FIG 3.

p97-mediated postubiquitinational regulation of IκBα is a common pathway of IκBα proteolysis. p97 was depleted using siRNA oligonucleotides in multiple cell lines. The function of p97 in postubiquitinational regulation of IκBα under either TNF-α or IL-1β was evaluated. The p97 antibody is from Cell Signaling. (A) sip97 blocked IκBα proteolysis in U2OS cells treated with either TNF-α or IL-1β. (B) β-TRCP depletion blocked TNF-α-induced IκBα ubiquitination, whereas silencing of p97 inhibited TNF-α-induced IκBα proteolysis in U2OS cells. (C) sip97 inhibited IκBα destruction in 293T cells treated with TNF-α.