The C-terminal nonapeptide of mature chemerin activates the chemerin receptor with low nanomolar potency
The C-terminal nonapeptide of mature chemerin activates the chemerin receptor with low nanomolar potency
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DOI：
10.1074/jbc.m313016200
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发表时间：
2004-03-12
影响因子：
4.8
通讯作者：
Parmentier, M
中科院分区：
文献类型：
--
作者：
Wittamer, V;Grégoire, F;Parmentier, M
Chemerin是一种新型蛋白，被鉴定为ChemR23 （chemerinR）的天然配体，chemerinR是一种在未成熟树突状细胞和巨噬细胞中表达的孤儿G蛋白偶联受体。趋化素是作为一种分泌的前体合成的，前趋化素活性较差，但通过蛋白水解去除最后六个氨基酸转化为趋化素r的完全激动剂。在目前的工作中，我们已经合成了一些源自人前趋化素c端结构域的肽，并研究了它们作为人前趋化素r的激动剂或拮抗剂的功能特性。我们发现非肽（149）YFPGQFAFS(157) (chemerin-9)，对应于加工的趋化素的C端，保留了大部分全尺寸蛋白的活性，关于趋化素r的拮抗剂。该肽在其N端延伸不会增加活性，而进一步截断会迅速产生无活性化合物。肽的c末端似乎对其活性至关重要，因为添加单个氨基酸或去除两个氨基酸会使效力改变四个数量级。丙氨酸扫描诱变鉴定出Tyr（149）、Phe（150）、Gly（152）、Phe（154）和Phe（156）等残基是激活chemerinR的关键位点。合成了修饰肽YHSFFFPGQFAFS，并对其进行碘化处理，建立了放射性配体结合实验。在结合实验中发现，各种肽激活趋化素受体的能力与它们的亲和力密切相关。这些结果证实了一个精确的c末端处理是生成chemerinR激动剂所必需的。在G蛋白偶联受体配体中，将中等大小的蛋白质限制为非肽，同时对其受体保持低纳摩尔亲和力的可能性是不寻常的。这些短生物活性肽的鉴定将大大加快chemerin-chemerinR相互作用的药理学分析。
Chemerin is a novel protein identified as the natural ligand of ChemR23 (chemerinR), a previously orphan G protein-coupled receptor expressed in immature dendritic cells and macrophages. Chemerin is synthesized as a secreted precursor, prochemerin, which is poorly active, but converted into a full agonist of chemerinR by proteolytic removal of the last six amino acids. In the present work, we have synthesized a number of peptides derived from the C-terminal domain of human prochemerin and have investigated their functional properties as agonists or antagonists of human chemerinR. We found that the nonapeptide (149)YFPGQFAFS(157) (chemerin-9), corresponding to the C terminus of processed chemerin, retained most of the activity of the full-size protein, with regard to agonism toward the chemerinR. Extension of this peptide at its N terminus did not increase the activity, whereas further truncations rapidly resulted in inactive compounds. The C-terminal end of the peptide appeared crucial for its activity, as addition of a single amino acid or removal of two amino acids modified the potency by four orders of magnitude. Alanine- scanning mutagenesis identified residues Tyr(149), Phe(150), Gly(152), Phe(154), and Phe(156) as the key positions for chemerinR activation. A modified peptide (YHSFFFPGQFAFS) was synthesized and iodinated, and a radioligand binding assay was established. It was found that the ability of the various peptides to activate the chemerin receptor was strictly correlated with their affinity in the binding assay. These results confirm that a precise C-terminal processing is required for the generation of a chemerinR agonist. The possibility to restrict a medium sized protein to a nonapeptide, while keeping a low nanomolar affinity for its receptor is unusual among G protein-coupled receptors ligands. The identification of these short bioactive peptides will considerably accelerate the pharmacological analysis of chemerin-chemerinR interactions.