Bruton’s tyrosine kinase (BTK) was initially identified as a member of the src family for protein-tyrosine kinases that was involved in X-linked agamma-globulinaemia, and has since been shown to involved in a number of signaling pathways in hemapoietic lineage. It has recently been shown to interact with members of the toll-like receptor (TLR) family such as TLR4, 6, 8, and 9. The TLRs are critical molecules in both the innate and adaptive immunity and can recognize diverse microbial pathogens. BTK has also been shown to interact with key proteins involved in TLR4 signal transduction such as MyD88, TIRAP, and IRAK, but not TRAF-6, suggesting that BTK is involved in lipopolysaccharide signal transduction.
