Lyn B: Proteins and Enzymes

The nonreceptor tyrosine kinase Lyn (lck/yes-related novel tyrosine kinase) is widely expressed, and the predominant Src family member present in B cells. Activation of Lyn occurs upon its association with cell surface receptors such as BCR and CD40. Analyses from both loss- and gain-of-function mutant mice have revealed that Lyn is an essential regulator of B cell activation, maturation, and tolerance.