Clathrin-coated vesicles from human placenta contain GTP-binding proteins.
Biochemical and morphological techniques were used to investigate the GTP-binding proteins of clathrin-coated vesicles. Binding of [3H]GTP to clathrin coats was demonstrated by electron microscopic autoradiography. Purified coated vesicles bound 5.2 pmol [35S]GTP gamma S/mg protein. Addition of GTP or GTP gamma S, but not ATP nor GMP, inhibited binding of [35S]GTP gamma S to intact coated vesicles and Triton X-100-extracted coats. A series of 23-24 kDa GTP-binding proteins with isoelectric points between pH 5-8 were detected in coated vesicles. We suggest that the low molecular weight ras-like GTP-binding protein(s) play a role in regulating vesicle-mediated protein transport or signal transduction within intracellular organelles.
Lenhard
J M
JM
Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110.
Levy
M A
MA
Stahl
P D
PD
D001345:Autoradiography; D002462:Cell Membrane / Q000648:ultrastructure; D002966:Clathrin / Q000737:chemistry*; D019204:GTP-Binding Proteins / Q000737:chemistry*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006801:Humans; D007526:Isoelectric Point; D008970:Molecular Weight; D017830:Octoxynol; D015388:Organelles / Q000378:metabolism*; D010920:Placenta / Q000648:ultrastructure*; D011092:Polyethylene Glycols; D015398:Signal Transduction
D002966:Clathrin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D011092:Polyethylene Glycols; D017830:Octoxynol; D019204:GTP-Binding Proteins