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

• Published in: Biochemical and biophysical research communications 2002-06, Vol.294 (2), p.254-260
• Main Authors: Shinotsuka, Chisa, Waguri, Satoshi, Wakasugi, Masaki, Uchiyama, Yasuo, Nakayama, Kazuhisa
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Vesicular Transport; ADP-ribosylation factor; ADP-Ribosylation Factors - antagonists & inhibitors; ADP-Ribosylation Factors - genetics; ADP-Ribosylation Factors - metabolism; Amino Acid Substitution; Animals; AP-1; BIG2; Biological Transport - drug effects; Biological Transport - physiology; Brefeldin A - pharmacology; Carrier Proteins - metabolism; Cell Line; Coat Protein Complex I - metabolism; Endosome; Endosomes - metabolism; Genes, Dominant; GGA; Guanine nucleotide exchange factor; Guanine Nucleotide Exchange Factors - antagonists & inhibitors; Guanine Nucleotide Exchange Factors - genetics; Guanine Nucleotide Exchange Factors - metabolism; HeLa Cells; Hepatocytes - cytology; Hepatocytes - drug effects; Hepatocytes - metabolism; Humans; Kidney - cytology; Kidney - metabolism; Macromolecular Substances; Mannose 6-phosphate receptor; Membrane Proteins - metabolism; Protein Transport - drug effects; Protein Transport - physiology; Rats; trans-Golgi network; trans-Golgi Network - drug effects; trans-Golgi Network - metabolism; Transcription Factor AP-1 - metabolism; Transfection
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/S0006-291X(02)00456-4

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.