Biology subjects

Conesa, C.

Publications and source records attributed to Conesa, C..

3 recordsLinked to original sources

bioRxiv2023

Maf1 phosphorylation is regulated through the action of prefoldin-like Bud27 on PP4 phosphatase in Saccharomyces cerevisiae

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 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.

molecular biology↗

bioRxiv2022

A proteomic screen of Ty1 integrase partners identifies the protein kinase CK2 as a regulator of Ty1 retrotransposition

BackgroundTransposable elements are ubiquitous and play a fundamental role in shaping genomes during evolution. Since excessive transposition can be mutagenic, mechanisms exist in the cells to keep these mobile elements under control. Although many cellular factors regulating the mobility of the retrovirus-like transposon Ty1 in Saccharomyces cerevisiae have been identified in genetic screens, only very few of them interact physically with Ty1 integrase (IN). ResultsHere, we perform a proteomic screen to establish Ty1 IN interactome. Among the 265 potential interacting partners, we focus our study on the conserved CK2 kinase. We confirm the interaction between IN and CK2, demonstrate that IN is a substrate of CK2 in vitro and identify the modified residues. We find that Ty1 IN is phosphorylated in vivo and that these modifications are dependent in part on CK2. No significant change in Ty1 retromobility could be observed when we introduce phospho-ablative mutations that prevent IN phosphorylation by CK2 in vitro. However, the absence of CK2 holoenzyme results in a strong stimulation of Ty1 retrotransposition, characterized by an increase in Ty1 mRNA and protein levels and a high accumulation of cDNA. ConclusionOur study highlights an important role of CK2 in the regulation of Ty1 retrotransposition. We provide the first evidence that Ty1 IN is post-translationally modified in vivo, as observed for retroviral INs, and demonstrate that CK2 strongly represses Ty1 mobility by inhibiting Ty1 transcription. The proteomic approach enabled the identification of many new Ty1 IN interacting partners, whose potential role in the control of Ty1 mobility will be interesting to study.

biochemistry↗

bioRxiv2019

The Ty1 integrase nuclear localization signal is necessary and sufficient for retrotransposon targeting to tRNA genes

Integration of transposable elements into the genome is mutagenic. Mechanisms that target integration into relatively safe locations and minimize deleterious consequences for cell fitness have emerged during evolution. In budding yeast, the integration of the Ty1 LTR retrotransposon upstream of RNA polymerase III (Pol III)-transcribed genes requires the interaction between the AC40 subunit of Pol III and Ty1 integrase (IN1). Here we show that the IN1-AC40 interaction involves a short linker sequence in the bipartite nuclear localization signal (bNLS) of IN1. Mutations in this sequence do not impact the frequency of Ty1 retromobility, instead they decrease the recruitment of IN1 to Pol III-transcribed genes and the subsequent integration of Ty1 at these loci. The replacement of Ty5 retrotransposon targeting sequence by the IN1 bNLS induces Ty5 integration into Pol III-transcribed genes. Therefore, the IN1 bNLS is both necessary and sufficient to confer integration site specificity on Ty1 and Ty5 retrotransposons.

molecular biology↗