Structural organization and dynamics of FCHo2 docking on membranes.

El Alaoui, Fatima; Casuso, Ignacio; Sanchez-Fuentes, David; Arpin-Andre, Charlotte; Rathar, Raissa; Baecker, Volker; Castro, Anna; Lorca, Thierry et al. · Elife · 2022

basic_science · Level V

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Abstract

Clathrin-mediated endocytosis (CME) is a central trafficking pathway in eukaryotic cells regulated by phosphoinositides. The plasma membrane phosphatidylinositol-4,5-bisphosphate (PI(4,5)P<sub>2</sub>) plays an instrumental role in driving CME initiation. The F-BAR domain-only protein 1 and 2 complex (FCHo1/2) is among the early proteins that reach the plasma membrane, but the exact mechanisms triggering its recruitment remain elusive. Here, we show the molecular dynamics of FCHo2 self-assembly on membranes by combining minimal reconstituted in vitro and cellular systems. Our results indicate that PI(4,5)P<sub>2</sub> domains assist FCHo2 docking at specific membrane regions, where it self-assembles into ring-like-shaped protein patches. We show that the binding of FCHo2 on cellular membranes promotes PI(4,5)P<sub>2</sub> clustering at the boundary of cargo receptors and that this accumulation enhances clathrin assembly. Thus, our results provide a mechanistic framework that could explain the recruitment of early PI(4,5)P<sub>2</sub>-interacting proteins at endocytic sites.

Medical subject headings