Regulatory proteins of R-Ras, TC21/R-Ras2, and M-Ras/R-Ras3

J Biol Chem. 2000 Jun 30;275(26):20020-6. doi: 10.1074/jbc.M000981200.

Abstract

We studied the regulation of three closely related members of Ras family G proteins, R-Ras, TC21 (also known as R-Ras2), and M-Ras (R-Ras3). Guanine nucleotide exchange of R-Ras and TC21 was promoted by RasGRF, C3G, CalDAG-GEFI, CalDAG-GEFII (RasGRP), and CalDAG-GEFIII both in 293T cells and in vitro. By contrast, guanine nucleotide exchange of M-Ras was promoted by the guanine nucleotide exchange factors (GEFs) for the classical Ras (Ha-, K-, and N-), including mSos, RasGRF, CalDAG-GEFII, and CalDAG-GEFIII. GTPase-activating proteins (GAPs) for Ras, Gap1(m), p120 GAP, and NF-1 stimulated all of the R-Ras, TC21, and M-Ras proteins, whereas R-Ras GAP stimulated R-Ras and TC21 but not M-Ras. We did not find any remarkable difference in the subcellular localization of R-Ras, TC21, or M-Ras when these were expressed with a green fluorescent protein tag in 293T cells and MDCK cells. In conclusion, TC21 and R-Ras were regulated by the same GEFs and GAPs, whereas M-Ras was regulated as the classical Ras.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Line
  • DNA, Complementary / metabolism
  • Endoplasmic Reticulum / metabolism
  • GTP Phosphohydrolases / biosynthesis
  • GTP Phosphohydrolases / chemistry*
  • GTP Phosphohydrolases / classification
  • GTPase-Activating Proteins / chemistry
  • GTPase-Activating Proteins / pharmacology
  • Gene Library
  • Glutathione Transferase / metabolism
  • Golgi Apparatus / metabolism
  • Guanine Nucleotide Exchange Factors / chemistry
  • Guanine Nucleotide Exchange Factors / pharmacology
  • Humans
  • Membrane Proteins / biosynthesis
  • Membrane Proteins / chemistry*
  • Membrane Proteins / classification
  • Mice
  • Molecular Sequence Data
  • Monomeric GTP-Binding Proteins / biosynthesis
  • Monomeric GTP-Binding Proteins / chemistry*
  • Monomeric GTP-Binding Proteins / classification
  • Plasmids
  • Sequence Homology, Amino Acid
  • Spectrometry, Fluorescence
  • Temperature
  • Time Factors
  • Transfection
  • ras Proteins / biosynthesis
  • ras Proteins / chemistry*
  • ras Proteins / classification

Substances

  • DNA, Complementary
  • GTPase-Activating Proteins
  • Guanine Nucleotide Exchange Factors
  • Membrane Proteins
  • Glutathione Transferase
  • RRAS2 protein, human
  • Rras2 protein, mouse
  • GTP Phosphohydrolases
  • Mras protein, mouse
  • RRAS protein, human
  • Rras protein, mouse
  • Monomeric GTP-Binding Proteins
  • ras Proteins