Epsin is an EH-domain-binding protein implicated in clathrin-mediated endocytosis.
During endocytosis, clathrin and the clathrin adaptor protein AP-2, assisted by a variety of accessory factors, help to generate an invaginated bud at the cell membrane. One of these factors is Eps15, a clathrin-coat-associated protein that binds the alpha-adaptin subunit of AP-2. Here we investigate the function of Eps15 by characterizing an important binding partner for its region containing EH domains; this protein, epsin, is closely related to the Xenopus mitotic phosphoprotein MP90 and has a ubiquitous tissue distribution. It is concentrated together with Eps15 in presynaptic nerve terminals, which are sites specialized for the clathrin-mediated endocytosis of synaptic vesicles. The central region of epsin binds AP-2 and its carboxy-terminal region binds Eps15. Epsin is associated with clathrin coats in situ, can be co-precipitated with AP-2 and Eps15 from brain extracts, but does not co-purify with clathrin coat components in a clathrin-coated vesicle fraction. When epsin function is disrupted, clathrin-mediated endocytosis is blocked. We propose that epsin may participate, together with Eps15, in the molecular rearrangement of the clathrin coats that are required for coated-pit invagination and vesicle fission.
Howard Hughes Medical Institute and Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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H
Chen
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S
Fre
V I
VI
Slepnev
M R
MR
Capua
K
K
Takei
M H
MH
Butler
P P
PP
Di Fiore
P
P
De Camilli
D033965:Adaptor Protein Complex alpha Subunits; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism; D016466:CHO Cells; D002135:Calcium-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D002352:Carrier Proteins / Q000737:chemistry / Q000502:physiology*; D002966:Clathrin / Q000502:physiology*; D006224:Cricetinae; D004705:Endocytosis / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry / Q000502:physiology*; D010750:Phosphoproteins / Q000378:metabolism / Q000502:physiology*; D011485:Protein Binding; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D033921:Vesicular Transport Proteins
D033965:Adaptor Protein Complex alpha Subunits; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D002966:Clathrin; C094318:Eps15-rs protein, mouse; D008565:Membrane Proteins; D009479:Neuropeptides; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D033921:Vesicular Transport Proteins; C114154:epsin