NLRP13 protein

NLRPs (acronym for "NACHT, LRR and PYD domains-containing protein), together with the NOD1 and NOD2 proteins, are members of the NLR (Nod-like receptor) protein family and play a major role in innate immunity as pathogen recognition receptors (PPRs). Like the NOD proteins, NLRPs are exclusively expressed cytoplasmically. In humans, all NLRPs (they all contain a pyrin domain) are encoded by a common gene family. NLRPs are characterized by their ability to activate the different inflammasome complexes.

NLRP13 is a cytosolic protein that in humans is encoded by the NLRP13 gene located on chromosome 19q13.43 within a cluster of other NLRP genes.

Inflammasomes are differently composed cytosolic protein complexes, whereby the various NLRPs are of major importance for their functionality. Inflammasomes are predominantly found in immune cells such as dendritic cells and macrophages.

Activation of an inflammasome complex leads to the expression of different caspases that convert inactive interleukin-1beta and interleukin-18 into their active form.

Most short NLRPs have an N-terminal pyrin domain (PYD), followed by the NACHT domain, a NACHT-associated domain (NAD), and a C-terminal leucine-rich region (LRR). NLRP13 has a regulatory function in the innate and adaptive immune system.

Activation of an inflammasome complex leads to the expression of different caspases that convert inactive interleukin-1beta and interleukin-18 into their active form.

Little is known about the mode of action of NLRP13. Functions in certain infections are known. Toxoplasma gondii infected macrophages react to this pathogen with an upregulation of pathogen recognition receptors such as NLRP1, NLRP3, NLRC4, NLRP6, NLRP8, NLRP13, AIM2 and NAIP. This results in the activation of inflammasomes.

1. Chu JQ et al (2016) Production of IL-1β and Inflammasome with Up-Regulated Expressions of NOD-Like Receptor Related Genes in Toxoplasma gondii-Infected THP-1 Macrophages. Korean J Parasitol 54(:711-717.

2. Ponsuksili S et al (2006) Bovine NALP5, NALP8, and NALP9 genes: assignment to a QTL region and the expression in adult tissues, oocytes, and preimplantation embryos. Biol Reprod 74:577-584.