| First Author | Mambetsariev N | Year | 2016 |
| Journal | Proc Natl Acad Sci U S A | Volume | 113 |
| Issue | 4 | Pages | 1032-7 |
| PubMed ID | 26755589 | Mgi Jnum | J:229924 |
| Mgi Id | MGI:5754902 | Doi | 10.1073/pnas.1514586113 |
| Citation | Mambetsariev N, et al. (2016) Nuclear TRAF3 is a negative regulator of CREB in B cells. Proc Natl Acad Sci U S A 113(4):1032-7 |
| abstractText | The adaptor protein TNF receptor-associated factor 3 (TRAF3) regulates signaling through B-lymphocyte receptors, including CD40, BAFF receptor, and Toll-like receptors, and also plays a critical role inhibiting B-cell homoeostatic survival. Consistent with these findings, loss-of-function human TRAF3 mutations are common in B-cell cancers, particularly multiple myeloma and B-cell lymphoma. B cells of B-cell-specific TRAF3(-/-) mice (B-Traf3(-/-)) display remarkably enhanced survival compared with littermate control (WT) B cells. The mechanism for this abnormal homeostatic survival is poorly understood, a key knowledge gap in selecting optimal treatments for human B-cell cancers with TRAF3 deficiency. We show here for the first time to our knowledge that TRAF3 is a resident nuclear protein that associates with the transcriptional regulator cAMP response element binding protein (CREB) in both mouse and human B cells. The TRAF-C domain of TRAF3 was necessary and sufficient to localize TRAF3 to the nucleus via a functional nuclear localization signal. CREB protein was elevated in TRAF3(-/-) B cells, without change in mRNA, but with a decrease in CREB ubiquitination. CREB-mediated transcriptional activity was increased in TRAF3-deficient B cells. Consistent with these findings, Mcl-1, an antiapoptotic target of CREB-mediated transcription, was increased in the absence of TRAF3 and enhanced Mcl-1 was suppressed with CREB inhibition. TRAF3-deficient B cells were also preferentially sensitive to survival inhibition with pharmacologic CREB inhibitor. Our results identify a new mechanism by which nuclear TRAF3 regulates B-cell survival via inhibition of CREB stability, information highly relevant to the role of TRAF3 in B-cell malignancies. |
