Figure 6.

JNK1α1 has an antiapoptotic function. (A) Knockdown of JNK1α1 in Colo205 cells by JNK1α1 shRNA expression plasmid. Cells were nucleofected with JNK1α1 or scrambled shRNA expression plasmids. Total RNA was isolated 24 h after transfection and JNK expression was detected with primers detecting all JNK1 mRNA isoforms or primers specific to JNK1α1 or JNK1β1 isoforms. (B) Western blot analysis of the expression of the short (JNK1α1 and β1) and long (JNK1α2 and β2) isoforms of JNK1 in JNK1α1 shRNA expressing cells. (C) Knockdown of JNK1α1 increases apoptosis induced by selective activation of DR4 or DR5. Colo205 cells were treated with agonistic DR4/5 antibodies (5 nM) or rhTRAIL (20 ng ml⁻¹) for 3 h, after which percentage of apoptotic cells was determined with Annexin V. The graph shows the average cell death induced±s.e.m. of five independent experiments (sum of Ann V⁺/PI⁻ and Ann V⁺/PI⁺ percentages). The ^* indicates significant differences (P<0.05).