マツイ　タケシ   Takeshi Matsui   松井　毅    所属   応用生物学部 応用生物学科    職種   教授
言語種別	英語
発行・発表の年月	1995
形態種別	学術論文
査読	査読あり
標題	A novel GTPase-activating protein for R-Ras
執筆形態	共著
掲載誌名	Journal of Biological Chemistry
掲載区分	国外
巻・号・頁	270(51),pp.30557-30561
総ページ数	5
著者・共著者	Takaharu Yamamoto, Takeshi Matsui, Masato Nakafuku, Akihiro Iwamatsu, Kozo Kaibuchi
概要	R-Ras, belonging to the Ras small GTP-binding pro- tein superfamily, has been implicated in regulation of various cell functions such as gene expression, cell pro- liferation, 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 5γ-(3-O-thio)triphosphate, a nonhydrolyz- able GTP analog)・R-Ras but not to GDPγR-Ras, GTPγS・R- Ras with a mutation in the effector domain (R-RasA64), GTPγS・Ha-Ras, or GTPγS・RalA. We obtained a cDNA en- coding 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 pro- tein 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.