MUTANT CHINESE-HAMSTER OVARY CELLS PLEIOTROPICALLY DEFECTIVE IN RECEPTOR-MEDIATED ENDOCYTOSIS
MUTANT CHINESE-HAMSTER OVARY CELLS PLEIOTROPICALLY DEFECTIVE IN RECEPTOR-MEDIATED ENDOCYTOSIS
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DOI：
10.1083/jcb.96.4.1064
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发表时间：
1983-01-01
影响因子：
7.8
通讯作者：
MARSHALL, JL
中科院分区：
文献类型：
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作者：
ROBBINS, AR;PENG, SS;MARSHALL, JL
选择抗白喉毒素的中国仓鼠卵巢细胞群高度富集了缺乏通过甘露糖 6-磷酸受体摄取溶酶体水解酶的突变体。一种双缺陷突变体 DTF 1-5-1 尽管能够正常结合和内化病毒，但表现出对辛德比斯病毒的抵抗力增强。病毒结合后，将突变体暴露于酸性 pH 值 2 分钟，即可正常产生病毒。 pH 值变为酸性后，DTF 1-5-1 对白喉毒素的敏感性增加了 12 倍。突变体对溶酶体水解酶的摄取减少与细胞表面 6-磷酸甘露糖受体活性降低相关；乳过氧化物酶催化碘化的结果表明，表面相关受体存在，但在 DTF 1-5-1 上失活。突变体中总甘露糖 6-磷酸受体活性也降低，这种降低通过溶酶体水解酶分泌的增加反映出来。 DTF 1-5-1 的表型在很多方面与用氨处理的细胞相似。 DTF 1-5-1 的缺陷可能源于无法将病毒、白喉毒素和溶酶体水解酶递送至酸性区室。其他配体可能通过不同的途径被内吞，因为 DTF 1-5-1 的缺陷不会降低蓖麻毒素、莫德霉素或假单胞菌毒素的内吞作用，并且对低密度脂蛋白的摄取和降解影响最小。
Populations of Chinese hamster ovary cells selected for resistance to diphtheria toxin were highly enriched for mutants deficient in the uptake of lysosomal hydrolases via the mannose 6-phosphate receptor. One doubly defective mutant, DTF 1-5-1, exhibited increased resistance to Sindbis virus, although it was able to bind and internalize virus normally. Normal production of virus was obtained when, subsequent to virus binding, the mutant was exposed for 2 min to acidic pH. A shift to acidic pH increased the sensitivity of DTF 1-5-1 to diphtheria toxin 12-fold. Decreased uptake of lysosomal hydrolases by the mutant correlated with decreased mannose 6-phosphate receptor activity at the cell surface; results of lactoperoxidase-catalyzed iodination indicated that the surface-associated receptor was present but inactive on DTF 1-5-1. Total mannose 6-phosphate receptor activity was also decreased in the mutant and this decrease was reflected by increased secretion of lysosomal hydrolases. The phenotype of DTF 1-5-1 resembles in many ways that of cells treated with ammonia. The defect in DTF 1-5-1 may stem from an inability to deliver virus, diphtheria toxin and lysosomal hydrolases to an acidic compartment. Other ligands may be endocytosed through a different pathway since the defect of DTF 1-5-1 did not decrease the endocytosis of ricin, modeccin, or Pseudomonas toxin and had minimal effects on uptake and degradation of low density lipoprotein.