Gluconeogenesis, a pathway for glucose synthesis from non-carbohydrate substances, begins with the synthesis of oxaloacetate (OA) from pyruvate and intermediates of citric acid cycle in hepatocyte mitochondria. The traditional view is that OA does not cross the mitochondrial membrane and must be shuttled to the cytosol, where most enzymes involved in gluconeogenesis are compartmentalized, in the form of malate. Thus, the possibility of transporting OA in the form of aspartate has been ignored. In the article is shown that malate supply to the cytosol increases only when fatty acid oxidation in the liver is activated, such as during starvation or untreated diabetes. Alternatively, aspartate synthesized from OA by mitochondrial aspartate aminotransferase (AST) is transported to the cytosol in exchange for glutamate via the aspartate-glutamate carrier 2 (AGC2). If the main substrate for gluconeogenesis is an amino acid, aspartate is converted to OA via urea cycle, therefore, ammonia detoxification and gluconeogenesis are simultaneously activated. If the main substrate is lactate, OA is synthesized by cytosolic AST, glutamate is transported to the mitochondria through AGC2, and nitrogen is not lost. It is concluded that, compared to malate, aspartate is a more suitable form of OA transport from the mitochondria for gluconeogenesis.

• Klíčová slova
• AGC2, Citrin, Mitochondrial carriers, Oxaloacetate, Urea cycle,
• MeSH
• glukoneogeneze * MeSH
• glutamáty metabolismus   MeSH
• kyselina aspartová * metabolismus   MeSH
• kyselina mléčná MeSH
• kyselina pyrohroznová MeSH
• maláty MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• glutamáty MeSH
• kyselina aspartová * MeSH
• kyselina mléčná MeSH
• kyselina pyrohroznová MeSH
• maláty MeSH
• malic acid MeSH Prohlížeč

To date, the effects of specific modification types and sites on protein lifetime have not been systematically illustrated. Here, we describe a proteomic method, DeltaSILAC, to quantitatively assess the impact of site-specific phosphorylation on the turnover of thousands of proteins in live cells. Based on the accurate and reproducible mass spectrometry-based method, a pulse labeling approach using stable isotope-labeled amino acids in cells (pSILAC), phosphoproteomics, and a unique peptide-level matching strategy, our DeltaSILAC profiling revealed a global, unexpected delaying effect of many phosphosites on protein turnover. We further found that phosphorylated sites accelerating protein turnover are functionally selected for cell fitness, enriched in Cyclin-dependent kinase substrates, and evolutionarily conserved, whereas the glutamic acids surrounding phosphosites significantly delay protein turnover. Our method represents a generalizable approach and provides a rich resource for prioritizing the effects of phosphorylation sites on protein lifetime in the context of cell signaling and disease biology.

• Klíčová slova
• DeltaSILAC, data-independent acquisition, mass spectrometry, phosphomodiform, phosphorylation, protein lifetime, protein turnover, proteomics, pulse SILAC,
• MeSH
• buněčný cyklus fyziologie   MeSH
• cyklin-dependentní kinasy genetika   metabolismus   MeSH
• fosfoproteiny chemie   metabolismus   MeSH
• fosforylace MeSH
• glutamáty metabolismus   MeSH
• hmotnostní spektrometrie metody   MeSH
• izotopové značení metody   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• peptidy metabolismus   MeSH
• peroxiredoxin VI chemie   metabolismus   MeSH
• proteolýza * MeSH
• proteom genetika   metabolismus   MeSH
• proteomika metody   MeSH
• sekvence aminokyselin MeSH
• sestřihové faktory chemie   metabolismus   MeSH
• signální transdukce genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• cyklin-dependentní kinasy MeSH
• fosfoproteiny MeSH
• glutamáty MeSH
• peptidy MeSH
• peroxiredoxin VI MeSH
• PRDX6 protein, human MeSH Prohlížeč
• proteom MeSH
• sestřihové faktory MeSH
• SF3B1 protein, human MeSH Prohlížeč

Fertilization is a multiple step process leading to the fusion of female and male gametes and the formation of a zygote. Besides direct gamete membrane interaction via binding receptors localized on both oocyte and sperm surface, fertilization also involves gamete communication via chemical molecules triggering various signaling pathways. This work focuses on a mouse taste receptor, mTAS1R3, encoded by the Tas1r3 gene, as a potential receptor mediating chemical communication between gametes using the C57BL/6J lab mouse strain. In order to specify the role of mTAS1R3, we aimed to characterize its precise localization in testis and sperm using super resolution microscopy. The testis cryo-section, acrosome-intact sperm released from cauda epididymis and sperm which underwent the acrosome reaction (AR) were evaluated. The mTAS1R3 receptor was detected in late spermatids where the acrosome was being formed and in the acrosomal cap of acrosome intact sperm. AR is triggered in mice during sperm maturation in the female reproductive tract and by passing through the egg surroundings such as cumulus oophorus cells. This AR onset is independent of the extracellular matrix of the oocyte called zona pellucida. After AR, the relocation of mTAS1R3 to the equatorial segment was observed and the receptor remained exposed to the outer surroundings of the female reproductive tract, where its physiological ligand, the amino acid L-glutamate, naturally occurs. Therefore, we targeted the possible interaction in vitro between the mTAS1R3 and L-glutamate as a part of chemical communication between sperm and egg and used an anti-mTAS1R3-specific antibody to block it. We detected that the acrosome reacted spermatozoa showed a chemotactic response in the presence of L-glutamate during and after the AR, and it is likely that mTAS1R3 acted as its mediator.

• Klíčová slova
• L-glutamate, TAS1R family, acrosome reaction, chemoattractant, chemotaxis, gamete, mTAS1R3 receptor, mouse, sperm,
• MeSH
• buněčná diferenciace MeSH
• chemotaxe MeSH
• exprese genu MeSH
• glutamáty metabolismus   MeSH
• interakce spermie a vajíčka * MeSH
• messenger RNA genetika   MeSH
• mezibuněčná komunikace * MeSH
• myši MeSH
• receptory spřažené s G-proteiny genetika   metabolismus   MeSH
• spermie cytologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glutamáty MeSH
• messenger RNA MeSH
• receptory spřažené s G-proteiny MeSH
• taste receptors, type 1 MeSH Prohlížeč

Bordetella pertussis is the causative agent of human whooping cough, a highly contagious respiratory disease which despite vaccination programs remains the major cause of infant morbidity and mortality. The requirement of the RNA chaperone Hfq for virulence of B. pertussis suggested that Hfq-dependent small regulatory RNAs are involved in the modulation of gene expression. High-throughput RNA sequencing revealed hundreds of putative noncoding RNAs including the RgtA sRNA. Abundance of RgtA is strongly decreased in the absence of the Hfq protein and its expression is modulated by the activities of the two-component regulatory system BvgAS and another response regulator RisA. Whereas RgtA levels were elevated under modulatory conditions or in the absence of bvg genes, deletion of the risA gene completely abolished RgtA expression. Profiling of the ΔrgtA mutant in the ΔbvgA genetic background identified the BP3831 gene encoding a periplasmic amino acid-binding protein of an ABC transporter as a possible target gene. The results of site-directed mutagenesis and in silico analysis indicate that RgtA base-pairs with the region upstream of the start codon of the BP3831 mRNA and thereby weakens the BP3831 protein production. Furthermore, our data suggest that the function of the BP3831 protein is related to transport of glutamate, an important metabolite in the B. pertussis physiology. We propose that the BvgAS/RisA interplay regulates the expression of RgtA which upon infection, when glutamate might be scarce, attenuates translation of the glutamate transporter and thereby assists in adaptation of the pathogen to other sources of energy.

• Klíčová slova
• Bordetella, riboregulation, sRNA, signal transduction, translational repression,
• MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• Bordetella pertussis genetika   metabolismus   MeSH
• glutamáty metabolismus   MeSH
• lidé MeSH
• malá nekódující RNA genetika   MeSH
• regulace genové exprese u bakterií MeSH
• signální transdukce * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• glutamáty MeSH
• malá nekódující RNA MeSH

UNLABELLED: Glutamate carboxypeptidase III (GCPIII) is best known as a homologue of glutamate carboxypeptidase II [GCPII; also known as prostate-specific membrane antigen (PSMA)], a protease involved in neurological disorders and overexpressed in a number of solid cancers. However, mouse GCPIII was recently shown to cleave β-citrylglutamate (BCG), suggesting that these two closely related enzymes have distinct functions. To develop a tool to dissect, evaluate and quantify the activities of human GCPII and GCPIII, we analysed the catalytic efficiencies of these enzymes towards three physiological substrates. We observed a high efficiency of BCG cleavage by GCPIII but not GCPII. We also identified a strong modulation of GCPIII enzymatic activity by divalent cations, while we did not observe this effect for GCPII. Additionally, we used X-ray crystallography and computational modelling (quantum and molecular mechanical calculations) to describe the mechanism of BCG binding to the active sites of GCPII and GCPIII, respectively. Finally, we took advantage of the substantial differences in the enzymatic efficiencies of GCPII and GCPIII towards their substrates, using enzymatic assays for specific detection of these proteins in human tissues. Our findings suggest that GCPIII may not act merely as a complementary enzyme to GCPII, and it more likely possesses a specific physiological function related to BCG metabolism in the human body. DATABASE: The X-ray structure of GCPII Glu424Ala in complex with BCG has been deposited in the RCSB Protein Data Bank under accession code 5F09.

• Klíčová slova
• GCPIII, QM/MM calculations, arene-binding site, prostate-specific membrane antigen, β-citryl-l-glutamate,
• MeSH
• antigeny povrchové chemie   metabolismus   MeSH
• glutamátkarboxypeptidasa II chemie   metabolismus   MeSH
• glutamáty chemie   metabolismus   MeSH
• karboxypeptidasy chemie   metabolismus   MeSH
• katalytická doména MeSH
• lidé MeSH
• molekulární struktura MeSH
• substrátová specifita MeSH
• termodynamika MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• antigeny povrchové MeSH
• beta-citrylglutamic acid MeSH Prohlížeč
• FOLH1 protein, human MeSH Prohlížeč
• glutamátkarboxypeptidasa II MeSH
• glutamáty MeSH
• karboxypeptidasy MeSH
• NAALAD2 protein, human MeSH Prohlížeč

In humans, aging is accompanied by the deterioration of the hearing function--presbycusis. The major etiology for presbycusis is the loss of hair cells in the inner ear; less well known are changes in the central auditory system. Therefore, we used 1H magnetic resonance spectroscopy at 3T tomograph to examine metabolite levels in the auditory cortex of three groups of subjects: young healthy subjects less than 30 years old and subjects older than 65 years either with mild presbycusis corresponding to their age or with expressed presbycusis. Hearing function in all subjects was examined by pure tone audiometry (125-16,000 Hz). Significant differences were found in the concentrations of glutamate and N-acetylaspartate, with lower levels in aged subjects. Lactate was particularly increased in subjects with expressed presbycusis. Significant differences were not found in other metabolites, including GABA, between young and elderly subjects. The results demonstrate that the age-related changes of the inner ear are accompanied by a decrease in the excitatory neurotransmitter glutamate as well as a lactate increase in the auditory cortex that is more expressed in elderly subjects with large hearing threshold shifts.

• Klíčová slova
• Auditory cortex, EP, GABA, Glutamate, Lactate, MP, MR spectroscopy, N-acetylaspartate, NAA, Presbycusis, VOI, YC, elderly subjects with expressed presbycusis, elderly subjects with mild presbycusis, volume of interest, young subjects with physiologic hearing,
• MeSH
• audiometrie čistými tóny MeSH
• dospělí MeSH
• glutamáty metabolismus   MeSH
• kyselina aspartová analogy a deriváty   metabolismus   MeSH
• laktáty metabolismus   MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie * MeSH
• presbyakuze metabolismus   MeSH
• senioři MeSH
• sluchové korové centrum metabolismus   MeSH
• stárnutí metabolismus   MeSH
• studie případů a kontrol MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• glutamáty MeSH
• kyselina aspartová MeSH
• laktáty MeSH
• N-acetylaspartate MeSH Prohlížeč

Glutamate was converted to glutamine by Corynebacterium glutamicum permeabilized by ethanol (10%). ATP was supplied to the reaction by dried Saccharomyces cerevisiae or regenerated by acetyl kinase. High glutamine synthetase activity in C. glutamicum was induced by cultivation of the microorganism in media containing glutamate as the sole source of nitrogen.

• MeSH
• Corynebacterium enzymologie   růst a vývoj   metabolismus   MeSH
• glutamáty metabolismus   MeSH
• glutamin metabolismus   MeSH
• glutaminsynthetasa metabolismus   MeSH
• kultivační média MeSH
• permeabilita buněčné membrány MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glutamáty MeSH
• glutamin MeSH
• glutaminsynthetasa MeSH
• kultivační média MeSH

The activity of specific ouabain-sensitive Na+,K(+)-ATPase was studied in crude membrane fraction of the brain of 1- to 3-day-old chicks after the administration of a chemical aversant methylanthranilate (MeA), shown in previous behavioral studies to induce avoidance of pecking of an otherwise attractive stimulus. Enzyme activity was dramatically decreased (by 40-50%) in the time interval between 10 min-2 h after MeA administration onto the tongue of awake chicks. It was possible to localize these changes in Na+,K(+)-ATPase activity into forebrain structures contained within the dorsal ventricular ridge comprising the hyperstriatum accessorium (HA), hyperstriatum ventrale (HV), hyperstriatum dorsale (HD), and parts of neostriatum (N). In contrast, Na+,K(+)-ATPase activity in the ectostriatum (E), the medial neostriatum (NM), and the paleostriatal complex were unaffected. Results from experiments involving preincubation of membrane fractions and with partial purification using detergents, suggest that some substances with inhibitory effects were produced under the effect of MeA and bound to membrane fractions in their respective areas. A similar decrease of Na+,K(+)-ATPase activity as after MeA administration in vivo was observed when inhibitory mediators (GABA, glycine) were added to membrane fractions in vitro. These findings may have implications for memory processing in chicks following aversive learning using MeA as the aversant.

• MeSH
• chuť fyziologie   MeSH
• GABA metabolismus   MeSH
• glukosa metabolismus   MeSH
• glutamáty metabolismus   MeSH
• glycin metabolismus   MeSH
• jazyk fyziologie   MeSH
• kur domácí MeSH
• kyselina glutamová MeSH
• neostriatum fyziologie   MeSH
• ortoaminobenzoáty farmakologie   MeSH
• přední mozek enzymologie   MeSH
• sodíko-draslíková ATPasa izolace a purifikace   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• GABA MeSH
• glukosa MeSH
• glutamáty MeSH
• glycin MeSH
• kyselina glutamová MeSH
• methyl anthranilate MeSH Prohlížeč
• ortoaminobenzoáty MeSH
• sodíko-draslíková ATPasa MeSH

To define the ontogeny of "excitotoxic" neurodegeneration further, bilateral intracerebroventricular injection of N-methyl-D-aspartate agonist, quinolinate (QUIN), was administered to rats at Postnatal Days 12, 30, and 50. Excitotoxic injury was quantified by means of changes in [3H]glutamate binding to membranes isolated from the entorhinal cortex, hippocampal formation, cerebellum, and medulla oblongata 4 days after the injection of QUIN. Binding was significantly decreased only in the hippocampal formation of 30- and 50-day-old rats (by 25 and 32%, respectively). In contrast, binding to cortical membranes was elevated by 29 and 56% at Postnatal Days 30 and 50, respectively. Observed changes in the binding of glutamate were due to modifications in the equilibrium binding constants rather than in the density of the receptors. In the cerebellum, which exhibited the highest developmental increase, the statistically significant decrease of the binding (by 36%) following QUIN lesion was only observable on Day 30. The effects of QUIN lesions were not statistically significant in the medulla oblongata. The results suggest that in 30- and 50-day-old rats QUIN can be implicated in neurodegeneration of the entorhinohippocampal complex.

• MeSH
• glutamáty metabolismus   MeSH
• injekce intraventrikulární MeSH
• krysa rodu Rattus MeSH
• kyselina chinolinová aplikace a dávkování   farmakologie   MeSH
• kyselina glutamová MeSH
• mozek účinky léků   metabolismus   MeSH
• novorozená zvířata MeSH
• potkani Wistar MeSH
• regresní analýza MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glutamáty MeSH
• kyselina chinolinová MeSH
• kyselina glutamová MeSH

The growth and the production of extracellular and intracellular lipases were measured from Nocardia asteroides grown under different cultural conditions. Maximal growth and intracellular and extracellular activities were observed at 3 d after inoculation. Among the tested media, synthetic medium induced maximal growth and extracellular activity, whereas tryptic soy broth induced the maximal intracellular lipase activity. The best carbon and nitrogen sources for growth and lipolytic activity were glucose, fructose, glutamate and nitrate, respectively. The optimal C:N ratio for growth was in the range of 1:4 to 2:3 and for lipase activity the range was 2:3 to 3:2. Anything above or below this range was detrimental to the organism and its enzyme activity. Under the conditions of this study, N. asteroides grew best and had the highest lipase activity when compared to N. brasiliensis and N. caviae.

• MeSH
• bakteriologické techniky MeSH
• dusičnany metabolismus   MeSH
• fruktosa metabolismus   MeSH
• glukosa metabolismus   MeSH
• glutamáty metabolismus   MeSH
• kultivační média MeSH
• kyselina glutamová MeSH
• lidé MeSH
• lipasa biosyntéza   MeSH
• lipolýza * MeSH
• Nocardia asteroides růst a vývoj   metabolismus   patogenita   MeSH
• nokardióza etiologie   MeSH
• virulence MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusičnany MeSH
• fruktosa MeSH
• glukosa MeSH
• glutamáty MeSH
• kultivační média MeSH
• kyselina glutamová MeSH
• lipasa MeSH