| First Author | Ng CH | Year | 2007 |
| Journal | Blood | Volume | 110 |
| Issue | 1 | Pages | 259-66 |
| PubMed ID | 17363732 | Mgi Jnum | J:280795 |
| Mgi Id | MGI:6367629 | Doi | 10.1182/blood-2006-10-055194 |
| Citation | Ng CH, et al. (2007) Dok-3 plays a nonredundant role in negative regulation of B-cell activation. Blood 110(1):259-66 |
| abstractText | p62(dok) and Dok-3 are members of the Dok family of adaptors found in B cells, with the former cloned as a substrate of the p210(bcr/abl) oncoprotein in Ph + chronic myelogenous leukemia. A role for p62(dok) in FcgammaRIIB-mediated negative regulation of B-cell proliferation had been established previously. Here, we generated Dok-3(-/-) mice to assess the function of Dok-3 in B cells. Mice lacking Dok-3 have normal B-cell development but possess higher level of IgM antibodies in their sera. In comparison to wild-type mice, Dok-3(-/-) mice mounted significantly enhanced humoral immune responses to T cell-independent type I and II antigens. Dok-3-deficient B cells hyperproliferated, exhibited elevated level of calcium signaling as well as enhanced activation of NF-kappaB, JNK, and p38MAPK in response to B-cell receptor (BCR) engagement. In the absence of Dok-3, the localization of the inhibitory phosphatase SHIP-1 to the plasma membrane is intact while its phosphorylation is compromised, suggesting that Dok-3 could function to facilitate or sustain the activation of SHIP-1. The phenotype and responses of Dok-3(-/-) mice and B cells could be differentiated from those of the Dok-1(-/-) counterparts. Hence, we propose that Dok-3 plays a distinct and nonredundant role in the negative regulation of BCR signaling. |
