A lipid-centric view of endocytosis by caveolae

Caveolae have long been considered to be an alternative endocytic pathway, with distinct cargoes, but generally similar functions, to clathrin-coated pits. Here we suggest that the mechanisms of caveola formation and their scission are tightly interlinked and rely on specific lipids. These mechanisms are fundamentally different to those driving the formation and fission of coated pits. Both formation and scission of caveolae are driven by lipid-induced shaping of the caveolar domain, and we present biophysical models for lipid-driven curvature generation and its coupling with scission. In addition, we propose that these new insights have important implications for understanding the function of endocytosis mediated by caveolae. Rather than a parallel endocytic pathway for protein cargo, we argue that caveolae are a lipid-sensitive mobilized multifunctional surface domain.