Isolation and characterization of human lysosomal membrane glycoproteins, h-lamp-1 and h-lamp-2. Major sialoglycoproteins carrying polylactosaminoglycan.
Isolation and characterization of human lysosomal membrane glycoproteins, h-lamp-1 and h-lamp-2. Major sialoglycoproteins carrying polylactosaminoglycan.
复制标题
DOI：
10.1016/s0021-9258(18)37369-1
复制
发表时间：
1988-12
期刊：
影响因子：
--
通讯作者：
S. Carlsson;J. Roth;F. Piller;Minoru Fukuda
中科院分区：
文献类型：
--
作者：
S. Carlsson;J. Roth;F. Piller;Minoru Fukuda
从慢性髓性白血病细胞中纯化了两种主要的溶酶体膜糖蛋白，其表观Mr约为120，000。这些糖蛋白是含有聚乳糖胺聚糖的主要唾液酸糖蛋白，约占总细胞蛋白的0.1-0.2%。获得了对其中一种糖蛋白具有特异性的单克隆抗体和对另一种糖蛋白具有特异性的多克隆抗体。免疫电镜观察表明，这两种糖蛋白主要存在于溶酶体和多泡体中。免疫沉淀实验表明，许多不同的细胞系表达这些糖蛋白。然而，细胞系之间的表观分子量不同;这可能代表每个细胞系表达的聚乳糖胺聚糖量的差异。如以下论文所示（Fukuda，M.，Viitala，J.，Matteson，J.，和Carlsson，S. R.（1988）J.Biol.Chem.263，18920-18928），其中一种糖蛋白与小鼠对应物m-lamp-1非常同源。因此，这种糖蛋白的人类形式被命名为人类lamp-1（h-lamp-1），而另一种糖蛋白，即单克隆抗体，被称为人类lamp-2（h-lamp-2）。脉冲追踪标记实验检测到h-lamp-1和h-lamp-2首先作为87.5和84 kDa的前体形式产生，并且用内切-β-N-乙酰氨基葡萄糖苷酶H（endo-H）或内切-β-N-乙酰氨基葡萄糖苷酶F（endo-F）处理将其分子量分别降低至39.5和41.5 kDa。根据与endo-F的部分双链反应结果，估计h-lamp-1有18个N-连接的双链，h-lamp-2有16个。这些结果表明，这两种溶酶体膜糖蛋白被N-聚糖广泛修饰，其中一些被发现具有聚乳糖胺重复序列和唾液酸。因此，人lamp-1和lamp-2可作为了解聚乳糖胺聚糖形成以及含聚乳糖胺聚糖糖蛋白的生物合成和加工的良好模型。
Two major lysosomal membrane glycoproteins with apparent Mr approximately 120,000 were purified from chronic myelogenous leukemia cells. These glycoproteins are major sialoglycoproteins containing polylactosaminoglycan and represent approximately 0.1-0.2% of total cell proteins. A monoclonal antibody specific to one of the glycoproteins and polyclonal antibodies specific to the other glycoprotein were obtained. Immunoelectron microscopic examination of HeLa cells revealed that these two glycoproteins mainly reside in lysosomes and multivesicular bodies. Immunoprecipitation experiments showed that a number of different cell lines express these glycoproteins. However, the apparent molecular weights differed between cell lines; this probably represents differences in the amount of polylactosaminoglycan expressed by each cell line. As shown in the following paper (Fukuda, M., Viitala, J., Matteson, J., and Carlsson, S. R. (1988) J. Biol. Chem. 263, 18920-18928) one of the glycoproteins is very homologous to that of a mouse counterpart, m-lamp-1. The human form of this glycoprotein is therefore named human lamp-1 (h-lamp-1), while the other glycoprotein, to which the monoclonal antibody was made, is called human lamp-2 (h-lamp-2). Pulse-chase labeling experiments detected that h-lamp-1 and h-lamp-2 are produced first as precursor forms of 87.5 and 84 kDa, and treatment with endo-beta-N-acetylglucosaminidase H (endo-H) or endo-beta-N-acetylglucosaminidase F (endo-F) reduced their molecular masses to 39.5 and 41.5 kDa, respectively. It was estimated that h-lamp-1 has 18 N-linked saccharides and h-lamp-2 16, based on the results of partial digestions with endo-F. These results indicate that the two lysosomal membrane glycoproteins are extensively modified by N-glycans, and some of these were found to have polylactosaminyl repeats and sialic acid. Human lamp-1 and lamp-2, therefore, serve as good models for understanding polylactosaminoglycan formation and the biosynthesis and processing of polylactosaminoglycan-containing glycoprotein.