... preferentially the phosphorylation of the p46 isoform of JNK,whereas sorbitol treatment induced phosphorylation of both the p46 and p55 isoforms. To confirm functionalactivation of the JNK signaling ... not necessary for the intrinsic phosphatase activity of the enzyme. However,myristoylation determined the subcellular localization of JSP1, and was required for JSP1-induced activation of the ... phosphorylation of the transcription factorc-JUN was attenuated. Upon expression of wild-type JSP1, a subpopula-tion of cells, with the highest levels of the phosphatase, was induced tofloat off the dish...