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GBF1: A novel Golgi-associated BFA-resistant guanine nucleotide exchange factor that displays specificity for ADP-ribosylation factor 5.
- Source :
-
The Journal of cell biology [J Cell Biol] 1999 Jul 12; Vol. 146 (1), pp. 71-84. - Publication Year :
- 1999
-
Abstract
- Expression cloning from a cDNA library prepared from a mutant CHO cell line with Golgi-specific resistance to Brefeldin A (BFA) identified a novel 206-kD protein with a Sec7 domain termed GBF1 for Golgi BFA resistance factor 1. Overexpression of GBF1 allowed transfected cells to maintain normal Golgi morphology and grow in the presence of BFA. Golgi- enriched membrane fractions from such transfected cells displayed normal levels of ADP ribosylation factors (ARFs) activation and coat protein recruitment that were, however, BFA resistant. Hexahistidine-tagged-GBF1 exhibited BFA-resistant guanine nucleotide exchange activity that appears specific towards ARF5 at physiological Mg2+concentration. Characterization of cDNAs recovered from the mutant and wild-type parental lines established that transcripts in these cells had identical sequence and, therefore, that GBF1 was naturally BFA resistant. GBF1 was primarily cytosolic but a significant pool colocalized to a perinuclear structure with the beta-subunit of COPI. Immunogold labeling showed highest density of GBF1 over Golgi cisternae and significant labeling over pleiomorphic smooth vesiculotubular structures. The BFA-resistant nature of GBF1 suggests involvement in retrograde traffic.
- Subjects :
- ADP-Ribosylation Factors
Amino Acid Sequence
Animals
Biological Transport drug effects
CHO Cells
Cell Division drug effects
Cloning, Molecular
Coatomer Protein
Cricetinae
Cytosol metabolism
Cytosol ultrastructure
Drug Resistance genetics
Fungal Proteins chemistry
Fungal Proteins metabolism
GTP-Binding Proteins chemistry
GTP-Binding Proteins genetics
Gene Expression
Golgi Apparatus drug effects
Golgi Apparatus ultrastructure
Guanine Nucleotide Exchange Factors
Humans
Intracellular Membranes metabolism
Intracellular Membranes ultrastructure
Magnesium pharmacology
Male
Membrane Proteins metabolism
Molecular Sequence Data
Proteins chemistry
Proteins genetics
Rats
Rats, Sprague-Dawley
Brefeldin A pharmacology
GTP-Binding Proteins metabolism
Golgi Apparatus metabolism
Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9525
- Volume :
- 146
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- The Journal of cell biology
- Publication Type :
- Academic Journal
- Accession number :
- 10402461