TRP Ion Channels in Vomernasal and Taste Transduction

描述（由申请人提供）：最近的研究表明，脊椎动物的犁鼻和味觉转导具有相似的转导途径：G蛋白偶联受体通过磷脂酶C （PLC）信号打开TRP家族离子通道的一个成员，TRPC2用于犁鼻器官（VNO）， TRPM5用于味觉。TRPC2敲除小鼠对信息素缺乏反应，TRPM5敲除小鼠对苦味、甜味和氨基酸味道缺乏反应，这些离子通道对化学感觉的重要性得到了强调。了解TRP离子通道的门控机制在任何系统中都被证明是困难的，并且仍然是理解味觉和VNO转导的重要目标。在上一期研究中，我们发现TRPM5可被细胞内Ca +激活，这表明Ca +可能是某些味觉转导形式的第二信使。在下一个资助期，我们的目标是了解TRPM5调控的分子机制，以及TRPM5的分子特性如何影响味觉。我们将具体解决以下问题：(1)TRPM5通道激活和失活的机制是什么？在这些研究中，我们将使用膜片钳记录表达的TRPM5，以及通道的药理学和结构操作。(2) TRPM5阻滞剂是否会干扰味觉检测？阻断剂将通过膜片钳记录从表达TRPM5的细胞中鉴定出来，并确定鉴定出的阻断剂对小鼠味觉阈值的影响。(3)与TRPM5相似的通道是否在VNO转导中发挥作用？TRPM5及相关通道在体内广泛表达，这些通道的突变可能是某些病理状态的基础。通过了解这些通道的调节，我们可以了解它们在健康和疾病信号传导中的作用。

DESCRIPTION (provided by applicant): Recent work indicates that vomeronasal and taste transduction in vertebrates share similar transduction pathways: G protein-coupled receptors signal through phospholipase C (PLC) to open a member of the TRP family of ion channels, TRPC2 for the vomeronasal organ (VNO) and TRPM5 for taste. The importance of these ion channels for chemosensation is highlighted by the lack of response to pheromones in TRPC2 knockout mice and to bitter, sweet and amino acid tastes in TRPM5 knockout animals. Understanding the mechanisms by which TRP ion channels are gated, has proven difficult in any system, and remains an essential goal for understanding taste and VNO transduction. In the last grant period, we discovered that TRPM5 is activated by intracellular Ca +, suggesting that Ca + may be the second messenger for some forms of taste transduction. In the next grant period we aim to understand the molecular mechanisms that underlie regulation of TRPM5, and how molecular properties of TRPM5 influence taste sensation. We will specifically address the following questions: (1) What are the mechanisms by which TRPM5 channels are activation and inactivated? In these studies we will use patch-clamp recording of expressed TRPM5, together with pharmacological and structural manipulations of the channel. (2) Do blockers of TRPM5 interfere with taste detection? Blockers will be identified by patch-clamp recording from cells expressing TRPM5 and the effects of identified blockers on taste thresholds in mice will be determined (3) Do similar channels to TRPM5 play a role in VNO transduction? TRPM5 and related channels are widely expresed in the body, and mutations in these channels may underlie certain pathological states. By understanding the regulation of these channels, we can understand their contribution to signaling in health and disease.