Requirement of the Self-Glucosylating Initiator Proteins Glg1p and Glg2p for Glycogen Accumulation in <i>Saccharomyces cerevisiae</i>

Cheng, Christine; Mu, James; Farkas, Illés J.; Huang, Dongqing; Goebl, Mark G.; Roach, Peter J.

doi:10.1128/mcb.15.12.6632

Cited by 100 publications

(92 citation statements)

References 43 publications

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“…6). In the Glg proteins, the extreme COOH terminus may have a function in interactions with glycogen synthase (19,21). Glycogenin-2 has a Tyr in correspondence to rabbit muscle Tyr-194, the site of self-glucosylation, even though overall this is not a region of particularly high sequence conservation in different glycogenin and glycogenin-like proteins (6).…”

Section: Discussionmentioning

confidence: 99%

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Glycogenin-2, a Novel Self-glucosylating Protein Involved in Liver Glycogen Biosynthesis

Skurat

Roach

1997

Journal of Biological Chemistry

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Glycogenin is a self-glucosylating protein involved in the initiation phase of glycogen biosynthesis. A single mammalian gene had been reported to account for glycogen biogenesis in liver and muscle, the two major repositories of glycogen. We describe the characterization of novel forms of glycogenin, designated glycogenin-2 (GN-2), encoded by a second gene that is expressed preferentially in certain tissues, including liver, heart, and pancreas. Cloning of cDNAs encoding glycogenin-2 indicated the existence of multiple species, including three liver forms (GN-2␣, GN-2␤, and GN-2␥) generated in part by alternative splicing. Overall, GN-2 has 40 -45% identity to muscle glycogenin but is 72% identical over a 200-residue segment thought to contain the catalytic domain. GN-2 expressed in Escherichia coli or COS cells is active in self-glucosylation assays, and self-glucosylated GN-2 can be elongated by skeletal muscle glycogen synthase. Antibodies raised against GN-2 produced in E. coli recognized proteins of M r ϳ66,000 present in extracts of rat liver and in cultured H4IIEC3 hepatoma cells. In H4IIEC3 cells, most of the GN-2 was present as a free protein but some was covalently associated with glycogen fractions and was only released by treatment with ␣-amylase. H4IIEC3 cells also expressed the muscle form of glycogenin (glycogenin-1), which was attached to a chromatographically separable glycogen fraction.Glycogen, a branched polymer of glucose, is a metabolic energy reserve accumulated in many cell types (1). In mammals, the major glycogen deposits in absolute amount are those of skeletal muscle and liver. These glycogen reserves have somewhat different functions, but both pools contribute to blood glucose homeostasis. In eukaryotes, the pathway of glycogen biogenesis consists of an initiation step and a subsequent phase of bulk polysaccharide synthesis mediated by glycogen synthase and the branching enzyme (see, for example, Ref. 2).

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Section: Discussionmentioning

confidence: 99%

“…6). Two self-glucosylating proteins, Glg1p and Glg2p, from the yeast Saccharomyces cerevisiae have been characterized and shown to be required for glycogen accumulation in that organism (19). In addition, searching GenBank revealed that Caenorhabditis elegans, Caenorhabditis briggsae, and Arabidopsis thaliana all express multiple glycogenin-like messages (6).…”

mentioning

confidence: 99%

Glycogenin-2, a Novel Self-glucosylating Protein Involved in Liver Glycogen Biosynthesis

Skurat

Roach

1997

Journal of Biological Chemistry

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“…It has been reported that disruption of both S. cerevisiae glycogenin-encoding genes completely abolished glycogen synthesis in the live yeast, thus indicating that S. cerevisiae GS is unable to initiate glycogen synthesis (13). An expression vector coding for S. cerevisiae GSII was introduced into A. tumefaciens A1120 strain, which lacks glycogen-branching enzyme, ADP-Glc pyrophosphorylase, and GS activities.…”

Section: S Cerevisiae Gs Expressed In a Tumefaciens Participates Inmentioning

confidence: 99%

De novo synthesis of bacterial glycogen: Agrobacterium tumefaciens glycogen synthase is involved in glucan initiation and elongation

Ugalde

Parodi

Ugalde

2003

Proc. Natl. Acad. Sci. U.S.A.

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Evidence is presented indicating that initiation of glycogen synthesis in Agrobacterium tumefaciens does not require the presence of ␣(1,4)-linked glucans. Crude cell extracts incubated with ADPglucose (Glc) were able to form ␣(1,4)-linked glucans despite the fact that cells used for extract preparation displayed a genotype that prevented synthesis of Glc-containing sugar nucleotides and thus preformation of ␣(1,4)-linked glucans and that the defined growth medium used contained glycerol as carbon source. A. tumefaciens glycogen synthase (GS) purified to homogeneity from the above-mentioned cells was able to build its own primer by transferring Glc residues from ADP-Glc to an amino acid(s) in the same protein. Primed GS then became the substrate for further GS-catalyzed glucan elongation. It was concluded that, contrary to what happens in mammalian and yeast cells in which two different proteins are required for linear ␣(1,4)-linked glucan formation (glycogenin for initiation and GS for further elongation), in A. tumefaciens and probably in all other bacteria, the same protein is involved in both glycogen initiation and elongation.

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“…We tested glycogen synthase II from S. cerevisiae (Gsy2p) as a reporter, which normally elongates (1,4)-␣-glucan primers generated by glycogenin, but lacks the ability to initiate de novo (1,4)-␣-glucan synthesis (33,40). Overexpression of wildtype S. cerevisiae Gsy2p in S. pombe cells resulted in a brown staining, whereas low expression did not (Fig.…”

Section: The Intracellular Domain Of Ags1p Is Responsible For (14)-␣mentioning

confidence: 99%

Role of the Synthase Domain of Ags1p in Cell Wall α-Glucan Biosynthesis in Fission Yeast

Vos

Dekker

Distel

et al. 2007

Journal of Biological Chemistry

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The cell wall is important for maintenance of the structural integrity and morphology of fungal cells. Besides ␤-glucan and chitin, ␣-glucan is a major polysaccharide in the cell wall of many fungi. In the fission yeast Schizosaccharomyces pombe, cell wall ␣-glucan is an essential component, consisting mainly of (1,3)-␣-glucan with ϳ10% (1,4)-linked ␣-glucose residues. The multidomain protein Ags1p is required for ␣-glucan biosynthesis and is conserved among cell wall ␣-glucan-containing fungi. One of its domains shares amino acid sequence motifs with (1,4)-␣-glucan synthases such as bacterial glycogen synthases and plant starch synthases. Whether Ags1p is involved in the synthesis of the (1,4)-␣-glucan constituent of cell wall ␣-glucan had remained unclear. Here, we show that overexpression of Ags1p in S. pombe cells results in accumulation of (1,4)-␣-glucan. To determine whether the synthase domain of Ags1p is responsible for this activity, we overexpressed Ags1p-E1526A, which carries a mutation in a putative catalytic residue of the synthase domain, but observed no accumulation of (1,4)-␣-glucan. Compared with wild-type Ags1p, this mutant Ags1p showed a markedly reduced ability to complement the cell lysis phenotype of the temperature-sensitive ags1-1 mutant. Therefore, we conclude that, in S. pombe, the production of (1,4)-␣-glucan by the synthase domain of Ags1p is important for the biosynthesis of cell wall ␣-glucan.

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Requirement of the Self-Glucosylating Initiator Proteins Glg1p and Glg2p for Glycogen Accumulation in Saccharomyces cerevisiae

Cited by 100 publications

References 43 publications

Glycogenin-2, a Novel Self-glucosylating Protein Involved in Liver Glycogen Biosynthesis

Glycogenin-2, a Novel Self-glucosylating Protein Involved in Liver Glycogen Biosynthesis

De novo synthesis of bacterial glycogen: Agrobacterium tumefaciens glycogen synthase is involved in glucan initiation and elongation

Role of the Synthase Domain of Ags1p in Cell Wall α-Glucan Biosynthesis in Fission Yeast

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