标题：Identification and characterization of cells deficient in the mannose 6-phosphate receptor: evidence for an alternate pathway for lysosomal enzyme targeting
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1983
卷号：80
期号：3
页码：775-779
DOI：10.1073/pnas.80.3.775
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Newly synthesized lysosomal enzymes acquire phosphomannosyl units, which allow binding of the enzymes to the mannose 6-phosphate receptor and subsequent translocation to lysosomes. In some cell types, this sequence of events is necessary for the delivery of these enzymes to lysosomes. Using a slime mold lysosomal hydrolase as a probe, we have identified three murine cell lines that lack the receptor and one line that contains very low (3%) receptor activity. Each of these lines synthesizes the mannose 6-phosphate recognition marker on its lysosomal enzymes, but, unlike cell lines with high levels of receptor, the cells accumulate oligosaccharides containing phosphomonoesters. The receptor-deficient lines possess high levels of intracellular acid hydrolase activity, which is contained in dense granules characteristic of lysosomes. The data suggest that intracellular mechanisms independent of the mannose 6-phosphate receptor must exist in some cells for the delivery of acid hydrolases to lysosomal organelles.
