Alternative O-glycosylation/O-phosphorylation of the murine estrogen receptor β
Alternative O-glycosylation/O-phosphorylation of the murine estrogen receptor β
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DOI：
10.1021/bi000755i
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发表时间：
2000-09-26
期刊：
影响因子：
2.9
通讯作者：
Hart, GW
中科院分区：
文献类型：
--
作者：
Cheng, XG;Cole, RN;Hart, GW
雌激素受体β是雌激素受体ct的同源物，是类固醇激素受体家族的新成员。最近，我们记录了雌激素受体ct，像其他转录因子，被修改的O-连接的N-乙酰葡萄糖胺（O-GlcNAc），一个普遍存在的短暂的翻译后修饰的核和细胞质蛋白。在这里，我们报告说，雌激素受体β是交替修改O-GlcNAc或O-磷酸。体外翻译的蛋白质的凝集素层析首先表明鼠雌激素受体β（mER-β）是O-GlcNAc酰化的。在昆虫Sf 9细胞中过表达的mER-β上的碳水化合物部分的结构表征证实了O-GlcNAc的存在。在哺乳动物细胞中过表达的mER-β也是O-GlcNAc化的。来自Sf 9细胞的mER-β上O-GlcNAc的主要位点是靠近N-末端的Ser（16）。伴随分析还记录了mER-β在Ser的O-磷酸化（16）。MALDI-TOF质谱显示这两个丰富的和动态的翻译后修饰这个位点的替代占用。一个主要的O-GlcNAc/O-磷酸位点位于mER-β上的反式激活结构域附近，并作为PEST区域（快速蛋白降解的靶序列）的一部分，这表明这些修饰可能在调节雌激素受体β反式激活和周转中发挥作用。
Estrogen receptor beta, a homologue to estrogen receptor ct, is a new member of the steroid hormone receptor family. Recently, we documented that estrogen receptor ct, like other transcription factors, is modified by O-linked N-acetylglucosamine (O-GlcNAc), a ubiquitous transitory posttranslational modification on nuclear and cytoplasmic proteins. Here, we report that estrogen receptor beta is alternatively modified by either O-GlcNAc or O-phosphate. Lectin chromatography of in vitro translated protein first suggested that murine estrogen receptor beta (mER-beta) is O-GlcNAcylated. Structural characterization of the carbohydrate moieties on mER-beta, overexpressed in insect Sf9 cells, confirmed the presence of O-GlcNAc. mER-beta, overexpressed in mammalian cells, is also O-GlcNAcylated, The major site of O-GlcNAc on mER-beta from Sf9 cells is Ser(16) near the N-terminus. Concomitant analyses also documented the O-phosphorylation of mER-beta at Ser(16). MALDI-TOF mass spectrometry showed alternative occupancy of this locus by these two abundant and dynamic posttranslational modifications. The localization of a major O-GlcNAc/O-phosphate site in proximity of the transactivation domain and as part of a PEST region (target sequences for rapid protein degradation) on mER-beta suggests that these modifications may play a role in regulating estrogen receptor beta transactivation and turnover.