Agonist-evoked changes in TRPV ion channel selectivity

激动剂引起的 TRPV 离子通道选择性变化

• 批准号: 7539193
• 负责人: Michael J Caterina
• 金额: $ 25.11万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-07 至 2011-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7539193
• 关键词: Address; Afferent Neurons; Agonist; Amino Acids; Binding; Biological; Capsaicin; Cations; Cell Death; Cellular Morphology; Chemical Stimulation; Chemicals; Classification; DNA Sequence Rearrangement; Development; Divalent Cations; Doctor of Medicine; Doctor of Philosophy; Environment; Esthesia; Event; Excision; Exhibits; Fluorescence Microscopy; Goals; Heating; In Vitro; Ion Channel; Ions; Lipids; Mediating; Mus; Mutagenesis; Nerve; Neurotransmitters; Pain; Permeability; Phospholipids; Phosphorylation; Process; Property; Reagent; Regulation; Relative (related person); Reporting; Research Personnel; Role; Shapes; Signal Transduction; Stimulus; TRP channel; TRPV1 gene; Temperature; Testing; Time; Vanilloid; base; capsaicin receptor; chronic pain; cytokine; density; genetic regulatory protein; in vivo; insight; keratinocyte; member; mutant; neurotoxicity; neurotransmitter release; novel; programs; receptor; response

The capsaicin receptor, TRPV1, is one of four cation channels of the transient receptor potential vanilloid (TRPV) subfamily that can be activated by warm or painfully hot temperatures. Several of these channels (TRPV1, TRPV3, TRPV4) have been shown to participate in heat-evoked pain sensation in mice. We recently found that heat-evoked activation of TRPV3 results in a biphasic current response that reflects an initial channel block by divalent cations and subsequent removal of that block by persistent stimulation. This loss of block is dependent on channel density, proceeds synchronously, once initiated, and isassociated with increased permeability to the large organic cation N-methyl-d-glucamine (NMDG). Dynamic ion selectivity in TRPV channels could have implications for neurotransmitter release, pain sensation, and capsaicin neurbtoxicity, among other processes. We therefore propose to test the hypotheses that these changes in TRPV3 function reflect progressive heat-evoked dilation of the channel pore, and that TRPV1 also exhibits pore dilation in response to strong chemical or thermal activation. In addition, we will determine whether pore dilation occurs in native TRPV1 and TRPV3 expressed in sensory neurons and keratinocytes, respectively. Using electrophysiological and fluorescence microscopy approaches, we will examine the mechanistic basis of TRPV1 and TRPV3 pore dilation and explore the relationship between agonist-evoked pore dilation and known or presumed mechanisms of TRPV1 and TRPV3 regulation, such as phosphorylation and phospholipid binding. Finally, we will seek to identify amino acids that are selectively important for agonist-evoked pore dilation in TRPV1 and TRPV3 via systematic mutagenesis of residues within the domains adjacent to the selectivity filter. Mutants arising from this screen will be further examined for their abilities to mediate potential "downstream" effects of pore dilation, including changes in cell morphology, cell death, and neurotransmitter/cytokine release in native and non-native cellular contexts. These studies will allow us to determine whether and how the ion selectivities of TRPV1 and TRPV3 are regulated and may provide a rational basis for the development of either anti-dilation antagonists or dilation- promoting agonists, for the treatment of chronic pain.

辣椒素受体TRPV1是瞬时受体电位香草素的四个阳离子通道之一