Adaptor protein Nck in p120 RasGAP regulation.

Mindaugas Valius, Proteomics Centre, Vilnius, Lithuania

Marija Ger, Nadezda Sumilova, Austeja Androsiunaite, Mindaugas Valius

Small Ras GTPases are well-known regulators of various MAP kinases. The balance of GTP- and GDP-bound Ras is maintained by various GEF and GAP family proteins. Although GEF-dependent branch of positive regulation is elucidated in details, GAP-dependent branch and down-regulation of Ras GTPase activity is less investigated. We have demonstrated that negative regulator of Ras, p120 RasGAP associate with adaptor protein Nck. In this presentation the molecular mechanism of p120 RasGAP-Nck complex formation, intracellular localization and the role in regulation of p120 RasGAP catalytic activity will be demonstrated. The data suggest that adaptor proteins are involved in the control of not only GEF but also GAP branch of Ras regulators.