Osteoclast-stimulating factor-1 (OSTF1) is an intracellular protein produced by osteoclasts that indirectly induces osteoclast (OCL) formation and bone resorption. OSTF1 is highly expressed in OCL and contains structural domains such as SH3 and ankyrin repeats, which are potentially involved in protein-protein interactions. OSTF1 is ubiquitously expressed analogous to other regulators of OCL activity such as c-Src or transforming growth factor beta. Recombinant human OSTF1 protein, fused to His-tag at C-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.
