Conserved serine residues in serotonin transporter contribute to high-affinity cocaine binding
Conserved serine residues in serotonin transporter contribute to high-affinity cocaine binding
复制标题
DOI：
10.1016/j.bbrc.2006.03.096
复制
发表时间：
2006-05-19
影响因子：
3.1
通讯作者：
Han, DD
中科院分区：
文献类型：
--
作者：
Gu, HH;Wu, XH;Han, DD
5-羟色胺转运体（Serotonin transporter，SERT）是可卡因作用的关键蛋白质靶点之一。尽管进行了深入的研究，但尚不清楚可卡因在何处与其靶点结合，以及可卡因结合中涉及哪些残留物。我们克隆了家蚕5-羟色胺转运蛋白（Serotonin transporter，bmSERT）。当在培养细胞中表达时，bmSERT对可卡因的敏感性比果蝇SERT（dmSERT）低20倍以上。我们使用bmSERT和dmSERT进行物种扫描诱变。在bmSERT的跨膜结构域12中有两个相邻的苏氨酸残基，其中相应的残基在dmSERT和所有已知的哺乳动物单胺转运蛋白中是两个丝氨酸。用苏氨酸取代dmSERT中的丝氨酸残基降低可卡因敏感性;而将bmSERT中的两个苏氨酸残基转换为丝氨酸增加可卡因敏感性。多巴胺转运蛋白中相应残基的突变也改变了可卡因的亲和力。我们的研究结果表明，SERT中保守的丝氨酸残基有助于高亲和力的可卡因结合。(c)2006年爱思唯尔公司All rights reserved.
Serotonin transporter (SERT) is one of the key protein targets of cocaine. Despite intensive studies, it is not clear where cocaine binds to its targets and what residues are involved in cocaine binding. We have cloned the serotonin transporter from silkworm (Bombyx mori, bmSERT). When expressed in cultured cells, bmSERT is over 20-fold less sensitive to cocaine than Drosophila melanogaster SERT (dmSERT). We performed species-scanning mutagenesis using bmSERT and dmSERT. There are two adjacent threonine residues in transmembrane domain 12 of bmSERT where the corresponding residues are two serines in dmSERT and in all known mammalian monoamine transporters. Replacing the serine residues with threonines in dmSERT reduces cocaine sensitivity; while switching the two threonine residues in bmSERT to serines increased cocaine sensitivity. Mutations at the corresponding residues in dopamine transporter also changed cocaine affinity. Our results suggest that the conserved serine residues in SERT contribute to high-affinity cocaine binding. (c) 2006 Elsevier Inc. All rights reserved.