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Tuesday 2 December 2003

Members of the RAS superfamily of small GTP-binding proteins, as RAC1, appear to regulate a diverse array of cellular events, including the control of cell growth, cytoskeletal reorganization, and the activation of protein kinases (PKs).

Anchorage dependence of growth blocks cell proliferation in inappropriate environments, thereby inhibiting cancer cell invasion and metastasis. Inhibition of growth regulatory pathways, including Rac, Erk and PtdIns 3-kinase in non-adherent cells mediates this effect.

Rho GTPases

Rho GTPases control a variety of cellular processes. There are 3 subtypes of Rho GTPases in the Ras superfamily of small G proteins: RHO (MIM.165370), RAC (RAC1) (MIM.602048), and CDC42 (MIM.116952).

GTPase-activating proteins (GAPs) bind activated forms of Rho GTPases and stimulate GTP hydrolysis. Through this catalytic function, Rho GAPs negatively regulate Rho-mediated signals. GAPs may also serve as effector molecules and play a role in signaling downstream of Rho and other Ras-like GTPases.

See also

- integrin-mediated adhesion
- cholesterol-enriched membrane domains
- endocytosis
- caveolae
- caveolin-1
- integrins


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- Del Pozo MA, Schwartz MA. Rac, membrane heterogeneity, caveolin and regulation of growth by integrins. Trends Cell Biol. 2007 Mar 14; PMID: 17363257

- Sherman LS, Gutmann DH. Merlin : hanging tumor suppression on the Rac. Trends Cell Biol. 2001 Nov ;11(11):442-4. PMID : 11684412