title: GEF-H1 modulates localized RhoA activation during cytokinesis under the control of mitotic kinases.
abstract: Formation of the mitotic cleavage furrow is dependent upon both microtubules and activity of the small GTPase RhoA. GEF-H1 is a microtubule-regulated exchange factor that couples microtubule dynamics to RhoA activation. GEF-H1 localized to the mitotic apparatus in HeLa cells, particularly at the tips of cortical microtubules and the midbody, and perturbation of GEF-H1 function induced mitotic aberrations, including asymmetric furrowing, membrane blebbing, and impaired cytokinesis. The mitotic kinases Aurora A/B and Cdk1/Cyclin B phosphorylate GEF-H1, thereby inhibiting GEF-H1 catalytic activity. Dephosphorylation of GEF-H1 occurs just prior to cytokinesis, accompanied by GEF-H1-dependent GTP loading on RhoA. Using a live cell biosensor, we demonstrate distinct roles for GEF-H1 and Ect2 in regulating Rho activity in the cleavage furrow, with GEF-H1 catalyzing Rho activation in response to Ect2-dependent localization and initiation of cell cleavage. Our results identify a GEF-H1-dependent mechanism to modulate localized RhoA activation during cytokinesis under the control of mitotic kinases.
authors.affiliation: Departments of Immunology and Cell Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
authors.forename: Jörg
authors.initials: J
authors.lastname: Birkenfeld
authors.forename: Perihan
authors.initials: P
authors.lastname: Nalbant
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Bohl
authors.forename: Olivier
authors.initials: O
authors.lastname: Pertz
authors.forename: Klaus M
authors.initials: KM
authors.lastname: Hahn
authors.forename: Gary M
authors.initials: GM
authors.lastname: Bokoch
mesh_terms: D064127:Aurora Kinases; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D048749:Cytokinesis; D015536:Down-Regulation / Q000235:genetics; D004789:Enzyme Activation; D020662:Guanine Nucleotide Exchange Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport; D064067:Rho Guanine Nucleotide Exchange Factors; D013347:Subcellular Fractions / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: C577356:ARHGEF2 protein, human; D020662:Guanine Nucleotide Exchange Factors; D064067:Rho Guanine Nucleotide Exchange Factors; D006160:Guanosine Triphosphate; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; D020742:rhoA GTP-Binding Protein