Targeting of the SF/HGF receptor to the basolateral domain of polarized epithelial cells.
Scatter Factor, also known as Hepatocyte Growth Factor (SF/HGF), has pleiotropic functions including direct control of cell-cell and cell-substrate adhesion in epithelia. The subcellular localization of the SF/HGF receptor is controversial. In this work, the cell surface distribution of the SF/HGF receptor was studied in vivo in epithelial tissues and in vitro in polarized MDCK monolayers. A panel of monoclonal antibodies against the beta chain of the SF/HGF receptor stained the basolateral but not the apical surface of epithelia lining the lumen of human organs. Radiolabeled or fluorescent-tagged anti-receptor antibodies selectively bound the basolateral cell surface of MDCK cells, which form a polarized monolayer sealed by intercellular junctions, when grown on polycarbonate filters in a two-chamber culture system. The receptor was concentrated around the cell-cell contact zone, showing a distribution pattern overlapping with that of the cell adhesion molecule E-cadherin. The basolateral localization of the SF/HGF receptor was confirmed by immunoprecipitation after domain selective cell surface biotinylation. When cells were fully polarized the SF/HGF receptor became resistant to non-ionic detergents, indicating interaction with insoluble component(s). In pulse-chase labeling and surface biotinylation experiments, the newly synthesized receptor was found exclusively at the basolateral surface. We conclude that the SF/HGF receptor is selectively exposed at the basolateral plasma membrane domain of polarized epithelial cells and is targeted after synthesis to that surface by direct delivery from the trans-Golgi network.
Crepaldi
T
T
Dipartimento di Scienze Biomediche e Oncologia, Università di Torino, Italia.
Pollack
A L
AL
Prat
M
M
Zborek
A
A
Mostov
K
K
Comoglio
P M
PM
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001710:Biotin; D002460:Cell Line; D016764:Cell Polarity; D004285:Dogs; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D017228:Hepatocyte Growth Factor / Q000378:metabolism*; D006801:Humans; D008856:Microscopy, Fluorescence; D019859:Proto-Oncogene Proteins c-met; D020794:Receptor Protein-Tyrosine Kinases / Q000276:immunology / Q000378:metabolism*; D012995:Solubility
D000911:Antibodies, Monoclonal; D017228:Hepatocyte Growth Factor; D001710:Biotin; D019859:Proto-Oncogene Proteins c-met; D020794:Receptor Protein-Tyrosine Kinases