FAK, PDZ-RhoGEF and ROCKII cooperate to regulate adhesion movement and trailing-edge retraction in fibroblasts.
A key step in cell migration is the dynamic formation and disassembly of adhesions at the front and the concomitant movement and release of adhesions in the rear of the cell. Fibroblasts maintained in the absence of serum have stable adhesions within the rear of the cell and exhibit reduced trailing-edge retraction resulting in an elongated cell phenotype. Addition of lysophosphatidic acid (LPA) induced the movement of adhesions and retraction of the trailing edge, thus mimicking tail retraction in a migrating cell. Focal adhesion kinase (FAK), guanine nucleotide exchange factors (GEF) for Rho and the Rho effector Rho kinase II (ROCKII) are crucial for the regulation of adhesion movement and trailing-edge retraction. Downregulation of FAK by small interfering RNAs or small hairpin RNAs blocked LPA-induced adhesion movement and restoration of cell shape. This phenotype was rescued by the ectopic expression of PDZ-RhoGEF or a RhoA-effector-domain mutant that activates ROCK. Knockdown of PDZ-RhoGEF or ROCKII inhibited LPA-induced trailing-edge retraction and adhesion movement. Moreover, overexpressed PDZ-RhoGEF co-immunoprecipitated with FAK and localized to FAK-containing adhesions. These studies support a model in which FAK and PDZ-RhoGEF cooperate to induce Rho/ROCKII-dependent focal adhesion movement and trailing-edge retraction in response to LPA.
Iwanicki
Marcin P
MP
Department of Microbiology, University of Virginia Health System, Charlottesville, VA 22908, USA.
Vomastek
Tomas
T
Tilghman
Robert W
RW
Martin
Karen H
KH
Banerjee
Jayashree
J
Wedegaertner
Philip B
PB
Parsons
J Thomas
JT
D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D002465:Cell Movement; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006801:Humans; D008246:Lysophospholipids / Q000494:pharmacology; D051379:Mice; D041681:NIH 3T3 Cells; D010641:Phenotype; D064067:Rho Guanine Nucleotide Exchange Factors; D015398:Signal Transduction; D054460:rho-Associated Kinases / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
C577234:ARHGEF11 protein, human; D020662:Guanine Nucleotide Exchange Factors; D008246:Lysophospholipids; C523071:PDZ-RhoGEF, rat; D064067:Rho Guanine Nucleotide Exchange Factors; D051416:Focal Adhesion Protein-Tyrosine Kinases; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein; C032881:lysophosphatidic acid