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Maurya R, Kumar R, Saran S. Dictyostelium AMPKα regulates aggregate size and cell-type patterning. Open Biol 2018; 7:rsob.170055. [PMID: 28701378 PMCID: PMC5541345 DOI: 10.1098/rsob.170055] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/08/2017] [Indexed: 01/28/2023] Open
Abstract
Starved Dictyostelium cells aggregate into groups of nearly 105 cells. AMPK is a highly conserved serine/threonine protein kinase consisting of a catalytic and two regulatory subunits. As multi-cellular development in Dictyostelium is initiated upon starvation, we explored the role of the energy sensor, AMPK, which shows significant similarity to human AMPK and is expressed throughout development. Deletion of the ampkα gene results in the formation of numerous small-sized aggregates that develop asynchronously to form few fruiting bodies with small sori and long stalks. On the other hand, ampkαOE cells form fruiting bodies with small stalks and large sori when compared with wild-type, Ax2. A minimum of 5% ampkα− cells in a chimaera with Ax2 cells was sufficient to reduce the aggregate size. Also, the conditioned media collected from ampkα− cells triggered Ax2 cells to form smaller aggregates. The starved ampkα− cells showed low glucose levels and formed large aggregates when glucose was supplied exogenously. Interestingly, ampkα− cells exhibit abnormal cell-type patterning with increased prestalk region and a concomitant reduction of prespore region. In addition, there was a loss of distinct prestalk/prespore boundary in the slugs.
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Affiliation(s)
- Ranjana Maurya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Rakesh Kumar
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Shweta Saran
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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Steuer R, Junker BH. Computational Models of Metabolism: Stability and Regulation in Metabolic Networks. ADVANCES IN CHEMICAL PHYSICS 2008. [DOI: 10.1002/9780470475935.ch3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Gustafson GL, Wright BE, Coe EL. Analysis of Approaches Used in Studying Differentiation of the Cellular Slime Mold. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/10408417209103874] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Ryman BE, Whelan WJ. New aspects of glycogen metabolism. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 34:285-443. [PMID: 4335607 DOI: 10.1002/9780470122792.ch6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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5
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Williamson BD, Favis R, Brickey DA, Rutherford CL. Isolation and characterization of glycogen synthase in Dictyostelium discoideum. DEVELOPMENTAL GENETICS 2000; 19:350-64. [PMID: 9023987 DOI: 10.1002/(sici)1520-6408(1996)19:4<350::aid-dvg8>3.0.co;2-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We have partially purified the protein and isolated the glcS gene for glycogen synthase in Dictyostelium. glcS mRNA is present throughout development and is the product of a single gene coding for 775 amino acids, with a predicted molecular mass of 87 kD. The sequence is highly similar to glycogen synthase from human muscle, yeast, and rat liver, diverging significantly only at the amino and carboxy termini. Phosphorylation and UDPG binding sites are conserved, with K(m) values for UDPG being comparable to those determined for other organisms, but in vitro phosphorylation failing to convert between the G6P-dependent (D) and -independent (I) forms. Enzyme activity is relatively constant throughout the life cycle: the I form of the enzyme isolates with the soluble fraction in amoebae, switches to the D form, becomes pellet-associated during early development, and finally reverts during late development to the I form, which again localizes to the soluble fraction. Deletion analysis of the promoter reveals a GC-rich element which, when deleted, abolishes expression of glcS.
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Affiliation(s)
- B D Williamson
- Department of Biology, virginia Polytechnic Institute and State University, Blacksburg 24061-0406, USA
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Warner N, Rutherford CL. Purification and cloning of TF2: A novel protein that binds a regulatory site of the gp2 promoter in Dictyostelium. Arch Biochem Biophys 2000; 373:462-70. [PMID: 10620373 DOI: 10.1006/abbi.1999.1575] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The glycogen phosphorylase-2 gene is developmentally regulated and plays a central role in cellular differentiation in Dictyostelium. There are two isozymes of glycogen phosphorylase, GP1 and GP2. Both forms are developmentally regulated; gp1 is expressed in undifferentiated cells and gp2 during differentiation. We report here the identification, purification, and cloning of a second gp2 DNA-binding factor called TF2. This protein demonstrates a high specificity for a transcriptional regulatory element, the 5' C box. TF2 was first detected with electrophoretic mobility shift assays of DEAE chromatographic fractions of cell-free extracts. The specificity of TF2 for the 5' C box was tested by competition analysis using six other oligonucleotides. Purification of TF2 was achieved by ion-exchange chromatography, DNA affinity chromatography, gel filtration chromatography, and preparative SDS-PAGE. SDS-PAGE analysis indicated an apparent subunit molecular weight of 28 kDa. The apparent molecular weight of the native protein as estimated by gel filtration was about 53 kDa. This suggested that TF2 binds gp2 as a homodimer. Southern blot analysis indicated that there is only one form of the tf2 gene. Northern analysis showed little or no expression of tf2 in undifferentiated cells. During development tf2 expression increases up to a maximum at 8 h and then decreases in later stages. Attempts to disrupt the gene suggest that tf2 mutation may be lethal.
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Affiliation(s)
- N Warner
- Biology Department, Molecular and Cellular Biology Section, Blacksburg, Virginia 24061-0406, USA
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Rutherford CL, Selmin O, Peters-Weigel S. Temporal regulation of the Dictyostelium glycogen phosphorylase 2 gene. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1351:111-25. [PMID: 9116024 DOI: 10.1016/s0167-4781(96)00182-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The product of the glycogen phosphorylase-2 gene in Dictyostelium functions to provide the glucose units that are used to construct the structural components of the terminal stage of development. In this report, we link a 1233 bp upstream gp2 fragment to a luciferase reporter gene in order to study the sequences that are involved in the temporal expression of the gene. Various deletions of the promoter-luciferase fusion were then transformed into Dictyostelium cells. All deletion constructs, from -1216 to -486 nucleotides from the translational start codon, showed the same temporal pattern of expression as the authentic gp2 gene, as well as similar luciferase activities. Removal of an additional 37 nucleotides resulted in nearly 100-fold decrease in activity, yet retained the normal temporal expression of luciferase. Analysis of DNA binding proteins with the gel shift assay revealed a stage-dependent pattern of proteins that bound to the gp2 promoter. A similar pattern of temporal expression of the binding proteins was observed with either the full-length probe or with oligonucleotide probes that contained sequences that were identified as putative regulatory sites. Likewise, the full-length and oligonucleotide probes demonstrated identical binding patterns during several steps of purification of the DNA binding proteins. SDS-PAGE and Southwestern blot analysis of a DNA-affinity purified fraction, identified a 23 kDa peptide as the binding protein.
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Affiliation(s)
- C L Rutherford
- Biology Department, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
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Rogers PV, Sucic JF, Yin Y, Rutherford CL. Disruption of glycogen phosphorylase gene expression in Dictyostelium: evidence for altered glycogen metabolism and developmental coregulation of the gene products. Differentiation 1994; 56:1-12. [PMID: 8026640 DOI: 10.1046/j.1432-0436.1994.56120001.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Glycogen phosphorylase 1 and 2, the isozymes responsible for glycogen degradation, are encoded by separate genes in Dictyostelium. The two gene products display different transcriptional and translational expression and distinct post-translational regulation. Using DNA-mediated transformation, Dictyostelium clones which lacked either glycogen phosphorylase 1 or 2 (gp1 or gp2) expression were obtained. The loss of either enzyme did not change axenic growth patterns, developmental progression, or gross organismic morphology. In gp1- strains, glycogen accumulated to a 17- to 28-fold higher level during late stationary phase without any obvious detrimental effects. This implies that no alternative pathway for glycogen degradation is present in amoebae, and that glycogen metabolism is not critical for vegetative cell growth. Developmental glycogen concentrations were not altered significantly in any of the transformants, but in gp2- cells the posttranslational regulation of the intact gp1 enzyme was apparently modulated to compensate for the loss of gp2. Western blots of microdissected, lyophilized Dictyostelium slugs and early culminates showed that gp2 was found in both prestalk and prespore cells, with a slight enrichment in prespore cells. The gp1 protein was highly enriched in prestalk cells in the parental strain. In gp2- transformants, however, gp1 was detected in equal amounts in both cell types. The loss of gp2 led to a shift in the cell-type-specific expression pattern of gp1, presumably due to developmental coordinate regulation of gp1 and gp2 at the translational and/or transcriptional level.
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Affiliation(s)
- P V Rogers
- Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg 24061
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Sucic JF, Selmin O, Rutherford CL. Regulation of the Dictyostelium glycogen phosphorylase 2 gene by cyclic AMP. DEVELOPMENTAL GENETICS 1993; 14:313-22. [PMID: 8222346 DOI: 10.1002/dvg.1020140409] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A crucial developmental event in the cellular slime mold, Dictyostelium discoideum, is glycogen degradation. The enzyme that catalyzes this degradation, glycogen phosphorylase 2 (gp-2), is developmentally regulated and cAMP appears to be involved in this regulation. We have examined several aspects of the cAMP regulation of gp-2. We show that addition of exogenous cAMP to aggregation competent amoebae induced the appearance of gp-2 mRNA. The induction of gp-2 mRNA occurred within 1 and 1.5 h after the initial exposure to cAMP. Exposure to exogenous cAMP concentrations as low as 1.0 microM could induce gp-2 mRNA. We also examined the molecular mechanism through which cAMP induction of gp-2 occurs. Induction of gp-2 appears to result from a mechanism that does not require intracellular cAMP signaling, and may occur directly through a cAMP binding protein without the requirement of any intracellular signalling. We also examined the promoter region of the gp-2 gene for cis-acting elements that are involved in the cAMP regulation of gp-2. A series of deletions of the promoter were fused to a luciferase reporter gene and then analyzed for cAMP responsiveness. The results indicated that a region from -258 nucleotides to the transcriptional start site is sufficient for essentially full activity and appears to carry all necessary cis-acting sites for cAMP induction. Further deletion of 58 nucleotides from the 5' end, results in fivefold less activity in the presence of cAMP. Deletion of the next 104 nucleotides eliminates the cAMP response entirely.
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Affiliation(s)
- J F Sucic
- Biology Department, Virginia Polytechnic Institute and State University, Blacksburg 24061
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Brickey DA, Naranan V, Sucic JF, Rutherford CL. Regulation of the two forms of glycogen phosphorylase by cAMP and its analogs in Dictyostelium discoideum. Mol Cell Biochem 1990; 97:17-33. [PMID: 2174098 DOI: 10.1007/bf00231698] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have recently reported the existence of two forms of glycogen phosphorylase (1,4-alpha-D-glucan: orthophosphate-alpha-glucosyltransferase; EC 2.4.1.1) in Dictyostelium discoideum. During development the activity of the glycogen phosphorylase b form decreased as the activity of the a form increased. The total phosphorylase activity remained constant. The physical and kinetic properties of the Dictyostelium enzyme were similar to those of the mammalian enzyme. In mammals, cAMP regulates the conversion of the two forms by a cAMP dependent protein kinase (cAMPdPK). We report here that if cAMP is added to a single cell suspension, the Dictyostelium phosphorylase activity becomes independent of 5'AMP and a 104 kd peptide appears. We also show the effect of several cAMP analogs on the phosphorylase activity in these single-cell suspensions. The cAMP analogs were selected on the basis of their affinities for the membrane-bound cAMP receptor or the cytoplasmic cAMPdPK. We found that relatively low levels, 100 microM, of cAMP or 2'd-cAMP added to aggregation-competent cells in shaking culture caused a loss of phosphorylase b activity and the appearance of phosphorylase a activity. The analog, 2'd-cAMP, has a high affinity for the cAMP receptor but a low affinity for the cAMPdPK. Two other analogs, Bt2-cAMP and 8-Br-cAMP, which have low affinities for the cAMP receptor but high affinities for the cAMPdPK, required high levels (500 microM) for 'b' to 'a' conversion. cDNAs to three cAMP-regulated genes--PL3, D11, and D3--were used as controls in the above experiments. In order to determine if intracellular levels of cAMP were involved in the regulation of phosphorylase activity, both the phosphorylase and the PL3, D11 and D3 mRNA levels were examined in cells suspended in a glucose/albumin mixture--a medium in which adenylate cyclase is inhibited. Under these conditions, neither gene regulation nor a change in the phosphorylase b to a activity occurred in response to added extra cellular cAMP. The results suggest that an intracellular increase in cAMP is involved in the regulation of the two forms of glycogen phosphorylase in Dictyostelium.
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Affiliation(s)
- D A Brickey
- Department of Biology, Virginia Tech University, Blacksburg 24061
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Naranan V, Brickey DA, Rutherford CL. Glycogen phosphorylase 'b' in Dictyostelium: stability and endogenous phosphorylation. Mol Cell Biochem 1988; 83:89-104. [PMID: 3146689 DOI: 10.1007/bf00223202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The slime mold Dictyostelium discoideum has two forms of the enzyme glycogen phosphorylase. The inactive phosphorylase 'b' form requires 5' AMP for activity and is present in early development. The active phosphorylase 'a' form is 5' AMP independent and occurs during later development. We here show that the 92 kd 'b' enzyme subunit exists either as a singlet or a doublet upon SDS-PAGE, depending on the method of sample extraction. In the presence of exogenously added Mn2+ and ATP, the phosphorylase 'b' shows apparent conversion into a 5' AMP independent form as measured by enzyme activity. In addition, Mn2+ and ATP also support an in vitro phosphorylation of the 92 kd phosphorylase 'b' subunit. We also demonstrate phosphorylation of the 'b' enzyme subunit in vivo by 32-P incorporation into the enzyme protein. A protein kinase responsible for the observed in vitro phosphorylation of the phosphorylase 'b' subunit is characterized.
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Affiliation(s)
- V Naranan
- Biology Department, Virginia Tech, Blacksburg 24061
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Naranan V, Sucic JF, Brickey DA, Rutherford CL. The relationship between the two forms of glycogen phosphorylase in Dictyostelium discoideum. Differentiation 1988; 38:1-10. [PMID: 2846392 DOI: 10.1111/j.1432-0436.1988.tb00584.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The cellular slime mold, Dictyostelium disoideum, provides an ideal model system to study eukaryotic cell differentiation. In D. discoideum, glycogen degradation provides precursors for the synthesis of developmentally regulated structural products. The enzyme responsible for glycogen degradation, glycogen phosphorylase, exists in active and inactive forms. The active, or 'a' form, is independent of 5'adenosine monophosphate (5'AMP) while the inactive, or 'b' form, is 5'AMP-dependent. The activity of the 'b' form predominates early in development, while the activity of the 'a' form peaks in mid-late development; their combined specific activities remain constant at any point. Polyclonal antibodies raised to the purified forms of this enzyme showed low cross-reactivity. The anti-'a' serum reacted with a 104-kDa protein that was associated with phosphorylase 'a' activity; the anti-'b' serum reacted with a 92-kDa protein that was associated with phosphorylase 'b' activity and weakly cross-reacted with the 104-kDa protein. Immunoblots of peptide maps of the purified enzyme forms showed that each antibody was specific for the proteolytic fragments of its respective antigen. We also demonstrated in vitro phosphorylation of the 'b' form by an endogenous protein kinase. Cyclic AMP perturbation of intact cells caused induction of both phosphorylase-'a' activity and the 104-kDa protein. Immunotitration data suggested that the 'a' form accumulates due to de novo protein synthesis, although this result must be interpreted with caution.
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Affiliation(s)
- V Naranan
- Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg 24061
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13
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Glycogen phosphorylase in Dictyostelium. Developmental regulation of two forms and their physical and kinetic properties. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)47959-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Wright BE, Kelly PJ. Kinetic models of metabolism in intact cells, tissues, and organisms. CURRENT TOPICS IN CELLULAR REGULATION 1981; 19:103-58. [PMID: 7037313 DOI: 10.1016/b978-0-12-152819-5.50021-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Glycogen phosphorylase in Dictyostelium discoideum. I. Purification and properties of the enzyme. J Biol Chem 1976. [DOI: 10.1016/s0021-9258(17)33733-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Wright BE, Park DJ. An analysis of the kinetic positions held by five enzymes of carbohydrate metabolism in Dictyostelium discoideum. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)41705-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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17
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Hames BD, Ashworth JM. The metabolism of macromolecules during the differentiation of Myxamoebae of the cellular slime mould Dictyostelium discoideum containing different amounts of glycogen. Biochem J 1974; 142:301-15. [PMID: 4474880 PMCID: PMC1168281 DOI: 10.1042/bj1420301] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. Methods of obtaining myxamoebae of Dictyostelium discoideum strain Ax-2 (ATCC 24397) with glycogen contents in the range 0.05-5mg of glycogen/10(8) cells are described. The changes in cellular glycogen, protein and RNA content during the differentiation of such myxamoebae were determined. 2. Myxamoebal glycogen is not conserved during differentiation and gluconeogenesis may occur even in cells that contain a large amount of glycogen initially. 3. There is a marked net loss of cellular protein and RNA during differentiation and associated with this there are also marked decreases in the sizes of the intracellular pools of amino acids, acid-soluble proteins and pentose-containing materials. 4. During the early stages of development some protein and pentose(s) are excreted, but this cannot account for the decreased cellular content of protein and RNA. 5. There is a linear rate of production of NH(3) during development, and oxidation appears to be the fate of the major portion of the degraded protein and RNA. 6. However, provision of an alternative metabolizable energy source (glycogen) has little effect on the rate or extent of protein or RNA breakdown or on the changes in the sizes of the intracellular pools of amino acids, acid-soluble proteins and pentose-containing materials. 7. It is concluded that during development there is a requirement for the destruction of specific RNA and protein molecules for reasons other than the provision of oxidizable substrates. 8. The kinetic model of Wright et al. (1968) is discussed in relation to these changes in macromolecular content.
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Hames BD, Ashworth JM. The control of saccharide synthesis during development of Myxamoebae of Dictyostelium discoideum containing differing amounts of glycogen. Biochem J 1974; 142:317-25. [PMID: 4280305 PMCID: PMC1168282 DOI: 10.1042/bj1420317] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
1. Myxamoebae initially containing 5.59mg of glycogen/10(8) cells accumulate approx. 25% more cell-wall polysaccharide, 100% more mucopolysaccharide, 200% more glucose and 300% more trehalose during their development than do myxamoebae initially containing less than 0.3mg of glycogen/10(8) cells. 2. These observations restrict the number of possible control mechanisms operating to regulate carbohydrate metabolism during development. 3. Cells accumulating a large amount of trehalose (approx. 400mug/10(8) cells) have the same amount and pattern of changes in specific activity of trehalase and trehalose 6-phosphate synthase as do cells accumulating a smaller amount of trehalose (approx. 100mug/10(8) cells). 4. These two populations of cells do, however, differ markedly in the amount of UDP-glucose and glucose 6-phosphate that they contain. 5. It is concluded that this change in the intracellular pools of the metabolic precursors of trehalose accounts for the increased amount of trehalose synthesized by cells derived from myxamoebae containing an increased glycogen content.
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Wright BE, Rosness P, Jones TH, Marshall R. Glycogen metabolism during differentiation in Dictyostelium discoideum. Ann N Y Acad Sci 1973; 210:51-63. [PMID: 4349002 DOI: 10.1111/j.1749-6632.1973.tb47561.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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2 Uridine Diphosphoryl Glucose Pyrophosphorylase. GROUP TRANSFER PART A: NUCLEOTIDYL TRANSFER NUCLEOSIDYL TRANSFER ACYL TRANSFER PHOSPHORYL TRANSFER 1973. [DOI: 10.1016/s1874-6047(08)60062-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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21
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Wright BE, Gustafson GL. Expansion of the Kinetic Model of Differentiation in Dictyostelium discoideum. J Biol Chem 1972. [DOI: 10.1016/s0021-9258(20)81782-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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22
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Hames BD, Weeks G, Ashworth JM. Glycogen synthetase and the control of glycogen synthesis in the cellular slime mould Dictyostelium discoideum during cell differentiation. Biochem J 1972; 126:627-33. [PMID: 4672671 PMCID: PMC1178420 DOI: 10.1042/bj1260627] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
1. The variation in cellular glycogen content of differentiating cells derived from myxamoebae that initially contained a wide range of glycogen contents (0.047-5.56mg of glycogen/10(8) myxamoebae) has been studied. 2. Myxamoebae that initially contained 0.047-3.62mg of glycogen/10(8) myxamoebae all gave rise to fruiting bodies that contained similar amounts of glycogen (0.06-0.11mg of glycogen/10(8) cells) but myxamoebae that initially contained 5.56mg of glycogen formed fruiting bodies containing 0.5mg of glycogen/10(8) cells. 3. Despite the high net rate of glycogen disappearance (during cell differentiation) from cells that contained more than 2mg of glycogen/10(8) cells initially, there were still significant variations in the rate of glycogen synthesis. The rate of glycogen synthesis reached a peak at the aggregation stage. 4. Evidence is presented showing that the rate of this synthesis of glycogen is controlled by factors other than the intracellular concentration of glycogen synthetase. 5. Our results are discussed in the context of the theory that the rates of glycogen synthesis and degradation act as a control mechanism for cell differentiation. 6. Criteria are discussed for deciding whether a biochemical event is causally or secondarily related to morphogenesis.
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Weeks G, Ashworth JM. Glycogen synthetase and the control of glycogen synthesis in the cellular slime mould Dictyostelium discoideum during the growth (myxamoebal) phase. Biochem J 1972; 126:617-26. [PMID: 4672670 PMCID: PMC1178419 DOI: 10.1042/bj1260617] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
1. Myxamoebae of the cellular slime mould Dictyostelium discoideum Ax-2 that are grown in axenic medium containing 86mm-glucose have seven times the glycogen content of the same myxamoebae grown in the same medium but lacking added carbohydrate. 2. During the transition from the exponential to the stationary phase of growth in axenic medium containing glucose myxamoebae preferentially synthesize glycogen and can have as much as three times the glycogen content during the stationary phase as they have during the exponential phase of growth. 3. The rate of glycogen degradation by myxamoebae is, under all conditions of growth, small compared with the rate of glycogen accumulation and the changes in glycogen content thus reflect altered rates of glycogen synthesis. 4. There is no correlation between the rate of glycogen synthesis by myxamoebae and the glycogen synthetase content of the myxamoebae. 5. The activity of glycogen synthetase of D. discoideum is inhibited by a physiological concentration of ATP and this inhibition is overcome by glucose 6-phosphate. Both effects are especially marked at physiological concentrations of UDP-glucose. 6. The rate of glycogen accumulation by myxamoebae growing exponentially in axenic media can be satisfactorily accounted for in terms of the known intracellular concentrations of glucose 6-phosphate, UDP-glucose and glycogen synthetase. The rate-limiting factors controlling glycogen synthesis by the myxamoebae are apparently the substrate (UDP-glucose) and effector (glucose 6-phosphate and ATP) concentrations rather than the amount of the enzyme.
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Edmundson TD, Ashworth JM. 6-phosphogluconate dehydrogenase and the assay of uridine diphosphate glucose pyrophosphorylase in the cellular slime mould Dictyostelium discoideum. Biochem J 1972; 126:593-600. [PMID: 4672667 PMCID: PMC1178416 DOI: 10.1042/bj1260593] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
1. 6-Phosphogluconate dehydrogenase activity is present in all morphogenetic stages during cell differentiation in the cellular slime mould. 2. The different ratios of 6-phosphogluconate dehydrogenase/UDP-glucose pyrophosphorylase observed during this process can render spectrophotometric assays of UDP-glucose pyrophosphorylase inaccurate. 3. The disputed occurrence of increases in specific activity of UDP-glucose pyrophosphorylase during cell differentiation in the cellular slime mould is discussed in the light of these observations.
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Rosness PA, Gustafson G, Wright BE. Effects of adenosine 3',5'-monophosphate and adenosine 5'-monophosphate on glycogen degradation and synthesis in Dictyostelium discoideum. J Bacteriol 1971; 108:1329-37. [PMID: 5167809 PMCID: PMC247223 DOI: 10.1128/jb.108.3.1329-1337.1971] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Data are presented demonstrating that the presence in vivo of adenosine 3',5'-monophosphate (3',5'-AMP) causes a rapid depletion of glycogen storage material in the cellular slime mold. The effect of adenosine 5'-monophosphate (5'-AMP) is twofold, stimulating both glycogen degradation and synthesis. In pseudoplasmodia, cell-free extracts appear to contain at least two species of glycogen phosphorylase, one of which is severely inhibited by glucose-1-phosphate and another which is only partially inhibited by this hexose-phosphate. In some cases, 5'-AMP partially overcomes the inhibition by glucose-1-phosphate. Data presented here also indicate the existence of two forms of glycogen synthetase, the total activity of which does not change during 10 hr of differentiation from aggregation to culmination. During this period there is a quantitative conversion of glucose-6-phosphate-independent enzyme activity to glucose-6-phosphate-dependent activity. It is suggested that one effect of 3',5'-AMP is closely related to enzymatic processes involved in the rapid conversion of glycogen to cell wall material and other end products accumulating during sorocarp construction.
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Wright BE, Marshall R. Trehalose Synthesis during Differentiation in Dictyostelium discoideum. J Biol Chem 1971. [DOI: 10.1016/s0021-9258(18)61911-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Smith JE, Galbraith JC. Biochemical and physiological aspects of differentiation in the fungi. Adv Microb Physiol 1971; 5:45-134. [PMID: 4950260 DOI: 10.1016/s0065-2911(08)60405-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Jones TH, Wright BE. Partial purification and characterization of glycogen phosphorylase from Dictyostelium discoideum. J Bacteriol 1970; 104:754-61. [PMID: 5530813 PMCID: PMC285054 DOI: 10.1128/jb.104.2.754-761.1970] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Glycogen phosphorylase was isolated from cells of Dictyostelium discoideum in the culmination stage of development and purified 35-fold. The enzyme had a pH optimum of 6.9 and contained sulfhydryl groups essential for activity. The K(m) values for phosphate and glycogen were 3 mm and 0.06% (w/v), respectively. No dependence on, or stimulation by, any nucleotide was observed and a wide variety of nucleotides and glycolytic intermediates did not inhibit the enzyme. Nucleotide sugars competitively inhibited the enzyme. Guanosine diphosphoglucose and adenosine diphosphoglucose were the most effective, and uridine diphosphoglucose was the least effective of the nucleotide sugars tested. The specific activity of glycogen phosphorylase increased from about 0.004 unit per mg of protein in aggregating cells to about 0.024 unit per mg in culminating cells, and then decreased during sorocarp formation. This increase in enzyme specific activity during the starvation and aging of the system can account for the increased rate of glycogen degradation during this period of development. Amylase specific activity, measured at pH 4.8 and 6.9, varied between 0.005 and 0.013 unit per mg of protein during all stages of development.
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Graves IL. Extraction, separation and labeling with 14C-glucose of HeLa cell polyglucose, RNA and DNA and comparison of the molecular weights and buoyant densities of polyglucose from poliovirus-infected and noninfected cultures. Biopolymers 1970; 9:11-28. [PMID: 4312658 DOI: 10.1002/bip.1970.360090103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Newell PC, Sussman M. Uridine Diphosphate Glucose Pyrophosphorylase in Dictyostelium discoideum. J Biol Chem 1969. [DOI: 10.1016/s0021-9258(18)91721-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Abstract
The intercellular water present in pellets of centrifuged cell suspensions of the slime mold Dictyostelium discoideum was measured at four stages of differentiation.
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Wright BE. An analysis of metabolism underlying differentiation inDictyostelium discoideum. J Cell Physiol 1968. [DOI: 10.1002/jcp.1040720411] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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