| First Author | Miura K | Year | 2001 |
| Journal | J Biol Chem | Volume | 276 |
| Issue | 49 | Pages | 46276-83 |
| PubMed ID | 11560919 | Mgi Jnum | J:73177 |
| Mgi Id | MGI:2154655 | Doi | 10.1074/jbc.M102387200 |
| Citation | Miura K, et al. (2001) The Sos1-Rac1 signaling. Possible involvement of a vacuolar H(+)-ATPase E subunit. J Biol Chem 276(49):46276-83 |
| abstractText | We have purified and identified a 32-kDa protein interacting with the Dbl oncogene homology domain of mSos1(Sos-DH) from rat brains by glutathione S-transferase-Sos-DH affinity chromatography. Peptide sequencing revealed that the protein is identical to a positive regulatory E subunit (V-ATPase E) of a vacuolar H(+)-ATPase, which is responsible for acidification of endosome and alkalinization of intracellular pH. The interaction between V-ATPase E and Sos-DH was confirmed by yeast two-hybrid assay. A coimmunoprecipitation assay demonstrated that a V-ATPase E protein physiologically bound to mSos1, and the protein was colocalized with mSos1 in the cytoplasm, as determined by immunohistochemistry. mSos1 was found in the early endosome fraction together with V-ATPase E and Rac1, suggesting the functional involvement of mSos1/V-ATPase E complexes in the Rac1 activity at endosomes. Overexpression of V-ATPase E in COS cells enhanced the ability of mSos1 to promote the guanine nucleotide exchange activity for Rac1 and stimulated the kinase activity of Jun kinase, a downstream target of Rac1. Thus, the data indicate that V-ATPase E may participate in the regulation of the mSos1-dependent Rac1 signaling pathway involved in growth factor receptor-mediated cell growth control. |
