Generation of high curvature membranes mediated by direct endophilin bilayer interactions.
Endophilin 1 is a presynaptically enriched protein which binds the GTPase dynamin and the polyphosphoinositide phosphatase synptojanin. Perturbation of endophilin function in cell-free systems and in a living synapse has implicated endophilin in endocytic vesicle budding (Ringstad, N., H. Gad, P. Low, G. Di Paolo, L. Brodin, O. Shupliakov, and P. De Camilli. 1999. Neuron. 24:143-154; Schmidt, A., M. Wolde, C. Thiele, W. Fest, H. Kratzin, A.V. Podtelejnikov, W. Witke, W.B. Huttner, and H.D. Soling. 1999. Nature. 401:133-141; Gad, H., N. Ringstad, P. Low, O. Kjaerulff, J. Gustafsson, M. Wenk, G. Di Paolo, Y. Nemoto, J. Crun, M.H. Ellisman, et al. 2000. Neuron. 27:301-312). Here, we show that purified endophilin can directly bind and evaginate lipid bilayers into narrow tubules similar in diameter to the neck of a clathrin-coated bud, providing new insight into the mechanisms through which endophilin may participate in membrane deformation and vesicle budding. This property of endophilin is independent of its putative lysophosphatydic acid acyl transferase activity, is mediated by its NH2-terminal region, and requires an amino acid stretch homologous to a corresponding region in amphiphysin, a protein previously shown to have similar effects on lipid bilayers (Takei, K., V.I. Slepnev, V. Haucke, and P. De Camilli. 1999. Nat. Cell Biol. 1:33-39). Endophilin cooligomerizes with dynamin rings on lipid tubules and inhibits dynamin's GTP-dependent vesiculating activity. Endophilin B, a protein with homology to endophilin 1, partially localizes to the Golgi complex and also deforms lipid bilayers into tubules, underscoring a potential role of endophilin family members in diverse tubulovesicular membrane-trafficking events in the cell.
Farsad
K
K
Howard Hughes Medical Institute and Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA.
Ringstad
N
N
Takei
K
K
Floyd
S R
SR
Rose
K
K
De Camilli
P
P
D000217:Acyltransferases / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure*; D048429:Cell Size; D034281:Dynamins; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006056:Golgi Apparatus / Q000502:physiology; D006801:Humans; D008051:Lipid Bilayers / Q000378:metabolism; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D051381:Rats; D017386:Sequence Homology, Amino Acid; D013572:Synaptic Vesicles / Q000648:ultrastructure
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D008051:Lipid Bilayers; D046911:Macromolecular Substances; D009419:Nerve Tissue Proteins; C107640:SH3GL2 protein, human; C075637:amphiphysin; D000217:Acyltransferases; C018764:2-acylglycerophosphate acyltransferase; D020558:GTP Phosphohydrolases; D034281:Dynamins