Subunit‐specific phosphorylation of pyruvate kinase in medullary thyroid carcinomas of the rat

Rijksen, Gert; Heijden, M.C.M. van der; Oskam, R.; Staal, Gerard E.J.

doi:10.1016/0014-5793(88)81357-7

Cited by 11 publications

(5 citation statements)

References 14 publications

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“…An example that supports this hypothesis is the observation that solid tumors (which are hyperproliferative, usually hypoxic, and highly dependent on glycolysis) re-express the fetal M 2 isozyme of PK in addition to an increased expression of all glycolytic enzymes and lactate dehydrogenase ( − ). This phenomena has been particularly well-documented for human neuroectodermal (brain) tumors () and breast tumors ().…”

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confidence: 94%

Determinants of Allosteric Activation of Yeast Pyruvate Kinase and Identification of Novel Effectors Using Computational Screening

et al. 2000

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We have analyzed the structural determinants of the allosteric activation of yeast pyruvate kinase (YPK) by mutational and kinetic analysis and initiated a structure-based design project to identify novel effectors that modulate its allosteric response by binding to the allosteric site for fructose-1,6-bisphosphate (FBP). The wild-type enzyme is strongly activated by fructose-1,6-bisphosphate and weakly activated by both fructose-1-phosphate and fructose-6-phosphate; the strength of the activation response is proportional to the affinity of the allosteric effector. A point mutation within the 6'-phosphate binding loop of the allosteric site (T403E) abolishes activation of the enzyme by fructose-1, 6-bisphosphate. The mutant enzyme is also not activated by F1P or F6P. The mutation alone (which incorporates a glutamic acid that is strictly conserved in mammalian M1 isozymes) slightly reduces cooperativity of substrate binding. Three novel compounds were identified that effect the allosteric regulation of YPK by FBP and/or act as novel allosteric activators of the enzyme. One is a physiologically important diphospho sugar, while the other two are hydrophobic compounds that are dissimilar to the natural effector. These results demonstrate that novel allosteric effectors may be identified using structure-based screening and are indicative of the potential of this strategy for drug discovery. Regulatory sites are generally more divergent than catalytic sites and therefore offer excellent opportunities for discrimination and specificity between different organisms or between different tissue types.

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confidence: 94%

Determinants of Allosteric Activation of Yeast Pyruvate Kinase and Identification of Novel Effectors Using Computational Screening

et al. 2000

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“…Malignant cells have a high rate of aerobic glycolysis and biosynthesis. It has been suggested that the shift towards the M 2 isozyme in tumors represents a mechanism to gain allosteric control of the enzyme and allows for sequential activation and inhibition of the enzyme during the cell cycle [11,12]. Inhibition may occur so that the cellular concentration of glycolytic intermediates may be elevated transiently, enhancing glucose breakdown via the hexose monophosphate shunt and accelerating synthesis of pyrimidine and purine nucleotides in proliferating cells.…”

Section: Introductionmentioning

confidence: 99%

The allosteric regulation of pyruvate kinase by fructose-1,6-bisphosphate

et al. 1998

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The structure and location of the allosteric activator site agrees with the pattern of alternate genetic splicing of the PK gene in multicellular eukaryotes that distinguishes between a non-regulated isozyme and the regulated fetal isozymes. The conformational differences observed between the active sites of inactive and fully active PK enzymes is in agreement with the recently determined thermodynamic mechanism of allosteric activation through a 'metal relay' that increases the affinity of the enzyme for its natural phosphoenolpyruvate substrate.

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“…The amount of phosphotyrosine detected after acid hydrolysis is small, not more than 507o of total phosphoamino acids, but was distinctly found in four different experiments. Tyrosine phosphorylation of PK seems not to be generally associated with cellular transformation as has been demonstrated by Rijksen et al [23]. M2-PK (or K4-type of PK) of medullary thyroid carcinomas of the rat contained phosphoserine and small amounts of phosphothreonine, but no phosphotyrosine was detectable.…”

Section: Resultsmentioning

confidence: 74%

Pyruvate kinase type M₂ is phosphorylated at tyrosine residues in cells transformed by Rous sarcoma virus

1988

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Chicken embryo cells (CECs) contain pyruvate kinase (PK) type M~ (M2-PK). Transformation of CECs by Rous sarcoma virus (RSV) leads to a reduction in the affinity of PK for the substrate phosphoeno/pyruvate. In vitro, M2-PK can be phosphorylated at tyrosine residues by pp60 v-~, the transforming protein of RSV. To study tyrosine phosphorylation of M2-PK in intact RSV-transformed cells, the protein was immunoprecipitated from a2P-labeled normal and RSV-SR-Atransformed CECs. Phosphoamino acid analysis of immunoprecipitated Mz-PK revealed that M2-PK of both normal and transformed CECs contained phosphoserine and small amounts of phosphothreonine. Only Mz-PK of transformed CECs contained phosphotyrosine in addition. For enzyme kinetic studies M2-PK was partially purified by chromatography upon DEAE-Sephacel and hydroxyapatite. A decreased affinity for phosphoenolpyruvate was observed 3 h after the onset of transformation using the temperature-sensitive mutant of RSV, ts-NY 68. The kinetic changes were correlated with tyrosine phosphorylation of Mz-PK, but there is no direct evidence that they are caused by post-translational modification of the enzyme.

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Subunit‐specific phosphorylation of pyruvate kinase in medullary thyroid carcinomas of the rat

Cited by 11 publications

References 14 publications

Determinants of Allosteric Activation of Yeast Pyruvate Kinase and Identification of Novel Effectors Using Computational Screening

Determinants of Allosteric Activation of Yeast Pyruvate Kinase and Identification of Novel Effectors Using Computational Screening

The allosteric regulation of pyruvate kinase by fructose-1,6-bisphosphate

Pyruvate kinase type M₂ is phosphorylated at tyrosine residues in cells transformed by Rous sarcoma virus

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Subunit‐specific phosphorylation of pyruvate kinase in medullary thyroid carcinomas of the rat

Cited by 11 publications

References 14 publications

Determinants of Allosteric Activation of Yeast Pyruvate Kinase and Identification of Novel Effectors Using Computational Screening

Determinants of Allosteric Activation of Yeast Pyruvate Kinase and Identification of Novel Effectors Using Computational Screening

The allosteric regulation of pyruvate kinase by fructose-1,6-bisphosphate

Pyruvate kinase type M2 is phosphorylated at tyrosine residues in cells transformed by Rous sarcoma virus

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Pyruvate kinase type M₂ is phosphorylated at tyrosine residues in cells transformed by Rous sarcoma virus