Editors' ChoiceEndocytosis

Initiator for Coated Pit Assembly

Science Signaling  08 Jun 2010:
Vol. 3, Issue 125, pp. ec174
DOI: 10.1126/scisignal.3125ec174

During clathrin-mediated endocytosis, it has been thought that the sensing and binding of the clathrin adaptor protein AP2 to cargo and lipids leads to the recruitment of clathrin, nucleating the formation of a clathrin-coated pit. Henne et al. have now found that this process of AP2 binding may not in fact represent either the first or the nucleation event of endocytosis. Instead, ubiquitous proteins called FCHo1/2 (F-BAR proteins) bind to the plasma membrane and define the sites of endocytosis independently of AP2. The F-BAR protein can generate very low curvatures and, at higher concentrations, generates higher curvatures like those required at the neck of budding vesicles. The C terminus of the protein has a μ-homology domain (with homology to the μ domain of the AP2 complex) that interacts with Eps15 and intersectin and via these proteins recruits AP2, which further recruits clathrin. Thus, a curvature-inducing protein can act to nucleate clathrin-coated pit assembly during endocytosis.

W. M. Henne, E. Boucrot, M. Meinecke, E. Evergren, Y. Vallis, R. Mittal, H. T. McMahon, FCHo proteins are nucleators of clathrin-mediated endocytosis. Science 328, 1281–1284 (2010). [Abstract] [Full Text]