Dominant inhibitory mutants of ARF1 block endoplasmic reticulum to Golgi transport and trigger disassembly of the Golgi apparatus.
Using three different trans dominant mutants of bovine ARF1 affecting GDP exchange or GTP hydrolysis we demonstrate the central role of ARF1 in controlling vesicular traffic from the endoplasmic reticulum (ER) to the Golgi apparatus and between successive Golgi compartments. Overexpression of ARF1(Q71L), a mutant likely to be restricted to the GTP-bound form, resulted in the accumulation of vesicular stomatitis virus glycoprotein in pre-Golgi intermediates, inhibited transport between successive Golgi compartments, and led to a striking association of beta-COP with pre-Golgi intermediates and the Golgi stack. In contrast, ARF1(T31N), a mutant which is likely to have a preferential affinity for GDP compared to the wild-type protein, inhibited export from the ER and triggered a brefeldin A-like phenotype, resulting in the redistribution of beta-COP from Golgi membranes to the cytosol and the collapse of the Golgi into the ER. This mutant, which may efficiently sequester an ARF-specific guanine nucleotide-exchange protein (ARF-GEF), suggests that ARF and ARF-GEF are essential for export from the ER. These results are discussed in the context of the GDP and GTP-bound forms of ARF in controlling both membrane structure and vesicular traffic through the early secretory pathway.
Dascher
C
C
Department of Cell and Molecular Biology, Scripps Research Institute, La Jolla, California 92037.
Balch
W E
WE
D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors; D000818:Animals; D001483:Base Sequence; D001692:Biological Transport; D002417:Cattle; D003001:Cloning, Molecular; D020756:Coatomer Protein; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005799:Genes, Dominant; D006023:Glycoproteins / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D006160:Guanosine Triphosphate / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008562:Membrane Glycoproteins; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D013329:Structure-Activity Relationship; D014162:Transfection; D014759:Viral Envelope Proteins / Q000378:metabolism
D020756:Coatomer Protein; C028391:G protein, vesicular stomatitis virus; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D008869:Microtubule-Associated Proteins; D009838:Oligodeoxyribonucleotides; D011498:Protein Precursors; D014759:Viral Envelope Proteins; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors