title: Glycogen synthase kinase-3 acts upstream of ADP-ribosylation factor 6 and Rac1 to regulate epithelial cell migration.
abstract: Cell sheet movement during epithelial wound closure is a complex process involving collective cell migration. We have found that glycogen synthase kinase-3 (GSK-3) activity is required for membrane protrusion and crawling of cells at the wound edge and those behind it in wounded Madin-Darby canine kidney (MDCK) epithelial cell monolayers. RNA interference-based silencing of GSK-3alpha and GSK-3beta expression also results in slowed cell sheet migration, with the effect being more pronounced with knockdown of GSK-3beta. Both GSK-3alpha and GSK-3beta are in activated states during the most active phase of cell migration. In addition to having a positive control or permissive, rather than negative, function in MDCK cell migration, GSK-3 appears to act upstream of the small GTPases ADP-ribosylation factor 6 (ARF6) and Rac1. Expression of constitutively active ARF6 restores a protrusive, migratory phenotype in cells treated with GSK-3 inhibitors. It does not, however, restore to normal levels the directional polarization of cells behind the wound edge toward the wound area, implying the existence of a separate ARF6-independent branch of the GSK-3 pathway that regulates proper wound-directed polarization of these cells. Finally, inhibition of GSK-3 also strongly reduces activation of Rac1 and cell scatter in response to hepatocyte growth factor/scatter factor, which triggers dispersal and migration of cells in monolayer culture as fibroblast-like individual cells, a mode of epithelial cell motility distinct from the collective migration of wound closure.
authors.affiliation: Department of Chemistry, University of Illinois, Chicago, IL 60607, USA.
authors.forename: Rizwan
authors.initials: R
authors.lastname: Farooqui
authors.forename: Shoutian
authors.initials: S
authors.lastname: Zhu
authors.forename: Gabriel
authors.initials: G
authors.lastname: Fenteany
mesh_terms: D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000378:metabolism*; D000627:Aminophenols / Q000494:pharmacology; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D022081:Cell Surface Extensions / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004285:Dogs; D004318:Doxycycline / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D008954:Models, Biological; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D000077191:Wortmannin; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
chemical_list: C417520:3-(3-chloro-4-hydroxyphenylamino)-4-(4-nitrophenyl)-1H-pyrrole-2,5-dione; D000089982:ADP-Ribosylation Factor 6; D000627:Aminophenols; D000730:Androstadienes; D004791:Enzyme Inhibitors; D008301:Maleimides; D000081082:Phosphoinositide-3 Kinase Inhibitors; D034741:RNA, Small Interfering; D017228:Hepatocyte Growth Factor; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3; C448021:glycogen synthase kinase 3 alpha; D020727:ADP-Ribosylation Factors; D020830:rac1 GTP-Binding Protein; D004318:Doxycycline; D000077191:Wortmannin