title: Guanine nucleotide exchange factor-H1 regulates cell migration via localized activation of RhoA at the leading edge.
abstract: Cell migration involves the cooperative reorganization of the actin and microtubule cytoskeletons, as well as the turnover of cell-substrate adhesions, under the control of Rho family GTPases. RhoA is activated at the leading edge of motile cells by unknown mechanisms to control actin stress fiber assembly, contractility, and focal adhesion dynamics. The microtubule-associated guanine nucleotide exchange factor (GEF)-H1 activates RhoA when released from microtubules to initiate a RhoA/Rho kinase/myosin light chain signaling pathway that regulates cellular contractility. However, the contributions of activated GEF-H1 to coordination of cytoskeletal dynamics during cell migration are unknown. We show that small interfering RNA-induced GEF-H1 depletion leads to decreased HeLa cell directional migration due to the loss of the Rho exchange activity of GEF-H1. Analysis of RhoA activity by using a live cell biosensor revealed that GEF-H1 controls localized activation of RhoA at the leading edge. The loss of GEF-H1 is associated with altered leading edge actin dynamics, as well as increased focal adhesion lifetimes. Tyrosine phosphorylation of focal adhesion kinase and paxillin at residues critical for the regulation of focal adhesion dynamics was diminished in the absence of GEF-H1/RhoA signaling. This study establishes GEF-H1 as a critical organizer of key structural and signaling components of cell migration through the localized regulation of RhoA activity at the cell leading edge.
authors.affiliation: Departments of Immunology and Microbial Science, and Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, USA. perihan.nalbant@uni-due.de
authors.forename: Perihan
authors.initials: P
authors.lastname: Nalbant
authors.forename: Yuan-Chen
authors.initials: YC
authors.lastname: Chang
authors.forename: Jörg
authors.initials: J
authors.lastname: Birkenfeld
authors.forename: Zee-Fen
authors.initials: ZF
authors.lastname: Chang
authors.forename: Gary M
authors.initials: GM
authors.lastname: Bokoch
mesh_terms: D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D002465:Cell Movement; D004789:Enzyme Activation; D022001:Focal Adhesions / Q000201:enzymology; D000080865:Formins; D020662:Guanine Nucleotide Exchange Factors / Q000172:deficiency / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D011554:Pseudopodia / Q000201:enzymology*; D064067:Rho Guanine Nucleotide Exchange Factors; D015398:Signal Transduction; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: C577356:ARHGEF2 protein, human; D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; C108962:DIAPH1 protein, human; D000080865:Formins; D020662:Guanine Nucleotide Exchange Factors; D064067:Rho Guanine Nucleotide Exchange Factors; D019000:Phosphotyrosine; D020742:rhoA GTP-Binding Protein