Cloning and characterization of the murine glucosamine-6-phosphate acetyltransferase EMeg32 - Differential expression and intracellular membrane association
Cloning and characterization of the murine glucosamine-6-phosphate acetyltransferase EMeg32 - Differential expression and intracellular membrane association
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DOI：
10.1074/jbc.275.17.12821
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发表时间：
2000-04-28
影响因子：
4.8
通讯作者：
Iscove, NN
中科院分区：
文献类型：
--
作者：
Boehmelt, G;Fialka, I;Iscove, NN
n -链糖基化是发生在许多真核生物分泌和表面结合蛋白中的翻译后修饰，对多种生理和病理过程产生影响。同样重要的是糖基磷脂酰肌醇连接物的产生，它将膜蛋白固定在细胞上。这两种蛋白修饰都依赖于中心核苷酸糖udp - n -乙酰氨基葡萄糖（UDP-GlcNAc）。导致核苷酸糖生成的酶促反应已经建立，但大多数相关基因仍有待克隆。我们描述了这样一个基因的特征，EMeg32，我们根据其在小鼠造血前体细胞中的差异表达进行了鉴定。我们进一步证明了在胚胎发生过程中的调控表达。EMeg32编码一种184个氨基酸的蛋白质，具有葡萄糖氨基-6-磷酸乙酰转移酶活性。因此，它在从头合成UDP-GlcNAc的途径中占有关键地位。令人惊讶的是，该蛋白与各种细胞膜的细胞质侧结合，在有丝分裂前积累，并与cdc48同源的p97/含缬氨酸蛋白合并。
N-Linked glycosylation is a post-translational modification occurring in many eukaryotic secreted and surface-bound proteins and has impact on diverse physiological and pathological processes. Similarly important is the generation of glycosylphosphatidylinositol linkers, which anchor membrane proteins to the cell. Both protein modifications depend on the central nucleotide sugar UDP-N-acetylglucosamine (UDP-GlcNAc). The enzymatic reactions leading to generation of nucleotide sugars are established, yet most of the respective genes still await cloning. We describe the characterization of such a gene, EMeg32, which we identified based on its differential expression in murine hematopoietic precursor cells. We further demonstrate regulated expression during embryogenesis. EMeg32 codes for a 184-amino acid protein exhibiting glucosamine-6-phosphate acetyltransferase activity. It thereby holds a key position in the pathway toward de novo UDP-GlcNAc synthesis. Surprisingly, the protein associates with the cytoplasmic side of various intracellular membranes, accumulates prior to mitosis, and copurifies with the cdc48 homolog p97/valosin-containing protein.