Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.26 (GSK)
 6,788 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genes encoding the regulatory (BCY1) and catalytic (TPK1, TPK2, and TPK3) subunits of the cAMP-dependent protein kinase (cAPK) are found in S. cerevisiae. bcy1- yeast strains do not respond properly to nutrient conditions. Unlike wild type, bcy1- strains do not accumulate glycogen, form spores, or become resistant to heat shock when nutrient limited. We have isolated mutant TPK genes that suppress all of the bcy1- defects. The mutant TPK genes appear to encode functionally attenuated catalytic subunits of the cAPK. bcy1- yeast strains containing the mutant TPK genes respond appropriately to nutrient conditions, even in the absence of CDC25, both RAS genes, or CYR1. Together, these genes encode the known components of the cAMP-generating machinery. The results indicate that cAMP-independent mechanisms must exist for regulating glycogen accumulation, sporulation, and the acquisition of thermotolerance in S. cerevisiae.
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PMID:cAMP-independent control of sporulation, glycogen metabolism, and heat shock resistance in S. cerevisiae. 283 63

We have isolated three genes (TPK1, TPK2, and TPK3) from the yeast S. cerevisiae that encode the catalytic subunits of the cAMP-dependent protein kinase. Gene disruption experiments demonstrated that no two of the three genes are essential by themselves but at least one TPK gene is required for a cell to grow normally. Comparison of the predicted amino acid sequences of the TPK genes indicates conserved and variable domains. The carboxy-terminal 320 amino acid residues have more than 75% homology to each other and more than 50% homology to the bovine catalytic subunit. The amino-terminal regions show no homology to each other and are heterogeneous in length. The TPK1 gene carried on a multicopy plasmid can suppress both a temperature-sensitive ras2 gene and adenylate cyclase gene.
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PMID:Three different genes in S. cerevisiae encode the catalytic subunits of the cAMP-dependent protein kinase. 303 73

In the yeast Saccharomyces cerevisiae, three genes TPK1, TPK2, and TPK3 encode catalytic subunits of cAMP-dependent protein kinase. We have purified and characterized the catalytic subunit, C1, encoded by the TPK1 gene. In order to purify C1 completely free of C2 and C3, a strain was constructed that contained only the TPK1 gene and genetic disruptions of the other two TPK genes. The cellular level of C1 was increased by expressing the genes for C1 (TPK1) and yeast regulatory subunit (BCY1) on multiple copy plasmids within this strain. Purification was accomplished by a two-column procedure in which holoenzyme was chromatographed on Sephacryl-200, then bound to an anti-regulatory subunit immunoaffinity column. Pure C1 was released from the antibody column by addition of cAMP. The protein migrated on a sodium dodecyl sulfate-polyacrylamide gel with an Mr of 52,000. Kinetic analysis showed that the apparent Km for ATP and Leu-Arg-Arg-Ala-Ser-Leu-Gly was 33 and 101 microM, respectively. The kcat was determined to be 640 min-1. The protein weakly autophosphorylated, incorporating less than 0.1 mol of phosphate/mol of catalytic subunit. NH2-terminal sequencing revealed that the protein was blocked.
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PMID:Purification and characterization of C1, the catalytic subunit of Saccharomyces cerevisiae cAMP-dependent protein kinase encoded by TPK1. 328 29

We have shown that mitochondrial (mt) transcription in yeast (S. cerevisiae) is governed in part by cAMP via a mt cAMP-dependent protein kinase (cAPK), and that the BCY1 gene product acts as regulatory subunit for that organellar enzyme, as it does for cytoplasmic cAPK. Here we assess mt cAPK activity and mt transcription in mutants for the TPK1, TPK2, and TPK3 genes, which encode catalytic subunits of cytoplasmic cAPK. Protein extracts from purified mitochondria from each of the three possible double TPK mutants show mt cAMP-dependent protein phosphorylation. Relative mt transcript levels in these mutants, however, suggest that TPK2 functions less well than does TPK1 or TPK3 in organellar transcriptional control. Thus, both mt and cytoplasmic cAPKs employ the same species of regulatory and catalytic proteins, and versions of the enzyme having various combinations of catalytic species function differentially in cAMP-dependent mt transcriptional control.
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PMID:Nature and transcriptional role of catalytic subunits of yeast mitochondrial cAMP-dependent protein kinase. 782 97

Three genes TPK1, TPK2 and TPK3 encode in Saccharomyces cerevisiae distinct catalytic subunits of cAMP-dependent protein kinase (cAPK). We have measured cAPK activity in vitro and, indirectly, in vivo in yeast strains carrying only one of the three TPK genes. The strain containing TPK3 as the only intact TPK gene showed nearly undetectable phosphorylating activity and no TPK3 mRNA could be detected, although the cells grow normally. Overexpression of TPK3 in a high copy vector or under the control of the inducible GAL1 promoter did not by itself result in a corresponding increase in activity but coexpression of BCY1, the gene coding for the regulatory subunit, was necessary in both cases to achieve high levels of phosphorylating activity. Moreover, BCY1 overexpression not only increased Tpk3 catalytic activity but also increased the amount of TPK3 mRNA detected in Northern blots.
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PMID:Low activity of the yeast cAMP-dependent protein kinase catalytic subunit Tpk3 is due to the poor expression of the TPK3 gene. 838 30

In Saccharomyces cerevisiae cAMP-dependent protein kinase (cAPK) is involved in nutrient sensing and growth regulation via the Ras/cAMP pathway. Target enzymes, e.g. neutral trehalase, are activated or inactivated rapidly by cAPK-mediated phosphorylation. In addition, stress-induced transcription of genes of the general stress-response, e.g. HSP12, is negatively regulated via cAPK. We have investigated the effect of low cAPK activity on the stress-induced expression of neutral trehalase Nth1p. For this purpose we used mutants (tpk1tpk2TPK3, tpk1TPK2tpk3 and TPK1tpk2tpk3) with double knockouts of the three TPK genes encoding catalytic subunits of cAPK. It is shown that the tpk1tpk2TPK3 mutant, which has very low cAPK activity, exhibits a heat-stress-induced inactivation of neutral trehalase that is not observed in tpk1TPK2tpk3, TPK1tpk2tpk3 mutants and wild-type cells. However, heat stress induces an increase in NTH1 mRNA in the tpk1tpk2TPK3 mutant. Introduction of a plasmid carrying the TPK1 or TPK2 gene into tpk1tpk2TPK3 cells restores the heat-induced increase of neutral trehalase activity. In vitro and in vivo results suggest that the heat induced inactivation of neutral trehalase is due to a reversible inactivation of Nth1p. Our data indicate that a certain level of phosphorylation is essential for maintenance of neutral trehalase activity during heat shock in S. cerevisiae. Two identical putative cAPK phosphorylation sites have been found in the sequence predicted for the Nth1p. Stabilization and activation of neutral trehalase may be regulated by these sites. Furthermore, our data suggest that the heat-stress-induced transcription of the NTH1 gene is not negatively regulated by cAPK, that the TPK genes have no effect on the glucose repression of the NTH1 gene, and that non-detectable neutral trehalase activity in derepressed tpk1tpk2TPK3 cells is correlated with the reduced thermotolerance observed in this strain, similar to the heat-shock-recovery defect reported for the nth1delta mutant.
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PMID:Stability of neutral trehalase during heat stress in Saccharomyces cerevisiae is dependent on the activity of the catalytic subunits of cAMP-dependent protein kinase, Tpk1 and Tpk2. 973 92

Yeast has three A kinase catalytic subunits, which have greater than 75% identity and are encoded by the TPK genes (TPK1, TPK2, and TPK3) [Toda, T., Cameron, S., Sass, P., Zoller, M. & Wigler, M. (1987) Cell 50, 277-287]. Although they are redundant for viability, the three A kinases are not redundant for pseudohyphal growth [Robertson, L. S. & Fink, G. R. (1998) Proc. Natl. Acad. Sci. USA 95, 13783-13787; Pan, X. & Heitman, J. (1999) Mol. Cell. Biol. 19, 4874-4887]; Tpk2, but not Tpk1 or Tpk3, is required for pseudohyphal growth. Genome-wide transcriptional profiling has revealed unique signatures for each of the three A kinases leading to the identification of additional functional diversity among these proteins. Tpk2 negatively regulates genes involved in iron uptake and positively regulates genes involved in trehalose degradation and water homeostasis. Tpk1 is required for the derepression of branched chain amino acid biosynthesis genes that seem to have a second role in the maintenance of iron levels and DNA stability within mitochondria. The fact that TPK2 mutants grow better than wild types on nonfermentable carbon sources and on media deficient in iron supports the unique role of Tpk2 in respiratory growth and carbon source use.
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PMID:The yeast A kinases differentially regulate iron uptake and respiratory function. 1081 93

Three founder transgenic mice were generated with a 108 kb human genomic fragment containing the entire autosomal dominant polycystic kidney disease (ADPKD) gene, PKD1, plus the tuberous sclerosis gene, TSC2. Two lines were established (TPK1 and TPK3) each with approximately 30 copies of the transgene. Both lines produced full-length PKD1 mRNA and polycystin-1 protein that was developmentally regulated, similar to the endogenous pattern, with expression during renal embryogenesis and neonatal life, markedly reduced at the conclusion of renal development. Tuberin expression was limited to the brain. Transgenic animals from both lines (and the TPK2 founder animal) often displayed a renal cystic phenotype, typically consisting of multiple microcysts, mainly of glomerular origin. Hepatic cysts and bile duct proliferation, characteristic of ADPKD, were also seen. All animals with two copies of the transgenic chromosome developed cysts and, in total, 48 of the 100 transgenic animals displayed a cystic phenotype. To test the functionality of the transgene, animals were bred with the Pkd1(del34) knockout mouse. Both transgenic lines rescued the embryonically lethal Pkd1(del34/del34) phenotype, demonstrating that human polycystin-1 can complement for loss of the endogenous protein. The rescued animals were viable into adulthood, although more than half developed hepatic cystic disease in later life, similar to the phenotype of older Pkd1(del34/+) animals. The TPK mice have defined a minimal area that appropriately expresses human PKD1. Furthermore, this model indicates that over-expression of normal PKD1 can elicit a disease phenotype, suggesting that the level of polycystin-1 expression may be relevant in the human disease.
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PMID:A human PKD1 transgene generates functional polycystin-1 in mice and is associated with a cystic phenotype. 1106 21

Thiamin pyrophosphokinase (TPK, EC 2.7.6.2) catalyses phosphorylation of thiamin to thiamin pyrophosphate, an active enzyme cofactor. Here we describe the cloning of complete human TPK1 cDNA from an adult liver library. Human TPK1 is 89% identical to murine TPK1 at the protein level. The gene maps to chromosome 7q34-36, consists of at least eight exons, and spans a distance at least of 420 kb. The mRNA of human TPK1 is highly expressed in testis, small intestine and kidney with lesser but detectable expression in brain, liver, placenta and spleen. The availability of the human TPK1 gene will provide another useful tool for studying the role of this enzyme in human thiamin metabolism and deficiency state.
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PMID:Molecular cloning of human thiamin pyrophosphokinase. 1134 17

The vacuole represents a pivotal plant organelle for management of ion homeostasis, storage of proteins and solutes, as well as deposition of cytotoxic compounds. Ion channels, pumps and carriers in the vacuolar membrane under control of cytosolic factors provide for ionic and metabolic homeostasis between this storage organelle and the cytoplasm. Here we show that AtTPK1 (KCO1), a vacuolar membrane localized K(+) channel of the TPK family, interacts with 14-3-3 proteins (general regulating factors, GRFs). Following in planta expression TPK1 and GRF6 co-localize at the vacuolar membrane. Co-localization of wild-type TPK1, but not the TPK1-S42A mutant, indicates that phosphorylation of the 14-3-3 binding motif of TPK1 represents a prerequisite for interaction. Pull-down assays and surface plasmon resonance measurements revealed GRF6 high-affinity interaction with TPK1. Following expression of TPK1 in yeast and isolation of vacuoles, patch-clamp studies identified TPK1 as a voltage-independent and Ca(2+)-activated K(+) channel. Addition of 14-3-3 proteins strongly increased the TPK1 activity in a dose-dependent manner. However, an inverse effect of GRF6 on the activity of the slow-activating vacuolar (SV) channel was observed in mesophyll vacuoles from Arabidopsis thaliana. Thus, TPK1 seems to provide for a Ca(2+)- and 14-3-3-sensitive mechanism capable of controlling cytoplasmic potassium homeostasis in plants.
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PMID:TPK1, a Ca(2+)-regulated Arabidopsis vacuole two-pore K(+) channel is activated by 14-3-3 proteins. 1776 16


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