Bruton's agammaglobulinemia tyrosine kinase (BTK)

Bruton's tyrosine kinase (BTK) is a non-receptor cytoplasmic tyrosine kinase crucial for B cell development, differentiation, and signaling. Mutations in BTK cause X-linked agammaglobulinemia (XLA). BTK plays a key role in transmitting signals from the pre-B cell receptor, activating pathways like phospholipase Cγ2, PI3K/Akt, and NF-κB. Beyond B cells, BTK participates in mast cell activation and Toll-like receptor signaling. Clinically, BTK is a therapeutic target in B-cell malignancies and autoimmune diseases, with inhibitors like Ibrutinib demonstrating efficacy. BTK's PH domain binds PIP3, leading to PLCγ2 phosphorylation and downstream signaling.

Inhibition of BTK kinase activity, preventing downstream signaling in B cells.