P-Rex2, a new guanine-nucleotide exchange factor for Rac

FEBS Lett. 2004 Aug 13;572(1-3):172-6. doi: 10.1016/j.febslet.2004.06.096.


We have identified a new guanine-nucleotide exchange factor, P-Rex2, and cloned it from human skeletal muscle and brain libraries. It has widespread tissue distribution but is not expressed in neutrophils. P-Rex2 is a 183 kDa protein that activates the small GTPase Rac and is regulated by phosphatidylinositol (3,4,5)-trisphosphate and the beta gamma subunits of heterotrimeric G proteins in vitro and in vivo. P-Rex2 has structure, activity and regulatory properties similar to P-Rex1 but has divergent tissue distribution, as P-Rex1 is mainly expressed in neutrophils. Together, they form an enzyme family capable of mediating Rac signalling downstream of G protein-coupled receptors and phosphoinositide 3-kinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Northern
  • Cloning, Molecular
  • Gene Library
  • Heterotrimeric GTP-Binding Proteins / metabolism
  • Humans
  • Inositol 1,4,5-Trisphosphate / metabolism
  • Organ Specificity
  • Protein Subunits / metabolism
  • Recombinant Proteins / metabolism
  • rac GTP-Binding Proteins / genetics
  • rac GTP-Binding Proteins / metabolism*


  • Protein Subunits
  • Recombinant Proteins
  • Inositol 1,4,5-Trisphosphate
  • Heterotrimeric GTP-Binding Proteins
  • rac GTP-Binding Proteins