Regulation of small GTPase activity by G1 cyclins.
Neus Pedraza, Tània Cemeli, Ma Ventura Monserrat, Eloi Garí, Francisco Ferrezuelo
Author Information
Neus Pedraza: a Cell Cycle Lab, Institut de Recerca Biomèdica de Lleida (IRBLleida) , and Departament de Ciències Mèdiques Bàsiques , Facultat de Medicina, Universitat de Lleida , Lleida , Catalonia , Spain.
Tània Cemeli: a Cell Cycle Lab, Institut de Recerca Biomèdica de Lleida (IRBLleida) , and Departament de Ciències Mèdiques Bàsiques , Facultat de Medicina, Universitat de Lleida , Lleida , Catalonia , Spain.
Ma Ventura Monserrat: a Cell Cycle Lab, Institut de Recerca Biomèdica de Lleida (IRBLleida) , and Departament de Ciències Mèdiques Bàsiques , Facultat de Medicina, Universitat de Lleida , Lleida , Catalonia , Spain.
Eloi Garí: a Cell Cycle Lab, Institut de Recerca Biomèdica de Lleida (IRBLleida) , and Departament de Ciències Mèdiques Bàsiques , Facultat de Medicina, Universitat de Lleida , Lleida , Catalonia , Spain.
Francisco Ferrezuelo: a Cell Cycle Lab, Institut de Recerca Biomèdica de Lleida (IRBLleida) , and Departament de Ciències Mèdiques Bàsiques , Facultat de Medicina, Universitat de Lleida , Lleida , Catalonia , Spain.
Together with a cyclin-dependent kinase (CDK) partner G1 cyclins control cell cycle entry by phosphorylating a number of nuclear targets and releasing a transcriptional program at the end of G1 phase. yeast G1 cyclins also operate on cytoplasmic targets involved in the polarization of the cytoskeleton and vesicle trafficking. These processes are mainly controlled by the small GTPase Cdc42, and G1 cyclins regulate the activity of this and other small GTPases through the modulation of their regulators and effectors. This regulation is key for different developmental outcomes in unicellular organisms. In mammalian cells cytoplasmic G1 cyclin D1 has been shown to promote the activity of Rac1 and Ral GTPases and to block RhoA. Regulation of these small GTPases by G1 cyclins may constitute a mechanism to coordinate proliferation with cell migration and morphogenesis, important processes not only during normal development and organogenesis but also for tumor formation and metastasis. Here we briefly review the evidence supporting a role of G1 cyclins and CDKs as regulators of the activity of small GTPases, emphasizing their functional relevance both in budding yeast and in mammalian cells.
