Abstract

Introduction

From Pits To Buds

How Clathrin Coated Buds Pinch Off

Cargo Selection

Outlook

Discussion
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Cells communicate with their external environment and internalize components of the plasma membrane by endocytosis, the best characterized example of which is mediated by clathrin and clathrin adaptors. Clathrin-coated vesicles are involved in the internalization of transmembrane receptors, channels and transporters, and the recycling of synaptic vesicles at the nerve terminal. A growing number of accessory proteins including AP180, dynamin, amphiphysin, synaptojanin, endophilin, Eps15, and epsin have been shown to participate in some aspect of clathrin-coated vesicle formation. Many of these endocytic proteins have functional homologs in yeast indicating that the basic mechanisms of endocytosis may be conserved from yeast to mammals. Cell-free studies combined with approaches in living cells have provided us with a tentative picture of how a vesicular bud might be formed and eventually be pinched off. As the molecular machinery involved in the various steps of vesicle formation is being unraveled we are beginning to understand some of the mechanisms which may regulate coated bud assembly and cargo protein selection in vivo. Our own studies on the recycling of synaptic vesicles from the plasma membrane suggest a putative model for the early steps of clathrin-coated vesicle formation which we will discuss here.

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Presentation Number SAhaucke, v.0212
Keywords: endocytosis, clathrin, dynamin, coat assembly, budding