共查询到20条相似文献，搜索用时 15 毫秒
1.
Philippe Marchetti Anne Trinh Raeeka Khamari Jerome Kluza 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(4):999-1005
Background
Besides its influence on survival, growth, proliferation, invasion and metastasis, cancer cell metabolism also greatly influences the cellular responses to molecular-targeted therapies.Scope of the review
To review the recent advances in elucidating the metabolic effects of BRAF and MEK inhibitors (clinical inhibitors of the MAPK/ERK pathway) in melanoma and discuss the underlying mechanisms involved in the way metabolism can influence melanoma cell death and resistance to BRAF and MEK inhibitors. We also underlined the therapeutic perspectives in terms of innovative drug combinations.Major conclusion
BRAF and MEK inhibitors inhibit aerobic glycolysis and induce high levels of metabolic stress leading to effective cell death by apoptosis in BRAF-mutated cancer cells. An increase in mitochondrial metabolism is required to survive to MAPK/ERK pathway inhibitors and the sub-population of cells that survives to these inhibitors are characterized by mitochondrial OXPHOS phenotype. Consequently, mitochondrial inhibition could be combined with oncogenic “drivers” inhibitors of the MAPK/ERK pathway for improving the efficacy of molecular-targeted therapy.General significance
Metabolism is a key component of the melanoma response to BRAF and/or MEK inhibitors. Mitochondrial targeting may offer novel therapeutic approaches to overwhelm the mitochondrial addiction that limits the efficacy of BRAF and/or MEK inhibitors. These therapeutic approaches might be quickly applicable to the clinical situation. 相似文献2.
Lin Wang Ziru Yu Shuyue Ren Junke Song Jinhua Wang Guanhua Du 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(10):2281-2292
Background
Metabolic reprogramming and hypoxia contribute to the resistance of conventional chemotherapeutic drugs in kinds of cancers. In this study, we investigated the effect of dihydrotanshinone I (DHTS) on reversing dysregulated metabolism of glucose and fatty acid in colon cancer and elucidated its mechanism of action.Methods
Cell viability was determined by MTT assay. Oxidative phosphorylation, glycolysis, and mitochondrial fuel oxidation were assessed by Mito stress test, glycolysis stress test, and mito fuel flex test, respectively. Anti-cancer activity of DHTS in vivo was evaluated in Colon cancer xenograft. Hexokinase activity and free fatty acid (FFA) content were assessed using respective Commercial kits. Gene expression patterns were determined by performing DNA microarray analysis and real-time PCR. Protein expression was assessed using immunoblotting and immunohistochemistry.Results
DHTS showed similar cytotoxicity against colon cancer cells under hypoxia and normoxia. DHTS decreased the efficiency of glucose and FA as mitochondrial fuels in HCT116 cells, which efficiently reversed by VO-OHpic trihydrate. DHTS reduced hexokinase activity and free fatty acid (FFA) content in tumor tissue of xenograft model of colon cancer. Gene expression patterns in metabolic pathways were dramatically differential between model and treatment group. Increases in PTEN and a substantial decrease in the expression of SIRT3, HIF1α, p-AKT, HKII, p-MTOR, RHEB, and p-ACC were detected.Conclusions
DHTS reversed metabolic reprogramming in colon cancer through PTEN/AKT/HIF1α-mediated signal pathway.General significance
The study is the first to report the reverse of metabolic reprogramming by DHTS in colon cancer. Meantime, SIRT3/PTEN/AKT/HIF1α mediated signal pathway plays a critical role during this process. 相似文献3.
Giulia Lori Tania Gamberi Paolo Paoli Anna Caselli Erica Pranzini Riccardo Marzocchini Alessandra Modesti Giovanni Raugei 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2533-2544
Background
Low Molecular Weight Phosphotyrosine Protein Phosphatase (LMW-PTP) is an enzyme involved not only in tumor onset and progression but also in type 2 diabetes. A recent review shows that LMW-PTP acts on several RTK (receptor tyrosine kinase) such as PDGFR, EGFR, EphA2, Insulin receptor. It is well described also its interaction with cSrc. It is noteworthy that most of these conclusions are based on the use of cell lines expressing low levels of LMW-PTP. The aim of the present study was to discover new LMW-PTP substrates in aggressive human tumors where the over-expression of this phosphatase is a common feature.Methods
We investigated, by proteomic analysis, the protein phosphorylation pattern of A375 human melanoma cells silenced for LMW-PTP. Two-dimensional electrophoresis (2-DE) analysis, followed by western blot was performed using anti-phosphotyrosine antibodies, in order to identify differentially phosphorylated proteins.Results
Proteomic analysis pointed out that most of the identified proteins belong to the glycolytic metabolism, such as α-enolase, pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase and triosephosphate isomerase, suggesting an involvement of LMW-PTP in glucose metabolism. Assessment of lactate production and oxygen consumption demonstrated that LMW-PTP silencing enhances glycolytic flux and slow down the oxidative metabolism. In particular, LMW-PTP expression affects PKM2 tyrosine-phosphorylation and nuclear localization, modulating its activity.Conclusion
All these findings propose that tumor cells are subjected to metabolic reprogramming after LMW-PTP silencing, enhancing glycolytic flux, probably to compensate the inhibition of mitochondrial metabolism.General significance
Our results highlight the involvement of LMW-PTP in regulating glucose metabolism in A375 melanoma cells. 相似文献4.
W.F. Theeuwes H.R. Gosker R.C.J. Langen N.A.M. Pansters A.M.W.J. Schols A.H.V. Remels 《生物化学与生物物理学报:疾病的分子基础》2018,1864(9):2913-2926
Background
Mitochondrial biogenesis is crucial for myogenic differentiation and regeneration of skeletal muscle tissue and is tightly controlled by the peroxisome proliferator-activated receptor-γ co-activator 1 (PGC-1) signaling network. In the present study, we hypothesized that inactivation of glycogen synthase kinase (GSK)-3β, previously suggested to interfere with PGC-1 in non-muscle cells, potentiates PGC-1 signaling and the development of mitochondrial biogenesis during myogenesis, ultimately resulting in an enhanced myotube oxidative capacity.Methods
GSK-3β was inactivated genetically or pharmacologically during myogenic differentiation of C2C12 muscle cells. In addition, m. gastrocnemius tissue was collected from wild-type and muscle-specific GSK-3β knock-out (KO) mice at different time-points during the reloading/regeneration phase following a 14-day hind-limb suspension period. Subsequently, expression levels of constituents of the PGC-1 signaling network as well as key parameters of mitochondrial oxidative metabolism were investigated.Results
In vitro, both knock-down as well as pharmacological inhibition of GSK-3β not only increased expression levels of important constituents of the PGC-1 signaling network, but also potentiated myogenic differentiation-associated increases in mitochondrial respiration, mitochondrial DNA copy number, oxidative phosphorylation (OXPHOS) protein abundance and the activity of key enzymes involved in the Krebs cycle and fatty acid β-oxidation. In addition, GSK-3β KO animals showed augmented reloading-induced increases in skeletal muscle gene expression of constituents of the PGC-1 signaling network as well as sub-units of OXPHOS complexes compared to wild-type animals.Conclusion
Inactivation of GSK-3β stimulates activation of PGC-1 signaling and mitochondrial biogenesis during myogenic differentiation and reloading of the skeletal musculature. 相似文献5.
6.
Joe Varghese Jithu James Sophie Vaulont Andrew Mckie Molly Jacob 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(9):1870-1882
Background
An iron-overloaded state has been reported to be associated with insulin resistance. On the other hand, conditions such as classical hemochromatosis (where iron overload occurs primarily in the liver) have been reported to be associated with increased insulin sensitivity. The reasons for these contradictory findings are unclear. In this context, the effects of increased intracellular iron per se on insulin signaling in hepatocytes are not known.Methods
Mouse primary hepatocytes were loaded with iron in vitro by incubation with ferric ammonium citrate (FAC). Intracellular events related to insulin signaling, as well as changes in gene expression and hepatocyte glucose production (HGP), were studied in the presence and absence of insulin and/or forskolin (a glucagon mimetic).Results
In vitro iron-loading of hepatocytes resulted in phosphorylation-mediated activation of Akt and AMP-activated protein kinase. This was associated with decreased basal and forskolin-stimulated HGP. Iron attenuated forskolin-mediated induction of the key gluconeogenic enzyme, glucose-6-phosphatase. It also attenuated activation of the Akt pathway in response to insulin, which was associated with decreased protein levels of insulin receptor substrates 1 and 2, constituting insulin resistance.Conclusions
Increased intracellular iron has dual effects on insulin sensitivity in hepatocytes. It increased basal activation of the Akt pathway, but decreased activation of this pathway in response to insulin.General significance
These findings may help explain why both insulin resistance and increased sensitivity have been observed in iron-overloaded states. They are of relevance to a variety of disease conditions characterized by hepatic iron overload and increased risk of diabetes. 相似文献7.
Xu Lu Dongmei Zhang Hayato Shoji Chengwei Duan Guowei Zhang Tomoya Isaji Yuqin Wang Tomohiko Fukuda Jianguo Gu 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(3):598-608
Background
α1,6-Fucosyltransferase-deficient (Fut8?/?) mice displayed increased locomotion and schizophrenia-like behaviors. Since neuroinflammation is a common pathological change in most brain diseases, this study was focused on investigating the effects of Fut8 in microglia and astrocytes.Methods
Brain tissues were analyzed using immunohistochemical staining. Core fucosylation and protein expression were analyzed using lectin blot and western blot, respectively. Fut8-knockout (KO) cells were established by the CRISPR/Cas9 system.Results
The number of Iba-1 positive cells and GFAP positive cells were significantly increased in both untreated and lipopolysaccharide stimulated inflammatory conditional Fut8?/? mice by comparison with both wild-type (Fut8+/+) and hetero (Fut8+/?) mice. Stimulation with pro-inflammatory factors, such as IFN-γ and IL-6, induced expression levels of fucosylation in primary microglia and astrocytes, as well as in glial cell lines. Cell motility and iNOS expression were easily induced by IFN-γ in Fut8-KO BV-2 cells compared with wild-type (WT) cells. In a similar manner, both Fut8-KO C6 cells and primary astrocytes treated with 2-fluoro-L-fucose, a specific inhibitor for fucosylation, showed a higher response to IL-6-stimulated phospho-STAT3 signaling, compared with WT cells.Conclusions
Core fucosylation negatively regulates the states of neuroinflammation by modulating the sensitivity of microglia and astrocytes to inflammatory mediators. The disorders of Fut8?/? mice are caused not only by neurons but also by glial cell dysfunction.General significance
Core fucose is a novel regulator for neuroinflammation in the central nervous system. 相似文献8.
L. Nadeau D.A. Patten A. Caron L. Garneau E. Pinault-Masson M. Foretz P. Haddad B.G. Anderson L.S. Quinn K. Jardine M.W. McBurney E.E. Pistilli M.E. Harper C. Aguer 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(2):395-407
Background
IL-15 is believed to play a role in the beneficial impact of exercise on muscle energy metabolism. However, previous studies have generally used supraphysiological levels of IL-15 that do not represent contraction-induced IL-15 secretion.Methods
L6 myotubes were treated acutely (3?h) and chronically (48?h) with concentrations of IL-15 mimicking circulating (1–10?pg/ml) and muscle interstitial (100?pg/ml ?20?ng/ml) IL-15 levels with the aim to better understand its autocrine/paracrine role on muscle glucose uptake and mitochondrial function.Results
Acute exposure to IL-15 levels representing muscle interstitial IL-15 increased basal glucose uptake without affecting insulin sensitivity. This was accompanied by increased mitochondrial oxidative functions in association with increased AMPK pathway and formation of complex III-containing supercomplexes. Conversely, chronic IL-15 exposure resulted in a biphasic effect on mitochondrial oxidative functions and ETC supercomplex formation was increased with low IL-15 levels but decreased with higher IL-15 concentrations. The AMPK pathway was activated only by high levels of chronic IL-15 treatment. Similar results were obtained in skeletal muscle from muscle-specific IL-15 overexpressing mice that show very high circulating IL-15 levels.Conclusions
Acute IL-15 treatment that mimics local IL-15 concentrations enhances muscle glucose uptake and mitochondrial oxidative functions. That mitochondria respond differently to different levels of IL-15 during chronic treatments indicates that IL-15 might activate two different pathways in muscle depending on IL-15 concentrations.General significance
Our results suggest that IL-15 may act in an autocrine/paracrine fashion and be, at least in part, involved in the positive effect of exercise on muscle energy metabolism. 相似文献9.
Marilene Demasi Fernanda Marques da Cunha 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2948-2954
Background
It has been almost three decades since the removal of oxidized proteins by the free 20S catalytic unit of the proteasome (20SPT) was proposed. Since then, experimental evidence suggesting a physiological role of proteolysis mediated by the free 20SPT has being gathered.Scope of review
Experimental data that favors the hypothesis of free 20SPT as playing a role in proteolysis are critically reviewed.Major conclusions
Protein degradation by the proteasome may proceed through multiple proteasome complexes with different requirements though the unequivocal role of the free 20SPT in cellular proteolysis towards native or oxidized proteins remains to be demonstrated.General significance
The biological significance of proteolysis mediated by the free 20SPT has been elusive since its discovery. The present review critically analyzes the available experimental data supporting the proteolytic role of the free or single capped 20SPT. 相似文献10.
Joya E. Nahon Menno Hoekstra Vanessa van Harmelen Patrick C.N. Rensen Ko Willems van Dijk Sander Kooijman Miranda Van Eck 《生物化学与生物物理学报:疾病的分子基础》2019,1865(2):494-501
Objective
Proteoglycan 4 (Prg4) has emerged from human association studies as a possible factor contributing to weight gain, dyslipidemia and insulin resistance. In the current study, we investigated the causal role of Prg4 in controlling lipid and glucose metabolism in mice.Methods
Prg4 knockout (KO) mice and wild-type (WT) littermates were challenged with an obesogenic high-fat diet (45% of total calories as fat) for 16?weeks. To further stimulate the development of metabolic alterations, 10% fructose water was provided starting from week 13.Results
Prg4 deficiency only tended to reduce diet-induced body weight gain, but significantly improved glucose handling (AUC: ?29%; p?<?0.05), which was also reflected by a tendency towards a reduced HOMA-IR score (?49%; p?=?0.06 as compared to WT mice). This coincided with lower hepatic expression of glycolysis (Gck: ?30%; p?<?0.05) and lipogenesis (Acc: ?21%; p?<?0.05 and Scd1: ?38%; p?<?0.001) genes, which translated in significantly lower hepatic triglyceride levels (?56%; p?<?0.001) in Prg4 KO mice as compared to WT mice. Prg4 KO mice likely had lower glucose utilization by skeletal muscle as compared to WT mice, judged by a significant reduction in the genes Glut4 (?29%; p?<?0.01), Pfkm (?21%; p?<?0.05) and Hk2 (?39%; p?<?0.001). Moreover, Prg4 KO mice showed a favorable white adipose tissue phenotype with lower uptake of triglyceride-derived fatty acids (?46%; p?<?0.05) and lower gene expression of inflammatory markers Cd68, Mcp1 and Tnfα (?65%, ?81% and ?63%, respectively; p?<?0.01) than WT mice.Conclusion
Prg4 KO mice are protected from high-fat diet-induced glucose intolerance and fatty liver disease. 相似文献11.
XiaoKang Liu Nan Zhou Xin Sui Yu Pei ZhenXing Liang Shuang Hao 《生物化学与生物物理学报:疾病的分子基础》2018,1864(12):3615-3622
Objective
To explore the underlying mechanisms of Hrd1/sema3a/IGF-1R on cardiomyocyte apoptosis.Methods
AMI model was established by the left-anterior descending coronary artery (LAD) ligation. The expressions of Hrd1, sema3a and IGF-1R were examined by western blot. The activity of caspase-3 and caspase-8 was measured using the corresponding activity detection kit. Cardiomyocyte apoptosis was detected by flow cytometry assay. Co-immunoprecipitation and ubiquitination assay were used to test the relationship among Hrd1, sema3a and IGF-1R.Results
Hrd1 expression and the activity of caspase-3 and caspase-8 were increased in cardiac tissues of AMI rats and hypoxia-induced cardiomyocytes, while IGF-1R expression was decreased. Hrd1 overexpression promoted IGF-1R degradation, whereas knockdown of sema3a suppressed this degradation. Moreover, knockdown of Hrd1 or sema3a could inhibit the decrease of IGF-1R expression induced by hypoxia, and reverse the enhanced activity of caspase-3 and caspase-8 and the increase of cardiomyocytes apoptosis induced by hypoxia, while si-IGF-1R countered these effects. In AMI rat experiments, interfering Hrd1 or sema3a reduced the infarct size and increased IGF-1R expression, but these could be abolished by si-IGF-1R.Conclusion
Hrd1 might mediate the ubiquitination of IGF-1R through sema3a and then participate in the regulation of cardiomyocyte apoptosis. 相似文献12.
Seong-Cheol Park Il Ryong Kim Jin-Young Kim Yongjae Lee Eun-Ji Kim Ji Hyun Jung Young Jun Jung Mi-Kyeong Jang Jung Ro Lee 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2545-2554
Background
It remains an open question whether plant phloem sap proteins are functionally involved in plant defense mechanisms.Methods
The antifungal effects of two profilin proteins from Arabidopsis thaliana, AtPFN1 and AtPFN2, were tested against 11 molds and 4 yeast fungal strains. Fluorescence profiling, biophysical, and biochemical analyses were employed to investigate their antifungal mechanism.Results
Recombinant AtPFN1 and AtPFN2 proteins, expressed in Escherichia coli, inhibited the cell growth of various pathogenic fungal strains at concentrations ranging from 10 to 160?μg/mL. The proteins showed significant intracellular accumulation and cell-binding affinity for fungal cells. Interestingly, the AtPFN proteins could penetrate the fungal cell wall and membrane and act as inhibitors of fungal growth via generation of cellular reactive oxygen species and mitochondrial superoxide. This triggered the AtPFN variant-induced cell apoptosis, resulting in morphological changes in the cells.Conclusion
PFNs may play a critical role as antifungal proteins in the Arabidopsis defense system against fungal pathogen attacks.General significance
The present study indicates that two profilin proteins, AtPFN1 and AtPFN2, can act as natural antimicrobial agents in the plant defense system. 相似文献13.
Simin Feng Zhuqing Dai Anna B. Liu Jinbao Huang Nihal Narsipur Grace Guo Bo Kong Kenneth Reuhl Wenyun Lu Zisheng Luo Chung S. Yang 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2018,1863(10):1274-1284
Objective
To investigate and compare the effects of two common dietary phytosterols, stigmasterol and β-sitosterol, in altering lipid metabolism and attenuating nonalcoholic fatty liver disease (NAFLD).Methods
Stigmasterol and β-sitosterol were administered to mice at 0.4% in a high-fat western-style diet (HFWD) for 17?weeks.Results
Stigmasterol and β-sitosterol significantly ameliorated HFWD-induced fatty liver and metabolic abnormalities, including elevated levels of hepatic total lipids, triacylglycerols, cholesterol and liver histopathology. Both phytosterols decreased the levels of intestinal bile acids, accompanied by markedly increased fecal lipid levels. In addition, they altered the expression of genes involved in lipid metabolism. β-Sitosterol was less effective in affecting most of these parameters. Lipidomic analysis of liver and serum samples showed that stigmasterol prevented the HFWD-induced elevation of some di- and triacylglycerol species and lowering of some phospholipid species. Stigmasterol also decreased serum levels of ceramides.Conclusion
Stigmasterol and β-sitosterol, at a dose corresponding to that suggested for humans by the FDA for lowering cholesterol levels, are shown to alleviate HFWD-induced NAFLD. Stigmasterol was more effective than β-sitosterol, possibly because of its suppression of hepatic lipogenic gene expression and modulation of circulating ceramide levels. 相似文献14.
Francesco Giangreco Siegfried Höfinger Evangelos Bakalis Francesco Zerbetto 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(9):1956-1963
Background
High levels of blood cholesterol are conventionally linked to an increased risk of developing cardiovascular disease (Grundy, 1986). Here we examine the molecular mode of action of natural products with known cholesterol-lowering activity, such as for example the green tea ingredient epigallocatechin gallate and a short pentapeptide, Ile-Ile-Ala-Glu-Lys.Methods
Molecular Dynamics simulations are used to gain insight into the formation process of mixed micelles and, correspondingly, how active agents epigallocatechin gallate and Ile-Ile-Ala-Glu-Lys could possibly interfere with it.Results
Self-assembly of physiological micelles occurs on the order of 35–50?ns; most of the structural properties of mixed micelles are unaffected by epigallocatechin gallate or Ile-Ile-Ala-Glu-Lys which integrate into the micellar surface; the diffusive motion of constituting lipids palmitoyl-oleoyl-phosphatidylcholine and cholesterol is significantly down-regulated by both epigallocatechin gallate and Ile-Ile-Ala-Glu-Lys;Conclusions
The molecular mode of action of natural compounds epigallocatechin gallate and Ile-Ile-Ala-Glu-Lys is a significant down-regulation of the diffusive motion of micellar lipids.General significance
Natural compounds like the green tea ingredient epigallocatechin gallate and a short pentapeptide, Ile-Ile-Ala-Glu-Lys, lead to a significant down-regulation of the diffusive motion of micellar lipids thereby modulating cholesterol absorption into physiological micelles. 相似文献15.
Katarina Psenakova Olivia Petrvalska Salome Kylarova Domenico Lentini Santo Dana Kalabova Petr Herman Veronika Obsilova Tomas Obsil 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(7):1612-1625
Background
Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) is a member of the Ca2+/calmodulin-dependent kinase (CaMK) family involved in adiposity regulation, glucose homeostasis and cancer. This upstream activator of CaMKI, CaMKIV and AMP-activated protein kinase is inhibited by phosphorylation, which also triggers an association with the scaffolding protein 14-3-3. However, the role of 14-3-3 in the regulation of CaMKK2 remains unknown.Methods
The interaction between phosphorylated CaMKK2 and the 14-3-3γ protein, as well as the architecture of their complex, were studied using enzyme activity measurements, small-angle x-ray scattering (SAXS), time-resolved fluorescence spectroscopy and protein crystallography.Results
Our data suggest that the 14-3-3 protein binding does not inhibit the catalytic activity of phosphorylated CaMKK2 but rather slows down its dephosphorylation. Structural analysis indicated that the complex is flexible and that CaMKK2 is located outside the phosphopeptide-binding central channel of the 14-3-3γ dimer. Furthermore, 14-3-3γ appears to interact with and affect the structure of several regions of CaMKK2 outside the 14-3-3 binding motifs. In addition, the structural basis of interactions between 14‐3-3 and the 14-3-3 binding motifs of CaMKK2 were elucidated by determining the crystal structures of phosphopeptides containing these motifs bound to 14-3-3.Conclusions
14-3-3γ protein directly interacts with the kinase domain of CaMKK2 and the region containing the inhibitory phosphorylation site Thr145 within the N-terminal extension.General significance
Our results suggested that CaMKK isoforms differ in their 14-3-3-mediated regulations and that the interaction between 14-3-3 protein and the N-terminal 14-3-3-binding motif of CaMKK2 might be stabilized by small-molecule compounds. 相似文献16.
17.
Shruti Chakraborty Sayak Ganguli Aritra Chowdhury Michael Ibba Rajat Banerjee 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(8):1801-1809
Background
Under oxidative stress cytoplasmic aminoacyl-tRNA synthetase (aaRSs) substrate specificity can be compromised, leading to tRNA mischarging and mistranslation of the proteome. Whether similar processes occur in mitochondria, which are major cellular sources of reactive oxygen species (ROS), is unknown. However, relaxed substrate specificity in yeast mitochondrial phenylalanyl-tRNA synthetase (ScmitPheRS) has been reported to increase tRNA mischarging and blocks mitochondrial biogenesis.Methods
Non-reducing denaturing PAGE, cysteine reactivity studies, MALDI-TOF mass spectrometry, enzyme assay, western blot, growth assay, circular dichroism, dynamic light scattering and fluorescence spectroscopy were used to study the effect of oxidative stress on ScmitPheRS activity.Results
ScmitPheRS is reversibly inactivated under oxidative stress. The targets for oxidative inactivation are two conserved cysteine residues resulting in reversible intra-molecular disulfide bridge formation. Replacement of either conserved cysteine residue increased viability during growth under oxidative stress.Conclusion
Formation of intra-molecular disulfide bridge under oxidative stress hinders the tRNAPhe binding of the enzyme, thus inactivating ScmitPheRS reversibly.General significance
The ScmitPheRS activity is compromised under oxidative stress due to formation of intra-molecular disulfide bridge. The sensitivity of ScmitPheRS to oxidation may provide a protective mechanism against error-prone translation under oxidative stress. 相似文献18.
19.
Shreyasi Asthana Zaved Hazarika Parth Sarathi Nayak Jyoti Roy Anupam Nath Jha Bibekanand Mallick Suman Jha 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(1):153-166
Background
Injection localized amyloidosis is one of the most prevalent disorders in type II diabetes mellitus (TIIDM) patients relying on insulin injections. Previous studies have reported that nanoparticles can play a role in the amyloidogenic process of proteins. Hence, the present study deals with the effect of zinc oxide nanoparticles (ZnONP) on the amyloidogenicity and cytotoxicity of insulin.Methods
ZnONP is synthesised and characterized using XRD, Zeta Sizer, UV-Visible spectroscope and TEM. The characterization is followed by ZnONP interaction with insulin, which is studied employing fluorescence spectroscopes, isothermal titration calorimetry and molecular dynamics simulations. The interaction leads insulin conformational rearrangement into amyloid-like fibril, which is studied using thioflavin T dye binding assay, circular dichroism spectroscopy and TEM, followed by cytotoxicity propensity using Alamar Blue dye reduction assay.Results
Insulin has very weak interaction with ZnONP interface. Insulin at studied concentration forms amorphous aggregates at physiological pH, whereas in presence of ZnONP interface amyloid-like fibrils are formed. While the amyloid-like fibrils are cytotoxic to MIN6 and THP-1 cell lines, insulin and ZnONP individual solutions and their fresh mixtures enhance the cells proliferation.Conclusions
The presence of ZnONP interface enhances insulin fibrillation at physiological pH by providing a favourable template for the nucleation and growth of insulin amyloids.General significance
The studied protein-nanoparticle system from protein conformational dynamics point of view throws caution over nanoparticle use in biological applications, especially in vivo applications, considering the amyloidosis a very slow but non-curable degenerative disease. 相似文献20.
Si-Eun Yun Min-Kyung Nam Hyangshuk Rhim 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(7):1602-1611