Current view on cellular function of S100A6 and its ligands, CacyBP/SIP and Sgt1.

S100A6, a calcium binding protein, whose gene was first identified as growth inducible one, has been linked to the process of cell proliferation and growth related phenomena ever since. While the structure and Ca2+ binding kinetics of S100A6 are rather well established the mechanism of its action has only recently begun to be elucidated. It is nonetheless evident that S100A6 exerts its biological role by interacting with a wide range of proteins ligands, many of which have been identified in our laboratory. Our research concentrates on two S100A6 ligands, CacyBP/SIP and Sgt1, which in turn possess their own interactomes. The imposing list of S100A6-interacting proteins indicates that together with its ligands it is a component of an extended network of cellular interactions and may be involved not only in cell proliferation but also in many other processes, of which cell differentiation and response to stress seem to be best documented.