The Met268Pro Mutation of Mouse TRPA1 Changes the Effect of Caffeine from Activation to Suppression
The Met268Pro Mutation of Mouse TRPA1 Changes the Effect of Caffeine from Activation to Suppression
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DOI：
10.1016/j.bpj.2010.10.014
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发表时间：
2010-12-01
影响因子：
3.4
通讯作者：
Kubo, Yoshihiro
中科院分区：
文献类型：
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作者：
Nagatomo, Katsuhiro;Ishii, Hiroshi;Kubo, Yoshihiro
瞬时受体电位A1通道（TRPA 1）可被多种化合物激活，包括异硫氰酸酯、薄荷醇和肉桂醛。啮齿动物和人类TRPA 1亚型对薄荷醇和半胱氨酸攻击化合物CMP 1的敏感性不同，这些差异的分子决定因素已在第5跨膜区（TM5）中确定。我们最近报道，咖啡因激活小鼠TRPA1（mTRPA1），但抑制人TRPA1（hTRPA1），在这里，我们的目的是确定分子决定因素，负责物种特异性差异的反应，咖啡因，通过分析功能，在非洲爪蟾卵母细胞中表达的各种嵌合体的性质我们最初发现mTRPA 1的远端N末端胞质区域中氨基酸231和287之间的区域是关键的。在该区域的诱变研究中，我们随后观察到将Met 268 Pro点突变引入mTRPA 1将咖啡因的作用从激活改变为抑制。这些结果与其他报道的配体结合位点和EF手基序不同，表明咖啡因反应是由一种独特的机制介导的，并证实了远端N末端区域对TRPA 1通道活性调节的重要性
The transient receptor potential A1 channel (TRPA1) is activated by various compounds including isothiocya nates menthol and cinnamaldehyde The sensitivities of the rodent and human isoforms of TRPA1 to menthol and the cysteine attacking compound CMP1 differ and the molecular determinants for these differences have been identified in the 5th transmembrane region (TM5) for menthol and TM6 for CMP1 We recently reported that caffeine activates mouse TRPA1 (mTRPA1) but suppresses human TRPA1 (hTRPA1) Here we aimed to identify the molecular determinant that is responsible for species specific differences in the response to caffeine by analyzing the functional properties of various chimeras expressed in Xenopus oocytes We initially found that the region between amino acids 231 and 287 in the distal N terminal cytoplasmic region of mTRPA1 is critical In a mutagenesis study of this region we subsequently observed that introduction of a Met268Pro point mutation into mTRPA1 changed the effect of caffeine from activation to suppression Because the region including Met 268 is different from other reported ligand binding sites and from the EF hand motif these results suggest that the caffeine response is mediated by a unique mechanism and confirm the importance of the distal N terminal region for regulation of TRPA1 channel activity