Figure 5.
The JAK3 N terminus competes with full-length JAK3 for binding to γc. COS cells were cotransfected with JAK3 (0.5 μg) and Tacγc (0.5 μg) together with the vector pME18s (5 μg) (lane 1), JAK2 (5 μg) (lane 2), or 1, 2, or 5 μg of J3(StuI) (lanes 3–5, respectively) or J3(ΔJH1) (lanes 6–8, respectively). These cell lysates were immunoprecipitated with anti-Tac and then blotted with anti-JAK3(N) (Left Upper) or anti-γc (Left Lower). The expression levels of various JAK3 mutants and JAK2 were analyzed by immunoblotting with anti-JAK3(N) (Right Upper) and anti-JAK2 (Right Lower), which immunoblots both JAK2 and JAK3. The unspecified middle band in all lanes shown on the anti-JAK2 blot is consistently recognized by this antibody as described by the manufacturer.