Fig. 1.

Effect of triptolide (TP) on the expression of mitogen-activated protein kinase phosphatase-1 (MKP-1) in immortalized HT22 cells. Cells were treated with indicated concentrations of TP for 6 h. The cells that were transiently transfected with either MKP-1 small interfering RNA (MKP-1 siRNA; Lane 5) or MKP-1 gene (Lane 6) served as the controls for MKP-1 expression, and were cultured for 6 h. Expression of MKP-1 was examined by Western blot analysis with anti-MKP-1 antibody, as described in materials and methods. Representative Western blots of three independent experiments are shown.