Gustatory sensory cells express a receptor responsive to protein breakdown products (GPR92)
Gustatory sensory cells express a receptor responsive to protein breakdown products (GPR92)
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DOI：
10.1007/s00418-013-1080-2
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发表时间：
2013-08-01
影响因子：
2.3
通讯作者：
Breer, Heinz
中科院分区：
文献类型：
--
作者：
Haid, Desiree;Widmayer, Patricia;Breer, Heinz
膳食蛋白质的摄入对于维持基本生理过程至关重要。味觉形态鲜味及其原型刺激物谷氨酸被认为是食物蛋白质含量的信号。鲜味被认为是由异二聚体氨基酸受体T1 R1 + T1 R3介导的。基于基因敲除研究，可能存在额外的鲜味受体。除了氨基酸之外，某些肽也可以引发和增强鲜味，这表明蛋白质分解产物可能有助于鲜味。最近去乙酰化的蛋白胨受体GPR 92（也称为GPR 93; LPAR 5）在胃肠内分泌细胞中表达，在那里它对蛋白质水解产物作出反应。因此，研究GPR 92受体是否在味觉感觉细胞中表达具有直接的意义。使用免疫组织化学方法，我们发现在小鼠味蕾中的大量细胞被GPR 92抗体标记。GPR 92细胞的分子表型分析显示，绝大多数GPR 92免疫反应性细胞表达PLC β 2，因此可归类为II型细胞。更详细的分析表明，GPR 92在大多数T1 R1阳性味觉细胞中表达。这些结果表明，鲜味细胞可能不仅对氨基酸，而且对蛋白质水解物中的肽也有反应。
The ingestion of dietary protein is of vital importance for the maintenance of fundamental physiological processes. The taste modality umami, with its prototype stimulus, glutamate, is considered to signal the protein content of food. Umami was thought to be mediated by the heterodimeric amino acid receptor, T1R1 + T1R3. Based on knockout studies, additional umami receptors are likely to exist. In addition to amino acids, certain peptides can also elicit and enhance umami taste suggesting that protein breakdown products may contribute to umami taste. The recently deorphanized peptone receptor, GPR92 (also named GPR93; LPAR5), is expressed in gastric enteroendocrine cells where it responds to protein hydrolysates. Therefore, it was of immediate interest to investigate if the receptor GPR92 is expressed in gustatory sensory cells. Using immunohistochemical approaches we found that a large population of cells in murine taste buds was labeled with an GPR92 antibody. A molecular phenotyping of GPR92 cells revealed that the vast majority of GPR92-immunoreactive cells express PLC beta 2 and can therefore be classified as type II cells. More detailed analyses have shown that GPR92 is expressed in the majority of T1R1-positive taste cells. These results indicate that umami cells may respond not only to amino acids but also to peptides in protein hydrolysates.