Functional partnership between amphiphysin and dynamin in clathrin-mediated endocytosis.
Amphiphysin, a protein that is highly concentrated in nerve terminals, has been proposed to function as a linker between the clathrin coat and dynamin in the endocytosis of synaptic vesicles. Here, using a cell-free system, we provide direct morphological evidence in support of this hypothesis. Unexpectedly, we also find that amphiphysin-1, like dynamin-1, can transform spherical liposomes into narrow tubules. Moreover, amphiphysin-1 assembles with dynamin-1 into ring-like structures around the tubules and enhances the liposome-fragmenting activity of dynamin-1 in the presence of GTP. These results show that amphiphysin binds lipid bilayers, indicate a potential function for amphiphysin in the changes in bilayer curvature that accompany vesicle budding, and imply a close functional partnership between amphiphysin and dynamin in endocytosis.
Takei
K
K
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Slepnev
V I
VI
Haucke
V
V
De Camilli
P
P
D000818:Animals; D001921:Brain / Q000378:metabolism; D002417:Cattle; D002474:Cell-Free System; D002966:Clathrin / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D003034:Coated Pits, Cell-Membrane / Q000502:physiology / Q000648:ultrastructure; D019281:Dimerization; D034284:Dynamin I; D034281:Dynamins; D004705:Endocytosis / Q000502:physiology*; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D007700:Kinetics; D008081:Liposomes; D008854:Microscopy, Electron; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure
D002966:Clathrin; D008081:Liposomes; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; C075637:amphiphysin; D034284:Dynamin I; D020558:GTP Phosphohydrolases; D034281:Dynamins