• MeSH
• acetylkoenzym A MeSH
• adenosinmonofosfát metabolismus   MeSH
• energetický metabolismus MeSH
• malonylkoenzym A MeSH
• obezita patofyziologie   MeSH
• proteinkinasy závislé na vápníku a kalmodulinu MeSH
• proteinkinasy fyziologie   MeSH
• receptor inzulinu MeSH
• syntázy mastných kyselin MeSH
• změny tělesné hmotnosti MeSH
• Publikační typ
• sborníky MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• vnitřní lékařství

Adenosine kinase (ADK) from Mycobacterium tuberculosis (Mtb) was selected as a target for design of antimycobacterial nucleosides. Screening of 7-(het)aryl-7-deazaadenine ribonucleosides with Mtb and human (h) ADKs and testing with wild-type and drug-resistant Mtb strains identified specific inhibitors of Mtb ADK with micromolar antimycobacterial activity and low cytotoxicity. X-ray structures of complexes of Mtb and hADKs with 7-ethynyl-7-deazaadenosine showed differences in inhibitor interactions in the adenosine binding sites. 1D (1)H STD NMR experiments revealed that these inhibitors are readily accommodated into the ATP and adenosine binding sites of Mtb ADK, whereas they bind preferentially into the adenosine site of hADK. Occupation of the Mtb ADK ATP site with inhibitors and formation of catalytically less competent semiopen conformation of MtbADK after inhibitor binding in the adenosine site explain the lack of phosphorylation of 7-substituted-7-deazaadenosines. Semiempirical quantum mechanical analysis confirmed different affinity of nucleosides for the Mtb ADK adenosine and ATP sites.

• MeSH
• adenin analogy a deriváty   chemie   MeSH
• adenosinkinasa antagonisté a inhibitory   chemie   metabolismus   MeSH
• adenosintrifosfát metabolismus   MeSH
• antituberkulotika chemie   farmakologie   MeSH
• konformace proteinů MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• Mycobacterium tuberculosis účinky léků   enzymologie   MeSH
• nukleární magnetická rezonance biomolekulární MeSH
• preklinické hodnocení léčiv MeSH
• ribonukleosidy chemie   farmakologie   MeSH
• vazebná místa MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• adenosintrifosfát MeSH
• replikace viru účinky záření   MeSH
• uracil analogy a deriváty   MeSH
• uridinkinasa MeSH
• virus newcastleské nemoci růst a vývoj   účinky léků   MeSH

In different systems, cyclic adenosine monophosphate (cAMP) either blocks or promotes cell cycle progression in mid to late G1 phase. Dog thyroid epithelial cells in primary culture constitute a model of positive control of DNA synthesis initiation and G0-S prereplicative phase progression by cAMP as a second messenger for thyrotropin (TSH). The cAMP-dependent mitogenic pathway is unique as it is independent of mitogen-activated protein kinase activation and differs from growth factor-dependent pathways at the level of the expression of several protooncogenes/transcription factors. This study examined the involvement of D-type G1 cyclins and their associated cyclin-dependent kinase (cdk4) in the cAMP-dependent G1 phase progression of dog thyroid cells. Unlike epidermal growth factor (EGF)+serum and other cAMP-independent mitogens, TSH did not induce the accumulation of cyclins D1 and D2 and partially inhibited the basal expression of the most abundant cyclin D3. However, TSH stimulation enhanced the nuclear detection of cyclin D3. This effect correlated with G1 and S phase progression. It was found to reflect both the unmasking of an epitope of cyclin D3 close to its domain of interaction with cdk4, and the nuclear translocation of cyclin D3. TSH and EGF+serum also induced a previously undescribed nuclear translocation of cdk4, the assembly of precipitable cyclin D3-cdk4 complexes, and the Rb kinase activity of these complexes. Previously, cdk4 activity was found to be required in the cAMP-dependent mitogenic pathway of dog thyrocytes, as in growth factor pathways. Here, microinjections of a cyclin D3 antibody showed that cyclin D3 is essential in the TSH/ cAMP-dependent mitogenesis, but not in the pathway of growth factors that induce cyclins D1 and D2. The present study (a) provides the first example in a normal cell of a stimulation of G1 phase progression occurring independently of an enhanced accumulation of cyclins D, (b) identifies the activation of cyclin D3 and cdk4 through their enhanced assembly and/or nuclear translocation, as first convergence steps of the parallel cAMP-dependent and growth factor mitogenic pathways, and (c) strongly suggests that this new mechanism is essential in the cAMP-dependent mitogenesis, which provides the first direct demonstration of the requirement for cyclin D3 in a G1 phase progression.

• MeSH
• AMP cyklický metabolismus   MeSH
• buněčné dělení účinky léků   fyziologie   MeSH
• buněčné jádro metabolismus   MeSH
• cyklin D3 MeSH
• cyklin-dependentní kinasa 4 MeSH
• cyklin-dependentní kinasy biosyntéza   metabolismus   MeSH
• cykliny metabolismus   MeSH
• epidermální růstový faktor farmakologie   MeSH
• epitopy analýza   MeSH
• fluorescenční protilátková technika MeSH
• G1 fáze fyziologie   MeSH
• hypoglykemika farmakologie   MeSH
• inzulin farmakologie   MeSH
• krevní proteiny farmakologie   MeSH
• kultivované buňky MeSH
• mitogeny farmakologie   MeSH
• protoonkogenní proteiny * MeSH
• psi MeSH
• štítná žláza cytologie   enzymologie   MeSH
• thyreotropin farmakologie   MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• adenosinmonofosfát MeSH
• králíci MeSH
• lipidy MeSH
• svaly enzymologie   MeSH
• Check Tag
• králíci MeSH

The allosteric influence of adenosine triphosphate (ATP) on the binding effectiveness of a series of peptide inhibitors with the catalytic subunit of 3'5'-cyclic adenosine monophosphate dependent protein kinase was investigated, and the dependence of this effect on peptide structure was analyzed. The allosteric effect was calculated as ratio of peptide binding effectiveness with the enzyme-ATP complex and with the free enzyme, quantified by the competitive inhibition of the enzyme in the presence of ATP excess, and by the enzyme-peptide complex denaturation assay, respectively It was found that the principle "better binding-stronger allostery" holds for interactions of the studied peptides with the enzyme, indicating that allostery and peptide binding with the free enzyme are governed by the same specificity pattern. This means that the allosteric regulation does not include new ligand-protein interactions, but changes the intensity (strength) of the interatomic forces that govern the complex formation in the case of each individual ligand. We propose that the allosteric regulation can be explained by the alteration of the intrinsic dynamics of the protein by ligand binding, and that this phenomenon, in turn, modulates the ligand off-rate from its binding site as well as the binding affinity. The positive allostery could therefore be induced by a reduction in the enzyme's overall intrinsic dynamics.

• MeSH
• 2-naftylamin analogy a deriváty   chemie   MeSH
• adenosintrifosfát chemie   metabolismus   MeSH
• alosterická regulace MeSH
• alosterické místo MeSH
• AMP cyklický chemie   metabolismus   MeSH
• barvení a značení metody   MeSH
• fluorescenční barviva chemie   MeSH
• inhibitory proteinkinas chemie   metabolismus   MeSH
• katalytická doména MeSH
• kinetika MeSH
• lidé MeSH
• ligandy MeSH
• peptidy chemie   metabolismus   MeSH
• proteinkinasy závislé na cyklickém AMP chemie   metabolismus   MeSH
• sekvence aminokyselin MeSH
• termodynamika MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Adenosine is secreted from adipocytes, binds to adenosine A1 receptor and modulates various functions of these cells. In the present study, the effects of an adenosine A1 receptor antagonist (DPCPX; 0.01, 0.1 and 1 µM) on lipogenesis, glucose transport, lipolysis and the antilipolytic action of insulin were tested in rat adipocytes. DPCPX had a very weak effect on lipogenesis and did not significantly affect glucose uptake. In adipocytes incubated with 1 µM DPCPX, lipolysis increased. This effect was blunted by insulin and by a direct inhibitor of protein kinase A. Moreover, 0.1 µM DPCPX substantially enhanced the lipolytic response to epinephrine and increased cAMP in adipocytes. However, DPCPX was ineffective when lipolysis was stimulated by direct activation of protein kinase A. Adipocyte exposure to epinephrine and insulin with or without 0.1 µM DPCPX demonstrated that this antagonist increased the release of glycerol. However, despite the presence of DPCPX, insulin was able to reduce lipolysis. It is concluded that DPCPX had a weak effect on lipogenesis, whereas lipolysis was significantly affected. The partial antagonism of adenosine A1 receptor increased lipolysis in cells incubated with epinephrine alone and epinephrine with insulin due to the synergistic action of 0.1 µM DPCPX and epinephrine.

• MeSH
• adenosin metabolismus   MeSH
• adrenalin metabolismus   MeSH
• AMP cyklický metabolismus   MeSH
• antagonisté adenosinového receptoru A1 MeSH
• glukosa metabolismus   MeSH
• glycerol metabolismus   MeSH
• inhibitory proteinkinas farmakologie   MeSH
• inzulin metabolismus   MeSH
• krysa rodu rattus MeSH
• lipogeneze účinky léků   MeSH
• lipolýza účinky léků   MeSH
• potkani Wistar MeSH
• proteinkinasy závislé na cyklickém AMP antagonisté a inhibitory   metabolismus   MeSH
• receptor adenosinový A1 metabolismus   MeSH
• techniky in vitro MeSH
• tukové buňky metabolismus   účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• xanthiny farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH

Extracellular adenosine is an important signaling molecule in neuromodulation, immunomodulation and hypoxia. Adenosine dysregulation can cause various pathologies, exemplified by a deficiency in adenosine deaminase in severe combined immunodeficiency. We have established a Drosophila model to study the effects of increased adenosine in vivo by mutating the main Drosophila adenosine deaminase-related growth factor (ADGF-A). Using a genetic screen, we show here that the increased extracellular adenosine in the adgf-a mutant is associated with hyperglycemia and impairment in energy storage. The adenosine works in this regard through the adenosine receptor as an anti-insulin hormone in parallel to adipokinetic hormone, a glucagon counterpart in flies. If not regulated properly, this action can lead to a loss of energy reserves (wasting) and death of the organism. Because adenosine signaling is associated with the immune response and the response to stress in general, our results mark extracellular adenosine as a good candidate signal involved in the wasting syndrome that accompanies various human pathologies.

• MeSH
• adenosin metabolismus   MeSH
• adipokiny metabolismus   MeSH
• dieta MeSH
• Drosophila melanogaster enzymologie   MeSH
• energetický metabolismus MeSH
• extracelulární prostor metabolismus   MeSH
• fenotyp MeSH
• fosforylasakinasa genetika   metabolismus   MeSH
• hemolymfa metabolismus   MeSH
• kalorická restrikce MeSH
• larva metabolismus   MeSH
• mutace genetika   MeSH
• proteiny Drosophily nedostatek   genetika   metabolismus   MeSH
• purinergní receptory P1 metabolismus   MeSH
• sacharidy krev   MeSH
• signální transdukce MeSH
• suprese genetická MeSH
• syndrom chřadnutí enzymologie   patologie   MeSH
• tukové těleso metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Adenosine (Ado) is a crucial metabolite that affects a wide range of physiological processes. Key proteins regulating Ado signaling, transport and metabolism are conserved among vertebrates and invertebrates. It is well known that Ado influences proliferation of several vertebrate and invertebrate cells. Here we show that Ado negatively influences viability, changes morphology and mitochondrial polarity of the Drosophila imaginal disc cell line (Cl.8+) via a mechanism exclusively dependent on cellular Ado uptake. High transport of Ado is followed by phosphorylation and ATP production as a part of Ado salvation, which at higher concentrations may interfere with cellular homeostasis. In contrast, hematopoietic cell line Mbn2, which grows well in high Ado concentration, preferentially uses adenosine deaminase as a part of the purine catabolic pathway. Our results show that different types of Drosophila cell lines use different pathways for Ado conversion and suggest that such differences may be an important part of complex mechanisms maintaining energy homeostasis in the body.

• MeSH
• adenosin metabolismus   toxicita   MeSH
• adenosinkinasa antagonisté a inhibitory   metabolismus   MeSH
• adenosintrifosfát metabolismus   MeSH
• buněčné linie MeSH
• Drosophila cytologie   metabolismus   MeSH
• energetický metabolismus MeSH
• proliferace buněk MeSH
• uridin metabolismus   MeSH
• viabilita buněk MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

• MeSH
• adenosintrifosfát MeSH
• adenylátcyklasy metabolismus   MeSH
• estery farmakologie   MeSH
• fosfodiesterasy metabolismus   MeSH
• játra enzymologie   MeSH
• proteinkinasy metabolismus   MeSH
• tuková tkáň enzymologie   MeSH