Revealing of Proteins Interacting with Na,K-ATPase

Proteins interacting with 11-type of Na,K-ATPase were revealed in pig kidney outer medulla and duck salt glands using three different methods (immunoprecipitation, protein overlay, and chemical cross-linking). Immunoprecipitation was performed after solubilization of protein homogenate with Triton X-100 so that both membrane and cytosol proteins bound to Na,K-ATPase could be revealed. Two other methods were used to study the interaction of cytosol proteins with purified Na,K-ATPase. The sets of proteins revealed by each method in outer medulla of pig kidney were different. Proteins interacting with Na,K-ATPase that have molecular masses 10, 15, 70, 75, 105, 120, and 190 kD were found using the immunoprecipitation method. The chemical cross-linking method revealed proteins with molecular masses 25, 35, 40, 58, 68-70, and 86-88 kD. The protein overlay method revealed in the same tissue proteins with molecular masses 38, 42, 43, 60, 62, 66, 70, and 94 kD.