阿片κ-受体和ORL1受体二聚化的初步研究

为探讨κ-受体(κ-opioid receptor,KOR)和阿片受体样受体(opioid receptor like-1 receptor,ORL1 receptor)是否能够形成异源性受体二聚体,在原代培养的大鼠神经元细胞和用带有HA(hemagglutinin,血细胞凝集素)、Myc或Flag标签的KOR和ORL1质粒共同转染的中国仓鼠卵巢(CHO)细胞、人胚肾上皮(HEK293)细胞上,采用免疫荧光和免疫共沉淀的方法,研究KOR和ORL1之间的共定位以及是否存在相互作用。结果表明:在原代培养的海马和皮质神经元上,KOR和ORL1的免疫荧光在细胞膜上有重叠。同样,在HA-KOR和Myc-ORL1共同瞬时转染的CHO和HEK293细胞上也有类似的发现。另外,在共同表达Flag-KOR和Myc-ORL1的CHO细胞裂解液中,KOR与ORL1的受体蛋白能够被相互免疫共沉淀。这些研究结果提示,作为阿片受体不同亚型的KOR和ORL1受体之间有可能存在着异源二聚体,这也为进一步解释阿片受体结构的多样性和功能的复杂性提供了新的实验依据。     

胰岛素样生长因子-1受体和胰岛素受体双重抑制剂类抗癌药Linsitinib

胰岛素样生长因子-1(IGF-Ⅰ)受体是一种跨膜受体酪氨酸激酶,与许多人类肿瘤的发生发展密切相关,由胞外α亚单位和含跨膜及胞内区部分的β亚单位构成,其中α亚单位负责与IGF-Ⅰ和-Ⅱ等可溶性IGF-Ⅰ受体配体结合,而β亚单位则发挥胞内受体酪氨酸激酶作用.与配体结合后,IGF-Ⅰ受体的同源二聚体和IGF-Ⅰ受体-受体酪氨酸激酶的异源二聚体便自身磷酸化,并激活下游PI3K/Akt/丝氨酸-苏氨酸蛋白激酶雷帕霉素靶蛋白(mTOR)和Ras/有丝分裂原活化蛋白激酶(MAPK)等信号通路,最终抑制细胞凋亡,促进细胞生长和迁移,导致肿瘤的生长和转移.     

雄激素受体抑制剂的研究进展

雄激素受体与前列腺癌的发生、发展密切相关,是配体依赖的转录因子,其与雄激素结合后发生构象转化形成二聚体而活化,并进入细胞核中与相应的 DNA 反应元件结合,促进靶基因的转录,进而促进细胞的增殖。在前列腺癌组织中,雄激素受体的增殖或突变能使其对血清中较低含量的雄激素敏感,是前列腺癌恶化的主要原因。设计合成对野生型及突变型雄激素受体具有较好抑制活性的药物是治疗前列腺癌的首要策略。该文综述了雄激素受体的结构、功能及其抑制剂的研究进展,期望为新型抗前列腺癌药物的设计研究提供参考。     

孕烷X受体对CYP3A基因表达的调控作用及其在药物代谢中的意义

细胞色素P450 3A(cytochrom e P4503As,CYP3As)在药物代谢过程中起重要作用,外源性化学物对肝脏CYP3A基因表达有明显的诱导作用。孕烷X受体(pregnane X recep-tor,PXR)是新发现的孤儿核受体(系统名:NR1 I2)。PXR与另一重要核受体RXR结合形成二聚体结合于CYP3A基因顺式反应元件,参与对CYP3A基因表达的调控作用。大量临床处方药物通过激活PXR而诱导CYP3A基因表达,构成了临床药物间相互作用的分子基础。     

肝X受体调控脂代谢研究进展

肝X受体(LXR)属于核受体家族成员,通过与类视黄醇X受体结合形成异二聚体,调控靶基因的表达.LXR是胆固醇和脂质代谢的重要调节因子,通过调控其靶蛋白ATP结合盒转运蛋白A1、ATP结合盒转运蛋白G1和细胞色素P4507A1等促进胆固醇逆转运.此外,LXR激动剂能够调控脂质代谢及炎症介质基因的表达,改善糖代谢,从而发挥...     

受体介导的肿瘤靶向治疗研究进展

肿瘤细胞表面过度表达一系列受体，能与特异性的配体结合并诱导细胞内化。以这些受体为作用靶点，使抗肿瘤药物与特异性配体结合即可将药物主动靶向肿瘤细胞。本文就近年来研究较多的受体如唾液酸糖蛋白受体、生长因子受体、低密度酯蛋白受体、转铁蛋白受体、叶酸受体、CD44等进行概述。     

肾脏中G蛋白偶联受体信号转导的多样性

G蛋白偶联受体(GPCR)是最重要的药物靶点之一;临床有超过30%处方药是直接作用在GPCR上的。在肾脏中,升压素受体、血管紧张素受体、内皮素受体、前列腺素受体和嘌呤受体等都对肾脏的多种功能有重要的调控作用,也是重要的治疗肾病的药物靶点。多种靶向这些肾脏GPCR的激动剂或者拮抗剂已经进入临床应用或者临床测试阶段。然而,这些GPCR药物的设计主要以激动剂和拮抗剂进行区分,与GPCR的功能多样性存在着一定的鸿沟。我们最近在研究靶向血管紧张素受体(AT1R)的药理学研究过程中,不仅发现了高同型半胱氨酸是血管紧张素受体的内源性配体,还发现Arrestin偏向性信号途径不仅可以介导传统的第二波信号途径,还可以在时序上进行第一波信号转导,通过激活TRPC3来促进肾上腺素的释放,从而产生在治疗心血管疾病时的有害作用。我们据此提出了更合理的靶向AT1R开发药物的方法。不仅如此,我们还针对升压素受体的磷酸化编码,阐明了Arrestin对GPCR的磷酸化编码的识别机制,Arrestin的多聚脯氨酸码头的分选机制,以及配体通过操控受体7此跨膜核心与Arrestin的相互作用来指导Arrestin功能的机制。这些研究工作为以后特异性的靶向GPCR的Arrestin信号通路开发药物奠定了基础。     

阿片类受体亚型间相互作用研究进展

阿片类受体是一种G蛋白偶联受体,在许多生理活动尤其是镇痛作用中发挥重要功能。近年来研究发现阿片类受体不同亚型间会发生结构或(和)功能上的相互作用,协同参与信号识别及转导,并能产生增强镇痛活性,减弱不良反应等效果。该文总结了阿片类受体间相互作用的最新研究进展,并对同时作用不同受体的镇痛药物可能的发展前景进行了展望。     

雌激素受体的生物学功能及其在骨骼肌发育和前列腺癌中作用的研究进展

雌激素受体(ER)是核受体家族中重要的一员,在多种组织中广泛表达,包括肌肉、乳腺、前列腺等.ER主要包括ERα 和ERβ,当雌激素与ER结合后,通过形成同源或异源二聚体进入细胞核中促进多种转录因子的激活,从而调节复杂、动态的基因网络.ER在调节细胞的增殖、凋亡和自噬等过程中发挥重要作用,且与多种疾病的发生与发展密切相关...     

腺苷受体在纤维化疾病发病中的作用研究进展

纤维化可发生于多种器官,持续进展可致器官结构破坏和功能衰退,乃至器官衰竭,严重威胁人类健康和生命。腺苷是一种内源性嘌呤核苷,在人体各组织中均能生成,主要通过与4种不同的G-蛋白偶联受体结合,在体内发挥不同的作用。近来研究发现,腺苷受体(adenosine receptors,ARs)在组织再生和纤维化过程中发挥重要作用,了解这些过程可能在纤维化疾病的治疗上能发挥重要作用。该文就近年来对ARs在纤维化疾病中的研究进展进行讨论。     

The future of G protein-coupled receptors as targets in drug discovery

G protein-coupled receptors (GPCRs) represent the most abundant drug targets today. A large number of GPCR-based drugs have already been developed for a variety of indications in human disease. However, orphan receptors with unidentified ligands serve as potential targets still to be explored. Moreover, research on the interaction of GPCRs with different molecules in the signal transduction pathways, and further studies on receptor dimerization may also lead to the discovery of new drugs. Structure-based drug design will eventually play a key role in generating better and more selective drugs more rapidly when high-resolution structures of GPCRs can be provided by expression, purification and crystallography technologies.     

Emerging role of homo- and heterodimerization in G-protein-coupled receptor biosynthesis and maturation

The idea that G-protein-coupled receptors (GPCRs) can function as dimers is now generally accepted. Although an increasing amount of data suggests that dimers represent the basic signaling unit for most, if not all, members of this receptor family, GPCR dimerization might also be necessary to pass quality-control checkpoints of the biosynthetic pathway of GPCRs. To date, this hypothesis has been demonstrated unambiguously only for a small number of receptors that must form heterodimers to be exported properly to the plasma membrane (referred to as obligatory heterodimers). However, increasing evidence suggests that homodimerization might have a similar role in the receptor maturation process for many GPCRs.     

Computational methods in drug design: Modeling G protein-coupled receptor monomers, dimers, and oligomers

G protein-coupled receptors (GPCRs) are membrane proteins that serve as very important links through which cellular signal transduction mechanisms are activated. Many vital physiological events such as sensory perception, immune defense, cell communication, chemotaxis, and neurotransmission are mediated by GPCRs. Not surprisingly, GPCRs are major targets for drug development today. Most modeling studies in the GPCR field have focused upon the creation of a model of a single GPCR (ie, a GPCR monomer) based upon the crystal structure of the Class A GPCR, rhodopsin. However, the emerging concept of GPCR dimerization has challenged our notions of the monomeric GPCR as functional unit. Recent work has shown not only that many GPCRs exist as homo- and heterodimers but also that GPCR oligomeric assembly may have important functional roles. This review focuses first on methodology for the creation of monomeric GPCR models. Special emphasis is given to the identification of localized regions where the structure of a GPCR may diverge from that of bovine rhodopsin. The review then focuses on GPCR dimers and oligomers and the bioinformatics methods available for identifying homo- and heterodimer interfaces.     

G蛋白偶联受体二聚化在药物开发中所发挥的特异性作用(英文)

G蛋白偶联受体(GPCRs)是与G蛋白相偶联的七次跨膜受体,其成员有上千种,是重要的药物靶点之一。目前,GPCRs相关药物占市场上药物的40%-50%。在过去的十年中,对GPCRs主要以单体的形式存在着的这一假说做出了重新评估,大量事实证明GPCRs也能以同源或异源二聚体,甚至是高阶寡聚体的形式存在,比较热门的领域是GPCRs二聚化。最近研究表明同源或异源二聚化有不同于单体的特异功能特征,包括配体识别、信号转导、运输等。同时,在较少副作用治疗疾病的新药开发上,具有不同病理和信号转导途径的二聚体的出现开辟了新的领域。本综述主要介绍二聚体的特异结构及其特异的信号转导途径,从而有助于在GPCRs药物开发中取得丰硕的成果。     

Gq protein-coupled receptors as targets for anesthetics

The mechanisms of action of anesthetics are unclear. Much attention has been focused on ion channels in the central nervous system as targets for anesthetics. During the last decade, major advances have been made in our understanding of the physiology and pharmacology of G-protein-coupled receptor (GPCR) signaling. Several lines of studies have shown that GPCRs are targets for anesthetics and that some anesthetics inhibit the functions of Gq-coupled receptors, including muscarinic acetylcholine (ACh) M(1), metabotropic type 5 glutamate, 5-hydroxytryptamine (5-HT) type 2A, and substance P receptors. Nearly 160 GPCRs have been identified, based on their gene sequence and ability to interact with known endogenous ligands. However, an estimated 500-800 additional GPCRs have been classified as "orphan" receptors (oGPCRs) because their endogenous ligands have not yet been identified. Given that known GPCRs are targets for anesthetics, these oGPCRs represent a rich group of receptor targets for anesthetics. This article highlights the effects of anesthetics on Gq-coupled receptors, and discusses whether GPCRs other than Gq-coupled receptors are targets for anesthetics.     

Structural insights into adrenergic receptor function and pharmacology

It has been over 50years since Sir James Black developed the first beta adrenergic receptor (βAR) blocker to treat heart disease. At that time, the concept of cell surface receptors was relatively new and not widely accepted, and most of the tools currently used to characterize plasma membrane receptors had not been developed. There has been remarkable progress in receptor biology since then, including the development of radioligand binding assays, the biochemical characterization of receptors as discrete membrane proteins, and the cloning of the first G-protein-coupled receptors (GPCRs), which led to the identification of other members of the large family of GPCRs. More recently, progress in GPCR structural biology has led to insights into the three-dimensional structures of βARs in both active and inactive states. Despite all of this progress, the process of developing a drug for a particular GPCR target has become more complex, time-consuming and expensive.     

Role of endocytosis in mediating downregulation of G-protein-coupled receptors

Many G-protein-coupled receptors (GPCRs) undergo agonist-induced endocytosis. Such endocytosis has been implicated in diverse processes of receptor regulation, including reversible sequestration of receptors in endosomes and proteolytic downregulation of receptors in lysosomes. The precise relationships between membrane pathways that mediate receptor sequestration and downregulation remain controversial. Recent studies suggest that GPCRs can be segregated within distinct microdomains of the plasma membrane before endocytosis occurs, and others suggest that certain GPCRs are sorted between divergent membrane pathways after endocytosis by clathrin-coated pits. Furthermore, emerging data implicate a specific role of the actin cytoskeleton and receptor phosphorylation in controlling endocytic sorting of a particular GPCR. In this article, recent research into endocytosis of GPCRs will be discussed together with some important and unresolved questions regarding the diversity and specificity of mechanisms that mediate downregulation of GPCRs.     

Pharmacological aspects of the effects of tramadol on G-protein coupled receptors

Tramadol is an analgesic that is used worldwide, but its mechanisms of action have not been elucidated. It has been speculated that tramadol acts primarily through the activation of micro-opioid receptors and the inhibition of monoamine reuptake. The majority of studies to date have focused on ion channels in the central nervous system as targets of anesthetics and analgesics. During the past decade, major advances have been made in our understanding of the physiology and pharmacology of G-protein coupled receptor (GPCR) signaling. Several studies have shown that GPCRs and ion channels are targets for analgesics and anesthetics. In particular, tramadol has been shown to affect GPCRs, including muscarinic acetylcholine receptors and 5-hydroxytryptamine receptors. Here, the effects of tramadol on monoamine transporters, GPCRs, and ion channels are presented, and recent research on the pharmacology of tramadol is discussed.     

Physiological relevance of GPCR oligomerization and its impact on drug discovery

The potentially large functional and physiological diversity of G-protein coupled receptor (GPCR) dimers has generated a great deal of excitement about the opportunity that dimerization provides for enabling novel drug discovery. The discovery of physiologically relevant GPCR dimers suggests that new drug targets for diseases such as schizophrenia and pre-eclampsia can be developed by targeting dimers. Most of the previous work on GPCR dimers made use of the overexpression of differentially tagged GPCRs in heterologous cell systems. Current emphasis on the development of physiologically relevant cell systems that endogenously express the appropriate combination of GPCR dimers and accessory proteins is leading to dramatic increases in our understanding of GPCR dimers. These and other new tools such as GPCR-specific antibodies will be required to develop GPCR dimer specific drugs. Given that ligands are available for only a small percentage of the large number of potentially druggable GPCRs, the use of GPCR dimers might provide the necessary targets to increase the breadth and depth of receptors available for therapeutic interventions.     

Heterodimerization and surface localization of G protein coupled receptors

G protein coupled receptors (GPCRs) are one of the largest human gene families, and are targets for many important therapeutic drugs. Over the last few years, there has been a major paradigm shift in our understanding of how these receptors function. Formerly, GPCRs were thought to exist as monomers that, upon agonist occupation, activated a heterotrimeric G protein to alter the concentrations of specific second messengers. Until recently, this relatively linear cascade has been the standard paradigm for signaling by these molecules. However, it is now clear that this model is not adequate to explain many aspects of GPCR function. We now know that many, if not most, GPCRs form homo- and/or hetero-oligomeric complexes and interact directly with intracellular proteins in addition to G proteins. It now appears that many GPCRs may not function independently, but might more accurately be described as subunits of large multi-protein signaling complexes. These observations raise many important new questions; some of which include: (1) how many functionally and pharmacologically distinct receptor subtypes exist in vivo? (2) Which GPCRs physically associate, and in what stochiometries? (3) What are the roles of individual subunits in binding ligand and activating responses? (4) Are the pharmacological or signaling properties of GPCR heterodimers different from monomers? Since these receptors are the targets for a large number of clinically useful compounds, such information is likely to be of direct therapeutic importance, both in understanding how existing drugs work, but also in discovering novel compounds to treat disease.