Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Protein Modification, Translational”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2006

Reversible post-translational modification of proteins by nitrated fatty acids in vivo.

Nitric oxide ((*)NO)-derived reactive species nitrate unsaturated fatty acids, yielding nitroalkene derivatives, including the clinically abundant nitrated oleic and linoleic acids. The olefinic nitro group renders these derivatives electrophilic at the carbon beta to the nitro group, thus competent for Michael addition reactions with cysteine and histidine. By using chromatographic and mass spectrometric approaches, we characterized this reactivity by using in vitro reaction systems, and we demonstrated that nitroalkene-protein and GSH adducts are present in vivo under basal conditions in healthy human red cells. Nitro-linoleic acid (9-, 10-, 12-, and 13-nitro-9,12-octadecadienoic acids) (m/z 324.2) and nitro-oleic acid (9- and 10-nitro-9-octadecaenoic acids) (m/z 326.2) reacted with GSH (m/z 306.1), yielding adducts with m/z of 631.3 and 633.3, respectively. At physiological concentrations, nitroalkenes inhibited glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which contains a critical catalytic Cys (Cys-149). GAPDH inhibition displayed an IC(50) of approximately 3 microM for both nitroalkenes, an IC(50) equivalent to the potent thiol oxidant peroxynitrite (ONOO(-)) and an IC(50) 30-fold less than H(2)O(2), indicating that nitroalkenes are potent thiol-reactive species. Liquid chromatography-mass spectrometry analysis revealed covalent adducts between fatty acid nitroalkene derivatives and GAPDH, including at the catalytic Cys-149. Liquid chromatography-mass spectrometry-based proteomic analysis of human red cells confirmed that nitroalkenes readily undergo covalent, thiol-reversible post-translational modification of nucleophilic amino acids in GSH and GAPDH in vivo. The adduction of GAPDH and GSH by nitroalkenes significantly increased the hydrophobicity of these molecules, both inducing translocation to membranes and suggesting why these abundant derivatives had not been detected previously via traditional high pressure liquid chromatography analysis. The occurrence of these electrophilic nitroalkylation reactions in vivo indicates that this reversible post-translational protein modification represents a new pathway for redox regulation of enzyme function, cell signaling, and protein trafficking.

Alkylation↗
PubMed2004

Translational and post-translational modifications of proteins as a new mechanism of action of alpha-interferon: review article.

Interferon-alpha (IFNalpha) is a recombinant protein widely used in the therapy of several neoplasms such as myeloma, renal cell carcinoma, epidermoid cervical and head and neck tumours and melanoma. IFNalpha, the first cytokine to be produced by recombinant DNA technology, has emerged as an important regulator of cancer cell growth and differentiation, affecting cellular communication and signal transduction pathways. However, the way by which tumour cell growth is directly suppressed by IFNalpha is not well known. Wide evidence exists on the possibility that cancer cells undergo apoptosis after the exposure to the cytokine. Here we will discuss data obtained by us and others on the post-translational regulation of the expression of proteins involved in the occurrence of apoptotic process such as tissue transglutaminase (tTG) or in the modulation of cell cycle such as the cyclin-dependent kinase inhibitor p27. This new way of regulation of p27 and tTG occurs through the modulation of their proteasome-dependent degradation induced by the cytokine. We will also review the involvement of protein synthesis machinery in the induction of cell growth inhibition by IFNalpha. In details, we will describe the effects of IFNalpha on the expression and activity of the protein kinase dependent from dsRNA (PKR) and on the eukaryotic initiation factor of protein synthesis 5A (eIF-5A) and their correlations with the regulation of cancer cell growth. These data strongly suggest that the antitumour activity of IFNalpha against human tumours could involve still unexplored mechanisms based on post-translational and translational control of the expression of proteins that regulate cell proliferation and apoptosis.

Animals↗
PubMed2006

Protection against glycation and similar post-translational modifications of proteins.

Glycation and other non-enzymic post-translational modifications of proteins have been implicated in the complications of diabetes and other conditions. In recent years there has been extensive progress in the search for ways to prevent the modifications and prevent the consequences of the modifications. These areas are covered in this review together with newer ideas on possibilities of reversing the chemical modifications.

Aspirin↗
PubMed1982

Phosphorylation and methylation of proteins during Myxococcus xanthus spore formation.

Post-translational modification of proteins was examined during the life cycle of Myxococcus xanthus. A specific pattern of protein phosphorylation was observed in vegetative cells. When spore formation was induced by glycerol, significant changes in the pattern of protein phosphorylation were observed, including the phosphorylation of two membrane proteins. In in vitro experiments, the same membrane proteins were phosphorylated by ATP when the membrane preparation from cells treated with glycerol was used. Changes in the pattern of protein methylation were also observed during spore formation induced by glycerol or fruiting body formation. These results suggest that post-translational protein modification may be required for spore formation or fruiting body formation.

Adenosine Triphosphate↗
PubMed2006

Detecting oxidative post-translational modifications in proteins.

Oxidative stress induces various post-translational modifications (PTM); some are reversible in vivo via enzymatic catalysis. The present paper reviews specific procedures for the detection of oxidative PTM in proteins, most of them including electrophoresis. Main topics are carbonylated and glutathionylated proteins as well as modification of selected amino acids (Cys, Tyr, Met, Trp, Lys).

Oxidation-Reduction↗
PubMed1997

Post-translational modification of proteins and the discovery of new medicine.

Post-translational modifications are fundamental to processes controlling behaviour, including cellular signaling, growth and transformation. As the molecular basis of protein modifications in normal and disease processes are becoming better defined, so new strategies for designing therapeutic entities to control complex disease processes are emerging.

Drug Design↗
PubMed2005

AutoMotif server: prediction of single residue post-translational modifications in proteins.

UNLABELLED: The AutoMotif Server allows for identification of post-translational modification (PTM) sites in proteins based only on local sequence information. The local sequence preferences of short segments around PTM residues are described here as linear functional motifs (LFMs). Sequence models for all types of PTMs are trained by support vector machine on short-sequence fragments of proteins in the current release of Swiss-Prot database (phosphorylation by various protein kinases, sulfation, acetylation, methylation, amidation, etc.). The accuracy of the identification is estimated using the standard leave-one-out procedure. The sensitivities for all types of short LFMs are in the range of 70%. AVAILABILITY: The AutoMotif Server is available free for academic use at http://automotif.bioinfo.pl/

Algorithms↗
PubMed2007

Post-translational synaptic protein modification as substrate for long-lasting, remote memory: an initial test.

The current view of the molecular basis for information storage is that post-translational modification (PTM) of brain proteins is important for the early stages of memory storage and that protein synthesis is necessary for long-lasting memory. This view has been challenged by the proposal that PTM of synaptic proteins is the critical instructive mechanism underlying both recent as well as long-lasting memories (Routtenberg and Rekart, 2005). As an initial test, a broad spectrum serine/threonine kinase inhibitor (H-7) was delivered bilaterally to rat anterior cingulate cortex 1 h before a 3 week retention test of contextual fear conditioning. This significantly blocked 21-Day retention. In the second experiment evaluating extinction of a 21-Day remote memory, H-7 injected into mouse medial prefrontal cortex blocked fear extinction. As the H-7-induced impairment in 21-Day retention was indexed by a decrease in freezing, while the extinction blockade by no decrease in freezing, the results could not be ascribed to a direct effect of the drug on behavioral performance. This represents the first demonstration, to our knowledge, that PTM inhibition, here serine/threonine kinase activity, interferes with long-lasting memory, providing initial support for the PTM model.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMedDate not supplied

Capillary affinity electrophoresis for the screening of post-translational modification of proteins with carbohydrates.

Glycosylation is one of the most important post-translational events for proteins, affecting their functions in health and disease, and plays significant roles in various information traffics for intracellular and intercellular biological events (Hancock, W. S. J. Proteome Res. 2002, 1, 297). We have attempted to obtain the information on the numbers and amounts of carbohydrate chains. Interaction between carbohydrate chains and proteins that recognize them is a target to understand the biological roles of glycosylation. To date, there have been a few strategies for simultaneous analysis of the interactions between complex mixtures of carbohydrates and proteins. Here, we report an approach to categorize carbohydrate chains using a few glycoprotein samples as models for the studies on the analysis of post-translational modification of proteins with carbohydrates. A combination of some specific lectins was used as carbohydrate-binding proteins. The method is based on high-resolution separation of fluorescent-labeled carbohydrates by capillary electrophoresis with laser-induced fluorescent detection in the presence of carbohydrate-binding proteins at different concentrations. The present technique affords (1) simultaneous determination of carbohydrate chains, (2) binding specificity of the constituent carbohydrate chains to specific proteins, and (3) kinetic data such as the association constant of each carbohydrate. We found that the lectins employed in the present study could discriminate subtle difference in linkages and resolved the carbohydrate mixtures. The results will be useful, for example, to understand the biological events expressed with carbohydrate changes on the cell surface.

Agglutinins↗
PubMed2003

Determination of post-translational modifications of proteins by high-sensitivity, high-resolution Fourier transform ion cyclotron resonance mass spectrometry.

The response of a cell to its extracellular environment is a multi-step process beginning with signal transduction that is governed by "subtle changes" often resulting in protein expression. Proteomics is the tracking of this protein expression. Post-translational modification (PTM) is a "subtle change" that has a major influence on signal transduction. Phosphorylation and glycosylation propagate signals by sequential, reversible modifications. High-sensitivity, high-resolution and multiple MS capabilities of Fourier transform ion cyclotron resonance mass spectrometry permit localization of the PTM(s) with electron-capture dissociation, and then structural determination of the PTM with infrared multiphoton dissociation.

Amino Acid Sequence↗
PubMed1989

Post-translational modifications of proteins: some problems left to solve.

Three major questions regarding the post-translational modification of amino acid side chains in proteins are briefly considered: (1) What are the biological functions of the reactions, (2) what is the specificity of the processing reactions in selecting only a few or sometimes even only one residue for modification, and (3) how do we solve the uniqueness of the processing steps in the production of recombinant proteins? The answers to these questions are not obvious at this time.

Protein Processing, Post-Translational↗
PubMed2001

Post-translational modifications of proteins: acetylcholinesterase as a model system.

Analysis of the expressed protein complement of cells requires knowledge of the diversity of post-translational modifications that can occur and which can be transient or permanent. The modifications range from amino acid changes through to the addition of macromolecules: lipid, carbohydrate or protein. Many variants of the common amino acids can occur, which can affect the structure or function of the protein. The major class of modification, however, is represented by glycosylation, N-linked, O-linked, or glycosylphosphatidylinositol(GPI)-linked. Such modifications have roles in protein stability and folding, targeting and recognition. Glycosylated proteins can be found in all cellular compartments and, intracellularly, O-GlcNAc modification is commonplace. Lipid modification of proteins (acylation, prenylation, GPI-anchoring) is also common, resulting in membrane association, and can play an important role in cell signalling. Targeting and turnover of proteins can also be mediated via covalent protein addition, for example by members of the ubiquitin family. Limited proteolysis as a post-translational modification will be discussed, focusing on the family of membrane protein secretases, in particular in relation to the Alzheimer's amyloid precursor protein. Finally, acetylcholinesterase will be used as a model example to illustrate the diversity of modifications occurring on a single protein.

Acetylcholinesterase↗
PubMed2026

Post-translational modification of proteins in the human testis development pathway.

BACKGROUND: The foetal testes produce the androgens necessary to masculinise the developing embryo and support the maturation of germ cells, that will eventually develop into sperm, thus ensuring future reproductive capacity. The testes develop from the bi-potential gonads in a highly orchestrated process resulting in the differentiation of a complex tissue with multiple cellular lineages. While recent transcriptomic and chromatin-based analyses of human foetal testes have provided an unprecedented level of insight into signalling pathways activated during this process, proteomic studies of the human foetal gonads remain limited. Proteins are active molecules and post-translational modification (PTM) of proteins influences protein activity, stability and localisation. Studies have shown that PTMs regulate critical proteins in testis development, and their disruptions are implicated in congenital disorders including differences of sex development (DSD), in which sex development is atypical. Despite this, the role and regulation of protein PTM during human testis development remains poorly understood due to limited access to human foetal gonadal tissue, a paucity of large-scale proteomics studies, and a lack of robust of human gonad in vitro models. OBJECTIVE AND RATIONALE: This review aims to provide a comprehensive analysis of validated PTMs affecting proteins critical for testicular development. We discuss PTMs with evidence for a role in normal testis development, and highlight those disrupted in DSD. We review emerging techniques, including proteomic technologies and organ modelling systems that may advance our understanding of PTMs in foetal testis development. We discuss challenges that have restricted the application of these technologies and how overcoming these will significantly improve our understanding of testis development and disease, diagnostics and patient outcomes. SEARCH METHODS: We searched PubMed and the University of Melbourne library for peer-reviewed English-language studies using keywords such as phosphorylation, SUMOylation, acetylation, ubiquitination alongside each protein of interest. PTM sites in proteins involved in testis development were identified using the PhosphoSitePlus database focusing those confirmed in in vitro or animal model studies. ClinVar and the Human Gene Mutation Database were used to identify patient variants that may disrupt PTM sites. OUTCOMES: Our review finds that proteins required for human foetal testis development are subject to extensive PTM. Several PTM sites and PTM-mediated pathways [e.g. MAPK (mitogen-activated protein kinase) pathway] are disrupted in patients with DSD or related conditions. While recent advances in proteomics technologies hold considerable promise, their application to human foetal gonads has been constrained by technical, ethical, and logistical challenges. Encouragingly, emerging high-sensitivity and low-input technologies, alongside stem cell-based approaches, offer viable pathways to overcoming these barriers. WIDER IMPLICATIONS: The relationship between gene regulation, protein expression, and cellular outcome is inherently non-linear, shaped by additional regulatory layers-most notably PTMs. The contribution of PTMs to human testis development in both typical and atypical contexts is a major knowledge gap. Addressing this gap has broad clinical and biological relevance: it may help improve genetic diagnosis or shed light on how proteins or pathways critical for testis development respond to environmental signals-an increasingly pressing question as declining global fertility rates bring testicular function under greater scrutiny. REGISTRATION NUMBER: N/A.

Humans↗
PubMed2004

Post-translational modifications of proteins: implications for aging, antigen recognition, and autoimmunity.

Proteins are complex organic molecules susceptible to numerous post-translational modifications occurring spontaneously during aging or as a consequence of physiologic or pathologic processes. Antigenicity and interactions of proteins with components of the immune system may be profoundly affected by post-translational modifications. Thus, modified self-antigens may be absent (not-tolerated) during early T-cell selection and trigger reactions by the immune system as they arise later in life. In turn, this may play a role in the initiation and pathogenesis of autoimmune diseases. This Review article presents an overview of protein modifications that have been shown to affect antigenicity and presentation of protein antigens in autoimmune diseases. The relevance of these observations is discussed, and the implications for future prophylactic and therapeutic interventions are outlined.

Aging↗
PubMedDate not supplied

VEMS 3.0: algorithms and computational tools for tandem mass spectrometry based identification of post-translational modifications in proteins.

Protein and peptide mass analysis and amino acid sequencing by mass spectrometry is widely used for identification and annotation of post-translational modifications (PTMs) in proteins. Modification-specific mass increments, neutral losses or diagnostic fragment ions in peptide mass spectra provide direct evidence for the presence of post-translational modifications, such as phosphorylation, acetylation, methylation or glycosylation. However, the commonly used database search engines are not always practical for exhaustive searches for multiple modifications and concomitant missed proteolytic cleavage sites in large-scale proteomic datasets, since the search space is dramatically expanded. We present a formal definition of the problem of searching databases with tandem mass spectra of peptides that are partially (sub-stoichiometrically) modified. In addition, an improved search algorithm and peptide scoring scheme that includes modification specific ion information from MS/MS spectra was implemented and tested using the Virtual Expert Mass Spectrometrist (VEMS) software. A set of 2825 peptide MS/MS spectra were searched with 16 variable modifications and 6 missed cleavages. The scoring scheme returned a large set of post-translationally modified peptides including precise information on modification type and position. The scoring scheme was able to extract and distinguish the near-isobaric modifications of trimethylation and acetylation of lysine residues based on the presence and absence of diagnostic neutral losses and immonium ions. In addition, the VEMS software contains a range of new features for analysis of mass spectrometry data obtained in large-scale proteomic experiments. Windows binaries are available at http://www.yass.sdu.dk/.

Algorithms↗
PubMed2002

Revisiting electroblotting of immobilized pH gradient gels: a new protocol for studying post-translational modification of proteins.

Currently, one of the most important techniques in proteome analysis is two-dimensional electrophoresis that is widely used for separation of thousands of different protein spots. Nevertheless, characterization of special aspects in protein patterns, e.g., separation of protein isoforms generated by post-translational modifications, requires individual detection methods, e.g., immunoblotting. Blotting of proteins after fractionation in immobilized pH gradients has always caused some problems. In this paper we present an optimized protocol for immunoblotting after isoelectric focusing using immobilized pH gradient (IPG) strips cast on Net-Fix as an internal support that is permeable to electric current. The focusing procedure can be carried out in commonly used IPG systems, e.g., the IPGphor by Amersham Biosciences, where electrically assisted rehydration can be performed. This may be of interest for many laboratories, because the same system as used for the first dimension of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is involved. As an example, we describe separation and detection of up to seven isoforms of recombinant erythropoietin beta using semidry blotting of IPG strips and visualization by chemiluminescence detection.

Electrophoresis, Gel, Two-Dimensional↗
PubMedDate not supplied

Post-translational modification of proteins by 15-carbon and 20-carbon isoprenoids in three mammalian cell lines.

A number of cellular proteins, including p21ras, lamin B, and the G-protein gamma subunits, undergo post-translational modification by 15-carbon farnesyl or 20-carbon geranylgeranyl isoprenoid moieties derived from pyrophosphate intermediates of the cholesterol biosynthetic pathway. In this study, isoprenylated proteins in three mammalian cell lines (Hela cells, Rat-6 fibroblasts and COS cells) were radiolabeled with an isoprenoid precursor, [3H]mevalonate, and resolved by SDS gel electrophoresis. Groups of proteins with different molecular masses were eluted from the gels and the chain-lengths of the radiolabeled isoprenyl groups, released from the proteins by Raney-nickel-catalyzed desulfurization, were established by gel permeation chromatography. 15-Carbon and 20-carbon isoprenyl groups were found in separate classes of proteins within each cell line. With the exception of p21ras, which incorporated a 15-carbon group when expressed in COS cells, the proteins in the region of the 21-28 kDa ras-related GTP binding proteins contained mostly 20-carbon isoprenyl chains. In contrast, proteins belonging to the 66-72 kDa nuclear lamin family, as well as unidentified proteins with molecular masses of 41-46 kDa and 53-55 kDa, contained predominantly 15-carbon isoprenyl chains. The chain-lengths of the isoprenoids associated with particular classes of proteins did not vary from one cell line to another, suggesting that the nature of the isoprenoid modification (farnesyl versus geranylgeranyl) is determined by intrinsic structural features of the proteins, rather than the cell type in which the proteins are expressed.

Animals↗
PubMed1989

Non-enzymic post-translational modification of proteins in aging. A review.

Various non-enzymic post-translational changes to proteins occur in vivo and some of these progress with aging. These changes are reviewed and linked to a number of age-related diseases, and to alterations in the charge distribution on protein surfaces. Modification by cyanate and by glucose 6-phosphate causes a partial unfolding of proteins, with loss of tertiary structure but retention of secondary structure. These products are reminiscent of the intermediate state observed during folding and unfolding of some proteins.

Aged↗