Sensory and Cognitive Food Sciences, National Food Research Institute, 2-1-12 Kannondai, Tsukuba-shi, Ibaraki 305-8642, Japan.
Chem Senses. 2010 Feb;35(2):171-7. doi: 10.1093/chemse/bjp097.
Inositol 1,4,5-triphosphate-mediated calcium (IP3-Ca2+) signal cascade is an essential process in sweet, bitter, and umami taste signal transduction. Although the main components of this cascade have been identified, the candidate regulators of them in taste tissues are still unclear. In an effort to identify genes involved in taste signal transduction, we found that a gene encoding lymphoid-restricted membrane protein (Lrmp/Jaw1) was expressed in mouse taste tissues. Here we report that Lrmp/Jaw1 is specifically expressed in sweet, bitter, and umami taste receptor-expressing cells of mouse circumvallate, foliate, and fungiform papillae. In addition to this specific expression patterns, we found that Lrmp/Jaw1 is associated with type III IP3 receptor (IP3R3) via its coiled-coil domain in the COS7 heterologous expression system. These results raise the possibility that Lrmp/Jaw1 interacts with IP3R3 in taste cells and suggest an important role for Lrmp/Jaw1 in the IP3-Ca2+ signal cascade in sweet, bitter, and umami taste signal transduction.
肌醇 1,4,5-三磷酸介导的钙（IP3-Ca2+）信号级联反应是甜味、苦味和鲜味味觉信号转导的一个基本过程。尽管该级联反应的主要成分已经确定，但味觉组织中它们的候选调节因子仍不清楚。为了鉴定参与味觉信号转导的基因，我们发现编码淋巴组织限定的膜蛋白（Lrmp/Jaw1）的基因在小鼠味觉组织中表达。在这里，我们报告 Lrmp/Jaw1 特异性表达于小鼠环状、叶状和菌状乳突的甜味、苦味和鲜味味觉受体表达细胞中。除了这种特异性表达模式外，我们还发现 Lrmp/Jaw1 通过其卷曲螺旋结构域与 COS7 异源表达系统中的 III 型肌醇 1,4,5-三磷酸受体（IP3R3）相互作用。这些结果表明 Lrmp/Jaw1 与味觉细胞中的 IP3R3 相互作用，并提示 Lrmp/Jaw1 在甜味、苦味和鲜味味觉信号转导的 IP3-Ca2+信号级联反应中具有重要作用。
