cIAP2 is a ubiquitin protein ligase for BCL10 and is dysregulated in mucosa-associated lymphoid tissue lymphomas
J. Clin. Invest. Shimin Hu, et al. 116:174 doi:10.1172/JCI25641 [Go to this article.]

Figure 4
cIAP2 inhibits antigen receptor signaling via BCL10 degradation. (A) Degradation of BCL10 in response to antigenic stimulation. Human primary T and B cells were treated with anti–CD3/CD28 and anti–IgM/CD40, respectively, for the indicated durations. (B) Ubiquitination of BCL10 after antigen receptor cross-linking in primary T lymphocytes. Human primary T cells were treated with anti–CD3/CD28 and TNF-α as indicated. BCL10 was immunoprecipitated from cell lysates and analyzed by Western blot. (C) cIAP2 accelerates the degradation of endogenous BCL10. Human CD4⁺ cells were transfected with a control GFP-expressing plasmid (C) or cIAP2 plasmid. Cells were then treated with anti–CD3/CD28 beads for the indicated durations. The transfection efficiency was approximately 80% based on GFP expression. (D) cIAP2Δ and cIAP2-MALT1 stabilize BCL10. Human primary CD4⁺ T cells were transfected with GFP (C), cIAP2Δ, or cIAP2-MALT1, plus murine CD8. Transfected live cells were purified using anti–murine CD8 beads. (E) Effects of cIAP2Δ on the degradation of BCL10. Human primary CD4⁺ T cells were transfected with HA-BCL10 together with GFP (C) or cIAP2Δ. Cells were then treated with anti–CD3/CD28 for the indicated durations, and the levels of HA-BCL10 were analyzed by Western blot with anti-HA antibody. (F) cIAP2 inhibits anti–CD3/CD28–mediated IL-2 induction. Human primary CD4⁺ T cells were transfected with GFP, cIAP2, cIAP2Δ, or cIAP2-MALT1, plus m/hCD28. Cells were stimulated with anti–human CD3 and anti–murine CD28 beads for 8 hours or left untreated. The fold IL-2 induction relative to untreated cells (UT) is shown. The data are representative of 3 independent experiments.