Mellroth Peter, Karlsson Jenny, Håkansson Janet, Schultz Niklas, Goldman William E, Steiner Håkan
Department of Genetics, Microbiology, and Toxicology, University of Stockholm, S-106 91 Stockholm, Sweden.
Proc Natl Acad Sci U S A. 2005 May 3;102(18):6455-60. doi: 10.1073/pnas.0407559102. Epub 2005 Apr 20.
Drosophila knockout mutants have placed peptidoglycan recognition proteins (PGRPs) in the two major pathways controlling immune gene expression. We now examine PGRP affinities for peptidoglycan. PGRP-SA and PGRP-LCx are bona fide pattern recognition receptors, and PGRP-SA, the peptidoglycan receptor of the Toll/Dif pathway, has selective affinity for different peptidoglycans. PGRP-LCx, the default peptidoglycan receptor of the Imd/Relish pathway, has strong affinity for all polymeric peptidoglycans tested and for monomeric peptidoglycan. PGRP-LCa does not have affinity for polymeric or monomeric peptidoglycan. Instead, PGRP-LCa can form heterodimers with LCx when the latter is bound to monomeric peptidoglycan. Hence, PGRP-LCa can be said to function as an adaptor, thus adding a new function to a member of the PGRP family.
果蝇基因敲除突变体已将肽聚糖识别蛋白(PGRPs)置于控制免疫基因表达的两条主要途径中。我们现在研究PGRPs对肽聚糖的亲和力。PGRP-SA和PGRP-LCx是真正的模式识别受体,并且PGRP-SA作为Toll/Dif途径的肽聚糖受体,对不同的肽聚糖具有选择性亲和力。PGRP-LCx是Imd/Relish途径的默认肽聚糖受体,对所有测试的聚合肽聚糖和单体肽聚糖都具有很强的亲和力。PGRP-LCa对聚合或单体肽聚糖没有亲和力。相反,当LCx与单体肽聚糖结合时,PGRP-LCa可以与LCx形成异二聚体。因此,可以说PGRP-LCa起到衔接子的作用,从而为PGRP家族的一个成员增添了新功能。