ABSTRACT
As a newly discovered posttranslational modification (PTM), crotonylation has been identified in histone and nonhistone proteins and has important roles in the regulation of various diseases and biological processes. With the development of high-resolution mass spectrometry approaches, an increasing number of endogenous crotonylation has been detected and identified. The discovery of crotonylation regulatory enzymes paved the way for the study of crotonylation mechanism. In this review, we summarize the biological functions and regulatory mechanism of crotonylation in eukaryotes and introduce the recent progress on crotonylation in malignant tumor.
ABSTRACT
Posttranslational modifications of antibody products affect their stability,charge distribution,and drug activity and are thus a critical quality attribute.The comprehensive mapping of antibody modifications and different charge isomers(CIs)is of utmost importance,but is challenging.We intended to quanti-tatively characterize the posttranslational modification status of CIs of antibody drugs and explore the impact of posttranslational modifications on charge heterogeneity.The CIs of antibodies were fraction-ated by strong cation exchange chromatography and verified by capillary isoelectric focusing-whole column imaging detection,followed by stepwise structural characterization at three levels.First,the differences between CIs were explored at the intact protein level using a top-down mass spectrometry approach;this showed differences in glycoforms and deamidation status.Second,at the peptide level,common modifications of oxidation,deamidation,and glycosylation were identified.Peptide mapping showed nonuniform deamidation and glycoform distribution among CIs.In total,10 N-glycoforms were detected by peptide mapping.Finally,an in-depth analysis of glycan variants of CIs was performed through the detection of enriched glycopeptides.Qualitative and quantitative analyses demonstrated the dynamics of 24 N-glycoforms.The results revealed that sialic acid modification is a critical factor ac-counting for charge heterogeneity,which is otherwise missed in peptide mapping and intact molecular weight analyses.This study demonstrated the importance of the comprehensive analyses of antibody CIs and provides a reference method for the quality control of biopharmaceutical analysis.
ABSTRACT
Accidents with venomous animals are a public health issue worldwide. Among the species involved in these accidents are scorpions, spiders, bees, wasps, and other members of the phylum Arthropoda. The knowledge of the function of proteins present in these venoms is important to guide diagnosis, therapeutics, besides being a source of a large variety of biotechnological active molecules. Although our understanding about the characteristics and function of arthropod venoms has been evolving in the last decades, a major aspect crucial for the function of these proteins remains poorly studied, the posttranslational modifications (PTMs). Comprehension of such modifications can contribute to better understanding the basis of envenomation, leading to improvements in the specificities of potential therapeutic toxins. Therefore, in this review, we bring to light protein/toxin PTMs in arthropod venoms by accessing the information present in the UniProtKB/Swiss-Prot database, including experimental and putative inferences. Then, we concentrate our discussion on the current knowledge on protein phosphorylation and glycosylation, highlighting the potential functionality of these modifications in arthropod venom. We also briefly describe general approaches to study "PTM-functional-venomics", herein referred to the integration of PTM-venomics with a functional investigation of PTM impact on venom biology. Furthermore, we discuss the bottlenecks in toxinology studies covering PTM investigation. In conclusion, through the mining of PTMs in arthropod venoms, we observed a large gap in this field that limits our understanding on the biology of these venoms, affecting the diagnosis and therapeutics development. Hence, we encourage community efforts to draw attention to a better understanding of PTM in arthropod venom toxins.(AU)
Subject(s)
Animals , Arthropod Venoms/toxicity , Protein Processing, Post-Translational , Phosphorylation , Scorpions , Mass Spectrometry/methods , Spiders , Wasps , Bees , GlycosylationABSTRACT
Heart failure from various cardiovascular diseases is a serious threat to human health. Systolic and diastolic dysfunction are the basic characteristics of heart failure. SERCA2a, a key enzyme for calcium transport, regulates intracellular free calcium ion concentration, affecting the myocardial diastolic process. This article mainly summarized the structure and function of SERCA2a gene, the expression and regulation of SERCA2a in heart failure, and the current situation of drug therapy, gene therapy and clinical research targeting SERCA2a gene.
ABSTRACT
Keratins, the epithelial-predominant members of the intermediate filament superfamily, are expressed in a pairwise, tissuespecific and differentiation-dependent manner. There are 28 type I and 26 type II keratins, which share a common structurecomprising a central coiled coil a-helical rod domain flanked by two nonhelical head and tail domains. These domainsharbor sites for major posttranslational modifications like phosphorylation and glycosylation, which govern keratin functionand dynamics. Apart from providing structural support, keratins regulate various signaling machinery involved in cellgrowth, motility, apoptosis etc. However, tissue-specific functions of keratins in relation to cell proliferation and differentiation are still emerging. Altered keratin expression pattern during and after malignant transformation is reported tomodulate different signaling pathways involved in tumor progression in a context-dependent fashion. The current reviewfocuses on the literature related to the role of keratins in the regulation of cell proliferation, differentiation and transformation in different types of epithelia.
ABSTRACT
Objective • To investigate the effect of histone H3K14M mutation on the activity of methyltransferase RomA, a secreted effector ofLegionella pneumophila in eukaryotic cells and the underlying mechanisms. Methods • Wide-type histone H3 (H3WT) and mutant histone H3 (the lysine residue 14 was replaced by methionine, isoleucine or arginine residue, and named as H3K14M, H3K14I, and H3K14R, respectively) recombinant expression plasmids were constructed. Packaged lentiviruses with these plasmids were used to infect eukaryotic cells 293T and THP-1 with or without over-expression of RomA. The H3K14 methylation and acetylation were analyzed by Western blotting. The interaction of RomA with H3WT and H3K14 mutants was detected by co-immunoprecipitation. Results • A secreted effector of Legionella pneumophila named RomA targeted the host cell nucleus to upregulate the H3K14 methylation level and downregulate the H3K14 acetylation level for inhibiting the gene expression in host cells and promoting Legionella pneumophila's efficient intracellular replication. But histone H3K14M mutation could promote the interaction between H3K14M and RomA and thus inhibited the methyltransferase activity of RomA. Conclusion • Histone H3K14M mutation significantly inhibits the activity of Legionella pneumophilamethyltransferase RomA.
ABSTRACT
Various posttranslational modifications (PTMs) participate in nearly all aspects of biological processes by regulating protein functions, and aberrant states of PTMs are frequently implicated in human diseases. Therefore, an integral resource of PTM-disease associations (PDAs) would be a great help for both academic research and clinical use. In this work, we reported PTMD, a well-curated database containing PTMs that are associated with human diseases. We manually collected 1950 known PDAs in 749 proteins for 23 types of PTMs and 275 types of diseases from the literature. Database analyses show that phosphorylation has the largest number of disease associations, whereas neurologic diseases have the largest number of PTM associations. We classified all known PDAs into six classes according to the PTM status in diseases and demonstrated that the upregulation and presence of PTM events account for a predominant proportion of disease-associated PTM events. By reconstructing a disease-gene network, we observed that breast cancers have the largest number of associated PTMs and AKT1 has the largest number of PTMs connected to diseases. Finally, the PTMD database was developed with detailed annotations and can be a useful resource for further analyzing the relations between PTMs and human diseases. PTMD is freely accessible at http://ptmd.biocuckoo.org.
Subject(s)
Humans , Databases, Protein , Disease , Genetics , Gene Regulatory Networks , Phosphorylation , Protein Processing, Post-Translational , Proteins , Metabolism , Search EngineABSTRACT
Gene expression technology has made great progress with the continuous developments and researches of molecular biology. Though many systems to produce recombinant proteins have been studied, none of them is available so far to satisfy the needs completely. With the increasing demands of bioactive peptides and protein drugs, expression quantity and correct posttranslational folding and modifications are also needed under the circumstance which can make proteins more close to native conformation and higher activity and stability. Based on our previous work, we summarized the factors affecting the folding and modifications of recombinant proteins correctly from five aspects, including expression system and hosts, secretory expression, coexpression, fusion expression, and the culture conditions, as well as improvement strategies.
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Vascular calcification is a pathologic phenomenon in which calcium phosphate is ectopically deposited in the arteries. Previously, calcification was considered to be a passive process in response to metabolic diseases, vascular or valvular diseases, or even aging. However, now calcification is recognized as a highly-regulated consequence, like bone formation, and many clinical trials have been carried out to elucidate the correlation between vascular calcification and cardiovascular events and mortality. As a result, vascular calcification has been implicated as an independent risk factor in cardiovascular diseases. Many molecules are now known to be actively associated with this process. Recently, our laboratory found that posttranslational modification of histone deacetylase (HDAC) 1 is actively involved in the development of vascular calcification. In addition, we found that modulation of the activity of HDAC as well as its protein stability by MDM2, an HDAC1-E3 ligase, may be a therapeutic target in vascular calcification. In the present review, we overview the pathomechanism of vascular calcification and the involvement of posttranslational modification of epigenetic regulators.
Subject(s)
Aging , Arteries , Calcium , Cardiovascular Diseases , Epigenomics , Histone Deacetylases , Histones , Metabolic Diseases , Mortality , Osteogenesis , Protein Processing, Post-Translational , Protein Stability , Risk Factors , Vascular CalcificationABSTRACT
By means of a circadian clock system, all the living organisms on earth including human beings can anticipate the environmental rhythmic changes such as light/dark and warm/cold periods in a daily as well as in a yearly manner. Anticipating such environmental changes provide organisms with survival benefits via manifesting behavior and physiology at an advantageous time of the day and year. Cell-autonomous circadian oscillators, governed by transcriptional feedback loop composed of positive and negative elements, are organized into a hierarchical system throughout the organisms and generate an oscillatory expression of a clock gene by itself as well as clock controlled genes (ccgs) with a 24 hr periodicity. In the feedback loop, hetero-dimeric transcription factor complex induces the expression of negative regulatory proteins, which in turn represses the activity of transcription factors to inhibit their own transcription. Thus, for robust oscillatory rhythms of the expression of clock genes as well as ccgs, the precise control of subcellular localization and/or timely translocation of core clock protein are crucial. Here, we discuss how sub-cellular localization and nuclear translocation are controlled in a time-specific manner focusing on the negative regulatory clock proteins.
Subject(s)
Humans , Circadian Clocks , Circadian Rhythm , CLOCK Proteins , Periodicity , Phosphorylation , Physiology , Protein Processing, Post-Translational , Repressor Proteins , Transcription FactorsABSTRACT
Hypoxia-inducible factor-1 (HIF-1) is a key transciptional regulator of cellular and systemic oxygen homeostasis,composed of the two subunits,HIF-1α and HIF-1β.HIF-1α is an inducible subunit regulated by hypoxia,which is posttranslationally modified by various ways,including ubiquitination,phosphorylation,hydroxylation,acetylation and glycation,accordingly affecting its protein's stability,nuclear translocation and regulation of its target genes.Small ubiquitin-related modifier (SUMO) is an micromolecule protein participating in posttranslational modifications of proteins dynamicly in eukaryotic organism,which is similar in structure to ubiquitin.SUMOylation and deSUMOylation are involved in multiple regulations of biologic processes,such as signal transduction,transcriptional regulation,cell cycle processes and biological rhythm.SUMOylation is related to HIF-1α stability and transcription activity in hypoxia,providing a newthread to study self-regulation mechanism of HIF-1α for us.