B cell class switch recombination is regulated by DYRK1A through MSH6 phosphorylation

Abstract

Protection from viral infections depends on immunoglobulin isotype switching, which endows antibodies with effector functions. Here, we find that the protein kinase DYRK1A is essential for B cell-mediated protection from viral infection and effective vaccination through regulation of class switch recombination (CSR). Dyrk1a-deficient B cells are impaired in CSR activity in vivo and in vitro. Phosphoproteomic screens and kinase-activity assays identify MSH6, a DNA mismatch repair protein, as a direct substrate for DYRK1A, and deletion of a single phosphorylation site impaired CSR. After CSR and germinal center (GC) seeding, DYRK1A is required for attenuation of B cell proliferation. These findings demonstrate DYRK1A-mediated biological mechanisms of B cell immune responses that may be used for therapeutic manipulation in antibody-mediated autoimmunity.

Class switch recombination (CSR) is a process by which B cells switch their immunoglobulin isotype and develop pathogen-eliminating antibodies. Here, the authors show that a protein kinase DYRK1A is required for protection from viral infection through the regulation of CSR and effective clonal expansion.