<i>Saccharomyces cerevisiae</i> gene SIT4 is involved in the control of glycogen metabolism

Posas, Francesc; Clotet, Josep; Ariño, Joaquı́n

doi:10.1016/0014-5793(91)80183-4

Cited by 36 publications

(21 citation statements)

References 29 publications

(4 reference statements)

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“…This was highly unexpected since phosphorylase is not supposed to be very active in a strain that hyperaccumulates glycogen. In this context it is worth noting that a similar situation has been observed recently in mutants carrying a disruption in the SIT4 gene, which in comparison with isogenic strains also present higher phosphorylase N activity [32] and hyperaccumulate glycogen (Clotet, J., unpublished results). Point mutations in the SIT4 gene also induce hyperaccumulation of glycogen [33].…”

Section: Fructose-t6-p2supporting

confidence: 78%

Glycogen hyperaccumulation in Saccharomyces cerevisiae ras2 mutant A biochemical study

et al. 1991

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The mechanism by which yeast rus2 mutant hyperaccumulates glycogen has been investigated. Total glycogen synthase activity WHS between 2.5 and 1.3 times higher in the rus2 mutant than in an isogenic strain. In addition, while in the normal strain the glycogen synthase activation state decreased along the exponential phase, in the mutant strain the opposite behaviour was observed: glycogen synthase activation state rose continuously reaching full activation at the beginning of the stationary phase. Glycogen phosphorylase a activity was up to 40 times higher in the mutant than in the normal strain. Glucose 6-phospha'te and fructose 2,G-bisphosphate levels were slightly more elevated in the mutants. The increase in total glycogen synthase and, particularly, the full activation of this enzyme may explain glycogen hyperaccumulation in the rus2 mutant even in the presence of elevated levels of glycogen phosphorylase a.

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Section: Fructose-t6-p2supporting

confidence: 78%

Glycogen hyperaccumulation in Saccharomyces cerevisiae ras2 mutant A biochemical study

et al. 1991

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“…In this characteristic, Yvh1p joins the Glc7p, Pph21, Pph22, Pgp1p/YNRO32w, and Sit4p phosphatases, which also regulate glycogen accumulation (8,(29)(30)(31). Experiments with YVH1 truncation alleles demonstrate that the alleles which suppress slow growth also suppress the spore maturation and glycogen accumulation defects.…”

Section: Discussionmentioning

confidence: 99%

The Dual-Specificity Protein Phosphatase Yvh1p Regulates Sporulation, Growth, and Glycogen Accumulation Independently of Catalytic Activity in Saccharomyces cerevisiae via the Cyclic AMP-Dependent Protein Kinase Cascade

Beeser

Cooper

2000

J Bacteriol

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Yvh1p, a dual-specific protein phosphatase induced specifically by nitrogen starvation, regulates cell growth as well as initiation and completion of sporulation. We demonstrate that yvh1 disruption mutants are also unable to accumulate glycogen in stationary phase. A catalytically inactive variant of yvh1 (C117S) and a DNA fragment encoding only the Yvh1p C-terminal 159 amino acids (which completely lacks the phosphatase domain) complement all three phenotypes as well as the wild-type allele; no complementation occurs with a fragment encoding only the C-terminal 74 amino acids. These observations argue that phosphatase activity is not required for the Yvh1p functions we measured. Mutations which decrease endogenous cyclic AMP (cAMP) levels partially suppress the sporulation and glycogen accumulation defects. In addition, reporter gene expression supported by a DRR2 promoter fragment, containing two stress response elements known to respond to cAMP-protein kinase A, decreases in a yvh1 disruption mutant. Therefore, our results identify three cellular processes that both require Yvh1p and respond to alterations in cAMP, and they lead us to suggest that Yvh1p may be a participant in and/or a contributor to regulation of the cAMP-dependent protein kinase cascade. The fact that decreasing the levels of cAMP alleviates the need for Yvh1p function supports this suggestion.

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“…The kanMX4 module containing the kanamycin resistance gene was recovered from plasmid pFA6a-kanMX4 (38) by digestion with SmaI and SpeI and was cloned into plasmid pUC19, previously digested with SmaI and XbaI. The insert was recovered by digestion with BglII and SphI and cloned into these same sites present in the coding region of the SIT4 gene in plasmid pJA-1 (28). The construct was linearized by digestion with BamHI, and the 2.75-kbp fragment was used for integration at the SIT4 locus.…”

Section: Methodsmentioning

confidence: 99%

The Yeast Ser/Thr Phosphatases Sit4 and Ppz1 Play Opposite Roles in Regulation of the Cell Cycle

Clotet

Garí

Aldea

et al. 1999

Molecular and Cellular Biology

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Yeast cells overexpressing the Ser/Thr protein phosphatase Ppz1 display a slow-growth phenotype. These cells recover slowly from ␣-factor or nutrient depletion-induced G 1 arrest, showing a considerable delay in bud emergence as well as in the expression of the G 1 cyclins Cln2 and Clb5. Therefore, an excess of the Ppz1 phosphatase interferes with the normal transition from G 1 to S phase. The growth defect is rescued by overexpression of the HAL3/SIS2 gene, encoding a negative regulator of Ppz1. High-copy-number expression of HAL3/SIS2 has been reported to improve cell growth and to increase expression of G 1 cyclins in sit4 phosphatase mutants. We show here that the described effects of HAL3/SIS2 on sit4 mutants are fully mediated by the Ppz1 phosphatase. The growth defect caused by overexpression of PPZ1 is intensified in strains with low G 1 cyclin levels (such as bck2⌬ or cln3⌬ mutants), whereas mutation of PPZ1 rescues the synthetic lethal phenotype of sit4 cln3 mutants. These results reveal a role for Ppz1 as a regulatory component of the yeast cell cycle, reinforce the notion that Hal3/Sis2 serves as a negative modulator of the biological functions of Ppz1, and indicate that the Sit4 and Ppz1 Ser/Thr phosphatases play opposite roles in control of the G 1 /S transition.

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Saccharomyces cerevisiae gene SIT4 is involved in the control of glycogen metabolism

Cited by 36 publications

References 29 publications

Glycogen hyperaccumulation in Saccharomyces cerevisiae ras2 mutant A biochemical study

Glycogen hyperaccumulation in Saccharomyces cerevisiae ras2 mutant A biochemical study

The Dual-Specificity Protein Phosphatase Yvh1p Regulates Sporulation, Growth, and Glycogen Accumulation Independently of Catalytic Activity in Saccharomyces cerevisiae via the Cyclic AMP-Dependent Protein Kinase Cascade

The Yeast Ser/Thr Phosphatases Sit4 and Ppz1 Play Opposite Roles in Regulation of the Cell Cycle

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