The 'scavenger' m7GpppX pyrophosphatase activity of Dcs1 modulates nutrient-induced responses in yeast

John Mccarthy, Naglis Malys, Kathleen Carroll, Jaleel Miyan, David Tollervey, John E G McCarthy

Research output: Contribution to journalArticlepeer-review

Abstract

Dcs1, the m7GpppX prophosphatase of Saccharomyces cerevisiae, has been reported to 'scavenge' capped 5′ end fragments generated by 3′→5′ MRNA degradation. We now show that the absence of Dcs1, and the closely related Dcs2 protein, compromises cellular responses to glucose-deprivation stress as well as to step changes in glucose availability. Dcs1 and Dcs2 form homo- and heterodimers, with the heterodimer appearing as cells enter diauxie. Despite the previously observed increase in abundance of the mRNA encoding the neutral trehalase (Nth1) in the stationary phase, the total enzyme activity of Nth1 decreases in this phase of growth. Changes in trehalase activity are significant because the non-reducing disaccharide trehalose is thought to stabilize cellular components under stress conditions. In the dcs1Δ and dcs1Δdcs2Δ mutants, normal regulation of trehalase activity is lost. Nutrient stress induces DCS1 and DCS2 transcription via the cAMP-PKA signalling pathway. Dcs1 also becomes phosphorylated as the availability of glucose diminishes, and we test the role of this phosphorylation in the stress response. Further evidence indicates that Dcs1 plays a complementary role to the translation factor elF4E in preventing capped 5′ fragments of mRNA from interfering with translation initiation. We conclude that Dcs1 function influences cellular responses to changes in nutrient avialability, while Dcs2 seems to act as a modulator of Dcs1 function. © Oxford University Press 2004; all rights reserved.
Original languageEnglish
Pages (from-to)3590-3600
Number of pages11
JournalNucleic acids research.
Volume32
Issue number12
Early online date1 Jan 2004
DOIs
Publication statusPublished - 15 Jun 2004

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