Analyses of M-ras/R-ras3 signaling and biology

Publisher Summary This chapter analyzes M-Ras/R-Ras3 signaling. The Ras subfamily of GTPases consists of about 19 members that share 40–98% identity with H-, K-, and N-Ras or each other. M-Ras (also referred to as R-Ras3 2 ) was originally cloned by rapid amplification of cDNA ends (RACE) as a GTPase expressed in a C2 myoblast cDNA library. It was also identified as a novel Ras-like sequence in the National Center for Biotechnology Information (NCBI) expressed sequence tag (EST) database. Finally, M-Ras was isolated by representational difference analysis as a gene induced by interleukin 9(IL-9) stimulation of helper T cell lines. Interestingly, M-Ras protein is broadly expressed, can be coimmunoprecipitated by the Ras monoclonal antibody Y 13-259, and is activated by known Ras guanine nucleotide exchange factors (GEFs) (Sos and guanine nucleotide release factor [GRF]). In addition, any studies using the dominant inhibitory mutant H-Ras (17N), which acts by titrating out GEFs, thus preventing their activation of endogenous Ras proteins, can also block M-Ras activation.