PDF(Pubmed)
Abstract：
Bud27 is a prefoldin-like protein that participates in transcriptional regulation mediated by the three RNA polymerases in Saccharomyces cerevisiae. Lack of Bud27 significantly affects RNA pol III transcription, although the involved mechanisms have not been characterized. Here, we show that Bud27 regulates the phosphorylation state of the RNA pol III transcriptional repressor, Maf1, influences its nuclear localization, and likely its activity. We demonstrate that Bud27 is associated with the Maf1 main phosphatase PP4 in vivo, and that this interaction is required for proper Maf1 dephosphorylation. Lack of Bud27 decreases the interaction among PP4 and Maf1, Maf1 dephosphorylation, and its nuclear entry. Our data uncover a new nuclear function of Bud27, identify PP4 as a novel Bud27 interactor and demonstrate the effect of this prefoldin-like protein on the posttranslational regulation of Maf1. Finally, our data reveal a broader effect of Bud27 on PP4 activity by influencing, at least, the phosphorylation of Rad53.
摘要：
Bud27是一种prefoldin样蛋白，参与酿酒酵母中三种RNA聚合酶介导的转录调控。Bud27的缺乏显著影响RNApolIII转录，尽管所涉及的机制尚未被描述。这里,我们显示Bud27调节RNApolIII转录阻遏物的磷酸化状态，Maf1，影响它的核定位，可能是它的活动。我们证明Bud27在体内与Maf1主要磷酸酶PP4有关，并且这种相互作用是正确的Maf1去磷酸化所必需的。缺乏Bud27会降低PP4和Maf1之间的相互作用，Maf1去磷酸化，和它的核进入。我们的数据揭示了Bud27的新核功能，将PP4鉴定为新型Bud27相互作用因子，并证明了这种prefoldin样蛋白对Maf1翻译后调节的影响。最后,我们的数据揭示了Bud27对PP4活性的更广泛影响，至少,Rad53的磷酸化。
