| Autor: |
Lin-Lee YC; Department of Hematopathology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA., Pham LV, Tamayo AT, Fu L, Zhou HJ, Yoshimura LC, Decker GL, Ford RJ |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of biological chemistry [J Biol Chem] 2006 Jul 07; Vol. 281 (27), pp. 18878-87. Date of Electronic Publication: 2006 Apr 27. |
| DOI: |
10.1074/jbc.M513315200 |
| Abstrakt: |
CD40 is a tumor necrosis factor (TNF) receptor superfamily, (TNFR; TNFRSF-5) member, that initiates important signaling pathways mediating cell growth, survival, and differentiation in B-lymphocytes. Although CD40 has been extensively studied as a plasma membrane-associated growth factor receptor, we demonstrate here that CD40 is present not only in the plasma membrane and cytoplasm but also in the nucleus of normal and neoplastic B-lymphoid cells. Confocal microscopy showed that transfected CD40-green fluorescent fusion protein entered B-cell nuclei. The CD40 protein contains a nuclear localization signal sequence that, when mutated, blocks entry of CD40 into the nucleus through the classic karyopherins (importins-alpha/beta) pathway. Nuclear fractionation studies revealed the presence of CD40 protein in the nucleoplasm fraction of activated B cells, and chromatin immunoprecipitation assays demonstrated that CD40 binds to and stimulates the BLyS/BAFF promoter, another TNF family member (TNFSF-13B) involved in cell survival in the B cell lineage. Like other nuclear growth factor receptors, CD40 appears to be a transcriptional regulator and is likely to play a larger and more complex role than previously demonstrated in regulating essential growth and survival pathways in B-lymphocytes. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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