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：2004
卷号：101
期号：2
页码：500-505
DOI：10.1073/pnas.0307228101
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Defects in O-mannosylation of {alpha}-dystroglycan are thought to cause certain types of congenital muscular dystrophies with neuronal migration disorders. Among these muscular dystrophies, Walker-Warburg syndrome is caused by mutations in the gene encoding putative protein O-mannosyltransferase 1 (POMT1), which is homologous to yeast protein O-mannosyltransferases. However, there is no evidence that POMT1 has enzymatic activity. In this study, we first developed a method to detect protein O-mannosyltransferase activity in mammalian cells. Then, using this method, we showed that coexpression of both POMT1 and POMT2 (another gene homologous to yeast protein O-mannosyltransferases) was necessary for the enzyme activity, but expression of either POMT1 or POMT2 alone was insufficient. The requirement of an active enzyme complex of POMT1 and POMT2 suggests that the regulation of protein O-mannosylation is complex. Further, protein O-mannosylation appears to be required for normal structure and function of {alpha}-dystroglycan in muscle and brain. In view of the potential importance of this form of glycosylation for a number of developmental and neurobiological processes, the ability to assay mammalian protein O-mannosyltransferase activity should greatly facilitate progress in the identification and localization of O-mannosylated proteins and the elucidation of their functional roles.
