Small GTPases, adhesion, cell cycle control and proliferation

In many cells, proliferation is under the coordinated control of growth factors and the extracellular matrix (ECM). Autocriny and anchorage-independent growth are observed in many transformed cells where this balance is often altered. The outside-in and inside-out exchanges are mediated by integrins, acting as molecular bridges between the ECM and the cytoskeleton. Integrins, as the major receptors for components of the ECM, are important not only for the physical aspects of cell adhesion, but also for two key aspects of cell fate: cell cycle progression, and apoptosis. The latter aspect will not be covered in the present analysis, which will rather focus on the data accumulated on Ras and Ras-related small GTPases such as Rho, Rac and Cdc42. (C) 2000 Editions scientifiques et medicales Elsevier SAS.