Biolegend, 646901, Purified anti-BTK Phospho (Tyr551)/ITK Phospho (Tyr512) Antibody

Bruton’s tyrosine kinase (BTK) is a Tec family kinase that plays a critical role in B cell development. Upon B cell receptor engagement, BTK translocates to the plasma membrane, where it is transphosphorylated by LYN and SYK kinases at Tyr 551. This initial phosphorylation event is followed by autophosphorylation at Tyr 223. Phosphorylated Tyr 223 is proposed to serve as a docking site for other proteins containing an SH2 domain. Downregulation of BTK activity is achieved through phosphorylation at Ser 180 by PKCβ, which results in reduced membrane recruitment and concomitant transphosphorylation. BTK-mediated B cell receptor signaling is required for B cell survival in the bone marrow and is a therapeutic target for certain B cell malignancies. Mutations in the BTK gene results in X-linked agammaglobulinemia (XLA), a primary immunodeficiency disease characterized by a failure in B cell maturation. Additionally, BTK plays a role in Toll-like receptor signaling in innate immune cells, and has been shown to play a direct role in NLRP3 inflammasome activation, thus contributing to ischaemic brain injury. IL2-inducible T-cell kinase (ITK) is a tyrosine kinase that is expressed in T cells. It regulates the proliferation, differentiation and development of conventional T cells and NK T cells. Once T cells are activated, a series of phosphorylation events occur leading to the phosphorylation of Tyr 512 in the activation loop by LCK. Subsequent autophosphorylation at Tyr 180 leads to activation of the kinase. Activated ITK can stimulated downstream intracellular calcium mobilization and NFAT nucleus translocation, and in turn, activate T cells. The phenotypes of mice deficient in ITK show severely affected immune response and development.