Cdk phosphorylation of the Ste11 transcription factor constrains differentiation-specific transcription to G<sub>1</sub>

Kjærulff, Søren; Andersen, Nicoline R.; Borup, Mia Trolle; Nielsen, Olaf

doi:10.1101/gad.407107

Cited by 30 publications

(34 citation statements)

References 59 publications

(47 reference statements)

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“…Furthermore, TiO 2 is extremely tolerant toward most buffers and salts used in biochemistry and cell biology laboratories [73]. This has resulted in a robust method for enrichment of phosphopeptides, which has already become a highly popular method for in large-scale phosphoproteomic studies [10,[77][78][79][80][81][82][83][84][85][86][87][88][89][90].…”

Section: Titanium Dioxide Chromatographymentioning

confidence: 99%

Analytical strategies for phosphoproteomics

2009

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Protein phosphorylation is a key regulator of cellular signaling pathways. It is involved in most cellular events in which the complex interplay between protein kinases and protein phosphatases strictly controls biological processes such as proliferation, differentiation, and apoptosis. Defective or altered signaling pathways often result in abnormalities leading to various diseases, emphasizing the importance of understanding protein phosphorylation. Phosphorylation is a transient modification, and phosphoproteins are often very low abundant. Consequently, phosphoproteome analysis requires highly sensitive and specific strategies. Today, most phosphoproteomic studies are conducted by mass spectrometric strategies in combination with phosphospecific enrichment methods. This review presents an overview of different analytical strategies for the characterization of phosphoproteins. Emphasis will be on the affinity methods utilized specifically for phosphoprotein and phosphopeptide enrichment prior to MS analysis, and on recent applications of these methods in cell biological applications.

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Section: Titanium Dioxide Chromatographymentioning

confidence: 99%

Analytical strategies for phosphoproteomics

2009

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“…In contrast, gcn5⌬ mutants do not have decreased cell size and cause a more limited effect on gene expression, primarily limited to Ste11 targets. Finally, we tested whether Gcn5 regulates cell cycle progression, as mating is restricted to the G1 phase in S. pombe, and a G1 delay can induce ectopic mating (Obara-Ishihara and Okayama 1994; Kjaerulff et al 2007). However, flow cytometry analysis of gcn5⌬ mutants revealed no defect in G1 progression (data not shown).…”

Section: Saga and S Pombe Sexual Differentiation Genes And Developmentmentioning

confidence: 99%

The S. pombe SAGA complex controls the switch from proliferation to sexual differentiation through the opposing roles of its subunits Gcn5 and Spt8

Helmlinger¹,

Marguerat²,

Villén³

et al. 2008

Genes Dev.

122

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The SAGA complex is a conserved multifunctional coactivator known to play broad roles in eukaryotic transcription. To gain new insights into its functions, we performed biochemical and genetic analyses of SAGA in the fission yeast, Schizosaccharomyces pombe. Purification of the S. pombe SAGA complex showed that its subunit composition is identical to that of Saccharomyces cerevisiae. Analysis of S. pombe SAGA mutants revealed that SAGA has two opposing roles regulating sexual differentiation. First, in nutrient-rich conditions, the SAGA histone acetyltransferase Gcn5 represses ste11 + , which encodes the master regulator of the mating pathway. In contrast, the SAGA subunit Spt8 is required for the induction of ste11 + upon nutrient starvation. Chromatin immunoprecipitation experiments suggest that these regulatory effects are direct, as SAGA is physically associated with the ste11 + promoter independent of nutrient levels. Genetic tests suggest that nutrient levels do cause a switch in SAGA function, as spt8⌬ suppresses gcn5⌬ with respect to ste11 + derepression in rich medium, whereas the opposite relationship, gcn5⌬ suppression of spt8⌬, occurs during starvation. Thus, SAGA plays distinct roles in the control of the switch from proliferation to differentiation in S. pombe through the dynamic and opposing activities of Gcn5 and Spt8.[Keywords: S. pombe; transcription; differentiation; SAGA; Gcn5; Ste11] Supplemental material is available at http://www.genesdev.org.

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“…During mitotic growth, Ste11 is inhibited by Cdk1 phosphorylation (Kjaerulff et al, 2007). Nitrogen limitation inactivates Cdk1 and induces the expression of ste11 + mRNA and that of many other genes required for conjugation and sporulation in fission yeast (Sugimoto et al, 1991).…”

Section: Fission Yeast Ampk Regulates Ste11 Levels Under Nitrogen Depmentioning

confidence: 99%

AMPK phosphorylation by Ssp1 is required for proper sexual differentiation in fission yeast

Valbuena¹,

Moreno²

2012

Journal of Cell Science

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SummaryThe AMP-activated protein kinase (AMPK) is a central regulator of cellular energy homeostasis, which, in response to a fall in intracellular ATP levels, activates energy-producing pathways and inhibits energy-consuming processes. Here, we report that fission yeast cells lacking AMPK activity are unable to advance entry into mitosis in response to nitrogen starvation and cannot undergo proper G1 arrest and cell differentiation. We also show that AMPK is important in the promotion of the nuclear localization and accumulation of the Ste11 transcription factor. As in animal cells, the fission yeast CaMKK ortholog (Ssp1) phosphorylates and activates the catalytic subunit of AMPK (Ssp2) in its activation loop (Thr189) when cells are starved for nitrogen or glucose. Interestingly, we found that the phosphorylation of Ssp2 on Thr189 is required for nuclear accumulation of AMPK. Our data demonstrate the existence of a signal transduction pathway activated by nutrient starvation that triggers Ssp2 phosphorylation and AMPK redistribution from the cytoplasm to the nucleus. This pathway is important to advance fission cells into mitosis and to establish a timely pre-Start G1 cell cycle arrest for mating.

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Cdk phosphorylation of the Ste11 transcription factor constrains differentiation-specific transcription to G₁

Cited by 30 publications

References 59 publications

Analytical strategies for phosphoproteomics

Analytical strategies for phosphoproteomics

The S. pombe SAGA complex controls the switch from proliferation to sexual differentiation through the opposing roles of its subunits Gcn5 and Spt8

AMPK phosphorylation by Ssp1 is required for proper sexual differentiation in fission yeast

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Cdk phosphorylation of the Ste11 transcription factor constrains differentiation-specific transcription to G1

Cited by 30 publications

References 59 publications

Analytical strategies for phosphoproteomics

Analytical strategies for phosphoproteomics

The S. pombe SAGA complex controls the switch from proliferation to sexual differentiation through the opposing roles of its subunits Gcn5 and Spt8

AMPK phosphorylation by Ssp1 is required for proper sexual differentiation in fission yeast

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Cdk phosphorylation of the Ste11 transcription factor constrains differentiation-specific transcription to G₁