Guanine nucleotide exchange factors: activators of the Ras superfamily of proteins

Bioessays. 1995 May;17(5):395-404. doi: 10.1002/bies.950170507.


Ras proteins function as critical relay switches that regulate diverse signaling pathways between cell surface receptors and the nucleus. Over the past 2-3 years researchers have identified many components of these pathways that mediate Ras activation and effector function. Among these proteins are several guanine nucleotide exchange factors (GEFs), which are responsible for directly interacting with and activating Ras in response to extracellular stimuli. Analogous GEFs regulate Ras-related proteins that serve other diverse cellular functions. In particular, a growing family of proteins (Dbl homology proteins) has recently been identified, which may function as GEFs for the Rho family of Ras-related proteins. This review summarizes our current knowledge of the structure, biochemistry and biology of Ras and Rho family GEFs. Additionally, we describe mechanisms of GEF activation of Ras in signal transduction and address the potential that deregulated GEFs might contribute to malignant transformation through chronic Ras protein activation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Guanine Nucleotide Exchange Factors
  • Humans
  • Proteins / chemistry
  • Proteins / metabolism*
  • Rho Factor / metabolism*
  • Signal Transduction
  • ras Guanine Nucleotide Exchange Factors
  • ras Proteins / chemistry
  • ras Proteins / metabolism*


  • Guanine Nucleotide Exchange Factors
  • Proteins
  • Rho Factor
  • ras Guanine Nucleotide Exchange Factors
  • ras Proteins