B-cell linker protein (BLNK, also known as SLP65, BASH, and BCA) is a B cell adaptor that plays an important role in B cell development and in BCR-signal transduction. Since BLNK does not encode any intrinsic enzymatic activity, its function is to serve as a scaffold for assembling macromolecular complexes which includes enzymes (PLC gamma, Vav and Btk) and additional linker proteins (Grb2 and Nck) (1-3) . In addition, BLNK binds Btk and is required for activation of the transcription factor NF-kB. Tyrosine phosphorylation of BLNK by Syk provides specific docking sites for these SH2-containing effector proteins which in turn permits phosphorylation and/or activation of their respective signaling pathways.