|
Fig. 5 MAP2K7 stabilizes IRF7 by enhancing its K63-linked polyubiquitination. (A) Overexpression of MAP2K7 specifically increases the expression of IRF7. EPC cells were transfected with the indicated plasmids (1 μg each) for 24 h. (B) Overexpression of MAP2K7 increased the expression of endogenous IRF7 under the stimulation of poly I:C. EPC cells were transfected with the indicated plasmids (1 μg each). At 24 hpt, cells were transfected with poly I:C (1 mg/mL). (C) EPC cells were cotransfected with IRF7-mCherry and MAP2K7-EGFP or empty vector (1 μg each) for 24 h; then the cells were fixed and subjected to confocal microscopy analysis. Red signals represent the IRF7, and blue staining indicates the nucleus region (original magnification, ×10). Scale bar, 100 μm. (D and E) MAP2K7 increases the K63-inked ubiquitination of IRF7. EPC cells were transfected with 5 μg IRF7-Flag, 5 μg MAP2K7-HA, or empty vector and 2 μg Ub-HA, Ub-K48O-HA, or Ub-K63O-HA. At 24 hpt, cell lysates were IP with anti-Flag affinity gels. Then the immunoprecipitates and whole-cell lysates (WCLs) were analyzed by IB with the Abs.