Zurhove Kai, Nakajima Chikako, Herz Joachim, Bock Hans H, May Petra
Department of Medicine II, University Hospital, University of Freiburg, 79106 Freiburg, Germany.
Sci Signal. 2008 Nov 25;1(47):ra15. doi: 10.1126/scisignal.1164263.
Inflammation is a potentially self-destructive process that needs tight control. We have identified a nuclear signaling mechanism through which the low-density lipoprotein receptor-related protein 1 (LRP1) limits transcription of lipopolysaccharide (LPS)-inducible genes. LPS increases the proteolytic processing of the ectodomain of LRP1, which results in the gamma-secretase-dependent release of the LRP1 intracellular domain (ICD) from the plasma membrane and its translocation to the nucleus, where it binds to and represses the interferon-gamma promoter. Basal transcription of LPS target genes and LPS-induced secretion of proinflammatory cytokines are increased in the absence of LRP1. The interaction between LRP1-ICD and interferon regulatory factor 3 (IRF-3) promotes the nuclear export and proteasomal degradation of IRF-3. Feedback inhibition of the inflammatory response through intramembranous processing of LRP1 thus defines a physiological role for gamma-secretase.
炎症是一个需要严格调控的潜在自我破坏过程。我们已经确定了一种核信号传导机制，通过该机制低密度脂蛋白受体相关蛋白1（LRP1）限制脂多糖（LPS）诱导基因的转录。LPS增加LRP1胞外域的蛋白水解加工，这导致LRP1细胞内结构域（ICD）从质膜上以γ-分泌酶依赖的方式释放，并转运至细胞核，在细胞核中它与干扰素-γ启动子结合并抑制其活性。在缺乏LRP1的情况下，LPS靶基因的基础转录和LPS诱导的促炎细胞因子分泌增加。LRP1-ICD与干扰素调节因子3（IRF-3）之间的相互作用促进IRF-3的核输出和蛋白酶体降解。因此，通过LRP1的膜内加工对炎症反应进行反馈抑制确定了γ-分泌酶的生理作用。
