Identification of amino acid residues that direct differential ligand selectivity of mammalian and nonmammalian V1a type receptors for arginine vasopressin and vasotocin - Insights into molecular coevolution of V1a type receptors and their ligands
Identification of amino acid residues that direct differential ligand selectivity of mammalian and nonmammalian V1a type receptors for arginine vasopressin and vasotocin - Insights into molecular coevolution of V1a type receptors and their ligands
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DOI：
10.1074/jbc.m408909200
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发表时间：
2004-12-24
影响因子：
4.8
通讯作者：
Kwon, HB
中科院分区：
文献类型：
--
作者：
Acharjee, S;Do-Rego, JL;Kwon, HB
精氨酸催产素（VT）是哺乳动物精氨酸加压素（AVP）在所有非哺乳类脊椎动物中的直向同源物。我们以前已经克隆了一个两栖动物V1 a型催产素受体（VT 1 R），表现出更高的敏感性VT比AVP，而哺乳动物V1 a型受体（V1 aR）响应AVP比VT。在本研究中，我们确定了氨基酸残基，赋予大鼠V1 aR和牛蛙VT 1 R（bfVT 1 R）之间的AVP和VT的差异配体选择性。嵌合大鼠V1 aR具有跨膜结构域（TMD）VI的羧基末端尾（C-尾）的bfVT 1 R表现出反向配体偏好AVP和VT，而嵌合VT 1 R与TMD VI大鼠V1 aR的C-尾表现出对AVP的敏感性大大增加。V1 aR的TMD VI中的单个突变（Ile（315（6.53））至Thr）增加了VT的敏感性，而单个突变（Phe（313（6.51））至Tyr或Pro（334（7.33））至Thr）降低了AVP的敏感性。有趣的是，V1 aR的三重突变（Phe（313（6.51））突变为Tyr，Ile（6.53）突变为Thr，Pro（7.33）突变为Thr）增加了对VT的敏感性，但大大降低了对AVP的敏感性，表现得像bfVT 1 R。此外，与V1 aR一样，bfVT 1 R的双突变体（Tyr（306（6.51））为Phe，Thr（327（7.33））为Pro）显示出对AVP的敏感性增加。这些结果表明，Phe/Tyr（6.51），Ile/Thr（6.53）和Pro/Thr（7.33）负责大鼠V1 aR和bfVT 1 R之间的不同配体选择性。VT/AVP与其受体的分子相互作用的信息可能对开发新的AVP类似物具有重要意义。
Arginine vasotocin (VT) is the ortholog in all nonmammalian vertebrates of arginine vasopressin (AVP) in mammals. We have previously cloned an amphibian V1a-type vasotocin receptor (VT1R) that exhibited higher sensitivity for VT than AVP, while the mammalian V1a type receptor (V1aR) responded better to AVP than VT. In the present study, we identified the amino acid residues that confer differential ligand selectivity for AVP and VT between rat V1aR and bullfrog VT1R (bfVT1R). A chimeric rat V1aR having transmembrane domain (TMD) VI to the carboxyl-terminal tail (C-tail) of bfVT1R showed a reverse ligand preference for AVP and VT, whereas a chimeric VT1R with TMD VI to the C-tail of rat V1aR showed a great increase in sensitivity for AVP. A single mutation (Ile(315(6.53)) to Thr) in TMD VI of V1aR increased the sensitivity for VT, while a single mutation (Phe(313(6.51)) to Tyr or Pro(334(7.33)) to Thr) reduced sensitivity toward AVP. Interestingly the triple mutation (Phe(313(6.51)) to Tyr, Ile(6.53) to Thr, and Pro(7.33) to Thr) of V1aR increased sensitivity to VT but greatly reduced sensitivity to AVP, behaving like bfVT1R. Further, like V1aR, a double mutant (Tyr(306(6.51)) to Phe and Thr(327(7.33)) to Pro) of bfVT1R showed an increased sensitivity to AVP. These results suggest that Phe/Tyr(6.51), Ile/Thr(6.53), and Pro/Thr(7.33) are responsible for the differential ligand selectivity between rat V1aR and bfVT1R. This information regarding the molecular interaction of VT/AVP with their receptors may have important implications for the development of novel AVP analogs.