Ezrin is an effector of hepatocyte growth factor-mediated migration and morphogenesis in epithelial cells.
The dissociation, migration, and remodeling of epithelial monolayers induced by hepatocyte growth factor (HGF) entail modifications in cell adhesion and in the actin cytoskeleton through unknown mechanisms. Here we report that ezrin, a membrane-cytoskeleton linker, is crucial to HGF-mediated morphogenesis in a polarized kidney-derived epithelial cell line, LLC-PK1. Ezrin is a substrate for the tyrosine kinase HGF receptor both in vitro and in vivo. HGF stimulation causes enrichment of ezrin recovered in the detergent-insoluble cytoskeleton fraction. Overproduction of wild-type ezrin, by stable transfection in LLC-PK1 cells, enhances cell migration and tubulogenesis induced by HGF stimulation. Overproduction of a truncated variant of ezrin causes mislocalization of endogenous ezrin from microvilli into lateral surfaces. This is concomitant with altered cell shape, characterized by loss of microvilli and cell flattening. Moreover, the truncated variant of ezrin impairs the morphogenic and motogenic response to HGF, thus suggesting a dominant-negative mechanism of action. Site-directed mutagenesis of ezrin codons Y145 and Y353 to phenylalanine does not affect the localization of ezrin at microvilli, but perturbs the motogenic and morphogenic responses to HGF. These results provide evidence that ezrin displays activities that can control cell shape and signaling.
Crepaldi
T
T
Institut Curie-UMR 144 Centre National de la Recherche Scientifique, Laboratoire de Morphogenèse et Signalisation Cellulaires, 75231 Paris Cedex 05, France.
Gautreau
A
A
Comoglio
P M
PM
Louvard
D
D
Arpin
M
M
D000818:Animals; D002450:Cell Communication; D002458:Cell Fractionation; D002465:Cell Movement / Q000502:physiology*; D016764:Cell Polarity; D048429:Cell Size; D003598:Cytoskeletal Proteins; D004847:Epithelial Cells; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D007684:Kidney Tubules / Q000254:growth & development; D018374:LLC-PK1 Cells / Q000166:cytology*; D008871:Microvilli; D009024:Morphogenesis; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D019859:Proto-Oncogene Proteins c-met; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D013552:Swine; D000099149:Ezrin
D003598:Cytoskeletal Proteins; D017228:Hepatocyte Growth Factor; D010750:Phosphoproteins; D019859:Proto-Oncogene Proteins c-met; D020794:Receptor Protein-Tyrosine Kinases; D000099149:Ezrin