Associates with apoptosis-associated specklike protein containing a CARD domain (ASC) and modulates its ability to collaborate with pyrin and cryopyrin in NF-kappa-B and pro- caspase-1 activation. Suppresses kinase activity of NF-kappa-B inhibitor kinase (IKK) complex, expression of NF-kappa-B inducible genes and inhibits NF-kappa-B activation by cytokines and LPS.