| First Author | Friedrich ML | Year | 2005 |
| Journal | Int Immunol | Volume | 17 |
| Issue | 11 | Pages | 1379-90 |
| PubMed ID | 16172133 | Mgi Jnum | J:102316 |
| Mgi Id | MGI:3607358 | Doi | 10.1093/intimm/dxh315 |
| Citation | Friedrich ML, et al. (2005) DRAK2, a lymphoid-enriched DAP kinase, regulates the TCR activation threshold during thymocyte selection. Int Immunol 17(11):1379-90 |
| abstractText | DAP kinases are a family of serine/threonine kinases known to regulate intrinsic apoptotic processes. DAP-related apoptotic kinase-2 (DRAK2) is highly expressed in lymphoid organs, with differential expression during thymocyte development. Low levels of transcript were observed in CD4/CD8 double-positive (DP) and double-negative populations, whereas single-positive thymocytes possessed elevated levels. Ex vivo stimulation of DP thymocytes with phorbol myristate acetate or antibodies that activate the TCR complex led to the accumulation of DRAK2 in a protein kinase C- and MAP Kinase-dependent fashion. Although DAP kinase family members are thought to potentiate apoptosis, ectopic expression of DRAK2 using retroviral transduction of primary T cells and NIH3T3 fibroblasts failed to decrease rates of survival, suggesting that DRAK2 expression is not sufficient to promote apoptosis. Rather, our results demonstrate that DRAK2 is a primary response gene activated by TCR stimulation in DP thymocytes. Further, we observed that DRAK2 controlled the threshold for calcium signaling in the thymus since positively selected Drak2-deficient thymocytes displayed a reduced requirement for TCR cross-linking. These findings are consistent with a role for DRAK2 in thymocyte selection and lymphoid maturation, and demonstrate that DRAK2 transduces non-apoptotic signals during thymocyte differentiation. |
