期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2014
卷号：111
期号：31
页码：11431-11436
DOI：10.1073/pnas.1400539111
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The adaptor Downstream-of-Kinase (DOK) 3 functions as a negative regulator and attenuates B-cell receptor-mediated calcium signaling. Although DOK3 is dispensable for early B-cell development, its role in plasma cell (PC) differentiation is unknown. Here, we show that Dok3-/- mice have increased populations of T follicular-helper (Tfh) and germinal center (GC) B cells upon immunization with a T-cell-dependent antigen. However, interestingly, they generate significantly fewer PCs. Bone marrow reconstitution experiments show that the PC defect is B-cell intrinsic and due to the inability of Dok3-/- B cells to sustain programmed cell death 1 (PD-1) ligand 1 (PDL1) and up-regulate PD-1 ligand 2 (PDL2) expressions that are critical for PC differentiation. Overexpression of PDL2 rectifies the PC differentiation defect in Dok3-/- B cells. We further demonstrate that calcium signaling suppresses the transcription of PD-1 ligands. Abrogation of calcium signaling in B cells by deleting BTK or PLC{gamma}2 or inhibiting calcineurin with cyclosporine A leads to increased expression of PD-1 ligands. Thus, our study reveals DOK3 as a nonredundant regulator of PC differentiation by up-regulating PD-1 ligand expression through the attenuation of calcium signaling.
