Binds to zinc finger protein TNFAIP3 and inhibits NF-kappa-B activation induced by tumor necrosis factor, Toll-like receptor 4 (TLR4), interleukin-1 and 12-O-tetradecanoylphorbol-13-acetate. Overexpression inhibits NF-kappa-B-dependent gene expression in response to lipopolysaccharide at a level downstream of TRAF6 and upstream of IKBKB. NF-kappa-B inhibition is independent of TNFAIP3 binding. Interacts with TNFAIP3. Interacts with polyubiquitin. Highly expressed in lung, lymph node, thymus and fetal liver. Expressed at lower levels in bone marrow, brain, kidney, spleen, leukocytes and tonsils. Could be detected in heart, salivary gland, adrenal gland, pancreas, ovary and fetal brain. High levels detected in liver, colon, small intestine, muscle, stomach, testis, placenta, thyroid, uterus, prostate, skin and PBL. By Listeria infection. Expression is slightly down-regulated by dexamethasone and slightly up-regulated by IL-10. Strongly induced mRNA and protein expression by lipopolysaccharide. Truncated N-terminus.