Colocalization and coprecipitation of ankyrin and Na+,K+-ATPase in kidney epithelial cells.
Interactions between integral proteins of the plasma membrane and the cytoskeleton may be important for localizing certain membrane proteins in a nonrandom fashion at specialized domains of the cell surface. Here, we show that ankyrin, the key protein for the linkage of the erythrocyte anion exchanger (band 3) to the spectrin-based membrane cytoskeleton, is also present in kidney distal tubular cells where ankyrin is precisely colocalized with Na+,K+-ATPase. Both proteins are confined to the basolateral plasma membrane and are absent from the apical membrane, the junctional complex and the membrane surface that contacts the basal lamina. Purified Na+,K+-ATPase of sheep and pig kidney contains a binding site for erythrocyte ankyrin as demonstrated by immunoprecipitation experiments. A band 3-like binding site for ankyrin is likely, since binding of ankyrin to Na+,K+-ATPase could be inhibited in a competitive fashion by the isolated cytoplasmic domain of erythrocyte band 3.
Koob
R
R
Department of Anatomy and Cell Biology, University of Marburg/Federal Republic of Germany.
Zimmermann
M
M
Schoner
W
W
Drenckhahn
D
D
D000818:Animals; D017487:Ankyrins; D001798:Blood Proteins / Q000032:analysis*; D002462:Cell Membrane / Q000032:analysis / Q000201:enzymology; D011232:Chemical Precipitation; D004848:Epithelium / Q000032:analysis / Q000201:enzymology; D007684:Kidney Tubules / Q000032:analysis*; D007686:Kidney Tubules, Distal / Q000032:analysis* / Q000201:enzymology; D008565:Membrane Proteins / Q000032:analysis*; D008854:Microscopy, Electron; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis*
D017487:Ankyrins; D001798:Blood Proteins; D008565:Membrane Proteins; D000254:Sodium-Potassium-Exchanging ATPase