HIP1 exhibits an early recruitment and a late stage function in the maturation of coated pits.
Huntingtin interacting protein 1 (HIP1) is an accessory protein of the clathrin-mediated endocytosis (CME) pathway, yet its precise role and the step at which it becomes involved are unclear. We employed live-cell imaging techniques to focus on the early steps of CME and characterize HIP1 dynamics. We show that HIP1 is highly colocalized with clathrin at the plasma membrane and shares similar dynamics with a subpopulation of clathrin assemblies. Employing transferrin receptor fused to pHluorin, we distinguished between open pits to which HIP1 localizes and newly internalized vesicles that are devoid of HIP1. Moreover, shRNA knockdown of clathrin compromised HIP1 membranal localization, unlike the reported behavior of Sla2p. HIP1 fragment, lacking its ANTH and Talin-like domains, inhibits internalization of transferrin, but retains colocalization with membranal clathrin assemblies. These data demonstrate HIP1's role in pits maturation and formation of the coated vesicle, and its strong dependence on clathrin for membranal localization.
Gottfried
Irit
I
Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv, Israel.
Ehrlich
Marcelo
M
Ashery
Uri
U
D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002522:Chlorocebus aethiops; D002966:Clathrin / Q000235:genetics / Q000378:metabolism*; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology*; D020868:Gene Silencing; D006367:HeLa Cells; D006801:Humans; D011990:Receptors, Transferrin / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D002966:Clathrin; D004268:DNA-Binding Proteins; C073368:HIP1 protein, human; D011990:Receptors, Transferrin; D011993:Recombinant Fusion Proteins