Shigemoto R, Yokota Y, Tsuchida K, Nakanishi S
Institute for Immunology, Kyoto University Faculty of Medicine, Japan.
J Biol Chem. 1990 Jan 15;265(2):623-8.
Functional cDNA clones for rat neuromedin K receptor were isolated from a rat brain cDNA library by cross-hybridization with the bovine substance K receptor cDNA. Injection of the mRNA synthesized in vitro from the cloned cDNA into Xenopus oocytes elicited electrophysiological responses to tachykinins, with the most potent sensitivity being to neuromedin K. Ligand-binding displacement in membranes of mammalian COS cells transfected with the cDNA indicated the rank order of affinity of the receptor to tachykinins: neuromedin K greater than substance K greater than substance P. The hybridization analysis showed that the neuromedin K receptor mRNA is expressed in both the brain and the peripheral tissues at different levels. The rat neuromedin K receptor consists of 452 amino acid residues and belongs to the family of G protein-coupled receptors, which are though to have seven transmembrane domains. The sequence comparison of the rat neuromedin K, substance P, and substance K receptors revealed that these receptors are highly conserved in the seven transmembrane domains and the cytoplasmic sides of the receptors. They also show some structural characteristics, including the common presence of histidine residues in transmembrane segments V and VI and the difference in the numbers and distributions of serine and threonine residues as possible phosphorylation sites in the cytoplasmic regions. This paper thus presents the first comprehensive analysis of the molecular nature of the multiple peptide receptors that exhibit similar but pharmacologically distinguishable activities.
通过与牛速激肽K受体cDNA进行交叉杂交，从大鼠脑cDNA文库中分离出大鼠神经介素K受体的功能性cDNA克隆。将从克隆的cDNA体外合成的mRNA注射到非洲爪蟾卵母细胞中，可引发对速激肽的电生理反应，其中对神经介素K的敏感性最强。用该cDNA转染的哺乳动物COS细胞膜中的配体结合置换表明，该受体对速激肽的亲和力排序为：神经介素K＞速激肽K＞P物质。杂交分析表明，神经介素K受体mRNA在脑和外周组织中均有不同程度的表达。大鼠神经介素K受体由452个氨基酸残基组成，属于G蛋白偶联受体家族，该家族被认为具有七个跨膜结构域。大鼠神经介素K、P物质和速激肽K受体的序列比较显示，这些受体在七个跨膜结构域和受体的胞质侧高度保守。它们还表现出一些结构特征，包括跨膜片段V和VI中共同存在组氨酸残基，以及作为胞质区域可能磷酸化位点的丝氨酸和苏氨酸残基的数量和分布差异。因此，本文首次对表现出相似但药理学上可区分活性的多种肽受体的分子性质进行了全面分析。
