SQSTM1/p62 is an adapter protein which binds ubiquitin and regulates signaling cascades through ubiquitination. It may regulate the activation of NF-kappaB by TNF-alpha, nerve growth factor (NGF) and interleukin-1. SQSTM1/p62, a co-interacting protein of the atypical PKC isoforms, has a UBA domain at its C-terminal end, which binds non-covalently to polyubiquitin chain. SQSTM1's UBA domain is necessary for recruitment of polyubiquitin and aggresome formation. SQSTM1 may play a role in titin/TTN downstream signaling in muscle cells and may be involved in cell differentiation, apoptosis, immune response and regulation of K+ channels. Mutations in the ubiquitin-associated (UBA) domain of SQSTM1 commonly cause Paget's disease of bone since the UBA is necessary for aggregate sequestration and cell survival.Synonyms: EBI3-associated protein of 60 kDa, EBIAP, ORCA, OSIL, Phosphotyrosine-independent ligand for the Lck SH2 domain of 62 kDa, Sequestosome-1, Ubiquitin-binding protein p62, p60, p62