未折叠蛋白反应的信号通路

对于真核细胞来说,内质网（endoplasmic reticulum,ER）承担新生蛋白质的折叠、组装和转运。内质网的蛋白折叠机制对了解疾病的发展过程和治疗提供了新的方向,成为当下研究的热点。在蛋白质折叠过程中,由于各种原因会使得未折叠蛋白或错误折叠蛋白增多。然而,在细胞内存在一种机制,这一机制可以通过调整内质网折叠蛋白的数量和加强内质网的折叠能力,来减少未折叠蛋白或错误折叠蛋白的进一步生成,缓解内质网压力,即未折叠蛋白反应（unfolded protein response,UPR）。     

需肌醇酶1α及受其调控的依赖性衰减(IRE1α-RIDD)在免疫调节及自身免疫性疾病中的研究进展

内质网(ER)是蛋白质合成、折叠和修饰以及脂质合成和钙离子储存的重要细胞器。ER功能失调导致错误折叠或未折叠蛋白质在ER管腔中的积累,触发未折叠蛋白反应(UPR),需肌醇酶1α(IRE1α)是UPR分支中最保守的信号通路,切割编码转录因子XBP1的mRNA,导致XBP1剪接和激活。IRE1还通过受调控的IRE1依赖性衰减(RIDD)切割相关的mRNA或微小RNA (miRNA)。已有研究证明IRE1α-RIDD途径与免疫反应相关,但其信号级联与免疫协调的机制仍然不清楚,我们总结了IRE1α-RIDD对免疫细胞分化、成熟和免疫反应中细胞因子的表达等在免疫反应中的作用以及参与自身免疫性疾病的分子机制。     

未折叠蛋白反应——从内质网到细胞核的细胞内信号传导

在真核细胞中 ,内质网 (ER)中未折叠蛋白聚集时 ,细胞为生存便会启动未折叠蛋白反应 (unfoldedprotein response ,U PR) ,这种反应首先发现于酵母中 ,而其保守性使人们对哺乳动物细胞的 U PR有了一定的认识。近年来发现哺乳动物细胞的 U PR不仅参与蛋白质合成和分泌通路的调节 ,还与蛋白质翻译水平下调、细胞周期停滞、细胞凋亡及内质网相关性蛋白质降解 (ER- associated degradation ,ERAD)等生理过程有关。     

内质网应激介导细胞凋亡及免疫炎症反应的研究进展

内质网是一种细胞器,可以使新合成的蛋白质通过甲基化、羟基化、脂化或形成二硫键正确折叠。内质网应激(endoplasmic reticulum stress,ERS)是由内腔中未折叠蛋白的积累引起的细胞应激反应。为应对ERS,细胞建立了一种进化保守的机制,称为未折叠蛋白反应(unfolded protein respon...     

内质网应激调控NLRP3炎症小体的研究进展

内质网是真核细胞中负责蛋白合成和折叠的重要细胞器,当未折叠或错误折叠蛋白在内质网腔内累积引起内质网应激时,内质网通过启动未折叠蛋白反应维持细胞稳态。炎症小体是细胞内的一种多蛋白复合物,活化后剪切Pro-Caspase-1,产生IL-1β等促炎因子,引发细胞焦亡,在固有免疫和适应性免疫中均发挥重要作用。在目前已知的多种炎症小体中,NLRP3炎症小体研究得最为深入。近年来研究表明,内质网应激与NLRP3炎症小体有密切联系,参与调控NLRP3炎症小体的活化,并在炎症性疾病的发生发展中起重要作用。本文对内质网应激参与调控NLRP3炎症小体的相关研究进展进行简要综述。     

钙联蛋白调控内质网应激诱导的细胞凋亡

内质网应激(ERS)可诱导多种细胞凋亡,与疾病发生发展密切相关.钙联蛋白(CNX)是内质网中重要的类凝集素分子伴侣,通过参与未折叠蛋白反应募集凋亡相关因子、激活IRE1-JNK激酶等途径,调控ERS诱导的凋亡.本文就其研究现状进行阐述.     

内质网应激在急性肺损伤中的研究进展

内质网是细胞内重要的细胞器之一,主要参与蛋白质的加工和修饰,引导其正确的折叠与组装.在各种刺激因素如感染、氧化应激等的作用下,内质网会发生功能紊乱,导致内质网应激(endoplasmic reticulum stresses,ERS).持续的ERS可导致未折叠蛋白反应(unfolded protein response...     

内质网应激在丙肝病毒感染发病学中作用的研究进展

丙型肝炎病毒(HCV)常扰乱内质网稳态,其复制中间产物的积累可导致内质网应激(ERS),与多种疾病的发生密切相关.为了应对内质网应激所带来的有害影响,细胞激活未折叠蛋白反应(UPR)和凋亡通路.在病毒感染的初期,未折叠蛋白反应主要用于清除病毒产生的蛋白和其他中间产物;而当感染进一步深化,稳态不能维持时细胞则激活凋亡通路...     

内质网应激反应基因表达调控的多样性

内质网通过激活未折叠蛋白反应(unfolded protein response,UPR),包括蛋白合成暂停、内质网分子伴侣和折叠酶等蛋白表达上调、诱导内质网相关性降解(ER-associated degradation,ERAD),以至细胞功能不能恢复,最后诱导内质网相关性细胞凋亡,清除受损细胞,保护机体生存。所有这些内质网相关反应都是各种应激信号刺激内质网,引起多种内质网应激基因表达的结果。转录、翻译以及翻译后加工各个环节对内质网应激时基因的表达产生调控,且方式各不相同。     

未折叠蛋白反应在肝癌中的作用研究进展

内质网(ER)是交织分布于哺乳动物真核细胞内的一个膜的管道系统.各种生理和病理因素均可引发内质网应激(ERS)使细胞受损伤.由于ERS时ER内的未折叠蛋白和错误折叠蛋白增多,使ER功能紊乱,从而引发了未折叠蛋白反应(UPR),保护由内质网应激引起的细胞损伤,恢复细胞的正常功能.本文介绍了UPR的发生、发展机制,综述了国内外对UPR和肝癌的最新研究进展.     

The unfolded protein response--a stress signaling pathway of the endoplasmic reticulum

The endoplasmic reticulum (ER) is a factory for folding and maturation of newly synthesized transmembrane and secretory proteins. The ER provides stringent quality control systems to ensure that only correctly folded proteins exit the ER and unfolded or misfolded proteins are retained and ultimately degraded. A number of biochemical and physiological stimuli can change ER homeostasis, impose stress to the ER, and subsequently lead to accumulation of unfolded or misfolded proteins in the ER lumen. The ER has evolved stress response signaling pathways collectively called the unfolded protein response (UPR) to cope with the accumulation of unfolded or misfolded proteins. This review summarizes our understanding of the UPR signaling developed in the recent years.     

ER and aging—Protein folding and the ER stress response

The endoplasmic reticulum (ER) is a multifunctional organelle which co-ordinates protein folding, lipid biosynthesis, calcium storage and release. Perturbations that disrupt ER homeostasis lead to the misfolding of proteins, ER stress and up-regulation of a signaling pathway called the ER stress response or the unfolded protein response (UPR). The UPR is characterized by the induction of chaperones, degradation of misfolded proteins and attenuation of protein translation. Age-related declines and activity in key molecular chaperones and folding enzymes compromise proper protein folding and the adaptive response of the UPR. This review will highlight age-related changes in the protein folding machinery and in the UPR.     

Exploring ER stress response in cellular aging and neuroinflammation in Alzheimer's disease

One evident hallmark of Alzheimer’s disease (AD) is the irregular accumulation of proteins due to changes in proteostasis involving endoplasmic reticulum (ER) stress. To alleviate ER stress and reinstate proteostasis, cells undergo an integrated signaling cascade called the unfolded protein response (UPR) that reduces the number of misfolded proteins and inhibits abnormal protein accumulation. Aging is associated with changes in the expression of ER chaperones and folding enzymes, leading to the impairment of proteostasis, and accumulation of misfolded proteins. The disrupted initiation of UPR prevents the elimination of unfolded proteins, leading to ER stress. In AD, the accumulation of misfolded proteins caused by sustained cellular stress leads to neurodegeneration and neuronal death. Current research has revealed that ER stress can trigger an inflammatory response through diverse transducers of UPR. Although the involvement of a neuroinflammatory component in AD has been documented for decades, whether it is a contributing factor or part of the neurodegenerative events is so far unknown. Besides, a feedback loop occurs between neuroinflammation and ER stress, which is strongly associated with neurodegenerative processes in AD. In this review, we focus on the current research on ER stress and UPR in cellular aging and neuroinflammatory processes, leading to memory impairment and synapse dysfunction in AD.     

The Unfolded Protein Response in Homeostasis and Modulation of Mammalian Immune Cells

The endoplasmic reticulum (ER) plays important roles in eukaryotic protein folding and lipid biosynthesis. Several exogenous and endogenous cellular sources of stress can perturb ER homeostasis leading to the accumulation of unfolded proteins in the lumen. Unfolded protein accumulation triggers a signal-transduction cascade known as the unfolded protein response (UPR), an adaptive mechanism which aims to protect cells from protein aggregates and to restore ER functions. Further to this protective mechanism, in immune cells, UPR molecular effectors have been shown to participate in a wide range of biological processes such as cell differentiation, survival and immunoglobulin and cytokine production. Recent findings also highlight the involvement of the UPR machinery in the maturational program and antigen presentation capacities of dendritic cells. UPR is therefore a key element in immune system homeostasis with direct implications on both adaptive and innate immune responses. The present review summarizes the knowledge on the emerging roles of UPR signaling cascades in mammalian immune cells as well as the consequences of their dysregulation in relation to the pathogenesis of several diseases.