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Wang H, Qian L, Shang Z, Wang Z, Zhang Y, Cao C, Xiao H. Immobilized Titanium (IV) Ion Affinity Chromatography Contributes to Efficient Proteomics Analysis of Cellular Nucleic Acid-Binding Proteins. J Proteome Res 2021; 21:220-231. [PMID: 34780180 DOI: 10.1021/acs.jproteome.1c00788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cellular nucleic acid-binding proteins (NABPs), namely, DNA-binding proteins (DBPs) and RNA-binding proteins (RBPs), play important roles in many biological processes. However, extracting NABPs with high efficiency in living cells is challenging, which greatly limited their proteomics analysis and comprehensive characterization. Here, we discovered that titanium (IV) ion-immobilized metal affinity chromatography (Ti4+-IMAC) material could enrich DNA and RNA with high efficiency (96.82 ± 2.67 and 85.75 ± 2.99%, respectively). We therefore developed a Ti4+-IMAC method for the joint extraction of DBPs and RBPs. Through utilizing formaldehyde (FA) cross-linking, DBPs and RBPs were covalently linked to nucleic acids (NAs) and further denatured by organic solvents. After Ti4+-IMAC capture, 2000 proteins were identified in 293T cells, among which 417 DBPs and 999 RBPs were revealed, showing promising selectivity for NABPs. We further applied the Ti4+-IMAC capture method to lung cancer cell lines 95C and 95D, which have different tumor progression abilities. The DNA- and RNA-binding capabilities of many proteins have been dysregulated in 95D. Under our conditions, Ti4+-IMAC can be used as a selective and powerful tool for the comprehensive characterization of both DBPs and RBPs, which might be utilized to study their dynamic interactions with nucleic acids.
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Affiliation(s)
- Huiyu Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Liqiang Qian
- Department of Shanghai Lung Cancer Center, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Zhi Shang
- Institute of Clinical Immunology, Department of Liver Diseases, Central Laboratory, ShuGuang Hospital Affiliated to Shanghai University of Chinese Traditional Medicine, Shanghai 200021, China
| | - Zeyuan Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yan Zhang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chengxi Cao
- Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hua Xiao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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Genetic information from discordant sibling pairs points to ESRP2 as a candidate trans-acting regulator of the CF modifier gene SCNN1B. Sci Rep 2020; 10:22447. [PMID: 33384439 PMCID: PMC7775467 DOI: 10.1038/s41598-020-79804-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 12/10/2020] [Indexed: 11/08/2022] Open
Abstract
SCNN1B encodes the beta subunit of the epithelial sodium channel ENaC. Previously, we reported an association between SNP markers of SCNN1B gene and disease severity in cystic fibrosis-affected sibling pairs. We hypothesized that factors interacting with the SCNN1B genomic sequence are responsible for intrapair discordance. Concordant and discordant pairs differed at six SCNN1B markers (Praw = 0.0075, Pcorr = 0.0397 corrected for multiple testing). To identify the factors binding to these six SCNN1B SNPs, we performed an electrophoretic mobility shift assay and captured the DNA-protein complexes. Based on protein mass spectrometry data, the epithelial splicing regulatory protein ESRP2 was identified when using SCNN1B-derived probes and the ESRP2-SCNN1B interaction was independently confirmed by coimmunoprecipitation assays. We observed an alternative SCNN1B transcript and demonstrated in 16HBE14o- cells that levels of this transcript are decreased upon ESRP2 silencing by siRNA. Furthermore, we confirmed that mildly and severely affected siblings have different ESPR2 genetic backgrounds and that ESRP2 markers are linked to the response of CF patients' nasal epithelium to amiloride, indicating ENaC involvement (Pbest = 0.0131, Pcorr = 0.068 for multiple testing). Our findings demonstrate that sibling pairs clinically discordant for CF can be used to identify meaningful DNA regulatory elements and interacting factors.
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Galoian K, Luo S, Patel P. Analysis of IL6-protein complexes in chondrosarcoma. Biomed Rep 2018; 8:91-98. [PMID: 29399342 DOI: 10.3892/br.2017.1016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 10/26/2017] [Indexed: 11/06/2022] Open
Abstract
Cytokines produced in the tumour microenvironment serve important roles in cancer pathogenesis or in the supression of disease progression. Metastatic chondrosarcoma is a cancer of the cartilage, and our group previously reported from a human ELISA assay that interleukin 6 (IL6) expression in JJ012 chondrosarcoma cells was 86-fold lower than that in C28 chondrocytes, indicating its role as an anti-inflammatory and anti-tumorigenic factor. Additionally, to the best of our knowledge, the study was the first to demonstrate downregulation of IL6 in a human chondrosarcoma cell line. To fully elucidate the effect of this IL6 downregulation, it is important to identify protein complexes and components that bind IL6 and potentially affect its gene expression directly or indirectly. To investigate IL6-protein interactions leading to these differences in IL6 expression, the current study performed a gel retardation electrophoretic mobility shift assay (EMSA), followed by 2D gel phoresis, in-gel trypsin digestion and proteomic mass spectral analysis. The results indicated a presence of ubiquitination enzymes in C28 chondrocytes, while none were identified in JJ012 chondrosarcoma cells. While it seems counterintuitive, it may be that the absence of ubiquitination of certain factors leads to the downregulation of IL6 expression in human chondrosarcoma. Therefore, dysregulated ubiquitination may be among the possible mechanisms for the markedly reduced IL6 expression in chondrosarcoma.
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Affiliation(s)
- Karina Galoian
- Miller School of Medicine, Department of Orthopedics, University of Miami, Miami, FL 33136, USA
| | - Shihua Luo
- Miller School of Medicine, Department of Orthopedics, University of Miami, Miami, FL 33136, USA
| | - Parthik Patel
- Miller School of Medicine, Department of Orthopedics, University of Miami, Miami, FL 33136, USA
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Nagore LI, Jarrett HW. T(3): targeted proteomics of DNA-binding proteins. Anal Biochem 2015; 474:8-15. [PMID: 25644705 DOI: 10.1016/j.ab.2015.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/03/2015] [Accepted: 01/05/2015] [Indexed: 11/19/2022]
Abstract
A technique that allows the inclusion of a specific DNA to enrich and direct proteomic identification of transcription factors (TFs) while providing a route for high-throughput screening on a single platform would be valuable in investigations of gene expression and regulation. Polyvinylpyrrolidone binds DNA avidly while binding negligible amounts of protein. This observation is used in a proof-of-concept method to enrich for TFs by combining nuclear extract with a specific DNA sequence and immobilizing the DNA-protein complex on a polyvinylpyrrolidone (PVP)-coated MALDI (matrix-assisted laser desorption/ionization) plate. Any unbound proteins are washed away and further processed for analysis in a MALDI-TOF/TOF (tandem time-of-flight) mass spectrometer. Enrichment on a PVP-coated plate gives the unique advantage of purification, enzymatic digestion, and analysis on a single platform. The method is termed T(3) because it combines Targeted purification on a Target plate with Targeted proteomics. Validation was achieved in model experiments with a chimeric fusion protein, green fluorescent protein-CAAT enhancer binding protein (GFP-C/EBP), with an oligonucleotide containing the CAAT sequence. Both domains were identified with an expectation value of less than 10(-15) and more than 15% sequence coverage. The same oligonucleotide mixed with HEK293 cell nuclear extract allowed the unambiguous identification of native human C/EBP alpha with 24.3% sequence coverage.
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Affiliation(s)
- Linda I Nagore
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Harry W Jarrett
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA.
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Abstract
Southwestern blotting is a technique used to study DNA-protein interactions. This method detects specific DNA-binding proteins by incubating radiolabeled DNA with a gel blot, washing, and visualizing through autoradiography. A blot resulting from 1-dimensional SDS-PAGE reveals the molecular weight of the binding proteins. To increase separation and determine isoelectric point a 2-dimensional gel can be blotted. Additional dimensions of electrophoresis, such as a gel shift (EMSA), can precede isoelectric focusing and SDS-PAGE to further improve separation. Combined with other techniques, such as mass spectrometry, the DNA-binding protein can be identified.
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Nagore LI, Zhou Y, Nadeau RJ, Jia Y, Jarrett HW. Promoter trapping method: transcription factor purification using human telomerase reverse transcriptase promoter. Proteome Sci 2014; 12:53. [PMID: 25425973 PMCID: PMC4240814 DOI: 10.1186/s12953-014-0053-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 10/20/2014] [Indexed: 12/02/2022] Open
Abstract
Background Transcription factors bind to response elements on the promoter regions of genes to regulate transcriptional activity. One of the major problems with identifying transcription factors is their low abundance relative to other proteins in the cell. Developing a purification technique specific for transcription factors is crucial to the understanding of gene regulation. Promoter trapping is a method developed that uses the promoter regions as bait to trap proteins of interest and then purified using column chromatography. Here we utilize this technique to study the telomerase promoter, which has increased transcriptional activity in cancer cells. Gaining insight on how to control the enzyme at the promoter level may give new routes towards cancer treatments. Results Our findings show that the telomerase promoter (−170 - +91) and Promoter Trapping isolate a transcriptionally active and reproducible complex, when analyzed by liquid chromatography tandem mass spectrometry. We were also able to identify transcription factors, including AP-2 and SP1 known to bind this promoter, as well as show that these two proteins can bind to each other’s response element. Conclusion Here we focus on verifying the ability and versatility of Promoter Trapping coupled with additional well-characterized methods to identify already known factors responsible for telomerase transcriptional regulation. Electronic supplementary material The online version of this article (doi:10.1186/s12953-014-0053-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Linda I Nagore
- Department of Chemistry, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 USA
| | - YanWen Zhou
- Department of Chemistry, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 USA
| | - Robert J Nadeau
- Department of Chemistry, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 USA
| | - YinShan Jia
- Department of Chemistry, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 USA
| | - Harry W Jarrett
- Department of Chemistry, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 USA
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Nagore LI, Nadeau RJ, Guo Q, Jadhav YLA, Jarrett HW, Haskins WE. Purification and characterization of transcription factors. MASS SPECTROMETRY REVIEWS 2013; 32:386-398. [PMID: 23832591 PMCID: PMC3758410 DOI: 10.1002/mas.21369] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 11/19/2012] [Accepted: 11/19/2012] [Indexed: 06/02/2023]
Abstract
Transcription factors (TFs) are essential for the expression of all proteins, including those involved in human health and disease. However, TFs are resistant to proteomic characterization because they are frequently masked by more abundant proteins due to the limited dynamic range of capillary liquid chromatography-tandem mass spectrometry and protein database searching. Purification methods, particularly strategies that exploit the high affinity of TFs for DNA response elements (REs) on gene promoters, can enrich TFs prior to proteomic analysis to improve dynamic range and penetrance of the TF proteome. For example, trapping of TF complexes specific for particular REs has been achieved by recovering the element DNA-protein complex on solid supports. Additional methods for improving dynamic range include two- and three-dimensional gel electrophoresis incorporating electrophoretic mobility shift assays and Southwestern blotting for detection. Here we review methods for TF purification and characterization. We fully expect that future investigations will apply these and other methods to illuminate this important but challenging proteome.
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Affiliation(s)
- LI Nagore
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX, 78249
| | - RJ Nadeau
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX, 78249
- Protein Biomarkers Cores, University of Texas at San Antonio, San Antonio, TX, 78249
- Center for Interdisciplinary Health Research, University of Texas at San Antonio, San Antonio, TX, 78249
- Center for Research & Training in the Sciences, University of Texas at San Antonio, San Antonio, TX, 78249
| | - Q Guo
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX, 78249
- Protein Biomarkers Cores, University of Texas at San Antonio, San Antonio, TX, 78249
- Center for Interdisciplinary Health Research, University of Texas at San Antonio, San Antonio, TX, 78249
- Center for Research & Training in the Sciences, University of Texas at San Antonio, San Antonio, TX, 78249
| | - YLA Jadhav
- Pediatric Biochemistry Laboratory, University of Texas at San Antonio, San Antonio, TX, 78249
- RCMI Proteomics, University of Texas at San Antonio, San Antonio, TX, 78249
- Protein Biomarkers Cores, University of Texas at San Antonio, San Antonio, TX, 78249
- Center for Interdisciplinary Health Research, University of Texas at San Antonio, San Antonio, TX, 78249
- Center for Research & Training in the Sciences, University of Texas at San Antonio, San Antonio, TX, 78249
| | - HW Jarrett
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX, 78249
- Protein Biomarkers Cores, University of Texas at San Antonio, San Antonio, TX, 78249
- Center for Interdisciplinary Health Research, University of Texas at San Antonio, San Antonio, TX, 78249
| | - WE Haskins
- Pediatric Biochemistry Laboratory, University of Texas at San Antonio, San Antonio, TX, 78249
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX, 78249
- Departments of Biology, University of Texas at San Antonio, San Antonio, TX, 78249
- RCMI Proteomics, University of Texas at San Antonio, San Antonio, TX, 78249
- Protein Biomarkers Cores, University of Texas at San Antonio, San Antonio, TX, 78249
- Center for Interdisciplinary Health Research, University of Texas at San Antonio, San Antonio, TX, 78249
- Center for Research & Training in the Sciences, University of Texas at San Antonio, San Antonio, TX, 78249
- Departments of Medicine, Division of Hematology & Medical Oncology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229
- Cancer Therapy & Research Center, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229
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Chen Y, Yang LN, Cheng L, Tu S, Guo SJ, Le HY, Xiong Q, Mo R, Li CY, Jeong JS, Jiang L, Blackshaw S, Bi LJ, Zhu H, Tao SC, Ge F. Bcl2-associated athanogene 3 interactome analysis reveals a new role in modulating proteasome activity. Mol Cell Proteomics 2013; 12:2804-19. [PMID: 23824909 DOI: 10.1074/mcp.m112.025882] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bcl2-associated athanogene 3 (BAG3), a member of the BAG family of co-chaperones, plays a critical role in regulating apoptosis, development, cell motility, autophagy, and tumor metastasis and in mediating cell adaptive responses to stressful stimuli. BAG3 carries a BAG domain, a WW domain, and a proline-rich repeat (PXXP), all of which mediate binding to different partners. To elucidate BAG3's interaction network at the molecular level, we employed quantitative immunoprecipitation combined with knockdown and human proteome microarrays to comprehensively profile the BAG3 interactome in humans. We identified a total of 382 BAG3-interacting proteins with diverse functions, including transferase activity, nucleic acid binding, transcription factors, proteases, and chaperones, suggesting that BAG3 is a critical regulator of diverse cellular functions. In addition, we characterized interactions between BAG3 and some of its newly identified partners in greater detail. In particular, bioinformatic analysis revealed that the BAG3 interactome is strongly enriched in proteins functioning within the proteasome-ubiquitination process and that compose the proteasome complex itself, suggesting that a critical biological function of BAG3 is associated with the proteasome. Functional studies demonstrated that BAG3 indeed interacts with the proteasome and modulates its activity, sustaining cell survival and underlying resistance to therapy through the down-modulation of apoptosis. Taken as a whole, this study expands our knowledge of the BAG3 interactome, provides a valuable resource for understanding how BAG3 affects different cellular functions, and demonstrates that biologically relevant data can be harvested using this kind of integrated approach.
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Affiliation(s)
- Ying Chen
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
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