EHD2 and the Novel EH Domain Binding Protein EHBP1 Couple Endocytosis to the Actin Cytoskeleton*

Here we identified two novel proteins denoted EH domain protein 2 (EHD2) and EHD2-binding protein 1 (EHBP1) that link clathrin-mediated endocytosis to the actin cytoskeleton. EHD2 contains an N-terminal P-loop and a C-terminal EH domain that interacts with NPF repeats in EHBP1. Disruption of EHD2 or EHBP1 function by small interfering RNA-mediated gene silencing inhibits endocytosis of transferrin into EEA1-positive endosomes as well as GLUT4 endocytosis into cultured adipocytes. EHD2 localizes with cortical actin filaments, whereas EHBP1 contains a putative actin-binding calponin homology domain. High expression of EHD2 or EHBP1 in intact cells mediates extensive actin reorganization. Thus EHD2 appears to connect endocytosis to the actin cytoskeleton through interactions of its N-terminal domain with membranes and its C-terminal EH domain with the novel EHBP1 protein.