Deubiquitinating enzymes (DUB) form a family of cysteine proteases that digests ubiquitin
chains and reverses the process of protein ubiquitination. Despite the identification of a
large number of DUBs, their physiological functions remain poorly defined. Here we provide
genetic evidence that CYLD, a recently identified DUB, plays a crucial role in regulating the
peripheral development and activation of B cells. Disruption of the CYLD gene in mice
results in B cell hyperplasia and lymphoid organ enlargement. The CYLD-deficient B cells …