Effects of patient JAK3 mutations on JAK3/γc association. COS-7 cells were transfected with 5 μg of the indicated cDNAs. Cell lysates were immunoprecipitated with anti-Tac antibody and blotted with an anti-Jak3 antibody (top blot) or anti-γc (middle blot). Lysates were also blotted with anti-JAK3 Ab (bottom blot) to assess expression of the various JAK3 proteins.