AIM2 Gene

The AIM2 gene (AIM2 stands for "Absent In Melanoma 2") is a protein-coding gene located on chromosome 1q23.1-q23.2. AIM2 is a member of the IFI20X/IFI16 family. It plays a putative role in the control of cell proliferation. Interferon-gamma induces the expression of AIM2.

The AIM2 protein is involved in the innate immune response by recognizing cytosolic double-stranded DNA and inducing caspase-1-activating inflammasome formation in macrophages (Woerner SM et al.2007; Tsuchiya K et al. 2010). It is assumed that the AIM2 protein undergoes oligomerization after binding to DNA and associates with PYCARD (see PYCARD gene below), which initiates the recruitment of the caspase-1 precursor and the processing of interleukin-1 beta and interleukin-18 (Hornung V et al. 2009).

AIM2 recognizes cytosolic dsDNA of viral and bacterial origin in a non-sequence-specific manner (Fernandes-Alnemri T et al. 2009). Also acts as a mediator of pyroptosis/necroptosis and apoptosis(panoptosis) in response to bacterial infection. It can also trigger PYCARD-dependent, caspase-1-independent cell death, in which caspase-8 (see caspases below) is involved. AIM2 is active as a tumor suppressor and may act by suppressing NF-kappa-B transcriptional activity.

AIM2 is able to recognize perfluorooctane sulfonate (PFOS), a common PFAS, and trigger IL-1β secretion and pyroptosis. Mechanistically, PFOS activates the AIM2 inflammasome (see also inflammasome) in a process that involves the release of mitochondrial DNA via the Ca2+-PKC-NF-κB/JNK-BAX/BAK axis (Wang LQ et al. 2022).

AIMs plays a role in the "memory function" of epidermal stem cells (EpSCs). Upon a secondary inflammatory stimulus, genes controlled by these domains are rapidly transcribed. This memory is mediated by the Aim2 gene. The absence of the AIM2 protein or its downstream effectors, caspase-1 and interleukin-1β, abolishes the memory of EpSCs for inflammation (Naik, S et al. 2017).

Diseases associated with AIM2 include:

• melanoma

and

• Renal infectious diseases.

1. Fernandes-Alnemri T et al. (2009) AIM2 activates the inflammasome and cell death in response to cytoplasmic DNA. Nature 458:509-513.
2. Hornung V et al. (2009) AIM2 recognizes cytosolic dsDNA and forms a caspase-1-activating inflammasome with ASC. Nature 458:514-518.
3. Naik, S et al. (2017) Inflammatory memory sensitizes skin epithelial stem cells to tissue damage. Nature 550: 475-480.
4. Tsuchiya K et al. (2010) Involvement of absent in melanoma 2 in inflammasome activation in macrophages infected with Listeria monocytogenes. J Immunol 185:1186-1195.
5. Wang LQ et al. (2022) Perfluoroalkyl substance pollutants activate the innate immune system through the AIM2 inflammasome. Nat Commun. 2021 May 18;12(1):2915. doi: 10.1038/s41467-021-23201-0. Erratum in: Nat Commun 13: 5667.
6. Woerner SM et al.(2007) The putative tumor suppressor AIM2 is frequently affected by different genetic alterations in microsatellite unstable colon cancers. Genes Chromosomes Cancer 46:1080-1089.