Ras Family

Research output: Chapter in Book/Report/Conference proceedingChapter

1 Scopus citations


Since its establishment as a guanosine triphosphate (GTP)-binding protein in 1979, Ras has become the prototype for a superfamily of approximately 150 GTPases that regulate a myriad of biological functions in eukaryotic cells. This superfamily can be subdivided based on primary sequence or biological function into five major subfamilies: Ras, Rho, Rab, Ran, and adenosine diphosphate ribosylation factor (ARF) plus outliers such as Rags. This article describes the 35-member Ras subfamily of proteins, including R-Ras, Ral, and Rap1, which regulate cell proliferation and differentiation. These proteins function as molecular switches, alternating between active GTP and inactive guanosine diphosphate (GDP)-bound conformations. Acquisition of the GTP-bound state and its hydrolysis to GDP are tightly regulated by guanine-nucleotide-exchange factors (GEFs) and GTPase-activating proteins (GAPs), respectively, which, in turn, receive direction from growth factor receptor-stimulated signal transduction pathways. Upon activation, Ras proteins bind specific downstream effector proteins, promoting their subcellular relocalization or conformational change. This results in their activation/transmission of a signal to induce biological events. Mutations in Ras that prevent GTP hydrolysis result in constitutive signaling to downstream effectors and promote uncontrolled cell growth. These mutations are found in many human cancers or can be created in Ras family proteins by researchers to probe their mechanism(s) of action.

Original languageEnglish (US)
Title of host publicationEncyclopedia of Biological Chemistry
Subtitle of host publicationSecond Edition
PublisherElsevier Inc.
Number of pages5
ISBN (Electronic)9780123786319
ISBN (Print)9780123786302
StatePublished - Feb 15 2013


  • GTPase-activating protein (GAP)
  • Guanine-nucleotide exchange factor (GEF)
  • M-Ras
  • R-Ras
  • RGK family
  • Ral
  • Rap1
  • Ras
  • Rheb
  • TC21

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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  • Cite this

    Quilliam, L. A. (2013). Ras Family. In Encyclopedia of Biological Chemistry: Second Edition (pp. 12-16). Elsevier Inc.. https://doi.org/10.1016/B978-0-12-378630-2.00322-4