The Nod-like receptor (NLR) family: a tale of similarities and differences.

Bibliographic Details
Title: The Nod-like receptor (NLR) family: a tale of similarities and differences.
Authors: Martina Proell, Stefan J Riedl, Jörg H Fritz, Ana M Rojas, Robert Schwarzenbacher
Source: PLoS ONE, Vol 3, Iss 4, p e2119 (2008)
Publisher Information: Public Library of Science (PLoS), 2008.
Publication Year: 2008
Collection: LCC:Medicine
LCC:Science
Subject Terms: Medicine, Science
More Details: Innate immunity represents an important system with a variety of vital processes at the core of many diseases. In recent years, the central role of the Nod-like receptor (NLR) protein family became increasingly appreciated in innate immune responses. NLRs are classified as part of the signal transduction ATPases with numerous domains (STAND) clade within the AAA+ ATPase family. They typically feature an N-terminal effector domain, a central nucleotide-binding domain (NACHT) and a C-terminal ligand-binding region that is composed of several leucine-rich repeats (LRRs). NLRs are believed to initiate or regulate host defense pathways through formation of signaling platforms that subsequently trigger the activation of inflammatory caspases and NF-kB. Despite their fundamental role in orchestrating key pathways in innate immunity, their mode of action in molecular terms remains largely unknown. Here we present the first comprehensive sequence and structure modeling analysis of NLR proteins, revealing that NLRs possess a domain architecture similar to the apoptotic initiator protein Apaf-1. Apaf-1 performs its cellular function by the formation of a heptameric platform, dubbed apoptosome, ultimately triggering the controlled demise of the affected cell. The mechanism of apoptosome formation by Apaf-1 potentially offers insight into the activation mechanisms of NLR proteins. Multiple sequence alignment analysis and homology modeling revealed Apaf-1-like structural features in most members of the NLR family, suggesting a similar biochemical behaviour in catalytic activity and oligomerization. Evolutionary tree comparisons substantiate the conservation of characteristic functional regions within the NLR family and are in good agreement with domain distributions found in distinct NLRs. Importantly, the analysis of LRR domains reveals surprisingly low conservation levels among putative ligand-binding motifs. The same is true for the effector domains exhibiting distinct interfaces ensuring specific interactions with downstream target proteins. All together these factors suggest specific biological functions for individual NLRs.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1932-6203
Relation: http://europepmc.org/articles/PMC2323615?pdf=render; https://doaj.org/toc/1932-6203
DOI: 10.1371/journal.pone.0002119
Access URL: https://doaj.org/article/ffc142f12c31457ca436b62854c8e521
Accession Number: edsdoj.ffc142f12c31457ca436b62854c8e521
Database: Directory of Open Access Journals
More Details
ISSN:19326203
DOI:10.1371/journal.pone.0002119
Published in:PLoS ONE
Language:English