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1.
Transl Cancer Res ; 13(5): 2308-2314, 2024 May 31.
Article in English | MEDLINE | ID: mdl-38881930

ABSTRACT

Background: Uric acid may play a critical role in protection against cancer by the suppression of inflammation. The association between serum uric acid (SUA) levels and prostate cancer risk is debatable yet has received little attention in the American population. Therefore, we used data from the National Health and Nutrition Examination Survey (NHANES) to determine their correlation. Methods: Using information from NHANES 1999-2010, a total of 62,160 individuals from the general population were included in this cross-sectional study. Additionally, a number of covariates were acquired. Prostate cancer was used to divide the participants into two groups: prostate cancer group (n=315) and non-prostate cancer group (n=7,545). A weighted adjusted logistic regression analysis was conducted to examine the potential correlation between SUA and prostate cancer. Results: Our study comprised a total of 7,860 participants. After full adjustment for confounders, SUA was not significantly associated with prostate cancer [odds ratio (OR) 0.91, 95% confidence interval (CI): 0.82-1.00, P=0.058]. In participants aged 60 years and above (≥60 years), a higher SUA was significantly associated with a lower risk of prostate cancer (OR 0.88, 95% CI: 0.80-0.96, P=0.003). However, among those younger than 60 years (<60 years), there was no association between SUA and prostate cancer risk (OR 1.29, 95% CI: 0.69-2.42, P=0.42). In addition, in the subgroup analysis stratified by body mass index, hypertension and diabetes, there was no significant correlation between SUA and prostate cancer. Conclusions: SUA is negatively associated with the risk of prostate cancer in older men, especially for those 60 years of age and beyond.

2.
Sensors (Basel) ; 24(9)2024 May 05.
Article in English | MEDLINE | ID: mdl-38733044

ABSTRACT

Film bulk acoustic-wave resonators (FBARs) are widely utilized in the field of radio frequency (RF) filters due to their excellent performance, such as high operation frequency and high quality. In this paper, we present the design, fabrication, and characterization of an FBAR filter for the 3.0 GHz-3.2 GHz S-band. Using a scandium-doped aluminum nitride (Sc0.2Al0.8N) film, the filter is designed through a combined acoustic-electromagnetic simulation method, and the FBAR and filter are fabricated using an eight-step lithographic process. The measured FBAR presents an effective electromechanical coupling coefficient (keff2) value up to 13.3%, and the measured filter demonstrates a -3 dB bandwidth of 115 MHz (from 3.013 GHz to 3.128 GHz), a low insertion loss of -2.4 dB, and good out-of-band rejection of -30 dB. The measured 1 dB compression point of the fabricated filter is 30.5 dBm, and the first series resonator burns out first as the input power increases. This work paves the way for research on high-power RF filters in mobile communication.

3.
Micromachines (Basel) ; 15(5)2024 Apr 25.
Article in English | MEDLINE | ID: mdl-38793136

ABSTRACT

With the development of wireless communication, increasing signal processing presents higher requirements for radio frequency (RF) systems. Piezoelectric acoustic filters, as important elements of an RF front-end, have been widely used in 5G-generation systems. In this work, we propose a Sc0.2Al0.8N-based film bulk acoustic wave resonator (FBAR) for use in the design of radio frequency filters for the 5G mid-band spectrum with a passband from 3.4 to 3.6 GHz. With the excellent piezoelectric properties of Sc0.2Al0.8N, FBAR shows a large Keff2 of 13.1%, which can meet the requirement of passband width. Based on the resonant characteristics of Sc0.2Al0.8N FBAR devices, we demonstrate and fabricate different ladder-type FBAR filters with second, third and fourth orders. The test results show that the out-of-band rejection improves and the insertion loss decreases slightly as the filter order increases, although the frequency of the passband is lower than the predicted ones due to fabrication deviation. The passband from 3.27 to 3.47 GHz is achieved with a 200 MHz bandwidth and insertion loss lower than 2 dB. This work provides a potential approach using ScAlN-based FBAR technology to meet the band-pass filter requirements of 5G mid-band frequencies.

4.
PLoS One ; 19(5): e0302588, 2024.
Article in English | MEDLINE | ID: mdl-38748740

ABSTRACT

Hebi is located in the northern part of China's Henan Province and is a typical receiving area for China's South-to-North Water Diversion Project. The assessment of habitat quality and water yield over a long time series is important for evaluating the stability of ecosystem services in Hebi and other receiving areas and for maintaining ecological security and promoting sustainable development. This paper aims to evaluate and dynamically analyse habitat quality and water yield in Hebi, and analyses the characteristics of changes in spatial and temporal patterns of land cover types, habitat quality and water yield in Hebi over the past 20 years, using 2000, 2005, 2010, 2015 and 2020 as horizontal years. The results indicate that: (1) During the study period, the overall land use type in Hebi City has been constantly changing, with the most significant conversion from arable land to other land types; combined with its landscape pattern index, Hebi City has a general characteristic of significant landscape fragmentation and complexity in land use. (2) Habitat quality in Hebi shows an overall trend towards better development, with water availability decreasing and then increasing; the zoning of ecosystem services in Hebi is divided into three classes: superior, good and general, with the area covered by the superior and general classes expanding year by year. (3) Correlation analysis by SPSS software shows that the correlation between habitat quality and landscape pattern index is greater than the correlation between habitat quality and climate change. Additionally, the correlation between water availability and climate change is greater than the correlation between water availability and landscape pattern index.


Subject(s)
Conservation of Natural Resources , Ecosystem , China , Conservation of Natural Resources/methods , Water Supply , Water , Environmental Monitoring/methods
5.
Article in English | MEDLINE | ID: mdl-38536694

ABSTRACT

We introduce a novel approach to learn geometries such as depth and surface normal from images while incorporating geometric context. The difficulty of reliably capturing geometric context in existing methods impedes their ability to accurately enforce the consistency between the different geometric properties, thereby leading to a bottleneck of geometric estimation quality. We therefore propose the Adaptive Surface Normal (ASN) constraint, a simple yet efficient method. Our approach extracts geometric context that encodes the geometric variations present in the input image and correlates depth estimation with geometric constraints. By dynamically determining reliable local geometry from randomly sampled candidates, we establish a surface normal constraint, where the validity of these candidates is evaluated using the geometric context. Furthermore, our normal estimation leverages the geometric context to prioritize regions that exhibit significant geometric variations, which makes the predicted normals accurately capture intricate and detailed geometric information. Through the integration of geometric context, our method unifies depth and surface normal estimations within a cohesive framework, which enables the generation of high-quality 3D geometry from images. We validate the superiority of our approach over state-of-the-art methods through extensive evaluations and comparisons on diverse indoor and outdoor datasets, showcasing its efficiency and robustness. Code and data are available at https://github.com/xxlong0/ASNDepth.

6.
Angew Chem Int Ed Engl ; 63(14): e202318897, 2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38326236

ABSTRACT

Mirror-image proteins (D-proteins) are useful in biomedical research for purposes such as mirror-image screening for D-peptide drug discovery, but the chemical synthesis of many D-proteins is often low yielding due to the poor solubility or aggregation of their constituent peptide segments. Here, we report a Lys-C protease-cleavable solubilizing tag and its use to synthesize difficult-to-obtain D-proteins. Our tag is easily installed onto multiple amino acids such as DLys, DSer, DThr, and/or the N-terminal amino acid of hydrophobic D-peptides, is impervious to various reaction conditions, such as peptide synthesis, ligation, desulfurization, and transition metal-mediated deprotection, and yet can be completely removed by Lys-C protease under denaturing conditions to give the desired D-protein. The efficacy and practicality of the new method were exemplified in the synthesis of two challenging D-proteins: D-enantiomers of programmed cell death protein 1 IgV domain and SARS-CoV-2 envelope protein, in high yield. This work demonstrates that the enzymatic cleavage of solubilizing tags under denaturing conditions is feasible, thus paving the way for the production of more D-proteins.


Subject(s)
Peptides , Proteins , Proteins/chemistry , Peptides/chemistry , Amino Acids/chemistry , Chemistry Techniques, Synthetic/methods , Peptide Hydrolases , Endopeptidases
7.
Angew Chem Int Ed Engl ; 63(9): e202313640, 2024 Feb 26.
Article in English | MEDLINE | ID: mdl-38193587

ABSTRACT

D-peptide ligands can be screened for therapeutic potency and enzymatic stability using synthetic mirror-image proteins (D-proteins), but efficient acquisition of these D-proteins can be hampered by the need to accomplish their in vitro folding, which often requires the formation of correctly linked disulfide bonds. Here, we report the finding that temporary installation of natural O-linked-ß-N-acetyl-D-glucosamine (O-GlcNAc) groups onto selected D-serine or D-threonine residues of the synthetic disulfide-bonded D-proteins can facilitate their folding in vitro, and that the natural glycosyl groups can be completely removed from the folded D-proteins to afford the desired chirally inverted D-protein targets using naturally occurring O-GlcNAcase. This approach enabled the efficient chemical syntheses of several important but difficult-to-fold D-proteins incorporating disulfide bonds including the mirror-image tumor necrosis factor alpha (D-TNFα) homotrimer and the mirror-image receptor-binding domain of the Omicron spike protein (D-RBD). Our work establishes the use of O-GlcNAc to facilitate D-protein synthesis and folding and proves that D-proteins bearing O-GlcNAc can be good substrates for naturally occurring O-GlcNAcase.


Subject(s)
Acetylglucosaminidase , Proteins , Peptides , Polysaccharides , Glucosamine
8.
Cell ; 186(24): 5363-5374.e16, 2023 11 22.
Article in English | MEDLINE | ID: mdl-37972591

ABSTRACT

Cav1.2 channels play crucial roles in various neuronal and physiological processes. Here, we present cryo-EM structures of human Cav1.2, both in its apo form and in complex with several drugs, as well as the peptide neurotoxin calciseptine. Most structures, apo or bound to calciseptine, amlodipine, or a combination of amiodarone and sofosbuvir, exhibit a consistent inactivated conformation with a sealed gate, three up voltage-sensing domains (VSDs), and a down VSDII. Calciseptine sits on the shoulder of the pore domain, away from the permeation path. In contrast, when pinaverium bromide, an antispasmodic drug, is inserted into a cavity reminiscent of the IFM-binding site in Nav channels, a series of structural changes occur, including upward movement of VSDII coupled with dilation of the selectivity filter and its surrounding segments in repeat III. Meanwhile, S4-5III merges with S5III to become a single helix, resulting in a widened but still non-conductive intracellular gate.


Subject(s)
Calcium Channels, L-Type , Elapid Venoms , Humans , Calcium Channels, L-Type/chemistry , Calcium Channels, L-Type/metabolism , Neurotoxins , Protein Domains , Cryoelectron Microscopy
9.
Angew Chem Int Ed Engl ; 62(33): e202306270, 2023 08 14.
Article in English | MEDLINE | ID: mdl-37357888

ABSTRACT

Membrane-associated D-proteins are an important class of synthetic molecules needed for D-peptide drug discovery, but their chemical synthesis using canonical ligation methods such as native chemical ligation is often hampered by the poor solubility of their constituent peptide segments. Here, we describe a Backbone-Installed Split Intein-Assisted Ligation (BISIAL) method for the synthesis of these proteins, wherein the native L-forms of the N- and C-intein fragments of the unique consensus-fast (Cfa) (i.e. L-CfaN and L-CfaC ) are separately installed onto the two D-peptide segments to be ligated via a removable backbone modification. The ligation proceeds smoothly at micromolar (µM) concentrations under strongly chaotropic conditions (8.0 M urea), and the subsequent removal of the backbone modification groups affords the desired D-proteins without leaving any "ligation scar" on the products. The effectiveness and practicality of the BISIAL method are exemplified by the synthesis of the D-enantiomers of the extracellular domains of T cell immunoglobulin and ITIM domain (TIGIT) and tropomyosin receptor kinase C (TrkC). The BISIAL method further expands the chemical protein synthesis ligation toolkit and provides practical access to challenging D-protein targets.


Subject(s)
Inteins , Proteins , Peptides/chemistry , Protein Splicing
10.
J Am Chem Soc ; 143(42): 17566-17576, 2021 10 27.
Article in English | MEDLINE | ID: mdl-34663067

ABSTRACT

The ß2-adrenergic receptor (ß2AR) is a G-protein-coupled receptor (GPCR) that responds to the hormone adrenaline and is an important drug target in the context of respiratory diseases, including asthma. ß2AR function can be regulated by post-translational modifications such as phosphorylation and ubiquitination at the C-terminus, but access to the full-length ß2AR with well-defined and homogeneous modification patterns critical for biochemical and biophysical studies remains challenging. Here, we report a practical synthesis of differentially modified, full-length ß2AR based on a combined native chemical ligation (NCL) and sortase ligation strategy. An array of homogeneous samples of full-length ß2ARs with distinct modification patterns, including a full-length ß2AR bearing both monoubiquitination and octaphosphorylation modifications, were successfully prepared for the first time. Using these homogeneously modified full-length ß2AR receptors, we found that different phosphorylation patterns mediate different interactions with ß-arrestin1 as reflected in different agonist binding affinities. Our experiments also indicated that ubiquitination can further modulate interactions between ß2AR and ß-arrestin1. Access to full-length ß2AR with well-defined and homogeneous modification patterns at the C-terminus opens a door to further in-depth mechanistic studies into the structure and dynamics of ß2AR complexes with downstream transducer proteins, including G proteins, arrestins, and GPCR kinases.


Subject(s)
Protein Processing, Post-Translational , Receptors, Adrenergic, beta-2/chemistry , Allosteric Regulation , Aminoacyltransferases/chemistry , Bacterial Proteins/chemistry , Cysteine Endopeptidases/chemistry , Humans , Phosphorylation , Receptors, Adrenergic, beta-2/metabolism , Staphylococcus aureus/enzymology , Ubiquitination , beta-Arrestin 1/metabolism
11.
Electrophoresis ; 42(6): 793-799, 2021 03.
Article in English | MEDLINE | ID: mdl-33354816

ABSTRACT

Western blot (protein immunoblot) is a widely used analytical technique in molecular biology. Utilizing the specific recognizing primary antibody, proteins immobilized on various matrix are investigated by subsequent visualization steps, for example, by the horse radish peroxidase conjugated secondary antibody incubation. Methods to improve the sensitivity in protein identification or quantification are appreciated by biochemists. Herein, we report a new strategy to amplify Western blot signals by constructing a probe with proximal labeling and IgG targeting abilities. The R118G mutation attenuated the biotin-AMP binding affinity of the bacterial biotin ligase BirA*, offering a proximity-dependent labeling ability, which could be used as a signal amplifier. We built a BirA*-protein A fusion protein (BioEnhancer) that specifically binds to IgG and adds biotin tags to its proximal amine groups, enhancing the immunosignal of target proteins. In our experiments, the BioEnhancer system amplified the immunosignal by tenfold compared to the standard western blot. Additionally, our strategy could couple with other signal enhancement methods to further increase the western blot sensitivity.


Subject(s)
Blotting, Western , Biotin , Carbon-Nitrogen Ligases , Escherichia coli Proteins , Immunoglobulin G , Repressor Proteins , Staphylococcal Protein A
12.
Urol Int ; 103(1): 68-73, 2019.
Article in English | MEDLINE | ID: mdl-31039566

ABSTRACT

OBJECTIVE: To study the feasibility of ultrasonography (US) as a replacement for CT during the diagnosis of ureteral calculi (UC). MATERIALS AND METHODS: Clinical and imaging data of patients with UC between January 2013 and December 2017 were retrospectively analyzed. According to the imaging method, patients were divided into 3 groups: Group A, CT alone; Group B, CT and US, Group C, US alone. Age, location, and the size of stones were compared among the groups. According to the maximum diameter (MD) measured by using CT in Group B, patients were subdivided into 3 groups (subgroup 1-3): MD <0.5 cm, 0.5 cm ≤ MD ≤1.0 cm, and MD >1.0 cm. The MD measured by US and CT were compared in the subgroups. RESULTS: A total of 1,289 patients with UC were admitted. The use of CT correlated with age (p = 0.000) and stone location (p = 0.004). The sensitivity and specificity of US were 71.3 and 100%. Positive US results correlated with stone size (p = 0.008), but not location (p = 0.861). The mean MDs of the calculi measured by US and CT: in subgroup 1:  0.80 ± 0.31 and 0.35 ± 0.05 cm (p = 0.000); in subgroup 2: 0.94 ± 0.32 and 0.72 ± 0.16 cm (p = 0.000); in subgroup 3: 1.75 ± 0.68 and 1.59 ± 0.52 cm (p = 0.094). CONCLUSIONS: US confirmed that UC do not require confirmatory CT. US can replace CT as the initial imaging examination of UC.


Subject(s)
Tomography, X-Ray Computed , Ultrasonography , Ureteral Calculi/diagnostic imaging , Adult , Aged , Female , Humans , Hydronephrosis/complications , Male , Middle Aged , Reproducibility of Results , Retrospective Studies , Ureter/diagnostic imaging , Ureteral Calculi/physiopathology
13.
J Contemp Brachytherapy ; 10(5): 405-410, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30479616

ABSTRACT

PURPOSE: The aim of this study was to establish a more reliable method to predict pubic arch interference (PAI) before permanent prostate brachytherapy. MATERIAL AND METHODS: We retrospectively analyzed the nuclear magnetic resonance imaging (MRI) results of forty patients with prostate cancer, who were treated with permanent implantation of 125I seeds (permanent brachytherapy). We measured and calculated six parameters based on the MRI results: 1. The prostate volume (PV); 2. The angle of the pubic arch (AoPA); 3. The angle of PAI (AoPAI, pubic symphysis level); 4. The height of PAI (hPAI, pubic symphysis level); 5. The maximum angle of PAI (AoPAIMax); 6. The maximum height of PAI (hPAIMax). We then tested which parameters could accurately predict PAI through receiver operating characteristic (ROC) curve analysis. RESULTS: The results of this study demonstrated that AoPAI, hPAI, hPAIMax, and AoPAIMax could predict PAI. Out of forty cases in our research, 10 cases were with PAI and 30 cases without PAI during the operation. The areas under the ROC curve for PV, AoPA, AoPAI (pubic symphysis level), hPAI (pubic symphysis level), AoPAIMax, and hPAIMax were 0.592, 0.567, 0.957, 0.940, 0.927, and 0.877, respectively. The AoPAI (pubic symphysis level), hPAI (pubic symphysis level), AoPAIMax, and hPAIMax were statistically correlated with PAI. The boundary values were 26.32°, 1.13 cm, 28.37°, and 1.51 cm, respectively. CONCLUSIONS: This new method derived from MRI has predictive value, as AoPAI, hPAI, hPAIMax, and AoPAIMax could predict PAI. Taking other factors into consideration, we suggest the use of AoPAI as a novel and very reliable predictor of PAI.

14.
Nat Genet ; 50(1): 62-72, 2018 01.
Article in English | MEDLINE | ID: mdl-29180699

ABSTRACT

Mutations in IDH1 and IDH2 (encoding isocitrate dehydrogenase 1 and 2) drive the development of gliomas and other human malignancies. Mutant IDH1 induces epigenetic changes that promote tumorigenesis, but the scale and reversibility of these changes are unknown. Here, using human astrocyte and glioma tumorsphere systems, we generate a large-scale atlas of mutant-IDH1-induced epigenomic reprogramming. We characterize the reversibility of the alterations in DNA methylation, the histone landscape, and transcriptional reprogramming that occur following IDH1 mutation. We discover genome-wide coordinate changes in the localization and intensity of multiple histone marks and chromatin states. Mutant IDH1 establishes a CD24+ population with a proliferative advantage and stem-like transcriptional features. Strikingly, prolonged exposure to mutant IDH1 results in irreversible genomic and epigenetic alterations. Together, these observations provide unprecedented high-resolution molecular portraits of mutant-IDH1-dependent epigenomic reprogramming. These findings have substantial implications for understanding of mutant IDH function and for optimizing therapeutic approaches to targeting IDH-mutant tumors.


Subject(s)
Chromatin/metabolism , Epigenesis, Genetic , Isocitrate Dehydrogenase/genetics , Mutation , Transcriptome , Animals , Astrocytes/metabolism , Cells, Cultured , DNA Methylation , Endogenous Retroviruses , Female , Gene Expression Profiling , Genomic Instability , Glioma/genetics , Glioma/metabolism , Histone Code , Humans , Isocitrate Dehydrogenase/metabolism , Mice, Inbred NOD , Mice, SCID , Phenotype
15.
Cell Rep ; 21(3): 628-640, 2017 Oct 17.
Article in English | MEDLINE | ID: mdl-29045832

ABSTRACT

Loss or inactivation of the histone H3K27 demethylase UTX occurs in several malignancies, including multiple myeloma (MM). Using an isogenic cell system, we found that loss of UTX leads to deactivation of gene expression ultimately promoting the proliferation, clonogenicity, adhesion, and tumorigenicity of MM cells. Moreover, UTX mutant cells showed increased in vitro and in vivo sensitivity to inhibition of EZH2, a histone methyltransferase that generates H3K27me3. Such sensitivity was related to a decrease in the levels of IRF4 and c-MYC and an activation of repressors of IRF4 characteristic of germinal center B cells such as BCL6 and IRF1. Rebalance of H3K27me3 levels at specific genes through EZH2 inhibitors may be a therapeutic strategy in MM cases harboring UTX mutations.


Subject(s)
Enhancer of Zeste Homolog 2 Protein/antagonists & inhibitors , Histone Demethylases/deficiency , Multiple Myeloma/pathology , Nuclear Proteins/deficiency , Animals , Carcinogenesis/drug effects , Carcinogenesis/genetics , Carcinogenesis/pathology , Cell Adhesion/drug effects , Cell Adhesion/genetics , Cell Dedifferentiation/drug effects , Cell Dedifferentiation/genetics , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Proliferation/genetics , Cell Survival/drug effects , Cell Survival/genetics , Clone Cells , Enhancer of Zeste Homolog 2 Protein/metabolism , Gene Expression Profiling , Gene Expression Regulation, Neoplastic/drug effects , Histone Demethylases/metabolism , Histones/metabolism , Indazoles/pharmacology , Interferon Regulatory Factors/metabolism , Lysine/metabolism , Methylation , Mice , Mice, Inbred NOD , Mice, SCID , Multiple Myeloma/genetics , Mutation/genetics , Nuclear Proteins/metabolism , Phenotype , Pyridones/pharmacology , Transcription, Genetic/drug effects
16.
Elife ; 62017 09 12.
Article in English | MEDLINE | ID: mdl-28895528

ABSTRACT

The repeating subunit of chromatin, the nucleosome, includes two copies of each of the four core histones, and several recent studies have reported that asymmetrically-modified nucleosomes occur at regulatory elements in vivo. To probe the mechanisms by which histone modifications are read out, we designed an obligate pair of H3 heterodimers, termed H3X and H3Y, which we extensively validated genetically and biochemically. Comparing the effects of asymmetric histone tail point mutants with those of symmetric double mutants revealed that a single methylated H3K36 per nucleosome was sufficient to silence cryptic transcription in vivo. We also demonstrate the utility of this system for analysis of histone modification crosstalk, using mass spectrometry to separately identify modifications on each H3 molecule within asymmetric nucleosomes. The ability to generate asymmetric nucleosomes in vivo and in vitro provides a powerful and generalizable tool to probe the mechanisms by which H3 tails are read out by effector proteins in the cell.


Subject(s)
Histones/analysis , Nucleosomes/chemistry , Saccharomyces cerevisiae Proteins/analysis , Saccharomyces cerevisiae/chemistry , Histones/genetics , Mass Spectrometry/methods , Protein Processing, Post-Translational , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/growth & development , Saccharomyces cerevisiae Proteins/genetics , Synthetic Biology/methods
17.
Curr Opin Chem Biol ; 33: 142-50, 2016 08.
Article in English | MEDLINE | ID: mdl-27371874

ABSTRACT

Histones are a group of proteins with a high number of post-translational modifications, including methylation, acetylation, phosphorylation, and monoubiquitination, which play critical roles in every chromatin-templated activity. The quantitative analysis of these modifications using mass spectrometry (MS) has seen significant improvements over the last decade. It is now possible to perform large-scale surveys of dozens of histone marks and hundreds of their combinations on global chromatin. Here, we review the development of three MS strategies for analyzing histone modifications that have come to be known as Bottom Up, Middle Down, and Top Down. We also discuss challenges and innovative solutions for characterizing and quantifying complicated isobaric species arising from multiple modifications on the same histone molecule.


Subject(s)
Histones/analysis , Mass Spectrometry/methods , Proteomics , Amino Acid Sequence , Chromatography, Liquid
18.
Proc Natl Acad Sci U S A ; 113(8): 2092-7, 2016 Feb 23.
Article in English | MEDLINE | ID: mdl-26862167

ABSTRACT

Antibodies have a well-established modular architecture wherein the antigen-binding site residing in the antigen-binding fragment (Fab or Fv) is an autonomous and complete unit for antigen recognition. Here, we describe antibodies departing from this paradigm. We developed recombinant antibodies to trimethylated lysine residues on histone H3, important epigenetic marks and challenging targets for molecular recognition. Quantitative characterization demonstrated their exquisite specificity and high affinity, and they performed well in common epigenetics applications. Surprisingly, crystal structures and biophysical analyses revealed that two antigen-binding sites of these antibodies form a head-to-head dimer and cooperatively recognize the antigen in the dimer interface. This "antigen clasping" produced an expansive interface where trimethylated Lys bound to an unusually extensive aromatic cage in one Fab and the histone N terminus to a pocket in the other, thereby rationalizing the high specificity. A long-neck antibody format with a long linker between the antigen-binding module and the Fc region facilitated antigen clasping and achieved both high specificity and high potency. Antigen clasping substantially expands the paradigm of antibody-antigen recognition and suggests a strategy for developing extremely specific antibodies.


Subject(s)
Antibodies, Monoclonal/chemistry , Antigens/chemistry , Binding Sites, Antibody , Histones/chemistry , Immunoglobulin Fab Fragments/chemistry , Antibodies, Monoclonal/genetics , Antigens/genetics , Crystallography, X-Ray , Histones/genetics , Humans , Immunoglobulin Fab Fragments/genetics , Methylation , Protein Structure, Quaternary
19.
Mol Cell Proteomics ; 15(3): 776-90, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26272979

ABSTRACT

Histones, and their modifications, are critical components of cellular programming and epigenetic inheritance. Recently, cancer genome sequencing has uncovered driver mutations in chromatin modifying enzymes spurring high interest how such mutations change histone modification patterns. Here, we applied Top-Down mass spectrometry for the characterization of combinatorial modifications (i.e. methylation and acetylation) on full length histone H3 from human cell lines derived from multiple myeloma patients with overexpression of the histone methyltransferase MMSET as the result of a t(4;14) chromosomal translocation. Using the latest in Orbitrap-based technology for clean isolation of isobaric proteoforms containing up to 10 methylations and/or up to two acetylations, we provide extensive characterization of histone H3.1 and H3.3 proteoforms. Differential analysis of modifications by electron-based dissociation recapitulated antagonistic crosstalk between K27 and K36 methylation in H3.1, validating that full-length histone H3 (15 kDa) can be analyzed with site-specific assignments for multiple modifications. It also revealed K36 methylation in H3.3 was affected less by the overexpression of MMSET because of its higher methylation levels in control cells. The co-occurrence of acetylation with a minimum of three methyl groups in H3K9 and H3K27 suggested a hierarchy in the addition of certain modifications. Comparative analysis showed that high levels of MMSET in the myeloma-like cells drove the formation of hypermethyled proteoforms containing H3K36me2 co-existent with the repressive marks H3K9me2/3 and H3K27me2/3. Unique histone proteoforms with such "trivalent hypermethylation" (K9me2/3-K27me2/3-K36me2) were not discovered when H3.1 peptides were analyzed by Bottom-Up. Such disease-correlated proteoforms could link tightly to aberrant transcription programs driving cellular proliferation, and their precise description demonstrates that Top-Down mass spectrometry can now decode crosstalk involving up to three modified sites.


Subject(s)
Histone-Lysine N-Methyltransferase/genetics , Histones/metabolism , Mass Spectrometry/methods , Multiple Myeloma/genetics , Proteome/metabolism , Repressor Proteins/genetics , Cell Line, Tumor , Epigenesis, Genetic , Humans , Lysine/metabolism , Methylation , Multiple Myeloma/metabolism , Up-Regulation
20.
PLoS Genet ; 10(9): e1004566, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25188243

ABSTRACT

Overexpression of the histone methyltransferase MMSET in t(4;14)+ multiple myeloma patients is believed to be the driving factor in the pathogenesis of this subtype of myeloma. MMSET catalyzes dimethylation of lysine 36 on histone H3 (H3K36me2), and its overexpression causes a global increase in H3K36me2, redistributing this mark in a broad, elevated level across the genome. Here, we demonstrate that an increased level of MMSET also induces a global reduction of lysine 27 trimethylation on histone H3 (H3K27me3). Despite the net decrease in H3K27 methylation, specific genomic loci exhibit enhanced recruitment of the EZH2 histone methyltransferase and become hypermethylated on this residue. These effects likely contribute to the myeloma phenotype since MMSET-overexpressing cells displayed increased sensitivity to EZH2 inhibition. Furthermore, we demonstrate that such MMSET-mediated epigenetic changes require a number of functional domains within the protein, including PHD domains that mediate MMSET recruitment to chromatin. In vivo, targeting of MMSET by an inducible shRNA reversed histone methylation changes and led to regression of established tumors in athymic mice. Together, our work elucidates previously unrecognized interplay between MMSET and EZH2 in myeloma oncogenesis and identifies domains to be considered when designing inhibitors of MMSET function.


Subject(s)
DNA Methylation/genetics , Epigenesis, Genetic/genetics , Histone-Lysine N-Methyltransferase/metabolism , Histones/metabolism , Multiple Myeloma/genetics , Polycomb Repressive Complex 2/metabolism , Protein Binding/genetics , Animals , Cell Line , Cell Transformation, Neoplastic/genetics , Chromatin/genetics , Female , HEK293 Cells , Histone-Lysine N-Methyltransferase/genetics , Histones/genetics , Humans , Lysine/genetics , Mice , Mice, Inbred C57BL , Multiple Myeloma/metabolism , Polycomb Repressive Complex 2/genetics , RNA, Small Interfering/genetics
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