title: EphrinA1-EphA2 signal induces compaction and polarization of Madin-Darby canine kidney cells by inactivating Ezrin through negative regulation of RhoA.
abstract: The epithelial cells exhibit either a columnar or a flat shape dependent on extracellular stimuli or the cell-cell adhesion. Membrane-anchored ephrinA stimulates EphA receptor tyrosine kinases as a ligand in a cell-cell contact-dependent manner. The mechanism through which ephrinA1/EphA2 signal regulates the cell morphology remains elusive. We demonstrate here that ephrinA1/EphA2 signal induces compaction and enhanced polarization (columnar change) of Madin-Darby canine kidney epithelial cells by regulating Ezrin, a linker that connects plasma membrane and actin cytoskeleton. Activation of EphA2 resulted in RhoA inactivation through p190RhoGAP-A and subsequent dephosphorylation of Ezrin on Thr-567 phosphorylated by Rho kinase. Consistently, the cells expressing an active mutant of Ezrin in which Thr-567 was replaced with Asp did not change their shape in response to ephrinA1. Furthermore, depletion of Ezrin led to compaction and enhanced polarization without ephrinA1 stimulation, suggesting the role for active Ezrin in keeping the flat cell shape. Ezrin localized to apical domain irrespective of ephrinA1 stimulation, whereas phosphorylated Ezrin on the apical domain was reduced by ephrinA1 stimulation. Collectively, ephrinA1/EphA2 signal negatively regulates Ezrin and promotes the alteration of cell shape, from flat to columnar shape.
authors: Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.
authors: Yuki
authors: Y
authors: Wakayama
authors: Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan. Electronic address: miurako@ri.ncvc.go.jp.
authors: Koichi
authors: K
authors: Miura
authors: Department of Molecular Biology, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, 060-8638, Japan.
authors: Hisataka
authors: H
authors: Sabe
authors: Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan. Electronic address: nmochizu@ri.ncvc.go.jp.
authors: Naoki
authors: N
authors: Mochizuki
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D002450:Cell Communication; D048430:Cell Shape; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004285:Dogs; D036382:Ephrin-A1 / Q000378:metabolism*; D036383:Ephrin-A2 / Q000378:metabolism*; D004847:Epithelial Cells / Q000166:cytology; D058750:Epithelial-Mesenchymal Transition; D005786:Gene Expression Regulation; D010766:Phosphorylation; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*; D000099149:Ezrin
chemical_list: D003598:Cytoskeletal Proteins; D036382:Ephrin-A1; D036383:Ephrin-A2; D034741:RNA, Small Interfering; D020742:rhoA GTP-Binding Protein; D000099149:Ezrin