Interaction between Pyrin and the Apoptotic Speck Protein (ASC) Modulates ASC-induced Apoptosis

• Published in: The Journal of biological chemistry Vol. 276; no. 42; pp. 39320 - 39329
• Main Authors: Richards, Neil, Schaner, Philip, Diaz, Arturo, Stuckey, Jeanne, Shelden, Eric, Wadhwa, Anish, Gumucio, Deborah L.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 19-10-2001; American Society for Biochemistry and Molecular Biology
• Subjects: Actins - metabolism; Amino Acid Sequence; Animals; Apoptosis; Apoptosis Regulatory Proteins; apoptotic speck protein; Arabidopsis Proteins; ASC protein; Blotting, Western; CARD Signaling Adaptor Proteins; Cell Line; Cell Survival; Cytoskeletal Proteins - chemistry; Cytoskeletal Proteins - genetics; Cytoskeletal Proteins - metabolism; DNA, Complementary - metabolism; Exons; familial Mediterranean fever; Fatty Acid Desaturases - chemistry; Fatty Acid Desaturases - genetics; Gene Library; HeLa Cells; Humans; In Situ Nick-End Labeling; Mice; Microscopy, Fluorescence; Models, Molecular; Molecular Sequence Data; Neutrophils - metabolism; Plasmids - metabolism; Precipitin Tests; Protein Binding; Protein Folding; Protein Structure, Tertiary; Proteins - chemistry; Proteins - genetics; Proteins - metabolism; Pyrin; Sequence Homology, Amino Acid; Transfection; Tubulin - metabolism; Two-Hybrid System Techniques; Uridine Triphosphate - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M104730200

Patients with familial Mediterranean fever suffer sporadic inflammatory attacks characterized by fever and intense pain (in joints, abdomen, or chest). Pyrin, the product of theMEFV locus, is a cytosolic protein whose function is unknown. Using pyrin as a “bait” to probe a yeast two-hybrid library made from neutrophil cDNA, we isolatedapoptotic speck protein containing a caspase recruitment domain (CARD) (ASC), a proapoptotic protein that induces the formation of large cytosolic “specks” in transfected cells. We found that when HeLa cells are transfected with ASC, specks are formed. After co-transfection of cells with ASC plus wild type pyrin, an increase in speck-positive cells is found, and speck-positive cells show increased survival. Immunofluorescence studies show that pyrin co-localizes with ASC in specks. Speck localization requires exon 1 of pyrin, but exon 1 alone of pyrin does not result in an increase in the number of specks. Exon 1 of pyrin and exon 1 of ASC show 42% sequence similarity and resemble death domain-related structures in modeling studies. These findings link pyrin to apoptosis pathways and suggest that the modulation of cell survival may be a component of the pathophysiology of familial Mediterranean fever.