GEF-H1 modulates localized RhoA activation during cytokinesis under the control of mitotic kinases.
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.
Birkenfeld
Jörg
J
Departments of Immunology and Cell Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Nalbant
Perihan
P
Bohl
Benjamin P
BP
Pertz
Olivier
O
Hahn
Klaus M
KM
Bokoch
Gary M
GM
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*
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