FIG. 5.

Effects of mutated Cot constructs on kinase activity and transcriptional reporters. (A) Kinase activity of mutated kinase-inactive (KI) Cot constructs. 293T cells were transfected with 5 μg of the indicated myc-tagged Cot constructs. The next day anti-myc immunoprecipitates were washed and kinase activity was determined as described in Materials and Methods. Δ424 and Δ397 are the truncations referred to in the text. Equivalent levels of transfected Cot constructs were confirmed by Western blotting (data not shown). (B) Functional effects on inducible transcription of the Cot serine mutations were determined by cotransfection with RE/AP or AP-1 luciferase (Luc.) reporters in Jurkat T cells. WT, wild type.