Bidirectional transport by distinct populations of COPI-coated vesicles.
Electron microscope immunocytochemistry reveals that both anterograde-directed (proinsulin and VSV G protein) and retrograde-directed (the KDEL receptor) cargo are present in COPI-coated vesicles budding from every level of the Golgi stack in whole cells; however, they comprise two distinct populations that together can account for at least 80% of the vesicles budding from Golgi cisternae. Segregation of anterograde- from retrograde-directed cargo into distinct sets of COPI-coated vesicles is faithfully reproduced in the cell-free Golgi transport system, in which VSV G protein and KDEL receptor are packaged into separable vesicles, even when budding is driven by highly purified coatomer and a recombinant ARF protein.
Orci
L
L
Department of Morphology, Faculty of Medicine, University of Geneva Medical Center, Switzerland.
Stamnes
M
M
Ravazzola
M
M
Amherdt
M
M
Perrelet
A
A
Söllner
T H
TH
Rothman
J E
JE
D000818:Animals; D000831:Animals, Newborn; D001692:Biological Transport / Q000502:physiology; D002474:Cell-Free System; D002478:Cells, Cultured; D018699:Coated Vesicles / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D020756:Coatomer Protein; D006056:Golgi Apparatus / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D010179:Pancreas / Q000166:cytology; D051381:Rats; D018000:Receptors, Peptide / Q000032:analysis
D020756:Coatomer Protein; C064459:KDEL receptor; D008565:Membrane Proteins; D018000:Receptors, Peptide