Bradbury F A, Menon K M
Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, 48109-0617, USA.
Biochem Biophys Res Commun. 2001 Mar 30;282(2):454-62. doi: 10.1006/bbrc.2001.4592.
In the first step of asparagine-linked oligosaccharide chain maturation, terminal glucose residues are removed from the high mannose oligosaccharide core by glucosidases I and II. The role that glucose residues play in trafficking the luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptor from the endoplasmic reticulum to the cell surface was investigated. Glucosidases I and II were inhibited by incubating 293 T cells transiently transfected with LH/hCG receptor cDNA with 5 mM 1-deoxynojirimycin (DNJ). DNJ treatment resulted in a marked reduction in cell surface [(125)I]hCG binding. Similar results were obtained from glucosidase I-deficient Lec 23 Chinese hamster ovarian (CHO) cells and wild-type CHO cells that were transiently transfected with LH/hCG receptor cDNA. Immunoprecipitation followed by Western blotting of transfected 293 T cells incubated in the presence or absence of 5 mM DNJ revealed that there is substantially less receptor in DNJ-treated cells than in control cells. These results show that the removal of glucose residues is necessary for trafficking the LH/hCG receptor to the cell surface.
在天冬酰胺连接的寡糖链成熟的第一步中，葡糖苷酶I和II从高甘露糖寡糖核心去除末端葡萄糖残基。研究了葡萄糖残基在将促黄体生成素/人绒毛膜促性腺激素（LH/hCG）受体从内质网运输到细胞表面中所起的作用。通过用5 mM 1-脱氧野尻霉素（DNJ）孵育瞬时转染了LH/hCG受体cDNA的293 T细胞来抑制葡糖苷酶I和II。DNJ处理导致细胞表面[(125)I]hCG结合显著减少。从瞬时转染了LH/hCG受体cDNA的葡糖苷酶I缺陷型Lec 23中国仓鼠卵巢（CHO）细胞和野生型CHO细胞也获得了类似结果。对在有或没有5 mM DNJ存在下孵育的转染293 T细胞进行免疫沉淀然后蛋白质印迹分析，结果显示，DNJ处理的细胞中的受体比对照细胞中的受体少得多。这些结果表明，去除葡萄糖残基对于将LH/hCG受体运输到细胞表面是必要的。
