Differential localization of G-proteins, G alpha o and G alpha i-1, -2, and -3, in polarized epithelial MDCK cells.
MDCK cells were stably transfected with rat G alpha o cDNA and confluent polarized monolayers were analyzed by immunocytochemistry to compare the intracellular targeting of G alpha o with the localization of the endogenously expressed G alpha i subunits. Immunofluorescence confocal microscopy showed that G alpha o is targeted strictly to the lateral membrane. Immunolocalization of G alpha i-1, -2, and -3 showed that G alpha i-1 and -2 are confined to the cytoplasm and G alpha i-3 is found on the lateral membrane, in the cytoplasm, and faintly on the apical surface of these cells. Thus, the different pertussis toxin-sensitive G-proteins are differentially localized in polarized epithelial cells.
Hamilton
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Department of Pharmacology, University of Washington School of Medicine, Seattle 98195, USA.
Nathanson
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D000818:Animals; D000911:Antibodies, Monoclonal; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry*; D016764:Cell Polarity; D003593:Cytoplasm / Q000737:chemistry*; D018076:DNA, Complementary / Q000235:genetics; D004285:Dogs; D004848:Epithelium / Q000737:chemistry; D005455:Fluorescent Antibody Technique; D019204:GTP-Binding Proteins / Q000032:analysis* / Q000276:immunology; D015870:Gene Expression; D018390:Gene Targeting; D015151:Immunoblotting; D007668:Kidney; D018613:Microscopy, Confocal; D037342:Pertussis Toxin; D051381:Rats; D014162:Transfection; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins