POP2 NFKB-INHIBITING POLYPEPTIDES, NUCLEIC ACIDS AND METHODSOF USE

This invention provides a novel pyrin-only protein (POP2), polypeptides, nucleic acids encoding them and methods for making and using them. The polypeptides of this invention have nuclear factor -.kappa.B (NF-.kappa.B) modulating activity. NF-.kappa.B is pivotal for transactivation of cell-cycl e regulatory, cytokine and adhesion molecule genes and is dysregulated in many cancers, neurodegenerative disorders, and inflammatory diseases. Proteins wi th Pyrin and/or caspase recruitment (CARD) domains have roles in apoptosis, innate immunity, and inflammation. Many pyrin domain proteins modulate NF- .kappa.B activity as well as participate in assembling both the perinuclear "apoptotic speck" and the pro- IL1.beta./IL-18 converting inflammasome complex. 'Pyrin-only' proteins are attractive as negative regulators of pyri n domain-mediated functions and one such protein, POP1 , has been reported. We teach a second Pyrin-only protein (POP2). POP2 is a 294 nt single exon gene located on human chromosome (3) encoding a (97) amino acid protein with sequence and predicted structural similarity to other pyrin domains. Highly similar to pyrin domains in CATERPILLER (CLR, NLR, NALP) family proteins, PO P2 is less like the prototypic Pyrin and ASC pyrin domains. POP2 is expressed principally in peripheral blood leukocytes and displays both cytoplasmic and nuclear expression patterns in transfected cells. TNF.alpha.-stimulated and p65 (ReIA) induced NF-.kappa.B-dependent gene transcription is inhibited by POP2 in vitro by a mechanism involving changes in NF-.kappa.B nuclear import or distribution. While colocalizing with ASC in perinuclear specks, POP2 als o inhibits the formation of specks by the CLR protein CIAS1/NALP3. Together these observations indicate that POP2 is a negative regulator of NF-.kappa.B activity that may influence the assembly of pyrin-domain dependent complexes .