Both stimulatory and inhibitory GDP/GTP exchange proteins, smg GDS and rho GDI, are active on multiple small GTP-binding proteins

Biochem Biophys Res Commun. 1992 Jan 31;182(2):921-30. doi: 10.1016/0006-291x(92)91820-g.


Six peaks of small GTP-binding proteins (G proteins) were separated by column chromatographies from the cytosol fraction of the differentiated HL-60 cells: two peaks of rho p21, one peak of smg/rap1 p21, two peaks of rac1 p21, and one peak of an unidentified small G protein with a Mr of about 20,000 (20 KG). smg GDS, previously thought to be a stimulatory GDP/GTP exchange protein for smg p21, Ki-ras p21, and rho p21, but not for Ha-ras p21 or smg p25A, was also active on rac1 p21. rho GDI, previously thought to be an inhibitory GDP/GTP exchange protein specific for rho p21, was also active on rac1 p21. These results indicate that both smg GDS and rho GDI are active on multiple small G proteins.

Publication types

  • Comparative Study

MeSH terms

  • Cell Differentiation
  • Cell Line
  • Chromatography, Ion Exchange
  • Cytosol / metabolism
  • GTP-Binding Proteins / isolation & purification
  • GTP-Binding Proteins / metabolism*
  • Guanine Nucleotide Dissociation Inhibitors*
  • Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
  • Guanosine Diphosphate / metabolism
  • Humans
  • Immunoblotting
  • Kinetics
  • Leukemia, Promyelocytic, Acute
  • rap GTP-Binding Proteins
  • rho-Specific Guanine Nucleotide Dissociation Inhibitors


  • Guanine Nucleotide Dissociation Inhibitors
  • rho-Specific Guanine Nucleotide Dissociation Inhibitors
  • Guanosine Diphosphate
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • GTP-Binding Proteins
  • rap GTP-Binding Proteins