NLR family pyrin domain containing 9 (NLRP9)

NLR family pyrin domain containing 9 (NLRP9) is a member of the NOD-like receptor (NLR) family, functioning as an intracellular pattern recognition receptor involved in the innate immune response[1][3][5]. Structurally, it possesses a central NACHT domain for nucleotide binding and oligomerization, a C-terminal leucine-rich repeat (LRR) important for ligand sensing, and an N-terminal pyrin domain (PYD) for protein-protein interaction and inflammasome assembly[2][4][5]. NLRP9 forms the core of the NLRP9 inflammasome, a multiprotein complex that can activate caspase-1, leading to the maturation and secretion of pro-inflammatory cytokines such as IL-1β and IL-18 and inducing pyroptosis (a form of inflammatory cell death)[1][3]. NLRP9 expression is prominent in reproductive tissues (oocyte, ovary, testis) and the intestinal epithelium, and it is a critical sensor for double-stranded RNA, especially from rotavirus, in the gut, where it restricts viral replication and intestinal damage[1]. Unlike some other NLRs, the precise mechanisms and regulatory requirements for NLRP9 inflammasome activation—including interactions with RNA helicases such as DHX9—are incompletely understood[1][2]. Dysfunctional NLRP9 activity has been implicated in susceptibility to infection and possibly reproductive failure, but therapeutic and biomarker utility remain to be determined.

Other names

NACHT, LRR and PYD domains-containing protein 9NALP9NOD6PAN12PYRIN and NACHT-containing protein 12Nucleotide-binding oligomerization domain protein 6CLR19.1NACHT, leucine rich repeat and PYD containing 9