Effect of JNK1, v-Jun, and S63/73L c-Jun mutant on FUS expression. (A) HA-FUS expression (top row) in lysates of 293T cells transfected with WT HA-FUS alone (lanes 1 to 4) or with c-Jun (lanes 2 to 4), FLAG-tagged WT JNK1 (lane 3), or a FLAG-tagged dominant-negative JNK1 (lane 4). Phospho-c-Jun levels (second row) were detected using an anti-phospho-Jun antibody (Santa Cruz Biotechnology, Inc.). Total c-Jun levels (third row) were monitored using a mix (1:1) of polyclonal anti-c-Jun antibodies (Santa Cruz Biotechnology and Oncogene Sciences). Levels of exogenous JNK1 (fourth row) were detected using an anti-FLAG antibody (Sigma). (B) HA-FUS expression (top row) in lysates of 293T cells transfected with WT HA-FUS alone (lanes 1 to 4) or with v-Jun (lane 2), c-Jun (lane 3), or the transactivation-deficient S63/73L c-Jun mutant (lane 4). c-Jun and v-Jun levels (second row) were detected using the polyclonal anti-c-Jun antibodies mix described for panel A. HSP90 levels were monitored as control for equal loading.