Identification of phosphatase 2A‐like Sit4‐mediated signalling and ubiquitin‐dependent protein sorting as modulators of caffeine sensitivity in <i>S. cerevisiae</i>

Hood-DeGrenier, Jennifer K.

doi:10.1002/yea.1830

Cited by 10 publications

(8 citation statements)

References 77 publications

(129 reference statements)

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“…Consistently, Tap42 phosphorylation, which mediates its interaction with PP2As, depends on the phosphatidylinositol-related kinases Tor1 and Tor2 ( T arget o f r apamycin), which regulate cell growth in response to nutrient availability and cell stress [58]. The last PP2A subunit that we found in Igo1 immunoprecipitates is Rts3, a poorly characterized protein that was found to interact with different PP2A and PP2A-like complexes [45], [59], [60] and whose deletion causes sensitivity to caffeine [61], which in turn inhibits the Tor complex TORC1 [62].…”

Section: Discussionsupporting

confidence: 57%

Budding Yeast Greatwall and Endosulfines Control Activity and Spatial Regulation of PP2ACdc55 for Timely Mitotic Progression

et al. 2013

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Entry into mitosis is triggered by cyclinB/Cdk1, whose activity is abruptly raised by a positive feedback loop. The Greatwall kinase phosphorylates proteins of the endosulfine family and allows them to bind and inhibit the main Cdk1-counteracting PP2A-B55 phosphatase, thereby promoting mitotic entry. In contrast to most eukaryotic systems, Cdc14 is the main Cdk1-antagonizing phosphatase in budding yeast, while the PP2ACdc55 phosphatase promotes, instead of preventing, mitotic entry by participating to the positive feedback loop of Cdk1 activation. Here we show that budding yeast endosulfines (Igo1 and Igo2) bind to PP2ACdc55 in a cell cycle-regulated manner upon Greatwall (Rim15)-dependent phosphorylation. Phosphorylated Igo1 inhibits PP2ACdc55 activity in vitro and induces mitotic entry in Xenopus egg extracts, indicating that it bears a conserved PP2A-binding and -inhibitory activity. Surprisingly, deletion of IGO1 and IGO2 in yeast cells leads to a decrease in PP2A phosphatase activity, suggesting that endosulfines act also as positive regulators of PP2A in yeast. Consistently, RIM15 and IGO1/2 promote, like PP2ACdc55, timely entry into mitosis under temperature-stress, owing to the accumulation of Tyr-phosphorylated Cdk1. In addition, they contribute to the nuclear export of PP2ACdc55, which has recently been proposed to promote mitotic entry. Altogether, our data indicate that Igo proteins participate in the positive feedback loop for Cdk1 activation. We conclude that Greatwall, endosulfines, and PP2A are part of a regulatory module that has been conserved during evolution irrespective of PP2A function in the control of mitosis. However, this conserved module is adapted to account for differences in the regulation of mitotic entry in different organisms.

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Section: Discussionsupporting

confidence: 57%

Budding Yeast Greatwall and Endosulfines Control Activity and Spatial Regulation of PP2ACdc55 for Timely Mitotic Progression

et al. 2013

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“…The transient relocalization and the abundance change suggest that Rts3 may play a key role in response to TORC1 inhibition. Indeed, we and others have found that Rts3 is required for cell survival in rapamycin ( Figure 5B) (Parsons et al, 2004;Xie et al, 2005;Hood-DeGrenier, 2011). Thus, flux network-based analysis of the proteome over time can highlight unusual proteome dynamics in response to environmental or genetic stress and facilitate attribution of protein function.…”

Section: Proteins Change In Localization or Abundance But Usually Notmentioning

confidence: 94%

Yeast Proteome Dynamics from Single Cell Imaging and Automated Analysis

Chong

Koh

Friesen

et al. 2015

Cell

272

387

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Proteomics has proved invaluable in generating large-scale quantitative data; however, the development of systems approaches for examining the proteome in vivo has lagged behind. To evaluate protein abundance and localization on a proteome scale, we exploited the yeast GFP-fusion collection in a pipeline combining automated genetics, high-throughput microscopy, and computational feature analysis. We developed an ensemble of binary classifiers to generate localization data from single-cell measurements and constructed maps of ∼3,000 proteins connected to 16 localization classes. To survey proteome dynamics in response to different chemical and genetic stimuli, we measure proteome-wide abundance and localization and identified changes over time. We analyzed >20 million cells to identify dynamic proteins that redistribute among multiple localizations in hydroxyurea, rapamycin, and in an rpd3Δ background. Because our localization and abundance data are quantitative, they provide the opportunity for many types of comparative studies, single cell analyses, modeling, and prediction. VIDEO ABSTRACT.

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“…5A). Loss of SIT4 and RRD1 have been previously shown to increase caffeine tolerance in high-throughput screens (Kapitzky et al 2010;Hood-DeGrenier 2011), but TIP41 has not. To confirm the contribution of TIP41 S162X we constructed the mutation using CRISPR-Cas9, and observed that TIP41 S162X increased growth in caffeine and rapamycin (Fig.…”

Section: Many Loss-of-function Mutations Contribute To Caffeine and R...mentioning

confidence: 99%

Experimental evolution ofS. cerevisiaefor caffeine tolerance alters multidrug resistance and TOR signaling pathways

Geck,

Moresi,

Anderson

et al. 2024

Preprint

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Caffeine is a natural compound that inhibits the major cellular signaling regulator TOR, leading to widespread effects including growth inhibition. S. cerevisiae yeast can adapt to tolerate high concentrations of caffeine in coffee and cacao fermentations and in experimental systems. While many factors affecting caffeine tolerance and TOR signaling have been identified, further characterization of their interactions and regulation remain to be studied. We used experimental evolution of S. cerevisiae to study the genetic contributions to caffeine tolerance in yeast, through a collaboration between high school students evolving yeast populations coupled with further research exploration in university labs. We identified multiple evolved yeast populations with mutations in PDR1 and PDR5, which contribute to multidrug resistance, and showed that gain-of-function mutations in multidrug resistance family transcription factors PDR1, PDR3, and YRR1 differentially contribute to caffeine tolerance. We also identified loss-of-function mutations in TOR effectors SIT4, SKY1, and TIP41, and show that these mutations contribute to caffeine tolerance. These findings support the importance of both the multidrug resistance family and TOR signaling in caffeine tolerance, and can inform future exploration of networks affected by caffeine and other TOR inhibitors in model systems and industrial applications.

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Identification of phosphatase 2A‐like Sit4‐mediated signalling and ubiquitin‐dependent protein sorting as modulators of caffeine sensitivity in S. cerevisiae

Cited by 10 publications

References 77 publications

Budding Yeast Greatwall and Endosulfines Control Activity and Spatial Regulation of PP2ACdc55 for Timely Mitotic Progression

Budding Yeast Greatwall and Endosulfines Control Activity and Spatial Regulation of PP2ACdc55 for Timely Mitotic Progression

Yeast Proteome Dynamics from Single Cell Imaging and Automated Analysis

Experimental evolution ofS. cerevisiaefor caffeine tolerance alters multidrug resistance and TOR signaling pathways

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