Activation of neutral trehalase by glucose and nitrogen source in <i>Schizosaccharomyces pombe</i> strains deficient in cAMP‐dependent protein kinase activity

Soto, Teresa; Fernández, José María Pérez; Vicente-Soler, Jero; Cansado, José; Gacto, Mariano

doi:10.1016/0014-5793(95)00583-u

Cited by 16 publications

(8 citation statements)

References 26 publications

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“…The results are shown in . In accordance with previous results suggesting that a glucose-repressible element is required in the glucose-induced signalling pathway, but not in that induced by a nitrogen source (Carrillo et al ., 1992; Soto et al ., 1995a, c), wild-type cells of Schiz. pombe lacked the glucose-induced activation of trehalase but still retained the ability to increase trehalase activity in response to the addition of asparagine ().…”

Section: Resultsmentioning

confidence: 99%

“…In the fission yeast Schizosaccharomyces pombe, a similar, although Ras-independent, pathway plays a regulatory role in the control of catabolite repression of fructose lY6-bisphosphatase (Fbpl ; Hoffman & Winston, 1991) and in trehalase activation after exposure to glucose and a nitrogen source (Carrillo et al, 1992;Soto et al, 1995a). There is recent evidence, however, that disruption of the gene encoding Pkal does not block the activation of trehalase induced by either glucose or a nitrogen source in the fission yeast (Soto …”

Section: Introductionmentioning

confidence: 99%

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Protein kinase Sck1 is involved in trehalase activation by glucose and nitrogen source in the fission yeast Schizosaccharomyces pombe

et al. 1997

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Summary: Trehalase activity is markedly enhanced upon addition of glucose and a nitrogen source to cells of the fission yeast Schizosaccharomyces pombe. This increase corresponds to a post-translational activation of the enzyme, which is controlled by cAMP-dependent and cAMP-independent pathways. Recent work has shown that overexpression of SCK1 in Schiz. pombe is able to suppress mutations that result in reduced Pka1 (cAMP-dependent protein kinase A activity, suggesting that Sck1 (suppressor of loss of cAMP-dependent protein kinase) might be a functional analogue of Pka1 in the fission yeast. Here, an analysis of the possible role of Sck1 in the activation of trehalase triggered by glucose and a nitrogen source is reported in cells that were deficient in either Pka1, Sck1 or both protein kinases. The results showed that, except in repressed cells, Sck1 probably mediates a cAMP-independent activation of trehalase following the signal(s) triggered by glucose and the nitrogen source. The absence of functional Sck1 in derepressed cells renders trehalase insensitive to activation by glucose and the nitrogen source even in the presence of Pka1, indicating that the Sck1-dependent, cAMP-independent pathway is the main signalling pathway controlling trehalase activation under derepression conditions. It is proposed that, during the activation of trehalase induced by glucose or a nitrogen source, the cAMP-Pka1 activation pathway previously characterized is to some extent parallel to this newly described one which includes Sck1 as ohosphorylating enzyme. Neither of these two pathways, however, plays a key role in the heat-induced increase in trehalase activity.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Protein kinase Sck1 is involved in trehalase activation by glucose and nitrogen source in the fission yeast Schizosaccharomyces pombe

et al. 1997

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“…As deletion of Sch9 causes slow growth that is suppressed by very high PKA activity, deletion of Sch9 in itself may be lethal in the absence of the partial increase in PKA activity. Also, in fission yeast Schizosaccharomyces pombe , strong evidence for cAMP‐independent and even PKA‐independent control of classical PKA targets such as neutral trehalase has been reported (Soto et al ., 1995a,b; 1997).…”

Section: Glucose Activation Of Camp Synthesis and Control Of Pka Targmentioning

confidence: 99%

Novel sensing mechanisms and targets for the cAMP–protein kinase A pathway in the yeast Saccharomyces cerevisiae

Thevelein

Winde

1999

Molecular Microbiology

608

554

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The cAMP–protein kinase A (PKA) pathway in the yeast Saccharomyces cerevisiae plays a major role in the control of metabolism, stress resistance and proliferation, in particular in connection with the available nutrient conditions. Extensive information has been obtained on the core section of the pathway, i.e. Cdc25, Ras, adenylate cyclase, PKA, and on components interacting directly with this core section, such as the Ira proteins, Cap/Srv2 and the two cAMP phosphodiesterases. Recent work has now started to reveal upstream regulatory components and downstream targets of the pathway. A G‐protein‐coupled receptor system (Gpr1–Gpa2) acts upstream of adenylate cyclase and is required for glucose activation of cAMP synthesis in concert with a glucose phosphorylation‐dependent mechanism. Although a genuine signalling role for the Ras proteins remains unclear, they appear to mediate at least part of the potent stimulation of cAMP synthesis by intracellular acidification. Recently, several new targets of the PKA pathway have been discovered. These include the Msn2 and Msn4 transcription factors mediating part of the induction of STRE‐controlled genes by a variety of stress conditions, the Rim15 protein kinase involved in stationary phase induction of a similar set of genes and the Pde1 low‐affinity cAMP phosphodiesterase, which specifically controls agonist‐induced cAMP signalling. A major issue that remains to be resolved is the precise connection between the cAMP–PKA pathway and other nutrient‐regulated components involved in the control of growth and of phenotypic characteristics correlated with growth, such as the Sch9 and Yak1 protein kinases. Cln3 appears to play a crucial role in the connection between the availability of certain nutrients and Cdc28 kinase activity, but it remains to be clarified which nutrient‐controlled pathways control Cln3 levels.

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“…Current evidence supports the view that the activity of fungal neutral trehalases results from a prior activation step, consisting of cAMP-dependent phosphorylation of the enzyme, which may be triggered in vivo by metabolic changes or stressing conditions and mimicked in vitro by mixtures containing ATP, PKA and cAMP [1,12,[42][43][44][45]. In contrast with trehalases from other yeasts, activation of S. pombe trehalase has not been achieved in vitro, although numerous results suggest that phosphorylation of the enzyme does occur in vivo [29,[46][47][48][49]. On the other hand, similar to that from Saccharomyces cerevisiae, the active form of trehalase in S. pombe represents dimers or trimers of Ntp1p [14,15].…”

Section: Discussionmentioning

confidence: 99%

A role for calcium in the regulation of neutral trehalase activity in the fission yeast Schizosaccharomyces pombe

Franco

Soto

Vicente-Soler

et al. 2003

Biochemical Journal

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Neutral trehalases mobilize trehalose accumulated by fungal cells as a protective and storage carbohydrate. A structural feature of these enzymes is the presence of an EF-like motif similar to that shown by many Ca2+-binding proteins. In this study we provide direct evidence for physical binding of Ca2+ to neutral trehalase (Ntp1p) of the fission yeast Schizosaccharomyces pombe, and show that aspartic residues at positions 97 and 108 in the conserved putative Ca2+-binding motif of Ntp1p appear to be responsible for this interaction. Mutations in these residues do not interfere with the ability of Ntp1p to associate in vivo with trehalose-6-phosphate synthase, but prevent activation of neutral trehalase triggered by the addition of glucose or by subjecting cells to stressing conditions. Strains expressing Ntp1p variants that are unable to bind Ca2+ partially resemble those devoid of the ntp1+ gene in terms of trehalose hyperaccumulation. Gel filtration of cell extracts from wild-type cells after EDTA treatment or from cells containing Ntp1p with mutations in aspartic acid residues within the Ca2+-binding site revealed that Ntp1p eluted mainly in an inactive conformation instead of the dimeric or trimeric active form of the enzyme. These results suggest that activation of S. pombe Ntp1p under different conditions depends upon Ca2+ binding through the Ca2+-binding motif as a prerequisite for correct enzyme oligomerization to its active form. Given the high degree of conservation of the Ca2+ accommodation site, this might be a general mechanism regulating neutral trehalase activity in other yeasts and filamentous fungi.

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Activation of neutral trehalase by glucose and nitrogen source in Schizosaccharomyces pombe strains deficient in cAMP‐dependent protein kinase activity

Cited by 16 publications

References 26 publications

Protein kinase Sck1 is involved in trehalase activation by glucose and nitrogen source in the fission yeast Schizosaccharomyces pombe

Protein kinase Sck1 is involved in trehalase activation by glucose and nitrogen source in the fission yeast Schizosaccharomyces pombe

Novel sensing mechanisms and targets for the cAMP–protein kinase A pathway in the yeast Saccharomyces cerevisiae

A role for calcium in the regulation of neutral trehalase activity in the fission yeast Schizosaccharomyces pombe

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