Dominant-negative mutant of BIG2, an ARF-guanine nucleotide exchange factor, specifically affects membrane trafficking from the trans-Golgi network through inhibiting membrane association of AP-1 and GGA coat proteins.
BIG2 is one of the guanine nucleotide exchange factors (GEFs) for the ADP-ribosylation factor (ARF) family of small GTPases, which regulate membrane association of COPI and AP-1 coat protein complexes and GGA proteins. Brefeldin A (BFA), an ARF-GEF inhibitor, causes redistribution of the coat proteins from membranes to the cytoplasm and membrane tubulation of the Golgi complex and the trans-Golgi network (TGN). We have recently shown that BIG2 overexpression blocks BFA-induced redistribution of the AP-1 complex but not TGN membrane tubulation. In the present study, we constructed a dominant-negative BIG2 mutant and found that when expressed in cells it induced redistribution of AP-1 and GGA1 and membrane tubulation of the TGN. By contrast, the mutant did not induce COPI redistribution or Golgi membrane tubulation. These observations indicate that BIG2 is involved in trafficking from the TGN by regulating membrane association of AP-1 and GGA through activating ARF.
Shinotsuka
Chisa
C
Institute of Biological Sciences and Gene Research Center, University of Tsukuba, Tsukuba Science City, Ibaraki 305-8572, Japan.
Waguri
Satoshi
S
Wakasugi
Masaki
M
Uchiyama
Yasuo
Y
Nakayama
Kazuhisa
K
D020727:ADP-Ribosylation Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D033942:Adaptor Proteins, Vesicular Transport; D019943:Amino Acid Substitution; D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D020126:Brefeldin A / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D020755:Coat Protein Complex I / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D005799:Genes, Dominant; D020662:Guanine Nucleotide Exchange Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D051381:Rats; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014162:Transfection; D021601:trans-Golgi Network / Q000187:drug effects / Q000378:metabolism*
C119088:ARFGEF2 protein, human; D033942:Adaptor Proteins, Vesicular Transport; D002352:Carrier Proteins; D020755:Coat Protein Complex I; C407306:GGA adaptor proteins; D020662:Guanine Nucleotide Exchange Factors; D046911:Macromolecular Substances; D008565:Membrane Proteins; D018808:Transcription Factor AP-1; D020126:Brefeldin A; D020727:ADP-Ribosylation Factors