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:1991
卷号:88
期号:11
页码:4606-4610
DOI:10.1073/pnas.88.11.4606
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:The substrates of ubiquitin-dependent proteolytic pathways include both damaged or otherwise abnormal proteins and undamaged proteins that are naturally short-lived. Few specific examples of the latter class have been identified, however. Previous work has shown that the cell type-specific MAT alpha 2 repressor of the yeast Saccharomyces cerevisiae is an extremely short-lived protein. We now demonstrate that alpha 2 is conjugated to ubiquitin in vivo. More than one lysine residue of alpha 2 can be joined to ubiquitin, and some of the ubiquitin moieties form a Lys48-linked multiubiquitin chain. Overexpression of degradation-impaired ubiquitin variants was used to show that at least a significant fraction of alpha 2 degradation is dependent on its ubiquitination.