Figure 4.

Expression of Na⁺,K⁺-ATPase α-subunit and activity in cells transiently transfected with different Pals-associated tight junction protein (PATJ) cDNA mutants. (A) Abundance of Na⁺,K⁺-ATPase (Na⁺,K⁺-ATPase α-subunit antibody) was examined in cell lysates obtained from opossum kidney (OK) cells expressing different PATJ deletion mutants by Western blot using antibodies against Na⁺,K⁺-ATPase (1:500). Equal amount of protein (50 µg) were loaded for each sample. (B) Functional relevance of PATJ during basal and (C) sodium-stimulated Na⁺,K⁺-ATPase activity (5 µM monensin for 30 min at room temperature). The studies were performed in OK cells expressing PATJ wild type (WT) and several deletion mutants. Each bar represents the mean + SEM of 8–11 independent experiments performed in triplicate determinations.