Regulatory proteins of R-Ras, TC21/R-Ras2, and M-Ras/R-Ras3.
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.
Ohba
Y
Y
Department of Pathology, Research Institute, International Medical Center of Japan, 1-21-1 Toyama, Shinjuku-ku, Tokyo 182-8655, Japan.
Mochizuki
N
N
Yamashita
S
S
Chan
A M
AM
Schrader
J W
JW
Hattori
S
S
Nagashima
K
K
Matsuda
M
M
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D018076:DNA, Complementary / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000096:biosynthesis / Q000737:chemistry* / Q000145:classification; D020690:GTPase-Activating Proteins / Q000737:chemistry / Q000494:pharmacology; D015723:Gene Library; D005982:Glutathione Transferase / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000145:classification; D051379:Mice; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000145:classification; D010957:Plasmids; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013997:Time Factors; D014162:Transfection; D018631:ras Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000145:classification
D018076:DNA, Complementary; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D008565:Membrane Proteins; D005982:Glutathione Transferase; C087360:RRAS2 protein, human; C490200:Rras2 protein, mouse; D020558:GTP Phosphohydrolases; C109418:Mras protein, mouse; C085929:RRAS protein, human; C513254:Rras protein, mouse; D020559:Monomeric GTP-Binding Proteins; D018631:ras Proteins