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Post translational modification

Diana Milena Sánchez-Lancheros, Luis Fernando Ospina-Giraldo, María Helena Ramírez-Hernández
Nicotinamide/nicotinate adenine dinucleotide (NAD+/NaAD) performs essential functions in cell metabolism and energy production due to its redox properties. The nicotinamide/nicotinate mononucleotide adenylyltransferase (NMNAT, EC enzyme catalyses the key step in the biosynthesis of NAD+. Previously, the enzyme NMNAT was identified in Trypanosoma cruzi (TcNMNAT), a pathogenic agent with epidemiological importance in Latin America. To continue with the functional characterisation of this enzyme, its subcellular location and its possible post-translational modifications were examined in this study...
October 24, 2016: Memórias do Instituto Oswaldo Cruz
Tobias Baumann, Matthias Exner, Nediljko Budisa
To date, the two systems most extensively used for noncanonical amino acid (ncAA) incorporation via orthogonal translation are based on the Methanococcus jannaschii TyrRS/tRNA CUA(Tyr) and the Methanosarcina barkeri/Methanosarcina mazei PylRS/tRNA CUA(Pyl) pairs. Here, we summarize the development and usage of the pyrrolysine-based system for orthogonal translation, a process that allows for the recombinant production of site-specifically labeled proteins and peptides. Via stop codon suppression in Escherichia coli and mammalian cells, genetically encoded biomolecules can be equipped with a great diversity of chemical functionalities including click chemistry handles, post-translational modifications, and photocaged sidechains...
October 26, 2016: Advances in Biochemical Engineering/biotechnology
Blanka Bucsella, Antoine Fornage, Catherine Le Denmat, Franka Kálmán
In biotechnological processes the intracellular level of nucleotides and nucleotide sugars have a direct impact on the post-translational modification (glycosylation) of the therapeutic protein products and on the exopolysaccharide pattern of the cells. Thus, they are precursors and also key components in the production of glycoproteins and glycolipids. All four nucleotides (at different phosphorylation stages) and their natural sugar derivatives coexist in biological samples. Their relative ratios depend on the actual conditions under which the cells are grown...
October 2016: Chimia
Ziyao Wang, Tinghe Yu, Ping Huang
The Forkhead box O (FOXO) protein family is predominantly involved in apoptosis, oxidative stress, DNA damage/repair, tumor angiogenesis, glycometabolism, regulating life span and other important biological processes. Its activity is affected by a variety of posttranslational modifications (PTMs), including phosphorylation, acetylation, ubiquitination, methylation and glycosylation. When cells are subjected to different environments, the corresponding PTMs act on the FOXO protein family, to change transcriptional activity or subcellular localization, and the expression of downstream target genes, will ultimately affect the biological behavior of the cells...
October 20, 2016: Molecular Medicine Reports
Yue Zhang, Shiaw-Lin Wu, Yinyin Li
Capture reagents are critical to affinity-based bioanalytical methods. The potential bias of capture reagents, for or against certain subpopulations of the target of interest, may lead to inaccurate quantitation. This issue is more profound for sensitive measurements, such as post-translational modification (PTM) profiling of therapeutic proteins from complex matrix. Here, a recently developed affinity purification coupled mass spectrometric method was utilized to assess the full sequence of a circulating therapeutic aglycosylated IgG1 (MAB3) in human subject, using two different capture reagents...
October 21, 2016: Biologicals: Journal of the International Association of Biological Standardization
Rakesh Kumar
Professor Ferid Murad has been a remarkable colleague and a mentor. During our very first meeting, he not only shared unresolved puzzles in Nitric Oxide (NO) research but also listened to my questions pointing to protein nitration and nitrosylation. This was start of a new avenue in my laboratory involving protein nitration, inducible nitric oxide synthase and nitrite production in the context of signaling and gene expression in cancer cells. Dynamic changes in the cytoskeleton remodeling in response to the cell membrane generated signals are regulated by p21-activated kinase 1 (PAK1) which also feed into microtubules (MT) dynamic via phosphorylating Tubulin Cofactor B (CoB) on serine 65 and serine 128...
2016: Current Medicinal Chemistry
Paolo Cifani, Alex Kentsis
Given superior analytical features, mass spectrometry proteomics is well suited for the basic investigation and clinical diagnosis of human disease. Modern mass spectrometry enables detailed functional characterization of the pathogenic biochemical processes, as achieved by accurate and comprehensive quantification of proteins and their regulatory chemical modifications. Here, we describe how high-accuracy mass spectrometry in combination with high-resolution chromatographic separations can be leveraged to meet these analytical requirements in a mechanism-focused manner...
October 24, 2016: Proteomics
Larisa Kordyukova
Two enveloped virus families, Orthomyxoviridae and Paramyxoviridae, comprise a large number of dangerous pathogens that enter the host cell via fusion of their envelope with a target cell membrane at acidic or neutral pH. The Class I prototypic glycoproteins responsible for this reaction are the Influenza virus haemagglutinin (HA) protein or paramyxovirus fusion (F) protein. X-ray crystallography and cryoelectron microscopy data are available for the HA and F ectodomains in pre- and post-fusion conformations, revealing similar spiky architectures, albeit with clear differences in the details...
October 20, 2016: Virus Research
Nandan S Gokhale, Alexa B R McIntyre, Michael J McFadden, Allison E Roder, Edward M Kennedy, Jorge A Gandara, Sharon E Hopcraft, Kendra M Quicke, Christine Vazquez, Jason Willer, Olga R Ilkayeva, Brittany A Law, Christopher L Holley, Mariano A Garcia-Blanco, Matthew J Evans, Mehul S Suthar, Shelton S Bradrick, Christopher E Mason, Stacy M Horner
The RNA modification N6-methyladenosine (m(6)A) post-transcriptionally regulates RNA function. The cellular machinery that controls m(6)A includes methyltransferases and demethylases that add or remove this modification, as well as m(6)A-binding YTHDF proteins that promote the translation or degradation of m(6)A-modified mRNA. We demonstrate that m(6)A modulates infection by hepatitis C virus (HCV). Depletion of m(6)A methyltransferases or an m(6)A demethylase, respectively, increases or decreases infectious HCV particle production...
October 18, 2016: Cell Host & Microbe
Toni M Mueller, Stefani D Yates, Vahram Haroutunian, James H Meador-Woodruff
Glycosylation is a post-translational modification that is an essential element in cell signaling and neurodevelopmental pathway regulation. Glycan attachment can influence the tertiary structure and molecular interactions of glycosylated substrates, adding an additional layer of regulatory complexity to functional mechanisms underlying central cell biological processes. One type of enzyme-mediated glycan attachment, fucosylation, can mediate glycoprotein and glycolipid cell surface expression, trafficking, secretion, and quality control to modulate a variety of inter- and intracellular signaling cascades...
October 20, 2016: Schizophrenia Research
Aimee Reed, Lisa Lin, Claire Ostertag-Hill, Qing Wang, Zhixing Wu, Tim Miller-Morgan, Ling Jin
Koi herpesvirus (KHV) is highly pathogenic to Cyprinus carpio. KHV can also become latent in recovered fish and reactivate from latency under stressful conditions. Understanding KHV latency is important for development of strategies against herpesvirus latent infection. Our previous studies found KHV ORF6 mRNA is detectable during latent infection. In this study, ORF6 protein expression was investigated by a polyclonal antibody specific to ORF6 peptide. Positive staining by an immunofluorescence assay was observed in both KHV infected CCB (common carp brain) cells and IgM(+) white blood cells (WBCs) from recovered KHV(+) koi...
October 20, 2016: Virology
Pedro G Carranza, Pablo R Gargantini, César G Prucca, Alessandro Torri, Alicia Saura, Staffan Svärd, Hugo D Lujan
During evolution, parasitic microorganisms have faced the challenges of adapting to different environments to colonize a variety of hosts. Giardia lamblia, a common cause of intestinal disease, has developed fascinating strategies to adapt both outside and inside its host's intestine, such as trophozoite differentiation into cyst and the switching of its major surface antigens. How gene expression is regulated during these adaptive processes remains undefined. Giardia lacks some typical eukaryotic features, like canonical transcription factors, linker histone H1, and complex promoter regions; suggesting that post-transcriptional and translational control of gene expression is essential for parasite survival...
October 19, 2016: International Journal of Biochemistry & Cell Biology
Mark Hedglin, Binod Pandey, Stephen J Benkovic
Translesion DNA synthesis (TLS) during S-phase uses specialized TLS DNA polymerases to replicate a DNA lesion, allowing stringent DNA synthesis to resume beyond the offending damage. Human TLS involves the conjugation of ubiquitin to PCNA clamps encircling damaged DNA and the role of this post-translational modification is under scrutiny. A widely-accepted model purports that ubiquitinated PCNA recruits TLS polymerases such as pol η to sites of DNA damage where they may also displace a blocked replicative polymerase...
October 22, 2016: ELife
Akhi Akhter, Emanuel Rosonina
The Saccharomyces cerevisiae transcription factor Gcn4 is expressed during amino acid starvation and its abundance is controlled by ubiquitin-mediated proteolysis. Cdk8, a kinase component of the RNA polymerase II Mediator complex, phosphorylates Gcn4 which triggers its ubiquitination/proteolysis and is thought to link Gcn4 degradation with transcription of target genes. In addition to phosphorylation and ubiquitination, we previously showed that Gcn4 becomes sumoylated in a DNA-binding dependent manner, while a non-sumoylatable form of Gcn4 showed increased chromatin occupancy, but only if Cdk8 was present...
October 21, 2016: Genetics
Liqing Wang, Suresh Kumar, Satinder Dahiya, Feng Wang, Jian Wu, Kheng Newick, Rongxiang Han, Arabinda Samanta, Ulf H Beier, Tatiana Akimova, Tricia R Bhatti, Benjamin Nicholson, Mathew P Kodrasov, Saket Agarwal, David E Sterner, Wei Gu, Joseph Weinstock, Tauseef R Butt, Steven M Albelda, Wayne W Hancock
Foxp3+ T-regulatory (Treg) cells are known to suppress protective host immune responses to a wide variety of solid tumors, but their therapeutic targeting is largely restricted to their transient depletion or "secondary" modulation, e.g. using anti-CTLA-4 monoclonal antibody. Our ongoing studies of the post-translational modifications that regulate Foxp3 demonstrated that the histone/protein acetyltransferase, Tip60, plays a dominant role in promoting acetylation, dimerization and function in Treg cells. We now show that the ubiquitin-specific protease, Usp7, controls Treg function largely by stabilizing the expression and promoting the multimerization of Tip60 and Foxp3...
October 15, 2016: EBioMedicine
Srikanth Appikonda, Kaushik N Thakkar, Michelle Craig Barton
Tripartite Motif-containing protein 24 (TRIM24) functions as an E3 ligase targeting p53 for ubiquitination, a histone 'reader' that interacts with a specific signature of histone post-translational modifications and a co-regulator of nuclear receptor-regulated transcription. Although mouse models of Trim24 depletion suggest that TRIM24 may be a liver-specific tumor suppressor, several studies show that human TRIM24 is an oncogene when aberrantly over expressed. This review focuses on the mechanisms of TRIM24 functions in oncogenesis and metabolic reprogramming, which underlie recent interest in therapeutic targeting of aberrant TRIM24 in human cancers...
March 2016: Drug Discovery Today. Technologies
Yuxin Shu, Yan Lu, Xiaojuan Pang, Wei Zheng, Yahong Huang, Jiahong Li, Jianguo Ji, Can Zhang, Pingping Shen
Peroxisome proliferator-activating receptor γ (PPARγ), a transcription factor, is involved in many important biological processes, including cell terminal differentiation, survival and apoptosis. However, the role of PPARγ, which regulates tumour promoter and oncogene expression, is not well understood in hepatocellular carcinoma (HCC). In the present study, based on evidence from clinical samples that phosphorylation of PPARγ at Ser84 is up-regulated in human liver tumours, we confirmed that phosphorylation of PPARγ was also significantly increased in an HCC mouse model and was increased by Mitogen-activated protein kinase (MEK)/ Extracellular-signal-regulated kinases (ERK) kinase...
October 19, 2016: Oncotarget
Junting Huang, Gerald W Zamponi
Calcium entry via voltage gated calcium channels mediates a wide range of physiological functions, whereas calcium channel dysregulation has been associated with numerous pathophysiological conditions. There are myriad cell signaling pathways that act on voltage gated calcium channels to fine tune their activities and to regulate their cell surface expression. These regulatory mechanisms include the activation of G protein-coupled receptors and downstream phosphorylation events, and their control over calcium channel trafficking through direct physical interactions...
October 18, 2016: Current Opinion in Pharmacology
Shobini Jayaraman, Jose Luis Sánchez-Quesada, Olga Gursky
Lipids in the body are transported via lipoproteins that are nanoparticles comprised of lipids and amphipathic proteins termed apolipoproteins. This family of lipid surface-binding proteins is over-represented in human amyloid diseases. In particular, all major proteins of high-density lipoproteins (HDL), including apoA-I, apoA-II and serum amyloid A, can cause systemic amyloidoses in humans upon protein mutations, post-translational modifications or overproduction. Here, we begin to explore how the HDL lipid composition influences amyloid deposition by apoA-I and related proteins...
October 18, 2016: Biochimica et Biophysica Acta
Michelle R Robinson, Jennifer S Brodbelt
Tyrosine sulfation is an important post-translational modification but remains difficult to detect in biological samples owing to its low stoichiometric abundance and the lack of effective enrichment methods. In the present study, weak anion exchange (WAX) is evaluated for the enrichment of sulfopeptides that have been modified via carbamylation to convert all primary amines to less basic carbamates. The decrease in basicity enhanced the binding of carbamylated sulfopeptides to WAX resin relative to non-sulfated peptides...
October 21, 2016: Analytical Chemistry
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