Displaying publications 1 - 20 of 152 in total

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  1. Zhou Y, Sun Y, Pan D, Xia Q, Zhou C
    J Sci Food Agric, 2023 Aug 30;103(11):5412-5421.
    PMID: 37038882 DOI: 10.1002/jsfa.12616
    BACKGROUND: Goose meat is rough and embedded with dense connective tissue, impairing protein solubility. Therefore, to improve the functional properties of goose myofibrillar protein (GMP), ultrasound was used to assist the phosphorylation of GMP.

    RESULTS: The fact that GMP attached covalently with the phosphate group of sodium tripolyphosphate (GMP-STP) was disclosed directly by Fourier transform infrared spectroscopy. Furthermore, ultrasound significantly improved the hydrophobicity and solubility of GMP-STP, which could be attributed to the conversion of α-helix to β-sheet, β-turns, and random coils by sonication. The spatial stabilization of the protein phosphorylation process was boosted by ultrasound, making the droplets more dispersed, and thus an improvement in the functional properties of GMP-STP was observed. Water-holding capacity, oil-binding capacity, and emulsifying and foaming properties were best at an ultrasound power of 400 W.

    CONCLUSION: Ultrasound-assisted phosphorylation has great potential to modulate the structure-function relationship of proteins. © 2023 Society of Chemical Industry.

    Matched MeSH terms: Phosphorylation
  2. Lai KM, Goh BH, Lee WL
    Growth Factors, 2021 03 15;38(3-4):167-176.
    PMID: 33719806 DOI: 10.1080/08977194.2021.1895144
    Cell entry of influenza A virus (IAV) was reported to be promoted by epidermal growth factor receptor (EGFR). On the other hand, binding of heparin-binding EGF-like growth factor (HB-EGF) to EGFR leads to internalisation and degradation of the receptors. This study aimed to testify whether or not HB-EGF-induced downregulation of EGFR could attenuate IAV cell entry and subsequently diminish the infection. Immunoblotting and plaque assay revealed that HB-EGF-induced degradation of EGFR led to reduction of viral matrix 1 protein level and suppressed virion production. In addition, immunoblotting and imaging flow cytometric analysis demonstrated that IAV-induced phosphorylation of STAT1 and its localisation to nucleus in the early stage of infection were inhibited by HB-EGF treatment. This suggested the potential of HB-EGF in modulating uncontrolled and exaggerated inflammatory response caused by IAV infection. Together these findings attest the potential of HB-EGF mediated endocytosis and degradation of EGFR as a novel anti-IAV strategy.
    Matched MeSH terms: Phosphorylation
  3. Balasubramaniam S, Choy YS, Talib A, Norsiah MD, van den Heuvel LP, Rodenburg RJ
    JIMD Rep, 2012;5:113-22.
    PMID: 23430926 DOI: 10.1007/8904_2011_107
    Mitochondrial disorders are a heterogeneous group of often multisystemic and early fatal diseases caused by defects in the oxidative phosphorylation (OXPHOS) system. Given the complexity and intricacy of the OXPHOS system, it is not surprising that the underlying molecular defect remains unidentified in many patients with a mitochondrial disorder. Here, we report the clinical features and diagnostic workup leading to the elucidation of the genetic basis for a combined complex I and IV OXPHOS deficiency secondary to a mitochondrial translational defect in an infant who presented with rapidly progressive liver failure, encephalomyopathy, and severe refractory lactic acidemia. Sequencing of the GFM1 gene revealed two inherited novel, heterozygous mutations: a.539delG (p.Gly180AlafsX11) in exon 4 which resulted in a frameshift mutation, and a second c.688G > A (p.Gly230Ser) mutation in exon 5. This missense mutation is likely to be pathogenic since it affects an amino acid residue that is highly conserved across species and is absent from the dbSNP and 1,000 genomes databases. Review of literature and comparison were made with previously reported cases of this recently identified mitochondrial disorder encoded by a nuclear gene. Although limited in number, nuclear gene defects causing mitochondrial translation abnormalities represent a new, rapidly expanding field of mitochondrial medicine and should potentially be considered in the diagnostic investigation of infants with progressive hepatoencephalomyopathy and combined OXPHOS disorders.
    Matched MeSH terms: Oxidative Phosphorylation
  4. Kuan CS, See Too WC, Few LL
    PLoS One, 2016;11(1):e0147886.
    PMID: 26807725 DOI: 10.1371/journal.pone.0147886
    Ethanolamine kinase (EK) catalyzes the phosphorylation of ethanolamine, the first step in the CDP-ethanolamine pathway for the biosynthesis of phosphatidylethanolamine (PE). Human EK exists as EK1, EK2α and EK2β isoforms, encoded by two separate genes, named ek1 and ek2. EK activity is stimulated by carcinogens and oncogenes, suggesting the involvement of EK in carcinogenesis. Currently, little is known about EK transcriptional regulation by endogenous or exogenous signals, and the ek gene promoter has never been studied.
    Matched MeSH terms: Phosphorylation
  5. Guo L, Wang Y, Xu X, Cheng KK, Long Y, Xu J, et al.
    J Proteome Res, 2021 01 01;20(1):346-356.
    PMID: 33241931 DOI: 10.1021/acs.jproteome.0c00431
    Identification of phosphorylation sites is an important step in the function study and drug design of proteins. In recent years, there have been increasing applications of the computational method in the identification of phosphorylation sites because of its low cost and high speed. Most of the currently available methods focus on using local information around potential phosphorylation sites for prediction and do not take the global information of the protein sequence into consideration. Here, we demonstrated that the global information of protein sequences may be also critical for phosphorylation site prediction. In this paper, a new deep neural network model, called DeepPSP, was proposed for the prediction of protein phosphorylation sites. In the DeepPSP model, two parallel modules were introduced to extract both local and global features from protein sequences. Two squeeze-and-excitation blocks and one bidirectional long short-term memory block were introduced into each module to capture effective representations of the sequences. Comparative studies were carried out to evaluate the performance of DeepPSP, and four other prediction methods using public data sets The F1-score, area under receiver operating characteristic curves (AUROC), and area under precision-recall curves (AUPRC) of DeepPSP were found to be 0.4819, 0.82, and 0.50, respectively, for S/T general site prediction and 0.4206, 0.73, and 0.39, respectively, for Y general site prediction. Compared with the MusiteDeep method, the F1-score, AUROC, and AUPRC of DeepPSP were found to increase by 8.6, 2.5, and 8.7%, respectively, for S/T general site prediction and by 20.6, 5.8, and 18.2%, respectively, for Y general site prediction. Among the tested methods, the developed DeepPSP method was also found to produce best results for different kinase-specific site predictions including CDK, mitogen-activated protein kinase, CAMK, AGC, and CMGC. Taken together, the developed DeepPSP method may offer a more accurate phosphorylation site prediction by including global information. It may serve as an alternative model with better performance and interpretability for protein phosphorylation site prediction.
    Matched MeSH terms: Phosphorylation
  6. A Rahaman SN, Mat Yusop J, Mohamed-Hussein ZA, Aizat WM, Ho KL, Teh AH, et al.
    PeerJ, 2018;6:e5377.
    PMID: 30280012 DOI: 10.7717/peerj.5377
    Proteins of the DUF866 superfamily are exclusively found in eukaryotic cells. A member of the DUF866 superfamily, C1ORF123, is a human protein found in the open reading frame 123 of chromosome 1. The physiological role of C1ORF123 is yet to be determined. The only available protein structure of the DUF866 family shares just 26% sequence similarity and does not contain a zinc binding motif. Here, we present the crystal structure of the recombinant human C1ORF123 protein (rC1ORF123). The structure has a 2-fold internal symmetry dividing the monomeric protein into two mirrored halves that comprise of distinct electrostatic potential. The N-terminal half of rC1ORF123 includes a zinc-binding domain interacting with a zinc ion near to a potential ligand binding cavity. Functional studies of human C1ORF123 and its homologue in the fission yeast Schizosaccharomyces pombe (SpEss1) point to a role of DUF866 protein in mitochondrial oxidative phosphorylation.
    Matched MeSH terms: Oxidative Phosphorylation
  7. Altamish M, Samuel VP, Dahiya R, Singh Y, Deb PK, Bakshi HA, et al.
    Drug Dev Res, 2020 02;81(1):23-31.
    PMID: 31785110 DOI: 10.1002/ddr.21627
    The well-known condition of heart failure is a clinical syndrome that results when the myocardium's ability to pump enough blood to meet the body's metabolic needs is impaired. Most of the cardiac activity is maintained by adrenoceptors, are categorized into two main α and β and three distinct subtypes of β receptor: β1-, β2-, and β3-adrenoceptors. The β adrenoreceptor is the main regulatory macro proteins, predominantly available on heart and responsible for down regulatory cardiac signaling. Moreover, the pathological involvement of Angiotensin-converting enzyme 1 (ACE1)/angiotensin II (Ang II)/angiotensin II type 1 (AT1) axis and beneficial ACE2/Ang (1-7)/Mas receptor axis also shows protective role via Gi βγ, during heart failure these receptors get desensitized or internalized due to increase in the activity of G-protein-coupled receptor kinase 2 (GRK2) and GRK5, responsible for phosphorylation of G-protein-mediated down regulatory signaling. Here, we investigate the various clinical and preclinical data that exhibit the molecular mechanism of upset level of GRK change the cardiac activity during failing heart.
    Matched MeSH terms: Phosphorylation
  8. Subramaniam S, Foo KY, Md Yusof EN, Jawad AH, Wilson LD, Sabar S
    Int J Biol Macromol, 2021 Dec 15;193(Pt B):1716-1726.
    PMID: 34742842 DOI: 10.1016/j.ijbiomac.2021.11.009
    Phosphorylated chitosan (P-CS) was successfully synthesized using a facile experimental setup of hydrothermal method that was applied to the adsorption of anionic Acid Red 88 (AR88) from aqueous media. The adsorption process obeyed the pseudo-second-order (PSO) kinetic model. In contrast, the adsorption isotherm conformed to the Langmuir model, with the maximum adsorption capacity (qm = 230 mg g-1) at 303 K. Both external and intraparticle diffusion strongly influenced the rate of adsorption. The insights from this study reveal that P-CS could be easily prepared and regenerated for reusability applications. The adsorption mechanism and intermolecular interaction between P-CS and AR 88 were investigated using Fourier transform infrared (FTIR) spectroscopy and calculations via Density Functional Theory (DFT). The key modes of adsorption for the P-CS/AR 88 system are driven by electrostatic attractions, H-bonding, and n-π interactions. The findings herein reveal that P-CS is a promising adsorbent for the removal of anionic dyes such as AR88 or similar pollutants from water.
    Matched MeSH terms: Phosphorylation
  9. Edwards MJ, Wilson GC, Keitsch S, Soddemann M, Wilker B, Müller CP, et al.
    J Neurochem, 2022 Nov;163(4):357-369.
    PMID: 36227646 DOI: 10.1111/jnc.15708
    Major depressive disorder (MDD) is a severe disease of unknown pathogenesis with a lifetime prevalence of ~10%. Therapy requires prolonged treatment that often fails. We have previously demonstrated that ceramide levels in the blood plasma of patients and in mice with experimental MDD are increased. Neutralization of blood plasma ceramide prevented experimental MDD in mice. Mechanistically, we demonstrated that blood plasma ceramide accumulated in endothelial cells of the hippocampus, inhibited phospholipase D (PLD) and thereby decreased phosphatidic acid in the hippocampus. Here, we demonstrate that phosphatidic acid binds to and controls the activity of phosphotyrosine phosphatase (PTP1B) in the hippocampus and thus determines tyrosine phosphorylation of a variety of cellular proteins including TrkB. Injection of PLD, phosphatidic acid, or inhibition of PTP1B abrogated MDD and normalized cellular tyrosine phosphorylation, including phosphorylation of TrkB and neurogenesis in the hippocampus. Most importantly, these treatments also rapidly normalized behavior of mice with experimental MDD. Since phosphatidic acid binds to and inhibits PTP1B, the lack of phosphatidic acid results in increased activity of PTP1B and thereby in reduced tyrosine phosphorylation of TrkB and other cellular proteins. Thus, our data indicate a novel pathogenetic mechanism of and a rapidly acting targeted treatment for MDD.
    Matched MeSH terms: Phosphorylation
  10. Hodder S, Fox M, Binti Ahmad Mokhtar AM, Mott HR, Owen D
    Small GTPases, 2023 Dec;14(1):14-25.
    PMID: 37194323 DOI: 10.1080/21541248.2023.2212573
    Activated Cdc42-associated kinase (ACK), a non-receptor tyrosine kinase, is an effector for the small GTPase Cdc42. ACK is emerging as an important component of the cancer landscape and thus, a promising target for the treatment of many malignancies. ACK is also being increasingly recognized as a potentially influential player in the regulation of protein homoeostasis. The delicate equilibrium between protein synthesis and protein degradation is crucial for healthy cell function and dysregulation of protein homoeostasis is a common occurrence in human disease. Here, we review the molecular mechanisms by which ACK regulates the stability of diverse cellular proteins (e.g. EGFR, p27, p53, p85 isoforms and RhoGDI-3), some of which rely on the kinase activity of ACK while others, interestingly, do not. Ultimately, further research will be required to bridge our knowledge gaps and determine if ACK regulates the stability of further cellular proteins but collectively, such mechanistic interrogation would contribute to determining whether ACK is a promising target for anti-cancer therapy. In therapeutics, proteasome inhibitors are an efficacious but problematic class of drugs. Targeting other modulators of proteostasis, like ACK, could open novel avenues for intervention.
    Matched MeSH terms: Phosphorylation
  11. Lim SH, Wu L, Kiew LV, Chung LY, Burgess K, Lee HB
    PLoS One, 2014;9(3):e82934.
    PMID: 24622277 DOI: 10.1371/journal.pone.0082934
    Reprogramming of energy metabolism is pivotal to cancer, so mitochondria are potential targets for anticancer therapy. A prior study has demonstrated the anti-proliferative activity of a new class of mitochondria-targeting rosamines. This present study describes in vitro cytotoxicity of second-generation rosamine analogs, their mode of action, and their in vivo efficacies in a tumor allografted mouse model. Here, we showed that these compounds exhibited potent cytotoxicity (average IC50<0.5 µM), inhibited Complex II and ATP synthase activities of the mitochondrial oxidative phosphorylation pathway and induced loss of mitochondrial transmembrane potential. A NCI-60 cell lines screen further indicated that rosamine analogs 4 and 5 exhibited potent antiproliferative effects with Log10GI50 = -7 (GI50 = 0.1 µM) and were more effective against a colorectal cancer sub-panel than other cell lines. Preliminary in vivo studies on 4T1 murine breast cancer-bearing female BALB/c mice indicated that treatment with analog 5 in a single dosing of 5 mg/kg or a schedule dosing of 3 mg/kg once every 2 days for 6 times (q2d×6) exhibited only minimal induction of tumor growth delay. Our results suggest that rosamine analogs may be further developed as mitochondrial targeting agents. Without a doubt proper strategies need to be devised to enhance tumor uptake of rosamines, i.e. by integration to carrier molecules for better therapeutic outcome.
    Matched MeSH terms: Oxidative Phosphorylation/drug effects*
  12. Md S, Gan SY, Haw YH, Ho CL, Wong S, Choudhury H
    Int J Biol Macromol, 2018 Oct 15;118(Pt A):1211-1219.
    PMID: 30001606 DOI: 10.1016/j.ijbiomac.2018.06.190
    Alzheimer's disease (AD) is an increasingly prevalent neurological disorder of the central nervous system. There is growing evidence that amyloidogenesis is a pathological hallmark for AD; this leads to the formation of senile plaques. Naringenin is a bioflavonoid which has neuroprotective effects through its antioxidant and anti-inflammatory properties. However, its clinical usage is limited due to its inefficient transport across biological membranes. In the present study, a naringenin nanoemulsion was prepared and its neuroprotective effects were tested against β-amyloid induced neurotoxicity in a human neuroblastoma cell line (SH-SY5Y). The optimised, naringenin-loaded nanoemulsion formulation had a droplet size of 113.83 ± 3.35 nm and around 50 nm, as assessed respectively by photon correlation spectroscopy and transmission electron microscopy. The preparation showed a low polydispersity index (0.312 ± 0.003), a high zeta potential (12.4 ± 1.05) and a high percentage transmittance (97.01%). The neuroprotective activity of naringenin nanoemulsions was determined by assessing their ability to protect SH-SY5Y neuroblastoma cells against the neurotoxic effect of beta amyloid (Aβ). Aβ-induced production of reactive oxygen species (ROS), amyloid precursor protein (APP), β-secretase (BACE), total tau and phosphorylated tau (pT231) was also determined. The naringenin loaded nanoemulsion significantly alleviated the direct neurotoxic effects of Aβ on SH-SY5Y cells; this was associated with a down-regulation of APP and BACE expression, indicating reduced amyloidogenesis. Furthermore, it decreased the levels of phosphorylated tau in SH-SY5Y cells exposed to Aβ. These results suggest that a naringenin-loaded nanoemulsion could be a promising agent for the treatment of Alzheimer's disease.
    Matched MeSH terms: Phosphorylation/drug effects
  13. Hasenan SM, Karsani SA, Jubri Z
    Exp Gerontol, 2018 11;113:1-9.
    PMID: 30248357 DOI: 10.1016/j.exger.2018.09.001
    Aging is characterized by progressive decline in biochemical and physiological functions. According to the free radical theory of aging, aging results from oxidative damage due to the accumulation of excess reactive oxygen species (ROS). Mitochondria are the main source of ROS production and are also the main target for ROS. Therefore, a diet high in antioxidant such as honey is potentially able to protect the body from ROS and oxidative damage. Gelam honey is higher in flavonoid content and phenolic compounds compared to other local honey. This study was conducted to determine the effects of gelam honey on age related protein expression changes in cardiac mitochondrial rat. A total of 24 Sprague-Dawley male rats were divided into two groups: the young group (2 months old), and aged group (19 months old). Each group were then subdivided into two groups: control group (force-fed with distilled water), and treatment group (force-fed with gelam honey, 2.5 g/kg), and were treated for 8 months. Comparative proteomic analysis of mitochondria from cardiac tissue was then performed by high performance mass spectrometry (Q-TOF LCMS/MS) followed by validation of selected proteins by Western blotting. Proteins were identified using Spectrum Mill software and were subjected to stringent statistical analysis. A total of 286 proteins were identified in the young control group (YC) and 241 proteins were identified in the young gelam group (YG). In the aged group, a total of 243 proteins were identified in control group (OC), and 271 proteins in gelam group (OG). Comparative proteome profiling identified 69 proteins with different abundance (p 
    Matched MeSH terms: Oxidative Phosphorylation*
  14. Yap PG, Choi SB, Liong MT
    Appl Biochem Biotechnol, 2020 May;191(1):226-244.
    PMID: 32125649 DOI: 10.1007/s12010-020-03265-2
    This study aimed to evaluate the effect of probiotic administration on obese and ageing models. Sprague Dawley rats were subjected to high-fat diet (HFD) and injected with D-galactose to induce premature ageing. Upon 12 weeks of treatment, the faecal samples were collected and subjected to gas chromatography-mass spectrophotometry (GC-MS) analysis for metabolite detection. The sparse partial least squares discriminant analysis (sPLS-DA) showed a distinct clustering pattern of metabolite profile in the aged and obese rats administered with probiotics Lactobacillus plantarum DR7 and L. reuteri 8513d, particularly with a significantly higher concentration of allantoin. Molecular docking simulation showed that allantoin promoted the phosphorylation (activation) of adenosine monophosphate-activated kinase (AMPK) by lowering the substrate free energy of binding (FEB) and induced the formation of an additional hydrogen bond between Val184 and the substrate AMP. Allantoin also suppressed cholesterol biosynthesis by either inducing enzyme inhibition, occupying or blocking the putative binding site to result in non-spontaneous substrate binding, as in the cases of 3-hydroxy-methylglutaryl-coA reductase (HMGCR), mevalonate kinase (MVK) and lanosterol demethylase (LDM) where positive FEBs were reported. These results demonstrated the potential of allantoin to alleviate age-related hypercholesterolaemia by upregulating AMPK and downregulating cholesterol biosynthesis via the mevalonate pathway and Bloch pathway.
    Matched MeSH terms: Phosphorylation/drug effects
  15. Teh AH, Yeap KH, Hisano T
    J Struct Biol, 2020 11 01;212(2):107602.
    PMID: 32798656 DOI: 10.1016/j.jsb.2020.107602
    DEPTOR is an inhibitor of the mTOR kinase which controls cell growth. DEPTOR consists of two DEP domains and a PDZ domain connected by an unstructured linker, and its stability is tightly regulated through post-translational modifications of its linker region that contains the 286SSGYFS291 degron. Based on the mTORC1 complex, our modelling suggests a possible spatial arrangement of DEPTOR which is characterised to form a dimer. Our model shows that the two PDZ domains of a DEPTOR dimer bind separately to the dimeric mTOR's FAT domains ~130 Å apart, while each of the two extended linkers is sufficiently long to span from the FAT domain to the kinase domain of mTOR and beyond to join a shared dimer of the DEP domains. This places the linker's S299 closest to the kinase's catalytic site, indicating that phosphorylation would start with it and successively upstream towards DEPTOR's degron. The CK1α kinase is reportedly responsible for the phosphorylation of the degron, and our docking analysis further reveals that CK1α contains sites to bind DEPTOR's pS286, pS287 and pT295, which may act as priming phosphates for the phosphorylation of the degron's S291. DEPTOR's linker can also be ubiquitylated by the UbcH5A-SCFβ-TrCP complex without its PDZ dissociating from mTOR according to the modelling. As the catalytic cleft of mTOR's kinase is restricted, interactions between the kinase's unstructured segment surrounding the cleft and DEPTOR's linker, which may involve S293 and S299, may be critical to controlling DEPTOR's access to the catalytic cleft and hence its phosphorylation by mTOR in a manner dependent on mTOR's activation.
    Matched MeSH terms: Phosphorylation/physiology
  16. Manoharan SD, Abdul Hamid H, Md Hashim NF, Cheema MS, Chiroma SM, Mustapha M, et al.
    Brain Res, 2024 Apr 15;1829:148793.
    PMID: 38309553 DOI: 10.1016/j.brainres.2024.148793
    Alzheimer's disease (AD) is a progressive neurological disorder that impairs memory and cognitive abilities, primarily in the elderly. The burden of AD extends beyond patients, impacting families and caregivers due to the patients' reliance on assistance for daily tasks. The main features of the pathogenesis of AD are beta-amyloid plaques and neurofibrillary tangles (NFTs), that strongly correlate with oxidative stress and inflammation. NFTs result from misfolded and hyperphosphorylated tau proteins. Various studies have focused on tau phosphorylation, indicating protein phosphatase 2A (PP2A) as the primary tau phosphatase and glycogen synthase kinase-3 beta (GSK-3β) as the leading tau kinase. Experimental evidence suggests that inhibition of PP2A and increased GSK-3β activity contribute to neuroinflammation, oxidative stress, and cognitive impairment. Hence, targeting PP2A and GSK-3β with pharmacological approaches shows promise in treating AD. The use of natural compounds in the drug development for AD have been extensively studied for their antioxidant, anti-inflammatory, anti-cholinesterase, and neuroprotective properties, demonstrating therapeutic advantages in neurological diseases. Alongside the development of PP2A activator and GSK-3β inhibitor drugs, natural compounds are likely to have neuroprotective effects by increasing PP2A activity and decreasing GSK-3β levels. Therefore, based on the preclinical and clinical studies, the potential of PP2A and GSK-3β as therapeutic targets of natural compounds are highlighted in this review.
    Matched MeSH terms: Phosphorylation/physiology
  17. Mohamed Saat A, Johan MR
    ScientificWorldJournal, 2014;2014:439839.
    PMID: 25506069 DOI: 10.1155/2014/439839
    Partially phosphorylated polyvinyl alcohol (PPVA) with aluminum phosphate (ALPO4) composites was synthesized by solution casting technique to produce (PPVA)(100-y) - (ALPO4)(y) (y = 0, 1, and 2). The surface structure and thermal properties of the films were characterized using Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The results showed that the films have higher thermal stability with strong bonding between PPVA and ALPO4.
    Matched MeSH terms: Phosphorylation
  18. Ayub A, Yip WK, Seow HF
    Biomed Pharmacother, 2015 Oct;75:40-50.
    PMID: 26463630 DOI: 10.1016/j.biopha.2015.08.031
    Triple-negative breast cancers (TNBCs) are aggressive cancers that do not benefit from hormonal therapy or therapies that target HER2 receptors. Insulin-like growth factor 1 receptor (IGF-1R), which has been shown to be overexpressed in breast cancer, activates numerous downstream kinases that associate with cell proliferation and survival. This study compared the effects caused by dual treatments targeting IGF-1R, PI3K, mTORC, or MEK with those by single treatments in a TNBC cell line, MDA-MB-231. We used small-molecule kinase inhibitors, namely, NVP-AEW541, NVP-BKM120, KU0063794, and PD0325901 to target IGF-1R, PI3K, mTORC, and MEK, respectively. Combination treatments of PD0325901 with NVP-AEW541, NVP-BKM120 or KU0063794 and NVP-AEW541 with KU0063794 demonstrated a significant synergistic growth inhibition. These dual treatments increased apoptosis and/or cell cycle arrest at G0/G1 phase and enhanced the inhibition of phosphorylation of Akt or downstream molecules of mTORC1, as compared to the single treatments. Our study suggests that targeting multiple kinases in IGF-1R signaling may be a promising therapeutic approach.
    Matched MeSH terms: Phosphorylation
  19. Sahebi M, Hanafi MM, van Wijnen AJ, Azizi P, Abiri R, Ashkani S, et al.
    Gene, 2016 Aug 10;587(2):107-19.
    PMID: 27154819 DOI: 10.1016/j.gene.2016.04.057
    Alternative pre-mRNA splicing provides a source of vast protein diversity by removing non-coding sequences (introns) and accurately linking different exonic regions in the correct reading frame. The regulation of alternative splicing is essential for various cellular functions in both pathological and physiological conditions. In eukaryotic cells, this process is commonly used to increase proteomic diversity and to control gene expression either co- or post-transcriptionally. Alternative splicing occurs within a megadalton-sized, multi-component machine consisting of RNA and proteins; during the splicing process, this complex undergoes dynamic changes via RNA-RNA, protein-protein and RNA-protein interactions. Co-transcriptional splicing functionally integrates the transcriptional machinery, thereby enabling the two processes to influence one another, whereas post-transcriptional splicing facilitates the coupling of RNA splicing with post-splicing events. This review addresses the structural aspects of spliceosomes and the mechanistic implications of their stepwise assembly on the regulation of pre-mRNA splicing. Moreover, the role of phosphorylation-based, signal-induced changes in the regulation of the splicing process is demonstrated.
    Matched MeSH terms: Phosphorylation
  20. Chang CC, Few LL, Konrad M, See Too WC
    PLoS One, 2016;11(5):e0154702.
    PMID: 27149373 DOI: 10.1371/journal.pone.0154702
    Choline kinase beta (CKβ) is one of the CK isozymes involved in the biosynthesis of phosphatidylcholine. CKβ is important for normal mitochondrial function and muscle development as the lack of the ckβ gene in human and mice results in the development of muscular dystrophy. In contrast, CKα is implicated in tumorigenesis and has been extensively studied as an anticancer target. Phosphorylation of human CKα was found to regulate the enzyme's activity and its subcellular location. This study provides evidence for CKβ phosphorylation by protein kinase A (PKA). In vitro phosphorylation of CKβ by PKA was first detected by phosphoprotein staining, as well as by in-gel kinase assays. The phosphorylating kinase was identified as PKA by Western blotting. CKβ phosphorylation by MCF-7 cell lysate was inhibited by a PKA-specific inhibitor peptide, and the intracellular phosphorylation of CKβ was shown to be regulated by the level of cyclic adenosine monophosphate (cAMP), a PKA activator. Phosphorylation sites were located on CKβ residues serine-39 and serine-40 as determined by mass spectrometry and site-directed mutagenesis. Phosphorylation increased the catalytic efficiencies for the substrates choline and ATP about 2-fold, without affecting ethanolamine phosphorylation, and the S39D/S40D CKβ phosphorylation mimic behaved kinetically very similar. Remarkably, phosphorylation drastically increased the sensitivity of CKβ to hemicholinium-3 (HC-3) inhibition by about 30-fold. These findings suggest that CKβ, in concert with CKα, and depending on its phosphorylation status, might play a critical role as a druggable target in carcinogenesis.
    Matched MeSH terms: Phosphorylation
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