LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 14

Search options

  1. Article ; Online: Differential glycosylation in mutant vitamin D-binding protein decimates the binding stability of vitamin D.

    Usama / Khan, Zahid / Ali, Aktar / Shah, Masaud / Imran, Muhammad

    Journal of biomolecular structure & dynamics

    2023  , Page(s) 1–11

    Abstract: Vitamin D (VD) is produced by the skin upon exposure to sunlight or is obtained from dietary sources. Several risk factors are associated with VD deficiency including mutations and post-translational modifications in its transport protein known as ... ...

    Abstract Vitamin D (VD) is produced by the skin upon exposure to sunlight or is obtained from dietary sources. Several risk factors are associated with VD deficiency including mutations and post-translational modifications in its transport protein known as vitamin D binding protein (VDBP) or GC-globulin. The two common single nucleotide polymorphisms rs7041 and rs4588 create three major isoforms of VDBP, including GC-1F also called wild type, GC1S, and GC-2. The 3D models for both GC-1F and GC-2 were constructed in their glycosylated states to decipher the effect of these mutations on the overall conformational changes and VD-binding affinity. The binding affinities were estimated using the Molecular Mechanics Poison-Boltzmann surface area (MM-PBSA) method and conformational changes were investigated after free energy landscapes estimations. Total free energies suggest that GC-1F exhibits stronger affinity (ΔE = -116.09 kJ/mol) than GC-2 (ΔE = -95 kJ/mol) variant with VD. The GC-1F isoforms had more streamlined motion compared to GC-2 isoforms, predicting a trade-off between cross-talk residues that significantly impacts protein structural stability. The data suggest that glycation at Thr418 plays a vital role in the overall VDBP-VD affinity by stabilizing the N-T loop that holds the domain I (VD-pocket) and domain III intact. The loss of glycation in GC-2 has a pivotal role in the inter-domain conformational stability of VDBP, which may ultimately affect VD transportation and maturation. These findings describe a novel mechanism in how mutations distant from the VD-active site change the overall conformational of the VDBP and abrogate the VDBP-VD interaction.Communicated by Ramaswamy H. Sarma.
    Language English
    Publishing date 2023-06-25
    Publishing country England
    Document type Journal Article
    ZDB-ID 49157-3
    ISSN 1538-0254 ; 0739-1102
    ISSN (online) 1538-0254
    ISSN 0739-1102
    DOI 10.1080/07391102.2023.2226742
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article: The junior doctor contract 2 years on: one trust's experience of exception reporting.

    Kirwan, Christopher J / Ali, Aktar / McCarten, Neil

    British journal of hospital medicine (London, England : 2005)

    2018  Volume 79, Issue 11, Page(s) 640–641

    Abstract: The new junior doctor contract allows trainees to exception report when they breach safe working hours. After a full year of foundation year 1 rotations, analysis from a large NHS trust in London showed that exception reporting works to highlight rota ... ...

    Abstract The new junior doctor contract allows trainees to exception report when they breach safe working hours. After a full year of foundation year 1 rotations, analysis from a large NHS trust in London showed that exception reporting works to highlight rota and working issues. It is unsurprising that trainees are busy but simple things such as competent infrastructure and senior support could go a long way to improving working conditions. In addition, results from a local survey suggest that trainees think the new contract is less safe for both doctors and patients, with inflexibility of rota patterns having a significant impact on the ability to take annual and study leave. A drive to modernise the way health care is delivered in hospitals is needed as a shortage of doctors will only worsen the situation.
    MeSH term(s) Attitude of Health Personnel ; Clinical Competence ; Humans ; Medical Staff, Hospital/organization & administration ; Medical Staff, Hospital/psychology ; Medical Staff, Hospital/standards ; Patient Safety/standards ; State Medicine ; Time Factors ; United Kingdom ; Workplace/psychology ; Workplace/standards
    Language English
    Publishing date 2018-11-12
    Publishing country England
    Document type Journal Article
    ISSN 1750-8460
    ISSN 1750-8460
    DOI 10.12968/hmed.2018.79.11.640
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article: The Estrogen-Related Receptor α Inverse Agonist XCT 790 Is a Nanomolar Mitochondrial Uncoupler

    Eskiocak, Banu / Ali Aktar / White Michael A

    Biochemistry. 2014 July 29, v. 53, no. 29

    2014  

    Abstract: XCT 790 is widely used to inhibit estrogen-related receptor α (ERRα) activity as an inverse agonist. Here, we report that XCT 790 potently activates AMP kinase (AMPK) in a dose-dependent and ERRα-independent manner, with active concentrations more ... ...

    Abstract XCT 790 is widely used to inhibit estrogen-related receptor α (ERRα) activity as an inverse agonist. Here, we report that XCT 790 potently activates AMP kinase (AMPK) in a dose-dependent and ERRα-independent manner, with active concentrations more than 25-fold below those typically used to perturb ERRα. AMPK activation is secondary to inhibition of energy production as XCT 790 rapidly depletes the pool of cellular ATP. A concomitant increase in oxygen consumption rates suggests uncoupling of the mitochondrial electron transport chain. Consistent with this, XCT 790 decreased mitochondrial membrane potential without affecting mitochondrial mass. Therefore, XCT 790 is a potent, fast-acting, mitochondrial uncoupler independent of its inhibition of ERRα. The biological activity together with structural features in common with the chemical uncouplers FCCP and CCCP indicates likely mode of action as a proton ionophore.
    Keywords AMP-activated protein kinase ; adenosine triphosphate ; agonists ; bioactive properties ; dose response ; electron transport chain ; energy ; mechanism of action ; membrane potential ; mitochondria ; mitochondrial membrane ; oxygen consumption
    Language English
    Dates of publication 2014-0729
    Size p. 4839-4846.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 1108-3
    ISSN 1520-4995 ; 0006-2960
    ISSN (online) 1520-4995
    ISSN 0006-2960
    DOI 10.1021%2Fbi500737n
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  4. Article ; Online: The estrogen-related receptor α inverse agonist XCT 790 is a nanomolar mitochondrial uncoupler.

    Eskiocak, Banu / Ali, Aktar / White, Michael A

    Biochemistry

    2014  Volume 53, Issue 29, Page(s) 4839–4846

    Abstract: XCT 790 is widely used to inhibit estrogen-related receptor α (ERRα) activity as an inverse agonist. Here, we report that XCT 790 potently activates AMP kinase (AMPK) in a dose-dependent and ERRα-independent manner, with active concentrations more than ... ...

    Abstract XCT 790 is widely used to inhibit estrogen-related receptor α (ERRα) activity as an inverse agonist. Here, we report that XCT 790 potently activates AMP kinase (AMPK) in a dose-dependent and ERRα-independent manner, with active concentrations more than 25-fold below those typically used to perturb ERRα. AMPK activation is secondary to inhibition of energy production as XCT 790 rapidly depletes the pool of cellular ATP. A concomitant increase in oxygen consumption rates suggests uncoupling of the mitochondrial electron transport chain. Consistent with this, XCT 790 decreased mitochondrial membrane potential without affecting mitochondrial mass. Therefore, XCT 790 is a potent, fast-acting, mitochondrial uncoupler independent of its inhibition of ERRα. The biological activity together with structural features in common with the chemical uncouplers FCCP and CCCP indicates likely mode of action as a proton ionophore.
    MeSH term(s) Cell Line ; Cell Survival/drug effects ; Drug Inverse Agonism ; Humans ; Membrane Potential, Mitochondrial/drug effects ; Mitochondria/drug effects ; Mitochondria/metabolism ; Nitriles/pharmacology ; Oxidation-Reduction ; Oxygen Consumption ; Phosphorylation ; Proton Ionophores/pharmacology ; Receptors, Estrogen/antagonists & inhibitors ; Receptors, Estrogen/metabolism ; Thiazoles/pharmacology ; ERRalpha Estrogen-Related Receptor
    Chemical Substances Nitriles ; Proton Ionophores ; Receptors, Estrogen ; Thiazoles ; XCT790
    Language English
    Publishing date 2014-07-14
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 1108-3
    ISSN 1520-4995 ; 0006-2960
    ISSN (online) 1520-4995
    ISSN 0006-2960
    DOI 10.1021/bi500737n
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: Fibulin-7, a heparin binding matricellular protein, promotes renal tubular calcification in mice.

    Tsunezumi, Jun / Sugiura, Hidekazu / Oinam, Lalhaba / Ali, Aktar / Thang, Bui Quoc / Sada, Aiko / Yamashiro, Yoshito / Kuro-O, Makoto / Yanagisawa, Hiromi

    Matrix biology : journal of the International Society for Matrix Biology

    2018  Volume 74, Page(s) 5–20

    Abstract: Ectopic calcification occurs during development of chronic kidney disease and has a negative impact on long-term prognosis. The precise molecular mechanism and prevention strategies, however, are not established. Fibulin-7 (Fbln7) is a matricellular ... ...

    Abstract Ectopic calcification occurs during development of chronic kidney disease and has a negative impact on long-term prognosis. The precise molecular mechanism and prevention strategies, however, are not established. Fibulin-7 (Fbln7) is a matricellular protein structurally similar to elastogenic short fibulins, shown to bind dental mesenchymal cells and heparin. Here, we report that Fbln7 is highly expressed in renal tubular epithelium in the adult kidney and mediates renal calcification in mice. In vitro analysis revealed that Fbln7 bound heparin at the N-terminal coiled-coil domain. In Fbln7-expressing CHO-K1 cells, exogenous heparin increased the release of Fbln7 into conditioned media in a dose-dependent manner. This heparin-induced Fbln7 release was abrogated in CHO-745 cells lacking heparan sulfate proteoglycan or in CHO-K1 cells expressing the Fbln7 mutant lacking the N-terminal coiled-coil domain, suggesting that Fbln7 was tethered to pericellular matrix via this domain. Interestingly, Fbln7 knockout (Fbln7
    MeSH term(s) Animals ; Binding Sites ; CHO Cells ; Calcium Phosphates/metabolism ; Calcium-Binding Proteins/chemistry ; Calcium-Binding Proteins/genetics ; Calcium-Binding Proteins/metabolism ; Cell Membrane/metabolism ; Cricetulus ; Disease Models, Animal ; Gene Knockout Techniques ; HEK293 Cells ; Heparan Sulfate Proteoglycans/metabolism ; Heparin/metabolism ; Humans ; Mice ; Mutation ; Nephrocalcinosis/chemically induced ; Nephrocalcinosis/genetics ; Nephrocalcinosis/metabolism ; Protein Binding
    Chemical Substances Calcium Phosphates ; Calcium-Binding Proteins ; Fbln7 protein, mouse ; Heparan Sulfate Proteoglycans ; Heparin (9005-49-6) ; calcium phosphate (97Z1WI3NDX)
    Language English
    Publishing date 2018-05-03
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1183793-7
    ISSN 1569-1802 ; 0945-053X
    ISSN (online) 1569-1802
    ISSN 0945-053X
    DOI 10.1016/j.matbio.2018.04.014
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article ; Online: Chronic innate immune activation of TBK1 suppresses mTORC1 activity and dysregulates cellular metabolism.

    Hasan, Maroof / Gonugunta, Vijay K / Dobbs, Nicole / Ali, Aktar / Palchik, Guillermo / Calvaruso, Maria A / DeBerardinis, Ralph J / Yan, Nan

    Proceedings of the National Academy of Sciences of the United States of America

    2017  Volume 114, Issue 4, Page(s) 746–751

    Abstract: Three-prime repair exonuclease 1 knockout ( ... ...

    Abstract Three-prime repair exonuclease 1 knockout (Trex1
    Language English
    Publishing date 2017-01-24
    Publishing country United States
    Document type Journal Article
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.1611113114
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article ; Online: Adipocyte Xbp1s overexpression drives uridine production and reduces obesity.

    Deng, Yingfeng / Wang, Zhao V / Gordillo, Ruth / Zhu, Yi / Ali, Aktar / Zhang, Chen / Wang, Xiaoding / Shao, Mengle / Zhang, Zhuzhen / Iyengar, Puneeth / Gupta, Rana K / Horton, Jay D / Hill, Joseph A / Scherer, Philipp E

    Molecular metabolism

    2018  Volume 11, Page(s) 1–17

    Abstract: Objective: The spliced transcription factor Xbp1 (Xbp1s), a transducer of the unfolded protein response (UPR), regulates lipolysis. Lipolysis is stimulated by fasting when uridine synthesis is also activated in adipocytes.: Methods: Here we have ... ...

    Abstract Objective: The spliced transcription factor Xbp1 (Xbp1s), a transducer of the unfolded protein response (UPR), regulates lipolysis. Lipolysis is stimulated by fasting when uridine synthesis is also activated in adipocytes.
    Methods: Here we have examined the regulatory role Xbp1s in stimulation of uridine biosynthesis in adipocytes and triglyceride mobilization using inducible mouse models.
    Results: Xbp1s is a key molecule involved in adipocyte uridine biosynthesis and release by activation of carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, dihydroorotase (CAD), the rate-limiting enzyme for UMP biosynthesis. Adipocyte Xbp1s overexpression drives energy mobilization and protects mice from obesity through activation of the pyrimidine biosynthesis pathway.
    Conclusion: These observations reveal that Xbp1s is a potent stimulator of uridine production in adipocytes, enhancing lipolysis and invoking a potential anti-obesity strategy through the induction of a futile biosynthetic cycle.
    MeSH term(s) Adipocytes/metabolism ; Animals ; Cells, Cultured ; Lipolysis ; Male ; Mice ; Mice, Inbred C57BL ; Obesity/metabolism ; Uridine/metabolism ; X-Box Binding Protein 1/genetics ; X-Box Binding Protein 1/metabolism
    Chemical Substances X-Box Binding Protein 1 ; Xbp1 protein, mouse ; Uridine (WHI7HQ7H85)
    Language English
    Publishing date 2018-03-02
    Publishing country Germany
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2708735-9
    ISSN 2212-8778 ; 2212-8778
    ISSN (online) 2212-8778
    ISSN 2212-8778
    DOI 10.1016/j.molmet.2018.02.013
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Article ; Online: Pin1 null mice exhibit low bone mass and attenuation of BMP signaling.

    Shen, Zhong-Jian / Hu, Jie / Ali, Aktar / Pastor, Johanne / Shiizaki, Kazuhiro / Blank, Robert D / Kuro-o, Makoto / Malter, James S

    PloS one

    2013  Volume 8, Issue 5, Page(s) e63565

    Abstract: Bone is constantly formed and resorbed throughout life by coordinated actions of osteoblasts and osteoclasts. However, the molecular mechanisms involved in osteoblast function remain incompletely understood. Here we show, for the first time, that the ... ...

    Abstract Bone is constantly formed and resorbed throughout life by coordinated actions of osteoblasts and osteoclasts. However, the molecular mechanisms involved in osteoblast function remain incompletely understood. Here we show, for the first time, that the peptidyl-prolyl isomerase PIN1 controls the osteogenic activity of osteoblasts. Pin1 null mice exhibited an age-dependent decrease in bone mineral density and trabecular bone formation without alteration in cortical bone. Further analysis identified a defect in BMP signaling in Pin1 null osteoblasts but normal osteoclast function. PIN1 interacted with SMAD5 and was required for the expression by primary osteoblasts of osteoblast specific transcription factors (CBFA1 and OSX), ECM (collagen I and OCN) and the formation of bone nodules. Our results thus uncover a novel aspect of the molecular underpinning of osteoblast function and identify a new therapeutic target for bone diseases.
    MeSH term(s) Animals ; Bone Density/genetics ; Bone Development/genetics ; Bone Morphogenetic Protein 2/metabolism ; Bone Morphogenetic Proteins/metabolism ; Bone and Bones/diagnostic imaging ; Bone and Bones/metabolism ; Calcium/blood ; Cell Differentiation ; Cholecalciferol/blood ; Gene Expression ; Mice ; Mice, Knockout ; NIMA-Interacting Peptidylprolyl Isomerase ; Osteoclasts/cytology ; Osteoclasts/metabolism ; Peptidylprolyl Isomerase/genetics ; Peptidylprolyl Isomerase/metabolism ; Protein Binding ; Radiography ; Signal Transduction ; Smad5 Protein/metabolism
    Chemical Substances Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins ; NIMA-Interacting Peptidylprolyl Isomerase ; Smad5 Protein ; Cholecalciferol (1C6V77QF41) ; Peptidylprolyl Isomerase (EC 5.2.1.8) ; Pin1 protein, mouse (EC 5.2.1.8) ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2013-05-10
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ISSN 1932-6203
    ISSN (online) 1932-6203
    DOI 10.1371/journal.pone.0063565
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article: Calcein as a fluorescent iron chemosensor for the determination of low molecular weight iron in biological fluids.

    Ali, Aktar / Zhang, Qi / Dai, Jisen / Huang, Xi

    Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine

    2003  Volume 16, Issue 2, Page(s) 285–293

    Abstract: The fluorescence quenching of calcein (CA) is not iron specific and results in a negative calibration curve. In the present study, deferoxamine (DFO), a strong iron chelator, was used to regenerate the fluorescence quenched by iron. Therefore, the ... ...

    Abstract The fluorescence quenching of calcein (CA) is not iron specific and results in a negative calibration curve. In the present study, deferoxamine (DFO), a strong iron chelator, was used to regenerate the fluorescence quenched by iron. Therefore, the differences in fluorescence reading of the same sample with or without addition of DFO are positively and specifically proportional to the amounts of iron. We found that the same iron species but different anions (e.g. ferric sulfate or ferric citrate) differed in CA fluorescence quenching, so did the same anions but different iron (e.g. ferrous or ferric sulfates). Excessive amounts of citrate competed with CA for iron and citrate could be removed by barium precipitation. After optimizing the experimental conditions, the sensitivity of the fluorescent CA assay is 0.02 microM of iron, at least 10 times more sensitive than the colorimetric assays. Sera from 6 healthy subjects were tested for low molecular weight (LMW) chelator bound iron in the filtrates of 10 kDa nominal molecular weight limit (NMWL). The LMW iron was marginally detectable in the normal sera. However, increased levels of LMW iron were obtained at higher transferrin (Tf) saturation (1.64-2.54 microM range at 80% Tf saturation, 2.77-3.15 microM range at 100% Tf saturation and 3.09-3.39 microM range at 120% Tf saturation). The application of the assay was further demonstrated in the filtrates of human liver HepG2 and human lung epithelial A549 cells treated with iron or iron-containing dusts.
    MeSH term(s) Body Fluids/chemistry ; Cell Line ; Citric Acid/analysis ; Citric Acid/blood ; Citric Acid/metabolism ; Coal ; Deferoxamine/metabolism ; Deferoxamine/pharmacology ; Dust ; Fluoresceins/analysis ; Fluoresceins/metabolism ; Fluorescence ; Fluorescent Dyes/analysis ; Fluorescent Dyes/metabolism ; Humans ; Iron/analysis ; Iron/blood ; Iron/chemistry ; Iron/pharmacology ; Iron Chelating Agents/metabolism ; Iron Chelating Agents/pharmacology ; Molecular Weight ; Transferrin/analysis
    Chemical Substances Coal ; Dust ; Fluoresceins ; Fluorescent Dyes ; Iron Chelating Agents ; Transferrin ; Citric Acid (2968PHW8QP) ; Iron (E1UOL152H7) ; Deferoxamine (J06Y7MXW4D) ; fluorexon (V0YM2B16TS)
    Language English
    Publishing date 2003-02-05
    Publishing country Netherlands
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 1112688-7
    ISSN 1572-8773 ; 0966-0844
    ISSN (online) 1572-8773
    ISSN 0966-0844
    DOI 10.1023/a:1020642808437
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: Distinct regulatory mechanisms governing embryonic versus adult adipocyte maturation.

    Wang, Qiong A / Tao, Caroline / Jiang, Lei / Shao, Mengle / Ye, Risheng / Zhu, Yi / Gordillo, Ruth / Ali, Aktar / Lian, Yun / Holland, William L / Gupta, Rana K / Scherer, Philipp E

    Nature cell biology

    2015  Volume 17, Issue 9, Page(s) 1099–1111

    Abstract: Pathological expansion of adipose tissue contributes to the metabolic syndrome. Distinct depots develop at various times under different physiological conditions. The transcriptional cascade mediating adipogenesis is established in vitro, and centres ... ...

    Abstract Pathological expansion of adipose tissue contributes to the metabolic syndrome. Distinct depots develop at various times under different physiological conditions. The transcriptional cascade mediating adipogenesis is established in vitro, and centres around a core program involving PPARγ and C/EBPα. We developed an inducible, adipocyte-specific knockout system to probe the requirement of key adipogenic transcription factors at various stages of adipogenesis in vivo. C/EBPα is essential for all white adipogenic conditions in the adult stage, such as adipose tissue regeneration, adipogenesis in muscle and unhealthy expansion of white adipose tissue during high-fat feeding or due to leptin deficiency. Surprisingly, terminal embryonic adipogenesis is fully C/EBPα independent, but does however depend on PPARγ; cold-induced beige adipogenesis is also C/EBPα independent. Moreover, C/EBPα is not vital for adipocyte survival in the adult stage. We reveal a surprising diversity of transcriptional signals required at different stages of adipogenesis in vivo.
    MeSH term(s) Adipocytes/physiology ; Adipogenesis ; Adipose Tissue, White/cytology ; Animals ; CCAAT-Enhancer-Binding Proteins/genetics ; Carbohydrate Metabolism ; Cell Shape ; Diet, High-Fat/adverse effects ; Embryo, Mammalian/cytology ; Female ; Gene Knockout Techniques ; Lipid Metabolism ; Male ; Mice, Obese ; Mice, Transgenic ; Organ Specificity ; PPAR gamma/metabolism ; Transcription, Genetic
    Chemical Substances CCAAT-Enhancer-Binding Proteins ; CEBPA protein, mouse ; PPAR gamma
    Language English
    Publishing date 2015-09
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 1474722-4
    ISSN 1476-4679 ; 1465-7392
    ISSN (online) 1476-4679
    ISSN 1465-7392
    DOI 10.1038/ncb3217
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top