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Critical Reviews™ in Eukaryotic Gene Expression

Impact factor: 1.660

ISSN Print: 1045-4403
ISSN Online: 2162-6502

Critical Reviews™ in Eukaryotic Gene Expression

DOI: 10.1615/CritRevEukarGeneExpr.v15.i3.70
pages 255-276

Signal Transduction and Actin in the Regulation of G1-Phase Progression

Johannes Boonstra
Department of Cell Architecture and Dynamics, Institute of Biomembranes, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands
Maarten J. A. Moes
Department of Cell Architecture and Dynamics, Institute of Biomembranes, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands

ABSTRACT

Regulation of cell proliferation is dependent on the integration of signal transduction systems that are activated by external signal molecules, such as growth factors and extracellular matrix components. Dependent on these signal transduction networks, the cells decide in the G1 phase to continue proliferation or, alternatively, to stop cell-cycle progression and undergo apoptosis, differentiation, or quiescence. The MAP kinase and PI-3 kinase pathways have been demonstrated to play an essential role in these G1-phase decisions. Interestingly, actin has been demonstrated to mutually interfere with signal transduction. In addition, it has been indicated that the FOXO transcription factors are involved in these decisions, as well. Actin has been demonstrated to play an important role in the regulation of G1-phase progression. Because of its properties as a structural protein, actin is essential in cytokinesis and in cell spreading and, thus, is involved in G1-phase progression. As an intermediate factor in signal transduction, actin is likely to be involved in cell-cycle regulation induced by external signal molecules. And, finally, actin has been demonstrated to play a direct role in transcription. These observations indicate a prominent role of actin in the regulation of G1-phase progression.