Modulation of thermo-TRP ion channel activity by phosphorylation and trafficking to the membrane

通过磷酸化和运输到膜来调节thermo-TRP离子通道活性

• 批准号: BB/F003072/1
• 负责人: Peter Anthony McNaughton
• 金额: $ 49.64万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FF003072%2F1
• 关键词: Modulation; thermo; TRP; ion; channel

In most sensory systems the perceived intensity of a constant stimulus decreases with time of exposure. This process, known as adaptation, is vital in enabling an animal to operate over the wide range of stimulus intensities present in our natural environment. The sensation of pain is different, however / pain does not decrease but instead increases with time, in a process known as sensitisation, which ensures that a potentially damaging stimulus is not ignored. While sensitisation is vital for the survival of the organism, it is also responsible for enhancing pain in chronic conditions such as arthritis and back pain, where the pain is inescapable, and is a major cause of personal suffering and economic loss. We are beginning to understand the cellular and molecular basis of the process of sensitisation, thanks to work at the level of single pain-sensitive neurons (called nociceptors) and at the level of their molecular components responsible for sensing painful stimuli. The work is important in terms of satisfying our natural curiosity about pain, a fundamental and important process with which we are all familiar. It also has potential benefits for the understanding of other similar signalling pathways, and to provide the underpinning knowledge which can be used in the future development of drugs to suppress pain. The main aim of this work will be to study how sensitisation enhances the function of thermally-activated ion channels. These ion channels, members of the wider TRP family, open in response to heating or cooling and so allow electrical current, in the form of ions, to flow into nerve cells and other cells. By opening, these ion channels alter the membrane voltage inside the cell / for instance, in the case of a nerve cell, opening of a heat-sensitive ion channel named TRPV1 makes the internal voltage more positive, and this initiates nerve impulses which in turn communicate the sensation of heat pain to higher centres. Previous work, much of it in the applicant lab, has shown that sensitisation of TRPV1 is caused by phosphorylation of particular amino acids, and that two separate mechanisms are at work: the sensitivity to heat of ion channels already in the cell membrane is enhanced, and more ion channels are inserted into the membrane. We will investigate the molecular mechanisms of these processes in more detail. Which enzymes (called kinases) carry out the phosphorylation, and which phosphorylated sites on TRPV1 are important for enhancing sensitivity or for promoting channel insertion? A scaffolding protein, AKAP79, seems to hold two such kinases into a macro-molecular complex, which improves the immediacy of signalling direct to TRPV1. Can we delete or antagonise this molecule and so abolish sensitisation? What is the molecular mechanism by which TRPV1 is trafficked to the membrane and removed from the membrane? We will investigate these questions in several systems: in cells where proteins such as TRPV1 have been artificially expressed; in real nociceptive neurons; and in intact animals genetically engineered to express altered levels of molecules such as AKAP79. And finally, how far do studies of TRPV1 generalise to the other thermo-TRPs? This work will enhance our understanding of pain and other sensations mediated by members of the thermo TRP family on ion channels. This information will provide the basis for the development of novel analgesics. In a wider sense our studies will enhance our understanding of how ion channels are trafficked to and from the cell surface membrane, and of how their sensitivity is modulated once they are in the membrane.

在大多数感觉系统中，持续刺激的感知强度随着暴露时间的延长而降低。这个被称为适应的过程，对于使动物能够在我们自然环境中存在的各种刺激强度下运行是至关重要的。疼痛的感觉是不同的，然而/疼痛不会随着时间的推移而减少，而是会随着时间的推移而增加，这一过程被称为敏感化，这确保了潜在的破坏性刺激不会被忽视。虽然敏感化对生物体的生存至关重要，但它也会加剧慢性疾病中的疼痛，如关节炎和背部疼痛，在这些情况下，疼痛是不可避免的，是个人痛苦和经济损失的主要原因。我们开始了解敏感化过程的细胞和分子基础，这要归功于在单个疼痛敏感神经元(称为伤害性感受器)水平上的工作，以及它们负责感知痛苦刺激的分子成分的水平。这项工作在满足我们对疼痛的自然好奇心方面很重要，这是我们都熟悉的一个基本而重要的过程。它也对了解其他类似的信号通路有潜在的好处，并提供了可用于未来止痛药物开发的基础知识。这项工作的主要目的将是研究敏化如何增强热激活离子通道的功能。这些离子通道是更广泛的Trp家族的成员，在加热或冷却时开放，因此允许电流以离子的形式流入神经细胞和其他细胞。通过打开这些离子通道，这些离子通道改变了细胞内的膜电压/例如，对于神经细胞，打开名为TRPV1的热敏离子通道使内部电压更正，这启动了神经冲动，进而将热痛感传递给更高级的中枢。之前的工作，其中大部分是在申请实验室进行的，已经表明TRPV1的敏化是由特定氨基酸的磷酸化引起的，并且有两种不同的机制在起作用：细胞膜中已经存在的离子通道对热的敏感性增强，以及更多的离子通道被插入膜中。我们将更详细地研究这些过程的分子机制。哪些酶(称为激酶)执行磷酸化，TRPV1上的哪些磷酸化位点对于增强敏感性或促进通道插入是重要的？一种名为AKAP79的支架蛋白似乎将两个这样的激酶结合成一个大分子复合体，这提高了直接向TRPV1发送信号的即时性。我们能删除或对抗这个分子，从而消除敏感化吗？TRPV1被转运到膜并从膜上移除的分子机制是什么？我们将在几个系统中研究这些问题：在人工表达TRPV1等蛋白质的细胞中；在真实的伤害性神经元中；以及在经过基因工程以表达改变水平的分子如AKAP79的完整动物中。最后，TRPV1的研究在多大程度上推广到了其他的热TRP？这项工作将加强我们对疼痛和其他由热色氨酸家族成员在离子通道上介导的感觉的理解。这些信息将为新型止痛药的开发提供依据。从更广泛的意义上说，我们的研究将加强我们对离子通道如何进出细胞表面膜的理解，以及一旦离子通道进入细胞表面膜，它们的敏感性是如何调节的。

项目成果

Protease activated receptors 1 and 4 sensitize TRPV1 in nociceptive neurones.

• DOI: 10.1186/1744-8069-6-61
• 发表时间: 2010-09-27
• 期刊: Molecular pain
• 影响因子: 3.3
• 作者: Vellani V;Kinsey AM;Prandini M;Hechtfischer SC;Reeh P;Magherini PC;Giacomoni C;McNaughton PA
• 通讯作者: McNaughton PA

Current perspectives on the modulation of thermo-TRP channels: new advances and therapeutic implications.

Thermo-TRP 通道调节的最新观点：新进展和治疗意义。

• DOI: 10.1586/ecp.10.41
• 发表时间: 2010
• 期刊: Expert review of clinical pharmacology
• 影响因子: 4.4
• 作者: Vay L

How anchoring proteins shape pain.

• DOI: 10.1016/j.pharmthera.2014.04.001
• 发表时间: 2014-09
• 期刊: Pharmacology & therapeutics
• 影响因子: 13.5
• 作者: M. Fischer;P. McNaughton

Functional lipidomics. Calcium-independent activation of endocannabinoid/endovanilloid lipid signalling in sensory neurons by protein kinases C and A and thrombin.

功能脂质组学。

• DOI: 10.1016/j.neuropharm.2008.01.010
• 发表时间: 2008
• 期刊: Neuropharmacology
• 影响因子: 4.7
• 作者: Vellani V

Mapping the binding site of TRPV1 on AKAP79: implications for inflammatory hyperalgesia.

• DOI: 10.1523/jneurosci.4991-12.2013
• 发表时间: 2013-05-22
• 期刊: The Journal of neuroscience : the official journal of the Society for Neuroscience
• 作者: Btesh J;Fischer MJM;Stott K;McNaughton PA
• 通讯作者: McNaughton PA