INHIBITION OF PROTEIN-PHOSPHORYLATION MODULATES EXPRESSION OF THE JAKFAMILY PROTEIN-TYROSINE KINASES

Treatment of murine Friend cells with a dose of the protein kinase inh ibitor staurosporine, which is able to block the response of the cells to interferons, appears to inhibit phosphorylation of Jak proteins an d, interestingly, to specifically reduce tyk2 and Jak1 expression and to increase Jak2 both in the presence and in the absence of interferon s. Therefore, a potential role for phosphorylation events in the regul ation of expression of the Jak family members is suggested.