A novel GTPase-activating protein for R-Ras

Takaharu Yamamoto, Takeshi Matsui, Masato Nakafuku, Akihiro Iwamatsu, Kozo Kaibuchi

研究成果: Article査読

54 被引用数 (Scopus)


R-Ras, belonging to the Ras small GTP-binding protein superfamily, has been implicated in regulation of various cell functions such as gene expression, cell proliferation, and apoptotic cell death. In the present study, we purified an R-Ras-interacting protein with molecular mass of about 98 kDa (p98) from bovine brain cytosol by glutathione S-transferase (GST)-R- Ras affinity column chromatography. This protein bound to GTPγS (guanosine 5'-(3-O-thio)triphosphate, a nonhydrolyzable GTP analog)·R-Ras but not to GDP·R-Ras, GTPγS·R-Ras with a mutation in the effector domain (R- Ras(A64)), GTPγS·Ha-Ras, or GTPγS·RalA. We obtained a cDNA encoding p98 on the basis of its partial amino acid sequences. The predicted protein consists of 834 amino acids whose calculated mass, 95,384 Da, is close to the apparent molecular mass of p98. The amino acid sequence shows a high degree of sequence similarity to the entire sequence of Gap1m, one of the GTPase- activating proteins (GAP) for Ha-Ras. A recombinant protein consisting of the GAP-related domain of p98 fused to maltose-binding protein stimulated GTPase activity of R-Ras, and showed a weak effect on that of Ha-Ras but not that of Rap1 or Rho. These results clearly indicate that p98 is a novel GAP for R- Ras. Thus, we designated this protein as R-Ras GAP.

ジャーナルJournal of Biological Chemistry
出版ステータスPublished - 22-12-1995

All Science Journal Classification (ASJC) codes

  • 生化学
  • 分子生物学
  • 細胞生物学


「A novel GTPase-activating protein for R-Ras」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。