Endophilin-Lamellipodin-VASP, key components in fast endophilin-mediated endocytosis, control actin polymerization within liquid-like condensates
Narayan KB, James HP, Cope J, Mondal S, Baeyens L, Milano F, Zheng J, Krause M, Baumgart T. Endophilin-Lamellipodin-VASP, key components in fast endophilin-mediated endocytosis, control actin polymerization within liquid-like condensates. J Biol Chem. 2025 Oct 16:110834. doi: 10.1016/j.jbc.2025.110834. Epub ahead of print. PMID: 41109347.
Abstract
Actin polymerization is essential in several clathrin-independent endocytic pathways including fast endophilin mediated endocytosis (FEME), however the actin machinery involved in FEME has been elusive. Here, we show that the actin polymerase VASP colocalizes and interacts directly with the FEME priming complex. We identify Endophilin as a VASP binding partner and establish novel non-canonical interactions between the SH3 domain of Endophilin and the EVH1 and EVH2 domains of VASP. We show that liquid-like condensates formed by Endophilin, Lamellipodin and VASP localize actin polymerization both in solution and on lipid membranes, and result in the formation of torus-shaped condensates in the bulk. We establish a new role for multivalent Endophilin-Lamellipodin interactions in the regulation of actin polymerization, and we identify a novel function for Endophilin as a promoter of actin bundling. Our findings support a model that explains the connection between local actin polymerization and dynamic formation and dissolution of endocytic priming patches in FEME.