Targeted disruption of pyrin, the FMF protein, causes heightened sensitivity to endotoxin and a defect in macrophage apoptosis

Mol Cell. 2003 Mar;11(3):591-604. doi: 10.1016/s1097-2765(03)00056-x.


Familial Mediterranean fever (FMF) is an inherited disorder characterized by recurrent episodes of fever and inflammation. Most patients with FMF carry missense mutations in the C-terminal half of the pyrin protein. To study the physiologic role of pyrin, we generated mice expressing a truncated pyrin molecule that, similar to FMF patients, retains the full PYRIN domain. Bacterial lipopolysaccharide (LPS) induces accentuated body temperatures and increased lethality in homozygous mutant mice. When stimulated, macrophages from these mice produce increased amounts of activated caspase-1 and, consequently, elevated levels of mature IL-1beta. Full-length pyrin competes in vitro with caspase-1 for binding to ASC, a known caspase-1 activator. Apoptosis is impaired in macrophages from pyrin-truncation mice through an IL-1-independent pathway. These data support a critical role for pyrin in the innate immune response, possibly by acting on ASC, and suggest a biologic basis for the selection of hypomorphic pyrin variants in man.

MeSH terms

  • Alternative Splicing
  • Animals
  • Apoptosis*
  • Blotting, Western
  • Body Temperature
  • Caspase 1 / metabolism
  • Cell Line
  • Cells, Cultured
  • Cytoskeletal Proteins
  • DNA Fragmentation
  • Endotoxins / metabolism*
  • Enzyme Activation
  • Enzyme-Linked Immunosorbent Assay
  • Familial Mediterranean Fever / genetics
  • Familial Mediterranean Fever / metabolism*
  • Genetic Vectors
  • Glutathione Transferase / metabolism
  • Interleukin-1 / metabolism
  • Kinetics
  • Lipopolysaccharides / metabolism
  • Macrophages / pathology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Models, Genetic
  • Monocytes / cytology
  • Monocytes / metabolism
  • Precipitin Tests
  • Protein Binding
  • Protein Biosynthesis*
  • Protein Isoforms
  • Protein Structure, Tertiary
  • Proteins / metabolism
  • Pyrin
  • Recombinant Fusion Proteins / metabolism
  • Temperature
  • Thioglycolates / metabolism
  • Time Factors


  • Cytoskeletal Proteins
  • Endotoxins
  • Interleukin-1
  • Lipopolysaccharides
  • Mefv protein, mouse
  • Protein Isoforms
  • Proteins
  • Pyrin
  • Recombinant Fusion Proteins
  • Thioglycolates
  • Glutathione Transferase
  • Caspase 1