The phosphorylation of 5'-oligoadenylic acids by adenylate kinase and adenosine triphosphate.
Ontology highlight
ABSTRACT:
SUBMITTER: Klemperer HG
PROVIDER: S-EPMC1198774 | biostudies-other | 1968 Jun
REPOSITORIES: biostudies-other
Similar Datasets
Project description:The progression of pressure-overload left ventricular hypertrophy (LVH) to chronic heart failure (CHF) may involve a relative deficit in energy supply and/or delivery.We measured myocardial creatine kinase (CK) metabolite concentrations and adenosine triphosphate (ATP) synthesis through CK, the primary energy reserve of the heart, to test the hypothesis that ATP flux through CK is impaired in patients with LVH and CHF. Myocardial ATP levels were normal, but creatine phosphate levels were 35% lower in LVH patients (n = 10) than in normal subjects (n = 14, P < 0.006). Left ventricular mass and CK metabolite levels in LVH were not different from those in patients with LVH and heart failure (LVH+CHF, n = 10); however, the myocardial CK pseudo first-order rate constant was normal in LVH (0.36 +/- 0.04 s(-1) in LVH versus 0.32 +/- 0.06 s(-1) in normal subjects) but halved in LVH+CHF (0.17 +/- 0.06 s(-1), P < 0.001). The net ATP flux through CK was significantly reduced by 30% in LVH (2.2 +/- 0.7 micromol x g(-1) x s(-1), P = 0.011) and by a dramatic 65% in LVH+CHF (1.1 +/- 0.4 micromol x g(-1) x s(-1), P < 0.001) compared with normal subjects (3.1 +/- 0.8 micromol x g(-1) x s(-1)).These first observations in human LVH demonstrate that it is not the relative or absolute CK metabolite pool sizes but rather the kinetics of ATP turnover through CK that distinguish failing from nonfailing hypertrophic hearts. Moreover, the deficit in ATP kinetics is similar in systolic and nonsystolic heart failure and is not related to the severity of hypertrophy but to the presence of CHF. Because CK temporally buffers ATP, these observations support the hypothesis that a deficit in myofibrillar energy delivery contributes to CHF pathophysiology in human LVH.
| S-EPMC1808438 | biostudies-literature
Project description:The influence of isotopically enriched magnesium on the creatine kinase catalyzed phosphorylation of adenosine diphosphate is examined in two independent series of experiments where adenosine triphosphate (ATP) concentrations were determined by a luciferase-linked luminescence end-point assay or a real-time spectrophotometric assay. No increase was observed between the rates of ATP production with natural Mg, (24)Mg, and (25)Mg, nor was any significant magnetic field effect observed in magnetic fields from 3 to 1,000 mT. Our results are in conflict with those reported by Buchachenko et al. [J Am Chem Soc 130:12868-12869 (2008)], and they challenge these authors' general claims that a large (two- to threefold) magnetic isotope effect is "universally observable" for ATP-producing enzymes [Her Russ Acad Sci 80:22-28 (2010)] and that "enzymatic phosphorylation is an ion-radical, electron-spin-selective process" [Proc Natl Acad Sci USA 101:10793-10796 (2005)].
| S-EPMC3277194 | biostudies-literature
Project description:Atypical protein kinase C (aPKC) isoenzymes are key modulators of insulin signalling, and their dysfunction correlates with insulin-resistant states in both mice and humans. Despite the engaged interest in the importance of aPKCs to type 2 diabetes, much less is known about the molecular mechanisms that govern their cellular functions than for the conventional and novel PKC isoenzymes and the functionally-related protein kinase B (Akt) family of kinases. Here we show that aPKC is constitutively phosphorylated and, using a genetically-encoded reporter for PKC activity, basally active in cells. Specifically, we show that phosphorylation at two key regulatory sites, the activation loop and turn motif, of the aPKC PKCζ in multiple cultured cell types is constitutive and independently regulated by separate kinases: ribosome-associated mammalian target of rapamycin complex 2 (mTORC2) mediates co-translational phosphorylation of the turn motif, followed by phosphorylation at the activation loop by phosphoinositide-dependent kinase-1 (PDK1). Live cell imaging reveals that global aPKC activity is constitutive and insulin unresponsive, in marked contrast to the insulin-dependent activation of Akt monitored by an Akt-specific reporter. Nor does forced recruitment to phosphoinositides by fusing the pleckstrin homology (PH) domain of Akt to the kinase domain of PKCζ alter either the phosphorylation or activity of PKCζ. Thus, insulin stimulation does not activate PKCζ through the canonical phosphatidylinositol-3,4,5-triphosphate-mediated pathway that activates Akt, contrasting with previous literature on PKCζ activation. These studies support a model wherein an alternative mechanism regulates PKCζ-mediated insulin signalling that does not utilize conventional activation via agonist-evoked phosphorylation at the activation loop. Rather, we propose that scaffolding near substrates drives the function of PKCζ.
| S-EPMC4888060 | biostudies-literature
Project description: Not available
| S-EPMC6263008 | biostudies-literature
Project description:Adenylate kinase 2 (AK2), which balances adenine nucleotide pool, is a multi-functional protein. Here we show that AK2 negatively regulates tumour cell growth. AK2 forms a complex with dual-specificity phosphatase 26 (DUSP26) phosphatase and stimulates DUSP26 activity independently of its AK activity. AK2/DUSP26 phosphatase protein complex dephosphorylates fas-associated protein with death domain (FADD) and regulates cell growth. AK2 deficiency enhances cell proliferation and induces tumour formation in a xenograft assay. This anti-growth function of AK2 is associated with its DUSP26-stimulating activity. Downregulation of AK2 is frequently found in tumour cells and human cancer tissues showing high levels of phospho-FADD(Ser194). Moreover, reconstitution of AK2 in AK2-deficient tumour cells retards both cell proliferation and tumourigenesis. Consistent with this, AK2(+/-) mouse embryo fibroblasts exhibit enhanced cell proliferation with a significant alteration in phospho-FADD(Ser191). These results suggest that AK2 is an associated activator of DUSP26 and suppresses cell proliferation by FADD dephosphorylation, postulating AK2 as a negative regulator of tumour growth.
| S-EPMC3948464 | biostudies-literature
Project description:Adenosine triphosphate phosphoribosyltransferase (ATP-PRT) catalyzes the first step in histidine biosynthesis, a pathway essential to microorganisms and a validated target for antimicrobial drug design. The ATP-PRT enzyme catalyzes the reversible substitution reaction between phosphoribosyl pyrophosphate and ATP. The enzyme exists in two structurally distinct forms, a short- and a long-form enzyme. These forms share a catalytic core dimer but bear completely different allosteric domains and thus distinct quaternary assemblies. Understanding enzymatic transition states can provide essential information on the reaction mechanisms and insight into how differences in domain structure influence the reaction chemistry, as well as providing a template for inhibitor design. In this study, the transition state structures for ATP-PRT enzymes from Campylobacter jejuni and Mycobacterium tuberculosis (long-form enzymes) and from Lactococcus lactis (short-form) were determined and compared. Intrinsic kinetic isotope effects (KIEs) were obtained at reaction sensitive positions for the reverse reaction using phosphonoacetic acid, an alternative substrate to the natural substrate pyrophosphate. The experimental KIEs demonstrated mechanistic similarities between the three enzymes and provided experimental boundaries for quantum chemical calculations to characterize the transition states. Predicted transition state structures support a dissociative reaction mechanism with a DN*AN‡ transition state. Weak interactions from the incoming nucleophile and a fully dissociated ATP adenine are predicted regardless of the difference in overall structure and quaternary assembly. These studies establish that despite significant differences in the quaternary assembly and regulatory machinery between ATP-PRT enzymes from different sources, the reaction chemistry and catalytic mechanism are conserved.
| S-EPMC6693643 | biostudies-literature
Project description:ATP leads to endothelial NO synthase (eNOS)/NO-mediated vasodilation, a process hypothesized to depend on the endothelial caveolar eNOS partitioning and subcellular domain-specific multisite phosphorylation state. We demonstrate herein that, in both the absence and presence of ATP, the uterine artery endothelial caveolae contain specific protein machinery related to subcellular partitioning and act as specific focal "hubs" for NO- and ATP-related proteins. ATP-induced eNOS regulation showed a complex set of multisite posttranslational phosphorylation events that were closely associated with the enzyme's partitioning between caveolar and noncaveolar endothelial subcellular domains. The comprehensive model that we present demonstrates that ATP repartitioned eNOS between the caveolar and noncaveolar subcellular domains; specifically, the stimulatory (PSer635)eNOS was substantially higher in the caveolar pool with subcellular domain-independent increased levels on ATP treatment. The stimulatory (PSer1179)eNOS was not altered by ATP treatment. However, the inhibitory (PThr495)eNOS was regulated predominantly in the caveolar domain with decreased levels on ATP action. In contrast, the agonist-specific (PSer114)eNOS was localized in the noncaveolar pool with increased levels on ATP stimulation. Thus, the endothelial caveolar membrane system plays a pivotal role(s) in ATP-associated subcellular partitioning and possesses the relevant protein machinery for ATP-induced NO regulation. Furthermore, these subcellular domain-specific phosphorylation/dephosphorylation events provide evidence relating to eNOS spatio-temporal dynamics.
| S-EPMC3337759 | biostudies-literature
Project description:BACKGROUND:Human PMS2 (hPMS2) homologues act to nick 5' and 3' to misincorporated nucleotides during mismatch repair in organisms that lack MutH. Mn(++) was previously found to stimulate the endonuclease activity of these homologues. ATP was required for the nicking activity of hPMS2 and yPMS1, but was reported to inhibit bacterial MutL proteins from Thermus thermophilus and Aquifex aeolicus that displayed homology to hPMS2. Mutational analysis has identified the DQHA(X)(2)E(X)(4)E motif present in the C-terminus of PMS2 homologues as important for endonuclease activity. METHODOLOGIES/PRINCIPAL FINDINGS:We examined the effect ATP had on the Mn(++) induced nicking of supercoiled pBR322 by full-length and mutant A. aeolicus MutL (Aae MutL) proteins. Assays were single time point, enzyme titration experiments or reaction time courses. The maximum velocity for MutL nicking was determined to be 1.6+/-0.08x10(-5) s(-1) and 4.2+/-0.3x10(-5) s(-1) in the absence and presence of ATP, respectively. AMPPNP stimulated the nicking activity to a similar extent as ATP. A truncated Aae MutL protein composed of only the C-terminal 123 amino acid residues was found to nick supercoiled DNA. Furthermore, mutations in the conserved C-terminal DQHA(X)(2)E(X)(4)E and CPHGRP motifs were shown to abolish Aae MutL endonuclease activity. CONCLUSIONS:ATP stimulated the Mn(++) induced endonuclease activity of Aae MutL. Experiments utilizing AMPPNP implied that the stimulation did not require ATP hydrolysis. A mutation in the DQHA(X)(2)E(X)(4)E motif of Aae MutL further supported the role of this region in endonclease activity. For the first time, to our knowledge, we demonstrate that changing the histidine residue in the conserved CPHGRP motif abolishes endonucleolytic activity of a hPMS2 homologue. Finally, the C-terminal 123 amino acid residues of Aae MutL were sufficient to display Mn(++) induced nicking activity.
| S-EPMC2744016 | biostudies-literature
Project description:Targeting the specific metabolic phenotypes of colorectal cancer stem cells (CRCSCs) is an innovative therapeutic strategy for colorectal cancer (CRC) patients with poor prognosis and relapse. However, the context-dependent metabolic traits of CRCSCs remain poorly elucidated. Here we report that adenylate kinase hCINAP is overexpressed in CRC tissues. Depletion of hCINAP inhibits invasion, self-renewal, tumorigenesis and chemoresistance of CRCSCs with a loss of mesenchymal signature. Mechanistically, hCINAP binds to the C-terminal domain of LDHA, the key regulator of glycolysis, and depends on its adenylate kinase activity to promote LDHA phosphorylation at tyrosine 10, resulting in the hyperactive Warburg effect and the lower cellular ROS level and conferring metabolic advantage to CRCSC invasion. Moreover, hCINAP expression is positively correlated with the level of Y10-phosphorylated LDHA in CRC patients. This study identifies hCINAP as a potent modulator of metabolic reprogramming in CRCSCs and a promising drug target for CRC invasion and metastasis.
| S-EPMC5454382 | biostudies-literature
Project description:The chemical synthesis of a adenosine triphosphate analogue, 1-adenosin-5'-yl 3-(3-methylbut-2-enyl) triphosphoric acid diester (ApppD), is described. ApppD is known to be an active metabolite of the mevalonate pathway in the human body like its structural isomer isopentenyl ester of ATP (ApppI). Very recently, ApppI has been found to possess novel function(s); now it will also be possible to examine the effects of ApppD more precisely because it can be synthesized in reasonable amounts. 1-Adenosin-5'-yl 3-(3-methylbut-2-enyl) diphosphoric acid diester (AppD; a adenosine diphosphate analogue) was also isolated from the synthesis mixture. Both ApppD and AppD were characterized by 1H, 13C, 31P NMR and mass spectrometry methods.
| S-EPMC6044877 | biostudies-literature