Pérez Cristian A, Margolskee Robert F, Kinnamon Sue C, Ogura Tatsuya
Department of Physiology & Biophysics, Howard Hughes Medical Institute, Mount Sinai School of Medicine, New York University, New York, NY 10029, USA.
Cell Calcium. 2003 May-Jun;33(5-6):541-9. doi: 10.1016/s0143-4160(03)00059-9.
The sense of taste plays a critical role in the life and nutritional status of organisms. During the last decade, several molecules involved in taste detection and transduction have been identified, providing a better understanding of the molecular physiology of taste receptor cells. However, a comprehensive catalogue of the taste receptor cell signaling machinery is still unavailable. We have recently described the occurrence of calcium signaling mechanisms in taste receptor cells via apparent store-operated channels and identified Trpm5, a novel candidate taste transduction element belonging to the mammalian family of transient receptor potential channels. Trpm5 is expressed in a tissue-restricted manner, with high levels in gustatory tissue. In taste cells, Trpm5 is co-expressed with taste-signaling molecules such as alpha-gustducin, Ggamma(13), phospholipase C beta(2) and inositol 1,4,5-trisphosphate receptor type III. Biophysical studies of Trpm5 heterologously expressed in Xenopus oocytes and mammalian CHO-K1 cells indicate that it functions as a store-operated channel that mediates capacitative calcium entry. The role of store-operated channels and Trpm5 in capacitative calcium entry in taste receptor cells in response to bitter compounds is discussed.
味觉在生物体的生命和营养状况中起着关键作用。在过去十年中，已鉴定出几种参与味觉检测和转导的分子，这使人们对味觉受体细胞的分子生理学有了更好的理解。然而，味觉受体细胞信号传导机制的完整目录仍然不可得。我们最近描述了味觉受体细胞中通过明显的储存-操纵性通道发生的钙信号机制，并鉴定出Trpm5，它是一种属于哺乳动物瞬时受体电位通道家族的新型味觉转导元件候选物。Trpm5以组织限制性方式表达，在味觉组织中水平较高。在味觉细胞中，Trpm5与味觉信号分子如α-味导素、Gγ(13)、磷脂酶Cβ(2)和III型肌醇1,4,5-三磷酸受体共表达。对在非洲爪蟾卵母细胞和哺乳动物CHO-K1细胞中异源表达的Trpm5的生物物理研究表明，它作为一种储存-操纵性通道发挥作用，介导容量性钙内流。本文讨论了储存-操纵性通道和Trpm5在味觉受体细胞对苦味化合物反应中容量性钙内流中的作用。
