INTERNALIZATION OF BLOCKING ANTIBODIES AGAINST MANNOSE-6-PHOSPHATE SPECIFIC RECEPTORS
INTERNALIZATION OF BLOCKING ANTIBODIES AGAINST MANNOSE-6-PHOSPHATE SPECIFIC RECEPTORS
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DOI：
10.1002/j.1460-2075.1985.tb03842.x
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发表时间：
1985-01-01
期刊：
影响因子：
11.4
通讯作者：
VONFIGURA, K
中科院分区：
文献类型：
--
作者：
GARTUNG, C;BRAULKE, T;VONFIGURA, K
针对 6-磷酸甘露糖特异性受体的抗体可抑制外源溶酶体酶的受体依赖性内吞作用以及内源溶酶体酶的分选。这种抑制与受体的明显丧失相关。用抗体处理细胞导致形成受体-抗体复合物，在免疫沉淀和检测受体之前，该复合物未被用于溶解受体的程序提取。天然抗体和 F(ab)2 片段均观察到受体明显丧失，但 Fab 片段则不然。所有 3 种形式的抗体均抑制溶酶体酶的转运。这种抑制归因于受体中酶结合位点的抗体的掩蔽。培养基中添加的抗体对内源性溶酶体酶分选的抑制表明分选位点处的 6-磷酸甘露糖特异性受体与细胞表面的受体处于动态平衡。在细胞表面形成的受体-抗体复合物似乎在细胞表面和细胞内膜之间循环。一部分内化抗体与受体分离，并在转移到哺乳动物溶酶体后被降解。与 Fab 复合会增加溶酶体中受体的浓度，并使受体的半衰期缩短 2 至 3 倍。
Antibodies against mannose-6-phosphate specific receptors inhibit the receptor-dependent endocytosis of exogenous lysosomal enzymes as well as the sorting of endogenous lysosomal enzymes. This inhibition was correlated with an apparent loss of the receptors. Treatment of cells with the antibody results in the formation of receptor-antibody complexes that are not extracted by the procedure used for the solubilization of receptors prior to immunoprecipitation and detection of the receptor. The apparent loss of receptors is observed with both native antibody and the F(ab)2 fragments, but not with Fab fragments. The transport of lysosomal enzymes is inhibited by all 3 forms of the antibody. The inhibition is ascribed to masking by the antibody of the enzyme-binding site in the receptor. The inhibition of the sorting of endogenous lysosomal enzymes by antibodies added to the medium indicates that the mannose-6-phosphate specific receptors at the sorting site are in dynamic equilibrium with those at the cell surface. The receptor-antibody complexes formed at the cell surface appear to cycle between the cell surface and intracellular membranes. A fraction of the internalized antibodies dissociates from the receptors and is degraded after transfer into [mammalian] lysosomes. Complexing with Fab increases the concentration of the receptor in the lysosomes and decreases 2- to 3- fold the half-life of the receptor.