginations of the cell membrane readily visualized via electron microscopy (A), which play a critical role in pro-survival and pro-growth signaling. The formation and stabilization of caveolae depend on the presence of cholesterol and the structural protein caveolin, and serve to spatially localize signaling receptors (B), including receptor tyrosine kinases (RTKs) and G-protein coupled receptors (GPCRs). Caveolin monomers (C), contains a palmitic acid anchor that serves to stabilize the protein within the cell membrane, and a scaffolding domain, which is the binding site for many pro-survival and pro-growth molecules. (Definitions: EGFR, epidermal growth factor receptor; IGFR, insulin growth factor receptor; PDGFR, platelet derived growth factor receptor; VEGFR, vascular endothelial growth factor receptor; AC, adenylyl cyclase; PKA, protein kinase A; PKC, protein kinase C; eNOS, endothelial nitric oxide synthase; SFK, Src family kinases; MAPK, mitogen activated protein kinases).