Back
Full-text
Journal article

The small GTP-binding protein Rac promotes the dissociation of gelsolin from actin filaments in neutrophils.

  • Arcaro A Institute of Biochemistry, University of Fribourg, CH-1700 Fribourg, Switzerland. arcaro@ludwig.ucl.ac.uk
  • 1998-02-14
Published in:
  • The Journal of biological chemistry. - 1998
Actins
Androstadienes
Animals
Calcium
Enzyme Inhibitors
GTP-Binding Proteins
Gelsolin
Guanine Nucleotide Exchange Factors
Guanosine 5'-O-(3-Thiotriphosphate)
Neutrophils
Phosphoinositide-3 Kinase Inhibitors
Proteins
Rabbits
Recombinant Proteins
Wortmannin
rac GTP-Binding Proteins
English Gelsolin is an actin filament-capping protein that has been shown to play a key role in cell migration. Here we have studied the involvement of phosphoinositide 3-kinase (PI 3-kinase) and GTP-binding proteins (G-proteins) in the regulation of gelsolin-actin interactions in neutrophils. Inhibition of PI 3-kinase activity in vivo by wortmannin did not affect the dissociation of actin-gelsolin (1:1) complexes induced by neutrophil stimulation with N-formyl-Met-Leu-Phe. Guanosine 5'-[gamma-thio]triphosphate (GTPgammaS) indirectly promoted the dissociation of actin-gelsolin complexes in a cell-free system using neutrophil cytosol, and this effect was blocked by the GDP dissociation inhibitor for Rho (Rho-GDI). The GTPgammaS-loaded ialpha2 and the beta1gamma2 subunits of heterotrimeric G-proteins (Gialpha2 and Gbeta1gamma2) also triggered actin-gelsolin dissociation in a Rho-GDI-sensitive manner. GTP-loaded activated Rac, but not activated Rho, induced the dissociation of cytosolic actin-gelsolin complexes. The guanine nucleotide exchange on Rac was increased by addition of GTPgammaS-loaded Gialpha2 or Gbeta1gamma2 to neutrophil cytosol. These findings suggest that activation of Rac by G-protein-coupled receptors in neutrophils triggers uncapping of actin filaments, independently of PI 3-kinase.
Language
  • English
Open access status
bronze
Identifiers
Persistent URL
https://sonar.ch/global/documents/289458
Statistics
Document views: 31 File downloads:
  • Full-text: 0