Dcp2 phosphorylation by Ste20 modulates stress granule assembly and mRNA decay in Saccharomyces cerevisiae

Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA.
The Journal of Cell Biology (Impact Factor: 9.83). 05/2010; 189(5):813-27. DOI: 10.1083/jcb.200912019
Source: PubMed


Translation and messenger RNA (mRNA) degradation are important sites of gene regulation, particularly during stress where translation and mRNA degradation are reprogrammed to stabilize bulk mRNAs and to preferentially translate mRNAs required for the stress response. During stress, untranslating mRNAs accumulate both in processing bodies (P-bodies), which contain some translation repressors and the mRNA degradation machinery, and in stress granules, which contain mRNAs stalled in translation initiation. How signal transduction pathways impinge on proteins modulating P-body and stress granule formation and function is unknown. We show that during stress in Saccharomyces cerevisiae, Dcp2 is phosphorylated on serine 137 by the Ste20 kinase. Phosphorylation of Dcp2 affects the decay of some mRNAs and is required for Dcp2 accumulation in P-bodies and specific protein interactions of Dcp2 and for efficient formation of stress granules. These results demonstrate that Ste20 has an unexpected role in the modulation of mRNA decay and translation and that phosphorylation of Dcp2 is an important control point for mRNA decapping.

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    • "Major signal transduction pathways can affect the localization and function of mRNA turnover factors, constituents of cytoplasmic RNA granules. In yeast, phosphorylation of DCP2 decapping enzyme in response to oxidative stress or glucose deprivation was shown to affect its localization to PBs, to promote SG formation and to stabilize a subset of mRNAs encoding ribosomal proteins (Yoon et al., 2010). Similarly in mammalian cells, phosphorylation of DCP1a by JNK in response to stress or inflammatory stimuli regulates localization of DCP1a to PBs affecting the mRNA levels of NF-kB target genes (Rzeczkowski et al., 2011). "
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    ABSTRACT: Messenger RNA (mRNA) turnover that determines the lifetime of cytoplasmic mRNAs is a means to control gene expression under both normal and stress conditions, whereas its impact on ageing and age-related disorders has just become evident. Gene expression control is achieved at the level of the mRNA clearance as well as mRNA stability and accessibility to other molecules. All these processes are regulated by cis-acting motifs and trans-acting factors that determine the rates of translation and degradation of transcripts. Specific messenger RNA granules that harbor the mRNA decay machinery or various factors, involved in translational repression and transient storage of mRNAs, are also part of the mRNA fate regulation. Their assembly and function can be modulated to promote stress resistance in adverse conditions and over time affect the ageing process and the lifespan of the organism. Here, we provide insights into the complex relationships of ageing modulators and mRNA turnover mechanisms.
    Mechanisms of ageing and development 10/2015; 152. DOI:10.1016/j.mad.2015.09.006 · 3.40 Impact Factor
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    • "Recombinant maltose-binding protein (MBP)-HuR was incubated with a buffer containing 20 mM Tris-HCl at pH 7.5, 100 mM KCl, 5 mM MgCl2 and 0.5% NP-40. Biotinylated SIRT1 and GAPDH 3′-untranslated regions were synthesized by PCR amplification of cDNA using forward primers that contained the T7 RNA polymerase promoter sequence (Supplementary Table S1) in the presence of biotinylated CTP and T7 RNA polymerase, as described (22,31). Proteins present in the pulldown material were studied by WB analysis. "
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    ABSTRACT: In response to stress conditions, many mammalian mRNAs accumulate in stress granules (SGs) together with numerous RNA-binding proteins that control mRNA turnover and translation. However, the signaling cascades that modulate the presence of ribonucleoprotein (RNP) complexes in SGs are poorly understood. Here, we investigated the localization of human antigen R (HuR), an mRNA-stabilizing RNA-binding protein, in SGs following exposure to the stress agent arsenite. Unexpectedly, the mobilization of HuR to SGs was prevented through the activation of Janus kinase 3 (JAK3) by the vitamin K3 analog menadione. JAK3 phosphorylated HuR at tyrosine 200, in turn inhibiting HuR localization in SGs, reducing HuR interaction with targets SIRT1 and VHL mRNAs, and accelerating target mRNA decay. Our findings indicate that HuR is tyrosine-phosphorylated by JAK3, and link this modification to HuR subcytoplasmic localization and to the fate of HuR target mRNAs.
    Nucleic Acids Research 10/2013; 42(2). DOI:10.1093/nar/gkt903 · 9.11 Impact Factor
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    • "However, a fraction of these deadenylated targets may be degraded through decapping when DCP2 and DCP1 are expressed. Additionally, DCP1 and DCP2 are phosphorylated under cellular stress conditions (47,48), and DCP1 is hyperphosphorylated during mitosis (49). Under these conditions, a subset of mRNAs is stabilized, suggesting that DCP1 and DCP2 phosphorylation inhibits decapping. "
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    ABSTRACT: MicroRNA (miRNA)-induced silencing complexes (miRISCs) repress translation and promote degradation of miRNA targets. Target degradation occurs through the 5'-to-3' messenger RNA (mRNA) decay pathway, wherein, after shortening of the mRNA poly(A) tail, the removal of the 5' cap structure by decapping triggers irreversible decay of the mRNA body. Here, we demonstrate that miRISC enhances the association of the decapping activators DCP1, Me31B and HPat with deadenylated miRNA targets that accumulate when decapping is blocked. DCP1 and Me31B recruitment by miRISC occurs before the completion of deadenylation. Remarkably, miRISC recruits DCP1, Me31B and HPat to engineered miRNA targets transcribed by RNA polymerase III, which lack a cap structure, a protein-coding region and a poly(A) tail. Furthermore, miRISC can trigger decapping and the subsequent degradation of mRNA targets independently of ongoing deadenylation. Thus, miRISC increases the local concentration of the decapping machinery on miRNA targets to facilitate decapping and irreversibly shut down their translation.
    Nucleic Acids Research 07/2013; 41(18). DOI:10.1093/nar/gkt619 · 9.11 Impact Factor
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