Evolution of the primate glutamate taste sensor from a nucleotide sensor
Evolution of the primate glutamate taste sensor from a nucleotide sensor
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DOI：
10.1016/j.cub.2021.08.002
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发表时间：
2021-08
期刊：
影响因子：
9.2
通讯作者：
Yasuka Toda;T. Hayakawa;Akihiro Itoigawa;Yosuke Kurihara;Tomoya Nakagita;Masahiro Hayashi;R. Ashino-
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文献类型：
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作者：
Yasuka Toda;T. Hayakawa;Akihiro Itoigawa;Yosuke Kurihara;Tomoya Nakagita;Masahiro Hayashi;R. Ashino-
味觉在食物选择中起着至关重要的作用。鲜味（咸味）味觉由味觉受体复合物T1 R1/T1 R3感知，该复合物检测蛋白质氨基酸。1对l-谷氨酸（l-Glu）的高敏感性是人类T1 R1/T1 R3的特征，但其他脊椎动物的T1 R1/T1 R3并不总是显示这种l-Glu反应。1，2在此，我们证明了T1 R1/T1 R3的L-Glu敏感性是一种衍生状态，在依赖于叶子作为蛋白质来源的大型灵长类动物中，在它们与食虫祖先分化之后，这种衍生状态已经反复进化。受体表达实验表明，在灵长类动物进化中，使T1 R1/T1 R3对L-Glu敏感的配体结合位点处的常见氨基酸取代独立地发生至少三次。与此同时，T1 R1/T1 R3在几种哺乳动物物种（包括食虫灵长类）中检测5′-核糖核苷酸而不是l-谷氨酸。我们的化学分析表明，l-谷氨酸是灵长类食物中的主要游离氨基酸之一，昆虫，但不是树叶，含有大量的游离5′-核糖核苷酸。将T1 R1/T1 R3的配体结合偏好从5′-核糖核苷酸改变为l-Glu可能会促进叶的消耗，克服苦味和厌恶的味道。总而言之，我们的研究结果提供了一个不同的哺乳动物辐射觅食生态学的见解，并帮助揭示如何进化的感觉基因促进新的生态位的入侵。
Taste perception plays an essential role in food selection. Umami (savory) tastes are sensed by a taste receptor complex, T1R1/T1R3, that detects proteinogenic amino acids.1High sensitivity to l-glutamate (l-Glu) is a characteristic of human T1R1/T1R3, but the T1R1/T1R3 of other vertebrates does not consistently show this l-Glu response.1,2Here, we demonstrate that the l-Glu sensitivity of T1R1/T1R3 is a derived state that has evolved repeatedly in large primates that rely on leaves as protein sources, after their divergence from insectivorous ancestors. Receptor expression experiments show that common amino acid substitutions at ligand binding sites that render T1R1/T1R3 sensitive to l-Glu occur independently at least three times in primate evolution. Meanwhile T1R1/T1R3 senses 5′-ribonucleotides as opposed to l-Glu in several mammalian species, including insectivorous primates. Our chemical analysis reveal that l-Glu is one of the major free amino acids in primate diets and that insects, but not leaves, contain large amounts of free 5′-ribonucleotides. Altering the ligand-binding preference of T1R1/T1R3 from 5′-ribonucleotides to l-Glu might promoteleaf consumption, overcoming bitter and aversive tastes. Altogether, our results provide insight into the foraging ecology of a diverse mammalian radiation and help reveal how evolution of sensory genes facilitates invasion of new ecological niches.