Coendocytosis of cadherin and c-Met coupled to disruption of cell-cell adhesion in MDCK cells – regulation by Rho, Rac and Rab small G proteins

Abstract

Both E-cadherin, a cell-cell adhesion molecule, and cMet, the hepatocyte growth factor (HGF)/scatter factor (SF) receptor, were colocalized at cell-cell adhesion sites of MDCK cells. HGF/SF or a phorbol ester, 12-Otetradecanoylphorbol-13-acetate (TPA), induced disruption of cell-cell adhesion, which was accompanied by endocytosis of both E-cadherin and c-Met. Reduction of medium Ca 2+ to a micromolar range showed the same e ects. Re-increase in medium Ca 2+ to a millimolar range formed cell-cell adhesion, which was accompanied by exocytosis of E-cadherin and c-Met, followed by their re-colocalization at the cell-cell adhesion sites. These results suggest that E-cadherin and c-Met are colocalized at cell-cell adhesion sites and undergo co-endo-exocytosis. We have previously shown that TPA does not induce disruption of cell-cell adhesion and subsequent scattering of MDCK cells stably expressing a dominant active mutant of RhoA or Rac1 small G protein or a dominant negative mutant of Rab5 small G protein. In these cell lines, the HGF-or TPA-induced coendocytosis of E-cadherin and c-Met was inhibited, but the coendocytosis of E-cadherin and c-Met in response to reduction of medium Ca 2+ was not a ected. Wortmannin, an inhibitor of phosphoinositide (PI) 3-kinase, inhibited the HGF-induced disruption of cell-cell junction and endocytosis of E-cadherin and c-Met, but not the TPA-induced ones. These results suggest that disruption of cell-cell adhesion is involved in the HGF-or TPAinduced coendocytosis of E-cadherin and c-Met in MDCK cells, and that the Rho and Rab family members indirectly regulate this coendocytosis. In addition, coendocytosis of E-cadherin and c-Met in response to HGF is partly mediated by PI 3-kinase. The cross-talk between cell-cell and cell-matrix adherens junctions is discussed.

Raf plus TGFβ-dependent EMT is initiated by endocytosis and lysosomal degradation of E-cadherin

“…It is also conceivable that liberation of E-cadherin during disruption of protein complexes forming adhesive junctions could indirectly enhance endocytosis and lysosomal degradation of E-cadherin. However, in several other systems, where endocytosis of E-cadherin was described, no downregulation of its levels was reported or documented (Kamei et al, 1999;Ivanov et al, 2004), suggesting that specific Raf-and TGFb-dependent mechanisms must regulate this process. In this report, we begin to identify these mechanisms.…”

Lysophosphatidic acid modulates c-Met redistribution and hepatocyte growth factor/c-Met signaling in human bronchial epithelial cells through PKC δ and E-cadherin

“…Co-localization of E-cadherin, a cell-cell adhesion molecule, and c-Met in cell-cell adhesion sites has been shown in MDCK cells [43]. In HBEpCs co-localization of E-cadherin and cMet in plasma membrane and cytoplasm were detected by double immunostaining with anti-E-cadherin and anti-c-Met antibodies.…”

Making and breaking contacts: the cellular biology of cadherin regulation

“…Indeed, cadherin adhesion itself appears to be one such factor. This was first suggested by the observation that cadherin internalisation increased when cell-cell contacts were broken by chelating extracellular calcium [3,20]. Similarly, EGF induced internalisation of E-cadherin by macropinocytosis in subconfluent, but not confluent, cultures [5].…”