Is AIM2 an NLR protein?

No, it isn’t. NLR proteins are characterized by the presence of a central nucleotide-binding and oligomerization (NACHT) domain, which is absent in AIM2.

AIM2 is an ALR protein belonging to the PYHIN protein family that typically consists of an N-terminal pyrin domain and one or two C-terminal hematopoietic IFN-inducible nuclear protein with 200 amino acids. However, AIM2 can facilitate inflammasome activation just like NLR proteins, although the two are not related either structurally or evolutionarily. Also, similar to NLR inflammasomes, AIM2 inflammasome results in IL-1β and IL-18 secretion and cell death.