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：2001
卷号：98
期号：6
页码：3056-3061
DOI：10.1073/pnas.071022298
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The RPN4 (SON1, UFD5) protein of the yeast Saccharomyces cerevisiae is required for normal levels of intracellular proteolysis. RPN4 is a transcriptional activator of genes encoding proteasomal subunits. Here we show that RPN4 is required for normal levels of these subunits. Further, we demonstrate that RPN4 is extremely short-lived (t1/2 {approx}2 min), that it directly interacts with RPN2, a subunit of the 26S proteasome, and that rpn4{Delta} cells are perturbed in their cell cycle. The degradation signal of RPN4 was mapped to its N-terminal region, outside the transcription-activation domains of RPN4. The ability of RPN4 to augment the synthesis of proteasomal subunits while being metabolically unstable yields a negative feedback circuit in which the same protein up-regulates the proteasome production and is destroyed by the assembled active proteasome.
