Cytoplasmic coat proteins involved in endosome function.
Endosomes are intermediates for a complex series of sorting and transport events that occur during receptor-mediated endocytosis. These involve the recognition of targeting determinants on the cytoplasmic domains of many membrane proteins as well as the formations of specific transport vesicles. Accordingly, endosome function is likely to be governed by the regulated assembly of cytoplasmic coat complexes. We have found that, in vitro, endosomes recruit a characteristic set of cytoplasmic proteins in a GTP gamma S-stimulated and brefeldin A-sensitive fashion. Among these are members of the COP-I and ARF families of coat proteins. In addition, endosomes were also found to assemble distinct, clathrin-like coats. Since microinjection of antibodies to beta-COP inhibits the entry of enveloped viruses via the endocytic pathway, it is apparent that the recruitment of COP-I or COP-I-related proteins plays an important role in the function of endosomes in intact cells.
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8002, USA.
J A
JA
Whitney
M
M
Gomez
D
D
Sheff
T E
TE
Kreis
I
I
Mellman
D020727:ADP-Ribosylation Factors; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D020126:Brefeldin A; D016466:CHO Cells; D002458:Cell Fractionation; D002522:Chlorocebus aethiops; D002966:Clathrin / Q000502:physiology; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism / Q000648:ultrastructure; D020756:Coatomer Protein; D006224:Cricetinae; D003517:Cyclopentanes / Q000494:pharmacology; D011992:Endosomes / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D019204:GTP-Binding Proteins / Q000378:metabolism; D006056:Golgi Apparatus / Q000502:physiology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006735:Horseradish Peroxidase; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D014168:Transferrin / Q000378:metabolism; D014709:Vero Cells; D014721:Vesicular stomatitis Indiana virus / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000096:biosynthesis
D002966:Clathrin; D020756:Coatomer Protein; D003517:Cyclopentanes; C028391:G protein, vesicular stomatitis virus; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D014168:Transferrin; D014759:Viral Envelope Proteins; D020126:Brefeldin A; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006735:Horseradish Peroxidase; D019204:GTP-Binding Proteins; D020727:ADP-Ribosylation Factors