Alpha,beta-unsaturated ketone is a core moiety of natural ligands for covalent binding to peroxisome proliferator-activated receptor gamma.
Alpha,beta-unsaturated ketone is a core moiety of natural ligands for covalent binding to peroxisome proliferator-activated receptor gamma.
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发表时间：
2005
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通讯作者：
T. Shiraki;N. Kamiya;Sayaka Shiki;T. Kodama;A. Kakizuka;H. Jingami
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作者：
T. Shiraki;N. Kamiya;Sayaka Shiki;T. Kodama;A. Kakizuka;H. Jingami
过氧化物酶体增殖物激活受体γ(PPARGamma)参与多种生物学过程，包括巨噬细胞和脂肪细胞的分化。几种天然脂质代谢物已被证明能激活PPAR-γ。在这里，我们报道了一些PPARGamma配体，包括15-脱氧-Delta12，14-前列腺素J2，通过Michael加成反应与PPARGamma配体结合口袋中的半胱氨酸残基共价结合。利用罗丹明-马来酰亚胺和质谱仪，我们证明了这些配体的结合是共价的和不可逆的。一致地，半胱氨酸残基的突变消除了这些配体激活PPARGamma的能力，而不是非共价合成激动剂BRL49653的能力，这表明天然配体中的α，β-不饱和酮是转录活性所必需的共价结合。对含有α，β-不饱和酮的脂质代谢产物的筛选表明，其他几种羟基二十碳四烯酸、羟基二十碳二烯酸和前列腺素的氧化代谢产物也可以作为PPARγ的新型共价配体。我们认为，PPARGamma通过识别这样的α，β-不饱和酮作为一个共同的部分来感觉脂肪酸的氧化。
Peroxisome proliferator-activated receptor gamma (PPARgamma) functions in various biological processes, including macrophage and adipocyte differentiation. Several natural lipid metabolites have been shown to activate PPARgamma. Here, we report that some PPARgamma ligands, including 15-deoxy-Delta12,14-prostaglandin J2, covalently bind to a cysteine residue in the PPARgamma ligand binding pocket through a Michael addition reaction by an alpha,beta-unsaturated ketone. Using rhodamine-maleimide as well as mass spectroscopy, we showed that the binding of these ligands is covalent and irreversible. Consistently, mutation at the cysteine residue abolished abilities of these ligands to activate PPARgamma, but not of BRL49653, a non-covalent synthetic agonist, indicating that covalent binding of the alpha,beta-unsaturated ketone in the natural ligands was required for their transcriptional activities. Screening of lipid metabolites containing the alpha,beta-unsaturated ketone revealed that several other oxidized metabolites of hydroxyeicosatetraenoic acid, hydroxyeicosadecaenoic acid, and prostaglandins can also function as novel covalent ligands for PPARgamma. We propose that PPARgamma senses oxidation of fatty acids by recognizing such an alpha,beta-unsaturated ketone as a common moiety.