Involvement of GTP-binding "G" proteins in transport through the Golgi stack.
GTP gamma S irreversibly inhibits protein transport between successive compartments of the Golgi stack in a cell-free system. Fluoride, potentiated by the addition of aluminum ion, also causes a strong inhibition. These are hallmarks of the involvement of a guanine nucleotide-binding or regulatory "G" protein. Inhibition by GTP gamma S requires a cytosolic inhibitory factor that binds to Golgi membranes during inhibition. Preincubation experiments reveal that GTP gamma S blocks the function of acceptor Golgi but not donor Golgi membranes. More specifically, a processing step in between vesicle attachment and the actual fusion event seems to be affected. Electron microscopy demonstrates a corresponding 5-fold accumulation of non-clathrin-coated buds and vesicles associated with the Golgi cisternae during inhibition by GTP gamma S.
Melançon
P
P
Department of Biochemistry, Stanford University, California 94305.
Glick
B S
BS
Malhotra
V
V
Weidman
P J
PJ
Serafini
T
T
Gleason
M L
ML
Orci
L
L
Rothman
J E
JE
D000535:Aluminum / Q000494:pharmacology; D017607:Aluminum Compounds; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D002474:Cell-Free System; D005459:Fluorides / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism; D008562:Membrane Glycoproteins; D008854:Microscopy, Electron; D013873:Thionucleotides / Q000494:pharmacology; D014721:Vesicular stomatitis Indiana virus; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins / Q000378:metabolism*
D017607:Aluminum Compounds; C028391:G protein, vesicular stomatitis virus; D008562:Membrane Glycoproteins; D013873:Thionucleotides; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D000535:Aluminum; D019204:GTP-Binding Proteins; D005459:Fluorides; C032311:aluminum fluoride