Figure 9.
Effect of lysosomal inhibitors on [Na+]i-dependent Na,K-ATPase cell surface expression in mpkCCDcl4 cells. Confluent mpkCCDcl4 cells grown on polycarbonate filters were first preincubated in the presence of either 15 or 135 mM Na+ without or with 10–6 M leupeptin or with 10–7 M choloroquine for 30 min at 37°C. After permeabilization by 1 μg/ml amphotericin B, cells were incubated for 1 h at 37°C. (A and B) Cell surface Na,K-ATPase was detected as described in the legend of Figure 2. (A) Representative immunoblot showing Na,K-ATPase cell surface expression. (B) Bars represent densitometric values expressed as the percentage of the optical density value measured in the presence of 15 mM Na+. Results are means ± SE from six independent experiments. *p < 0.05 vs. 15 mM Na+ values.