Biology:AIM2

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Interferon-inducible protein AIM2 also known as absent in melanoma 2 or simply AIM2 is a protein that in humans is encoded by the AIM2 gene.[1][2] Recent research has shown that AIM2 is part of the inflammasome and contributes to the defence against bacterial and viral DNA.[3]

Structure

AIM2 is a 343 amino acid protein with a N-terminal DAPIN (or pyrin) domain (amino acids 1-87) and a C-terminal HIN-200 domain (amino acids 138-337), which is known to have two oligonucleotide-binding folds.[4]

Function

AIM2 is a member of the Ifi202/IFI16 family. It plays a putative role in tumorigenic reversion and may control cell proliferation. Interferon-gamma induces expression of AIM2.[2]

Though there has been virtually no biochemistry performed, a model based on cell-based or in vivo experiments has led to the current model of how AIM2 triggers the inflammasome. The C-terminal HIN domain binds double stranded DNA (either viral, bacterial, or even host) and acts as a cytosolic dsDNA sensor. This leads to the oligomerization of the inflammasome complex. The N-terminal pyrin domain of AIM2 interacts with the pyrin domain of another protein ASC (or Apoptosis-associated Speck-like protein containing a caspase activation and recruitment domain). ASC also contains a CARD domain (caspase activation and recruitment domain), that recruits procaspase-1 to the complex. This leads to the autoactivation of caspase-1, an enzyme that processes proinflammatory cytokines (IL-1b and IL-18).[3] AIM2 inflammasome is activated by pharmacological disruption of nuclear envelope integrity.[5]

Clinical relevance

Elevated levels of AIM2 expression are found in skin cells from people with psoriasis.[6] In systemic lupus erythematosus, lysosome dysfunction allows DNA to gain access to the cytosol and activate AIM2 resulting in increased type 1 interferon production.[7]

References

  1. "Cloning a novel member of the human interferon-inducible gene family associated with control of tumorigenicity in a model of human melanoma". Oncogene 15 (4): 453–7. Aug 1997. doi:10.1038/sj.onc.1201206. PMID 9242382. 
  2. 2.0 2.1 "Entrez Gene: AIM2 absent in melanoma 2". https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=9447. 
  3. 3.0 3.1 "The inflammasomes". Cell 140 (6): 821–32. March 2010. doi:10.1016/j.cell.2010.01.040. PMID 20303873. 
  4. "AIM2 activates the inflammasome and cell death in response to cytoplasmic DNA". Nature 458 (7237): 509–13. March 2009. doi:10.1038/nature07710. PMID 19158676. Bibcode2009Natur.458..509F. 
  5. "AIM2 inflammasome is activated by pharmacological disruption of nuclear envelope integrity". Proceedings of the National Academy of Sciences of the United States of America 113 (32): E4671-80. August 2016. doi:10.1073/pnas.1602419113. PMID 27462105. 
  6. "Cytosolic DNA triggers inflammasome activation in keratinocytes in psoriatic lesions". Science Translational Medicine 3 (82): 82ra38. May 2011. doi:10.1126/scitranslmed.3002001. PMID 21562230. 
  7. "Defects in lysosomal maturation facilitate the activation of innate sensors in systemic lupus erythematosus". Proceedings of the National Academy of Sciences of the United States of America 113 (15): E2142-51. April 2016. doi:10.1073/pnas.1513943113. PMID 27035940. Bibcode2016PNAS..113E2142M. 

External links

Further reading