Synthesis of dolichyl-phosphate mannose

Dolichyl-phosphate-mannose (DPM, DOLPman) is the donor of mannose groups in the synthesis of the dolichyl pyrophosphate-linked precursor oligosaccharide in asparagine-linked glycosylation, in the synthesis of the glycosyl phosphatidylinositol (GPI) anchor precursor, in protein O-mannosylation and in protein C-mannosylation. Its synthesis proceeds in two steps. First, cytosolic GDP-mannose reacts with dolichyl phosphate exposed on the cytosolic face of the endoplasmic reticulum membrane to form DPM with its mannose moiety oriented toward the cytosol. The DPM molecule then flips in the endoplasmic reticulum membrane, so that its mannose moiety is in the endoplasmic reticulum lumen, accessible to the enzymes that catalyze its transfer to growing glycolipids and glycoproteins (Kinoshita and Inoue, 2000; Maeda et al, 2000).

Dolichyl-phosphate-mannose（DPM，DOLPman）是合成门冬氨酸连接糖基化中 dolichyl pyrophosphate 连接的前体寡糖、合成糖基磷脂酰肌醇（GPI）锚定前体、蛋白质 O-甘露糖基化以及蛋白质 C-甘露糖基化中甘露糖基团的供体。其合成过程分为两步。首先，细胞质中的 GDP-甘露糖与内质网膜细胞质面暴露的 dolichyl 磷酸反应，形成带有其甘露糖基团面向细胞质的 DPM。随后，DPM 分子在粗面内质网膜中翻转，使其甘露糖基团处于粗面内质网腔内，便于酶将其转移至正在生长的糖脂和糖蛋白（Kinoshita and Inoue, 2000；Maeda et al, 2000）。