Purification and characterization from rat liver cytosol of a GDP dissociation inhibitor (GDI) for liver 24K G, a ras p21-like GTP-binding protein, with properties similar to those of smg p25A GDI.
A regulatory protein for a liver GTP-binding protein (G protein) with a molecular weight value of 24,000 (24K G), which we have recently purified, was purified to near-homogeneity from rat liver cytosol and characterized. This regulatory protein, designated here as GDP dissociation inhibitor for 24K G (24K G GDI), inhibited the dissociation of GDP from and the subsequent binding of GTP to 24K G. 24K G GDI was inactive for other ras p21/ras p21-like small G proteins including c-Ha-ras p21, rhoB p20, smg p21B, and smg p25A. 24K G was, however, recognized by bovine brain smg p25A GDI which regulated the GDP/GTP exchange reaction of smg p25A. By analyses of sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), immunoblotting with anti-smg p25A GDI antibody, two-dimensional PAGE, and C4 column chromatography, 24K G GDI showed physical properties very similar to those of smg p25A GDI. The peptide map and the partial amino acid sequences of 24K G GDI were not identical with those of smg p25A GDI. Among the 83 residues, 2 amino acids were different between rat liver 24K G GDI and bovine brain smg p25A GDI. These results indicate that there is a specific regulatory protein for 24K G, 24K G GDI, in rat liver cytosol and that 24K G GDI has close similarity to smg p25A GDI.
Ueda
T
T
Department of Surgery (1st Division), Kobe University School of Medicine, Japan.
Takeyama
Y
Y
Ohmori
T
T
Ohyanagi
H
H
Saitoh
Y
Y
Takai
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D000837:Anion Exchange Resins; D001923:Brain Chemistry; D002417:Cattle; D002499:Centrifugation, Density Gradient; D002845:Chromatography; D003600:Cytosol / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D020730:Guanine Nucleotide Dissociation Inhibitors; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010449:Peptide Mapping; D016283:Proto-Oncogene Proteins p21(ras) / Q000737:chemistry; D051381:Rats; D011919:Rats, Inbred Strains; D012117:Resins, Synthetic; D020692:rab3 GTP-Binding Proteins; D020668:rap GTP-Binding Proteins; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors
D000837:Anion Exchange Resins; D020730:Guanine Nucleotide Dissociation Inhibitors; D012117:Resins, Synthetic; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C042855:Mono Q; D019204:GTP-Binding Proteins; D016283:Proto-Oncogene Proteins p21(ras); D020692:rab3 GTP-Binding Proteins; D020668:rap GTP-Binding Proteins