Fig. 5.

Ectopic expression of Cot1 inhibits 1,25D-induced monocytic differentiation and represses the 1,25D-increased expression of KSR1 and hKSR2 protein. A: HL60 or U937 cells were stably transfected with either vector control, or with the IRES2-Cot1 vector, then 1 nM 1,25D was added for 48 h, and monocytic differentiation markers CD11b and CD14 were determined by flow cytometry. B: The expression of Cot1, KSR1, and KSR2 proteins were determined by Western blots in HL60 and U937 cells. Crk-L protein was used as internal control for gel loading. Experiments were repeated at least three times, and differentiation data are presented as the mean ± SD (n = 3). The asterisk () denotes P < 0.05 for the difference in the expression of differentiation markers in cells transfected with the empty vector or with IRES-Cot1, and then treated with 1,25D.