Effect of LCs on ERK1/2 and p38 MAPK (immunoblots on the left side of the panel with corresponding bar graphs of densitometric measurements next to each immunoblot panel.

<p>Panel <b>A</b> shows inhibition of light chain (LC)-stimulated phosphorylation of ERK ½, and panel <b>B</b>, inhibition of phosphorylation of p38 MAPK by RAP pretreatment. After 1-h pretreatment with 1 µM RAP human proximal tubule cells were exposed to LC for 4 h (representative blots from 3 different experiments are shown; “C (−)” = negative control; “C (+)” = positive control; bars represent mean ± SE of three densitometric readings). <b><i>A</i></b><i>:</i> Effect of RAP pretreatment on LC-induced activation of ERK1/2. Cells were pretreated with RAP for 1 h and then treated with LC in the continued presence of RAP for 4 h. <b><i>Top</i></b>: RAP inhibited LC-induced activation of ERK1/2 (LC 25 µM+RAP 1 µM vs. positive control, C (+), *P<0.001; LC 25 µM+RAP 1 µM vs. LC 25 µM alone, P<0.05; LC 25 µM+RAP 1 µM vs. LC 50 µM alone, P<0.01; LC 25 µM+RAP 1 µM compared to negative control, C (−), P>0.05, Newman-Keuls Multiple Comparison Test). <b><i>Bottom</i></b>: Total ERK was not affected. <b><i>B</i></b><i>:</i> Effect of RAP pretreatment on LC-induced activation of p38 MAPK. <i>Top:</i> LC-induced activation of p38 was suppressed by RAP (LC 25 µM+RAP 1 µM vs. C (+), P<0.001; LC 25 µM+RAP 1 µM vs. LC 50 µM alone, # P<0.001. LC 25 µM+RAP 1 µM vs. LC 25 µM alone, P<0.001; LC 25 µM+RAP 1 µM vs. C (−), P>0.05, Newman-Keuls Multiple Comparison Test). <b><i>Bottom</i></b>: Total p38 was not affected (representative blots from 3 different experiments are shown).