HGF signaling regulates claudin-3 dynamics through its C-terminal tyrosine residues

Abstract

Claudin, HGF signaling, turnover, phosphorylation, cell-cell junctions, Tight Junction Abbreviations: HGF, Hepatocyte Growth Factor; MDCK, Madin Darby Canine Kidney; ERK2, Extracellular Signal-Regulated Kinase 2; PI3K, Phosphatidyl Inositol 3 Kinase; ZA, Zonula Adherens; NA, Nectin-based Adhesion; AJ, Adherens Junction; TJ, Tight Junction; CAM, Cell Adhesion Molecule; JAM, Junctional Adhesion Molecule; ZO, Zonula Occludens; FRAP, Fluorescence Recovery After Photobleaching; LAJ, Linear Adherens Junction; FAJ, Focal Adherens Junction; BFA, Brefeldin A; F-actin, Filamentous actin; GFP, Green Fluorescent Protein; ROCK, Rho-associated kinase; SILAC, Stable Isotope Labeling by Amino Acids in Cell Culture; EMT, Epithelial to Mesenchymal Transition; PDZ, Post synaptic density protein (PSD95), Drosophila disc large tumor suppressor (Dlg1), and Zonula Occludens-1 protein (ZO-1) The hormone hGF regulates morphogenesis and regeneration of multiple organs and increased hGF signaling is strongly associated with metastatic cancer. at the cellular level, one of the distinct effects of hGF is the de-stabilization of cell-cell junctions. several molecular mechanisms have been shown to be involved that mostly culminate at the e-cad-herin adhesion complex. One of the key determinants in hGF-driven morphological changes is the actomyosin cyto-skeleton whose organization and physical parameters changes upon stimulation. here we have investigated how hGF affects the different actomyosin-associated cell-cell junction complexes, Nectin Junctions, adherens Junctions and Tight Junctions in MDcK cells. We find that components of all complexes stay present at cell-cell contacts until their physical dissociation. We find that at cell-cell junctions, the mobility of claudin-3, but not that of other cell-cell adhesion receptors, is affected by hGF. This depends on tyrosine residues that likely affect PDZ-domain interactions at the c-terminal tail of claudin-3, although their phosphorylation is not directly regulated by hGF. Thus we uncovered claudins as novel targets of hGF signaling at cell-cell junctions. © 2013 Landes Bioscience.