SQSTM1 is an adapter protein which binds ubiquitin and regulates signaling cascades through ubiquitination. It may regulate the activation of NFKB1 by TNF-alpha, nerve growth factor (NGF) and interleukin-1 and play a role in titin/TTN downstream signaling in muscle cells. This protein also may be involved in cell differentiation, apoptosis, immune response and regulation of K+ channels. Mutations in the ubiquitin-associated (UBA) domain of the sequestosome 1 protein commonly cause Paget's disease since the UBA is necessary for aggregate sequestration and cell survival. Recombinant SQSTM1 protein, fused to His-tag at C-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.