Evidence for interaction of the fusion protein alpha-SNAP with membrane lipid.
alpha-SNAP [soluble N-ethylmaleimide-sensitive fusion protein (NSF)-attachment protein] is required for fusion of transport vesicles with their target membrane. In this study, we have examined the membrane-binding properties of alpha-SNAP. We have found that in several tissues a much larger amount of alpha-SNAP per unit weight of protein is bound to membranes than is free in the cytosol. Biochemical analysis shows that a fraction of alpha-SNAP behaves in ways characteristic of hydrophobic, lipid-associated proteins. These findings suggest that membrane binding may be accounted for, at least in part, by interaction with membrane lipid. Consistent with this idea, binding of newly synthesized alpha-SNAP to brain membranes was found to be independent of functional SNAP receptors and could be accounted for by direct binding of alpha-SNAP to membrane lipid. Furthermore, membrane lipid enhanced the ability of alpha-SNAP to stimulate NSF-dependent ATPase activity.
Steel
G J
GJ
Division of Biochemistry, School of Biological Sciences, University of Manchester Medical School, Oxford Road, Manchester M13 9PT, U.K.
Buchheim
G
G
Edwardson
J M
JM
Woodman
P G
PG
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001389:Azirines / Q000378:metabolism; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008081:Liposomes / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology; D008563:Membrane Lipids / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D050600:SNARE Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D013552:Swine; D014357:Trypsin / Q000378:metabolism; D033921:Vesicular Transport Proteins
D001389:Azirines; D002352:Carrier Proteins; D003432:Cross-Linking Reagents; D008081:Liposomes; D008563:Membrane Lipids; D008565:Membrane Proteins; D011994:Recombinant Proteins; D050600:SNARE Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D033921:Vesicular Transport Proteins; C033174:3-(trifluoromethyl)-3-(3-iodophenyl)diazirine; D014357:Trypsin; D000251:Adenosine Triphosphatases