Control of Rho family GTPases during cytokinesis

• Applicant: Professorin Dr. Esther Zanin
• Subject Area: Cell Biology
• Term: from 2009 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 123371423

Cytokinesis completes mitosis, dividing a single cell into two. To ensure that each daughter cell receives a single genomic complement, the cytokinetic furrow assembles in response to signals from the anaphase spindle, coupling cytokinesis to chromosome segregation. The anaphase spindle controls cortical remodeling by regulating the activity of members of the Rho family of small GTPases, which in turn control the structure and contractility of the actin-rich cortex. Signaling by the anaphase spindle generates an equatorial zone of active RhoA that directs the cortical accumulation of contractile ring components. In addition to activation of RhoA, recent work in my sponsor laboratory has shown that downregulation of the small GTPase Rac is also essential for furrow ingression during cytokinesis. To understand how the anaphase spindle coordinately regulates RhoA and Rac, I propose to develop probes to monitor their spatiotemporal activity in the Caenorhabditis elegans embryo. The C. elegans embryo has recently emerged as a powerful model system to study cell division because of the potential to combine advanced light microscopy with functional genomic approaches, biochemistry, and genetics. The active small GTPase probes will be used to distinguish between models for the function of two complexes that mediate communication between the spindle and cortex during cytokinesis. I will also use these probes to investigate the cross-talk between RhoA activation and Rac inactivation, and to examine the role of candidate small GTPase regulators in the control of cytokinesis.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Dr. Karen Oegema