FIG 7.

CK1α is crucial for IAV-induced phosphorylation and ubiquitination of IFNGR1 and IFNAR1. (A and B) HEK293 cells were transfected with FLAG-IFNGR1 (A) or cotransfected with FLAG-IFNGR1 and tHA-Ub (B). At 24 h posttransfection, cells were left uninfected or infected with IAV at an MOI of 1 in the presence of CK1α-I (5 μM) or solvent (DMSO). The cells were treated with NH₄Cl 6 h before harvest. At 24 hpi, the whole-cell lysates were subjected to a denatured IP experiment. The level of phosphorylation of IFNGR1 (A) or ubiquitination of IFNGR1 (B) was analyzed by Western blotting using the indicated antibodies. (C and D) HEK293 cells were transfected with FLAG-IFNAR1 (C) or cotransfected with FLAG-IFNAR1 and tHA-Ub (D), as indicated. At 24 h posttransfection, the cells were infected with IAV at an MOI of 1. The cells were treated with NH₄Cl 6 h before harvest. The phosphorylation of IFNAR1 (C) or ubiquitination of IFNAR1 (D) was assessed as described for panels A and B. Mass, molecular mass (kilodaltons).