The study identifies AIM2 (absent in melanoma 2) as a key component of the inflammasome that senses cytoplasmic DNA. AIM2, an interferon-inducible protein with an amino-terminal pyrin domain and a carboxy-terminal oligonucleotide/oligosaccharide-binding domain, interacts with ASC (apoptosis-associated speck-like protein containing a CARD) through its pyrin domain to activate caspase-1. This interaction leads to the formation of the ASC pyroptosome, which induces pyroptotic cell death. The study demonstrates that AIM2 oligomerization is induced by binding of cytoplasmic DNA to AIM2, and that AIM2 knockdown reduces inflammasome activation by cytoplasmic DNA in human and mouse macrophages. Stable expression of AIM2 in non-responsive cells confers responsiveness to cytoplasmic DNA. These findings highlight AIM2 as a critical component in the innate immune response to cytoplasmic DNA.The study identifies AIM2 (absent in melanoma 2) as a key component of the inflammasome that senses cytoplasmic DNA. AIM2, an interferon-inducible protein with an amino-terminal pyrin domain and a carboxy-terminal oligonucleotide/oligosaccharide-binding domain, interacts with ASC (apoptosis-associated speck-like protein containing a CARD) through its pyrin domain to activate caspase-1. This interaction leads to the formation of the ASC pyroptosome, which induces pyroptotic cell death. The study demonstrates that AIM2 oligomerization is induced by binding of cytoplasmic DNA to AIM2, and that AIM2 knockdown reduces inflammasome activation by cytoplasmic DNA in human and mouse macrophages. Stable expression of AIM2 in non-responsive cells confers responsiveness to cytoplasmic DNA. These findings highlight AIM2 as a critical component in the innate immune response to cytoplasmic DNA.