Overview:

PYK2 (also known as FAK2/RAFTK) is a member of the focal adhesion PTK family. PYK2/FAK2 can be activated by a variety of extracellular signals that elevate intracellular calcium concentration, and by stress signals (1). Unlike FAK, which is widely expressed in various tissues and links transmembrane integrin receptors to intracellular pathways, PYK2/FAK2 is expressed mainly in the central nervous system and in cells derived from hematopoietic lineages.In osteoclasts, although FAK is expressed, PYK2/FAK2 appears to be the predominant mediator of integrin alpha(v)beta3 signaling events that influence osteoclast physiology and pathology (2).

References:

1. Avraham, H. et al: RAFTK/Pyk2-mediated cellular signalling. Cell Signal. 2000 Mar;12(3):123-33. 2. Xiong, W C. et al: PYK2 and FAK in osteoclasts. Front Biosci. 2003 Sep 1;8:d1219-26.