| First Author | Nojima T | Year | 2006 |
| Journal | Immunol Lett | Volume | 105 |
| Issue | 1 | Pages | 48-54 |
| PubMed ID | 16481047 | Mgi Jnum | J:143854 |
| Mgi Id | MGI:3829159 | Doi | 10.1016/j.imlet.2005.12.004 |
| Citation | Nojima T, et al. (2006) Double knockout mice show BASH and PKCdelta have different epistatic relationships in B cell maturation and CD40-mediated activation. Immunol Lett 105(1):48-54 |
| abstractText | The development and survival of mature B cells requires an antigen-independent signal from the B cell receptor (BCR) through an adaptor protein containing an SH2 domain, BASH (BLNK/SLP-65). It also requires signaling through BAFF and the BAFF receptor (BAFF-R), and is negatively regulated by protein kinase Cdelta (PKCdelta). In PKCdelta-deficient mice, B cell maturation occurs independently of the BAFF receptor (BAFF-R), indicating that BAFF-R signaling promotes maturation by inhibiting the negative function of PKCdelta. To clarify which of the two signaling pathways plays the primary role in B cell maturation, we crossed BASH-deficient mice with PKCdelta-deficient mice to generate BASH/PKCdelta-double knockout (DKO) mice. In the DKO mice, B cell maturation was blocked at the transitional type 1 (T1) stage and B cells were prone to apoptosis, in common with BASH-deficient mice. This indicates that BASH-mediated BCR signaling primarily controls B cell survival and maturation, with BAFF-R signaling and its inhibition of PKCdelta acting as a secondary regulator. By contrast, CD40-mediated proliferation and antibody production, which are low in BASH-deficient mice, were rescued in the DKO mice, indicating that the suppression of CD40-mediated B cell activation by PKCdelta is epistatic to BASH-mediated promotion. The physiological relevance of these opposing hierarchical effects of BASH and PKCdelta in the regulation of B cell maturation and activation is discussed. |
