TLR2和TLR4的TLR/IL-1 receptor结构与功能

The structure and function of TLR2 and TLR4 TLR/ IL-1 receptors

Toll样受体（Toll like receptor，TLR）是架接固有免疫和适应性免疫的桥梁。迄今为止，已鉴定的人TLR有10种，分别命名为TLR1-TLR10，TLR是一种I型跨膜蛋白，由胞外富含亮氨酸重复序YtJ（LRR）结构域，胞内保守的Toll／IL-1受体（TIR）结构域和跨膜结构域构成。TLRs在识别病原体相关分子模式后，其信号的特异转导主要取决于TLRs的TIR功能域与下游接头分子的TIR功能域的特异相互作用。然而，TLR2和TLR4的TIR功能域在其与下游接头分子Mal和MyD88相互作用、以及TLRs同源或异源二聚化方面的作用模式存在明显的差异。本文就TLR2和TLR4的TIR结构与功能进行简要综述，有助于我们进一步了解TLRTIR功能域与下游接头分子的相互作用。

The discovery of Toll-like receptors （TLRs） has greatly advanced our understanding of innate immune responses. So far, 10 functional TLRs （TLR1-TLR10） have been identified in humans. TLRs are type I transmembrane proteins containing ectodomains of leucine-rich repeats, transmembrane domains, and intracellular Toll-interleukin 1 （IL-1） receptor （TIR） domains. Upon ligand induced receptor dimerisation, a series of homotypic TIR-TIR interactions leads to the recruitment of these TIR-containing adaptor proteins proximal to the receptor complex. TIR domain in TLR2 or TLR4 plays different role in interaction with adaptor molecular Mal and MyD88, besides TIR domains are also involved in diverse Toll receptor dimerization. Here we reviewed the structure-function studies of TLR2 and TLR4 TIR, which help define the TLRs TIR domain interface involved in protein- protein interactions.