GLYCOSYLATION OF THE C-MYC TRANSACTIVATION DOMAIN
GLYCOSYLATION OF THE C-MYC TRANSACTIVATION DOMAIN
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DOI：
10.1073/pnas.92.10.4417
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发表时间：
1995-05-09
影响因子：
11.1
通讯作者：
HART, GW
中科院分区：
文献类型：
--
作者：
CHOU, TY;DANG, CV;HART, GW
O-linked N-acetylglucosamine （O-GlcNAc）是一种丰富的、动态的翻译后修饰，由一个单糖GlcNAc组成，糖苷连接到丝氨酸或苏氨酸残基的侧链羟基上。尽管O-GlcNAc存在于无数的核蛋白和细胞质蛋白上，但迄今为止仅鉴定出少数。这些携带o - glcnac的蛋白也被磷酸化修饰，形成可逆的多聚物复合物。在这里，我们提出了O-GlcNAc糖基化癌蛋白c-Myc的证据，c-Myc是一种螺旋-环-螺旋/亮氨酸拉链磷酸化蛋白，与Max异源二聚体并参与正常和肿瘤细胞的基因转录调节，O-GlcNAc修饰c-Myc通过三种不同的方法显示：(i)使用蛋白质-蛋白质相互作用迁移转移试验证明凝集素与体外翻译蛋白结合；（ii）凝集素亲和层析分析糖苷酶或糖基转移酶处理的体外翻译蛋白；（iii）直接表征在昆虫细胞或中国仓鼠卵巢细胞中过表达的纯化重组蛋白的糖部分。对c-Myc序列缺失突变体的分析进一步表明，O-GlcNAc位点位于n端转录激活/恶性转化区域内或附近，该区域c-Myc突变在Burkitt和艾滋病相关淋巴瘤集群中经常发现。
O-linked N-acetylglucosamine (O-GlcNAc) is an abundant and dynamic posttranslational modification composed of a single monosaccharide, GlcNAc, glycosidically linked to the side-chain hydroxyl of serine or threonine residues, Although O-GlcNAc Occurs on a myriad of nuclear and cytoplasmic proteins, only a few have thus far been identified. These O-GlcNAc-bearing proteins are also modified by phosphorylation and form reversible multimeric complexes. Here we present evidence for O-GlcNAc glycosylation of the oncoprotein c-Myc, a helix-loop-helix/leucine zipper phosphoprotein that heterodimerizes with Max and participates in the regulation of gene transcription in normal and neoplastic cells, O-GlcNAc modification of c-Myc is shown by three different methods: (i) demonstration of lectin binding to in vitro translated protein using a protein-protein interaction mobility-shift assay; (ii) glycosidase or glycosyltransferase treatment of in vitro translated protein analyzed by lectin affinity chromatography; and (iii) direct characterization of the sugar moieties on purified recombinant protein overexpressed in either insect cells or Chinese hamster ovary cells. Analyses of serial deletion mutants of c-Myc further suggest that the O-GlcNAc site(s) are located within or near the N-terminal transcription activation/malignant transformation domain, a region where mutations of c-Myc that are frequently found in Burkitt and AIDS-related lymphomas cluster.