Immunity Review Regulation of the Antimicrobial Response by NLR Proteins Eran Elinav,1,3 Till Strowig,1,3 Jorge Henao-Mejia,1,3 and Richard A. Flavell1,2,* 1Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA 2Howard Hughes Medical Institute 3These authors contributed equally to this work *Correspondence: richard.fl
[email protected] DOI 10.1016/j.immuni.2011.05.007 Nucleotide-binding, oligomerization domain (NOD)-like receptor (NLR) proteins are a family of innate immune receptors that play a pivotal role in microbial sensing, leading to the initiation of antimicrobial immune responses. Dysregulation of the function of multiple NLR family members has been linked, both in mice and humans, to a propensity for infection and autoinflammatory disease. Despite our increased under- standing of NLR function and interactions, many aspects related to mechanisms of sensing, downstream signaling, and in vivo functions remain elusive. In this review, we focus on key members of the NLR family, describing their activation by diverse microbes, downstream effector functions, and interactions with each other and with other innate sensor protein families. Also discussed is the role of microbial sensing by NLR receptors leading to activation of the adaptive immune arm that collaborates in the antimicrobial defense. Introduction building block of the cell wall. Although it is present only in Nucleotide-binding, oligomerization domain-like receptor (NLR) smaller amounts in Gram-negative bacteria, its general abun- proteins are a family of proteins with diverse functions in the dance and its highly conserved structure make PGN a prime immune system, characterized by a shared domain architecture target for recognition by pattern recognition receptors (PRRs).