Detection of Epidermal Growth Factor Receptors and E‐Cadherins in the Basolateral Membrane of A431 Cells by Laser Scanning Fluorescence Microscopy

Abstract

We have examined the localization of epidermal growth factor (EGF) receptors and E‐cadherins in cultured A431 cells, an epidermoid carcinoma cell line, using a laser scanning fluorescence microscope. The fluorescence signals generated by monoclonal antihodies against EGF receptor and E‐cadherin were localized mainly in the cell‐cell contact sites, about 3 μm in width. When these areas for cell adhesion were scanned perpendicularly, fluorescence was detected from a point 4μ from the cell base for a distance of 8 μm towards the cell surface (about 16 μm from the cell base). These data suggest the subcellular localization of EGF receptors and E‐cadherins in the basolateral membrane of A431 cells.

β-Catenin Signaling in Fibroproliferative Disease

“…HGF not only promotes adherens junction disruption but is involved in E-cadherin endocytosis [55,56] and ␤-catenin release [57]. Epidermal growth factors (EGFs) signaling through the EGF receptor (EGFR), initiate changes in cell morphology [58] that are associated with EGFR co-localization with cadherin molecules at the cell membrane [58,59]. This co-localization induces tyrosine phosphorylation of ␤-catenin and destabilization of E-cadherin/␤-catenin complexes in adherens junctions [59,60], in turn resulting in cytoplasmic accumulation of tyrosine phosphorylated ␤-catenin.…”

Juxtacrine activation of EGFR regulates claudin expression and increases transepithelial resistance

“…In addition, proHB-EGF interacts with other integral membrane proteins, especially integrins, via the tetraspanin, CD9/DRAP27 (26,31). It is noteworthy that the HB-EGF-CD9-integrin complex and EGFR are both targeted to cell-cell junctions in polarized epithelial cells (13,31). In the mammalian kidney, HB-EGF expression is primarily localized to the collecting duct, the nephron segment with the highest TER (21).…”

Membrane-associated HB-EGF modulates HGF-induced cellular responses in MDCK cells

“…The transmembrane form of HB-EGF interacts with other integral membrane proteins, especially integrins, via the tetraspanin, CD9/DRAP27 (Lagaudriere-Gesbert et al, 1997;Nakamura et al, 1995). It is noteworthy that the HB-EGF-CD9-integrin complex and EGFR are both targeted to cell-cell junctions in some epithelial cells (Fukuyama and Shimizu, 1991;. HB-EGF also complexes with heparin sulfate proteoglycans (Paria et al, 1999).…”