The nucleotide exchange rates of Rho and Rac small GTP-binding proteins are enhanced to different extents by their regulatory protein Smg GDS

Takuya Sasaki, Masaki Kato, Takayuki Nishiyama, Yoshimi Takai

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

Rho p21 and rac p21 small GTP-binding proteins are regulated by the same inhibitory and stimulatory GDP/GTP exchange proteins termed rho GDI and smg GDS, respectively. RhoA p21 and rac1 p21 bind with similar affinities to rho GDI and both proteins also bind with similar affinities to smg GDS. RhoA p21 and rac1 p21 have similar GDP/GTP exchange rates in the absence of rho GDI and smg GDS. The velocity of the GDP/GTP exchange reaction for rhoA p21 was enhanced much more by smg GDS than was the velocity of nucleotide exchange for rac1 p21. In the presence and absence of smg GDS, rho GDI reduced the velocities of these nucleotide exchange reactions of rhoA p21 and rac1 p21 to similar extents. These results suggest that rhoA p21 is activated first followed by rac1 p21 activation in response to extracellular signals.

Original languageEnglish
Pages (from-to)1188-1193
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume194
Issue number3
DOIs
Publication statusPublished - Aug 16 1993

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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