FIGURE 5.

WDR82 regulates TRAF3 stability by promoting its K48-linked polyubiquitination. (A) WDR82 promotes the polyubiquitination of TRAF3. HEK293 cells were transfected with HA-tagged ubiquitin plasmids and Myc-WDR82. Twenty-four hours later, cells were infected with SeV and cell lysates were immunoprecipitated with anti-TRAF3. The immunoprecipitates were then immunoblotted with anti-HA or anti-TRAF3. The lysate was assayed with anti-Myc and anti–β-actin. (B and C) WDR82 promotes the K48-linked polyubiquitination of TRAF3. The experiments were performed as in (A), except K48 only or K63 only ubiquitin was used instead of wild-type. (D) HEK293 cells were transfected with the indicated plasmids. Twenty-four hours later, cell lysates were immunoblotted with indicated Abs. Relative protein level was labeled below the corresponding bands. (E and F) WDR82 overexpression impairs the interaction between TRAF3 with VISA or IKKε. HEK293 cells were transfected with the indicated plasmids. Twenty-four hours later, lysates were immunoprecipitated with anti-Flag. The immunoprecipitates and cell lysates were immunoblotted with indicated Abs.