<p>Nature Communications, Published online: 08 March 2026; <a href="https://www.nature.com/articles/s41467-026-70085-z">doi:10.1038/s41467-026-70085-z</a></p>The Src-family kinase Lyn plays multiple roles in myeloid and B cell development; thus, conventional or cell-type specific genomic deletion of Lyn does not allow clear functional readouts regarding specific mature B cell functions. Here the authors establish a mouse model in which Lyn is acutely deleted in a Tamoxifen inducible manner in B cells and find that Lyn plays a role in the anergy of DNA reactive Ars/A1 B cells via providing continuous inhibitory signalling.