Glc7/PP1 dephosphorylates histone H3T11 to regulate autophagy and telomere silencing in response to nutrient availability
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ABSTRACT:
PROVIDER: PRJNA943500 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR23822200_1.fastq.gz | Fastqsanger.gz | |||
| SRR23822200_2.fastq.gz | Fastqsanger.gz | |||
| SRR23822201_1.fastq.gz | Fastqsanger.gz | |||
| SRR23822201_2.fastq.gz | Fastqsanger.gz | |||
| SRR23822202_1.fastq.gz | Fastqsanger.gz |
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Project description:How cells adapt their gene expression to nutritional changes remains poorly understood. Histone H3T11 is phosphorylated by pyruvate kinase to repress gene transcription. Here, we identify the protein phosphatase 1 (PP1), Glc7 as the enzyme that specifically dephosphorylates H3T11. We also characterize two novel Glc7-containing subcomplexes and reveal their roles in regulating gene expression upon glucose starvation. Specifically, the Glc7-Sen1 subcomplex dephosphorylates H3T11 to activate the transcription of autophagy-related genes. The Glc7-Rif1-Rap1 subcomplex dephosphorylates H3T11 to derepress the transcription of telomere-proximal genes. Upon glucose starvation, Glc7 expression is up-regulated and more Glc7 translocates into the nucleus to dephosphorylate H3T11, leading to induction of autophagy and derepressed transcription of telomere-proximal genes. Furthermore, the functions of PP1/Glc7 and the two Glc7-containing subcomplexes are conserved in mammals to regulate autophagy and telomere structure. Collectively, our results reveal a novel mechanism to regulate gene expression and chromatin structure in response to glucose availability.
2023-04-18 | GSE227169 | GEO
Project description:How cells adapt their gene expression to nutritional changes remains poorly understood. Histone H3T11 is phosphorylated by pyruvate kinase to repress gene transcription. Here, we identify the protein phosphatase 1 (PP1), Glc7 as the enzyme that specifically dephosphorylates H3T11. We also characterize two novel Glc7-containing complexes and reveal their roles in regulating gene expression upon glucose starvation. Specifically, the Glc7-Sen1 complex dephosphorylates H3T11 to activate the transcription of autophagy-related genes. The Glc7-Rif1-Rap1 complex dephosphorylates H3T11 to derepress the transcription of telomere-proximal genes. Upon glucose starvation, Glc7 expression is up-regulated and more Glc7 translocates into the nucleus to dephosphorylate H3T11, leading to induction of autophagy and derepressed transcription of telomere-proximal genes. Furthermore, the functions of PP1/Glc7 and the two Glc7-containing complexes are conserved in mammals to regulate autophagy and telomere structure. Collectively, our results reveal a novel mechanism that regulate gene expression and chromatin structure in response to glucose availability.
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Project description:The Rif1 protein negatively regulates telomeric TG repeat length in the budding yeast S. cerevisiae, but how it prevents telomere over-extension is unknown. Rif1 was recently shown to control DNA replication by acting as a Protein Phosphatase 1 (PP1)-targeting subunit. Therefore we investigated whether Rif1 controls telomere length by targeting PP1 activity. We find that a Rif1 mutant that cannot interact with PP1 causes a long-telomere phenotype, similar to that of rif1∆ cells. Compromised PP1 function also causes telomere extension. Tethering PP1 at a specific telomere partially substitutes for Rif1 in limiting TG repeat length, confirming the importance of PP1 in telomere length control. Ablating Rif1-PP1 interaction leads to precocious activation of telomere-proximal replication origins and aberrantly early telomere replication. However, we find that Rif1 still limits telomere length even if nearby replication origins are deleted, indicating that effects of Rif1 on telomere length are not mediated through replication timing. Instead we find that, even at a telomere created after DNA synthesis during a mitotic block, Rif1-PP1 interaction is required to suppress telomere lengthening and prevent inappropriate recruitment of Tel1 kinase. Overall, our results show that Rif1 controls telomere length by recruiting PP1 to directly suppress telomerase-mediated TG repeat lengthening.
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Project description:Telomeres are organized into a heterochromatin structure and maintenance of silent heterochromatin is required for chromosome stability. How telomere heterochromatin is dynamically regulated in response to stimuli remains unknown. Pyruvate kinase Pyk1 forms a complex, named SESAME (Serine-responsive SAM-containing Metabolic Enzyme complex) to regulate gene expression by phosphorylating histone H3T11 (H3pT11). Here, we identified a novel function of SESAME in regulating telomere heterochromatin structure. SESAME phosphorylates H3T11 at telomeres, which promotes SIR (silent information regulator) complex assembly at telomeres and protects Sir2 from degradation by autophagy. Moreover, SESAMEcatalyzed H3pT11 directly represses autophagy-related gene expression to further prevent autophagy-mediated Sir2 degradation. By promoting H3pT11, serine increases Sir2 protein levels and enhances telomere silencing. Loss of H3pT11 leads to reduced Sir2 and compromised telomere silencing during chronological aging. Together, our study provides insights into dynamic regulation of silent heterochromatin by histone modifications and autophagy in response to cell metabolism and aging.
2020-12-04 | GSE147050 | GEO
Project description:The glycolytic enzyme, pyruvate kinase Pyk1 maintains telomere heterochromatin by phosphorylating histone H3T11 (H3pT11), which promotes SIR (silent information regulator) complex binding at telomeres and prevents autophagy-mediated Sir2 degradation. However, the exact action mechanism of H3pT11 is poorly understood. Here, we report that H3pT11 directly inhibits Dot1-catalyzed H3K79 tri-methylation (H3K79me3) and uncover how this histone crosstalk regulates autophagy and telomere silencing. Mechanistically, Pyk1-catalyzed H3pT11 directly reduces the binding of Dot1 to chromatin and inhibits Dot1-catalyzed H3K79me3, which leads to transcriptional repression of autophagy genes and reduced autophagy. Despite the antagonism between H3pT11 and H3K79me3, they work together to promote the binding of SIR complex at telomeres to maintain telomere silencing. Furthermore, we identify Reb1 as a telomere-associated factor that recruits Pyk1-containing SESAME (Serine-responsive SAM36 taining Metabolic Enzyme) complex to telomere regions to phosphorylate H3T11 and prevent the invasion of H3K79me3 from euchromatin into heterochromatin to maintain telomere silencing. Together, these results uncover a novel histone crosstalk and provide insights into dynamic regulation of silent heterochromatin and autophagy in response to cell metabolism.
2023-02-07 | PXD038138 | Pride
Project description:The glycolytic enzyme, pyruvate kinase Pyk1 maintains telomere heterochromatin by phosphorylating histone H3T11 (H3pT11), which promotes SIR (silent information regulator) complex binding at telomeres and prevents autophagy-mediated Sir2 degradation. However, the exact action mechanism of H3pT11 is poorly understood. Here, we identify Dot1-catalyzed H3K79 tri-methylation (H3K79me3) as the downstream effector of H3pT11 and uncover how this histone crosstalk regulates autophagy and telomere silencing. Mechanistically, Pyk1-catalyzed H3pT11 directly reduces the binding of Dot1 to chromatin and inhibits Dot1-catalyzed H3K79me3, which leads to transcriptional repression of autophagy genes and reduced autophagy. Despite the antagonism between H3pT11 and H3K79me3, they synergically promote the binding of SIR complex at telomeres to maintain telomere silencing. Furthermore, we identify Reb1 as a telomere-associated factor that recruits Pyk1-containing SESAME (Serine-responsive SAM-containing Metabolic Enzyme) complex to telomere regions to phosphorylate H3T11 and prevent the invasion of H3K79me3 from euchromatin into heterochromatin to maintain telomere silencing. Together, these results uncover a novel histone crosstalk and provide insights into dynamic regulation of silent heterochromatin and autophagy in response to cell metabolism.
2022-11-29 | GSE210908 | GEO
Project description:It was previously shown that expression of an activated Phactr1 mutant (Phactr1XXX) that constitutively forms the Phactr1/PP1 phosphatase holoenzyme, induces F-actin rearrangements in NIH3T3 fibroblasts. Expression of the Phactr1 PP1-binding domain (C-terminal) alone is also sufficient to induce such cytoskeletal changes. In contrast, expression of Phactr1XXXC derivative, which lacks the PP1 binding sequences does not result in alteration of cytoskeletal morphology (Wiezlak et al., 2012). These observations suggest that Phactr1/PP1 dephosphorylates target proteins involved in cytoskeletal dynamics. To identify potential Phactr1/PP1 substrates, we used differential SILAC phosphoproteomics in NIH3T3 cells inducibly expressing Phactr1XXX, Phactr1XXXC constructs or vector alone. Over 3000 phosphorylation sites were quantified, among which we determined Phactr1/PP1 target dephosphorylation sites by comparative analysis.
2020-10-28 | PXD019977 | Pride
Project description:The restrictor complex, WDR82/ZC3H4, is the major termination factor for antisense transcription from bidirectional promoters, but its mechanism of action is poorly understood. We report that the PP1 phosphatase nuclear targeting subunit PNUTS binds to restrictor via its WDR82 subunit. AlphaFold predicts a quaternary complex, PPWZ, in which PP1-associated PNUTS and ZC3H4 both contact WDR82. A chimera comprising inactive PP1H66K fused to the C-terminal PNUTS sequences including its WDR82 binding domain binds to restrictor and acts as a dominant negative inhibitor of antisense termination and CTD Ser5 dephosphorylation. The PP1H66K-PNUTS is a substrate trap that also interacts with pol II large subunit and nuclear exosome components. Ser5 hyperphosphorylated pol II has increased processivity and pauses less frequently than total pol II. We speculate that the elevated elongation efficiency of Ser5-P pol II antagonizes early termination and that Ser5 dephosphorylation by PP1/PNUTS/WDR82/ZC3H4 is coupled to termination of antisense transcription.
2025-04-05 | GSE269358 | GEO
Project description:The restrictor complex, WDR82/ZC3H4, is the major termination factor for antisense transcription from bidirectional promoters, but its mechanism of action is poorly understood. We report that the PP1 phosphatase nuclear targeting subunit PNUTS binds to restrictor via its WDR82 subunit. AlphaFold predicts a quaternary complex, PPWZ, in which PP1-associated PNUTS and ZC3H4 both contact WDR82. A chimera comprising inactive PP1H66K fused to the C-terminal PNUTS sequences including its WDR82 binding domain binds to restrictor and acts as a dominant negative inhibitor of antisense termination and CTD Ser5 dephosphorylation. The PP1H66K-PNUTS is a substrate trap that also interacts with pol II large subunit and nuclear exosome components. Ser5 hyperphosphorylated pol II has increased processivity and pauses less frequently than total pol II. We speculate that the elevated elongation efficiency of Ser5-P pol II antagonizes early termination and that Ser5 dephosphorylation by PP1/PNUTS/WDR82/ZC3H4 is coupled to termination of antisense transcription.
2025-04-05 | GSE269359 | GEO
Project description:The restrictor complex, WDR82/ZC3H4, is the major termination factor for antisense transcription from bidirectional promoters, but its mechanism of action is poorly understood. We report that the PP1 phosphatase nuclear targeting subunit PNUTS binds to restrictor via its WDR82 subunit. AlphaFold predicts a quaternary complex, PPWZ, in which PP1-associated PNUTS and ZC3H4 both contact WDR82. A chimera comprising inactive PP1H66K fused to C-terminal PNUTS sequences is a dominant-negative inhibitor of antisense termination and CTD Ser5 dephosphorylation and both activities require the PNUTS WDR82 binding domain. PP1H66K-PNUTS is a substrate trap that also interacts with pol II large subunit and nuclear exosome components. Ser5 hyperphosphorylated pol II has increased processivity and pauses less frequently than total pol II. We propose that the elevated elongation efficiency of Ser5-P pol II antagonizes early termination and that Ser5 dephosphorylation by PP1/PNUTS/WDR82/ZC3H4 is coupled to termination of antisense transcription.
2025-04-05 | GSE269357 | GEO