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Bertelli S, Zuccolini P, Gavazzo P, Pusch M. Molecular determinants underlying VRAC subunit dependent oxidation sensitivity. J Physiol 2022; 600:3965-3982. [PMID: 35861288 PMCID: PMC9540897 DOI: 10.1113/jp283321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/15/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract The volume‐regulated anion channel (VRAC) is formed by LRRC8 subunits. Besides their role in the maintenance of cell homeostasis, VRACs are critically involved in oxidative stress mechanisms: reactive oxygen species directly modulate VRACs in a subunit‐dependent manner. It was reported that LRRC8A–LRRC8E heteromeric channels are activated by oxidation, whereas LRRC8A–LRRC8C heteromers are inhibited. Here we adopted chimeric‐ as well as concatemeric‐based strategies to identify residues responsible for the divergent effect of oxidants. We identified two cysteines in the first two leucine rich repeats of LRRC8E, C424 and C448, as the targets of oxidation. Oxidation likely results in the formation of a disulfide bond between the two cysteines, which in turn induces a conformational change leading to channel activation. Additionally, we found that LRRC8C inhibition is caused by oxidation of the first methionine. We thus identified crucial molecular elements involved in channel activation, which are conceivably relevant in determining physiological ROS effects.
![]() Key points Volume‐regulated anion channels (VRACs) are heterohexameric complexes composed of an essential LRRC8A subunit and a variable number of LRRC8B–E subunits. VRACs are directly regulated by oxidation, with LRRC8A–LRRC8E heteromers being potentiated and LRRC8A–LRRC8C heteromers being inhibited by oxidation. We identified two LRRC8E specific intracellular cysteines that form a disulfide bond upon oxidation leading to LRRC8A–LRRC8E potentiation. Inhibition of LRRC8A–LRRC8C heteromers is mediated by the oxidation of the start methionine, being additionally dependent on the identity of the LRR domain. Besides providing physiological insights concerning the outcome of reactive oxygen species modulation, the results point to key structural elements involved in VRAC activation.
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Affiliation(s)
- Sara Bertelli
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy.,Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Paolo Zuccolini
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Paola Gavazzo
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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2
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Guillaubez JV, Pitrat D, Bretonnière Y, Lemoine J, Girod M. Unbiased Detection of Cysteine Sulfenic Acid by 473 nm Photodissociation Mass Spectrometry: Toward Facile In Vivo Oxidative Status of Plasma Proteins. Anal Chem 2021; 93:2907-2915. [PMID: 33522244 DOI: 10.1021/acs.analchem.0c04484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cysteine (Cys) is prone to diverse post-translational modifications in proteins, including oxidation into sulfenic acid (Cys-SOH) by reactive oxygen species generated under oxidative stress. Detection of low-concentration and metastable Cys-SOH within complex biological matrices is challenging due to the dynamic concentration range of proteins in the samples. Herein, visible laser-induced dissociation (LID) implemented in a mass spectrometer was used for streamlining the detection of Cys oxidized proteins owing to proper derivatization of Cys-SOH with a chromophore tag functionalized with a cyclohexanedione group. Once grafted, peptides undergo a high fragmentation yield under LID, leading concomitantly to informative backbone ions and to a chromophore reporter ion. Seventy-nine percent of the Cys-containing tryptic peptides derived from human serum albumin and serotransferrin tracked by parallel reaction monitoring (PRM) were detected as targets subjected to oxidation. These candidates as well as Cys-containing peptides predicted by in silico trypsin digestion of five other human plasma proteins were then tracked in real plasma samples to pinpoint the endogenous Cys-SOH subpopulation. Most of the targeted peptides were detected in all plasma samples by LID-PRM, with significant differences in their relative amounts. By eliminating the signal of interfering co-eluted compounds, LID-PRM surpasses conventional HCD (higher-energy collisional dissociation)-PRM in detecting grafted Cys-SOH-containing peptides and allows now to foresee clinical applications in large human cohorts.
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Affiliation(s)
- Jean-Valery Guillaubez
- Univ Lyon, CNRS, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, UMR 5280, 5 rue de la Doua, Villeurbanne F-69100, France
| | - Delphine Pitrat
- Univ Lyon, ENS de Lyon, CNRS UMR 5182, Université Lyon I, Laboratoire de Chimie, F-69342 Lyon, France
| | - Yann Bretonnière
- Univ Lyon, ENS de Lyon, CNRS UMR 5182, Université Lyon I, Laboratoire de Chimie, F-69342 Lyon, France
| | - Jérôme Lemoine
- Univ Lyon, CNRS, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, UMR 5280, 5 rue de la Doua, Villeurbanne F-69100, France
| | - Marion Girod
- Univ Lyon, CNRS, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, UMR 5280, 5 rue de la Doua, Villeurbanne F-69100, France
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Samet JM, Wages PA. Oxidative Stress from Environmental Exposures. CURRENT OPINION IN TOXICOLOGY 2018; 7:60-66. [PMID: 30079382 PMCID: PMC6069528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Oxidative stress is arguably the most common mechanism in the toxicology of environmental agents, unifying the action of broad classes of physichochemically disparate environmental pollutants, including oxidant gases, organic compounds, particulate surfaces, and metal ions. As advances in redox biology identify previously unrecognized targets for disruption by exposure to xenobiotics, redox toxicology has emerged as a new field of investigation. Environmental contaminants can induce oxidative stress on cells through mechanisms that are direct, indirect or involve the disruption of metabolic or bioenergetic processes that are regulated by thiol redox switches. Live-cell imaging has proven to be a powerful approach to the study of environmental oxidative stress. Cells are equipped with multiple complementary energy-dependent systems for maintaining redox homeostasis in the face of environmental oxidative stress.
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Affiliation(s)
- James M. Samet
- Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC 27707
| | - Phillip A. Wages
- Department of Chemistry, Vanderbilt University, Nashville, TN 49795
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Glycan structure of Gc Protein-derived Macrophage Activating Factor as revealed by mass spectrometry. Arch Biochem Biophys 2016; 606:167-79. [PMID: 27503803 DOI: 10.1016/j.abb.2016.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/03/2016] [Accepted: 08/04/2016] [Indexed: 01/22/2023]
Abstract
Disagreement exists regarding the O-glycan structure attached to human vitamin D binding protein (DBP). Previously reported evidence indicated that the O-glycan of the Gc1S allele product is the linear core 1 NeuNAc-Gal-GalNAc-Thr trisaccharide. Here, glycan structural evidence is provided from glycan linkage analysis and over 30 serial glycosidase-digestion experiments which were followed by analysis of the intact protein by electrospray ionization mass spectrometry (ESI-MS). Results demonstrate that the O-glycan from the Gc1F protein is the same linear trisaccharide found on the Gc1S protein and that the hexose residue is galactose. In addition, the putative anti-cancer derivative of DBP known as Gc Protein-derived Macrophage Activating Factor (GcMAF, which is formed by the combined action of β-galactosidase and neuraminidase upon DBP) was analyzed intact by ESI-MS, revealing that the activating E. coli β-galactosidase cleaves nothing from the protein-leaving the glycan structure of active GcMAF as a Gal-GalNAc-Thr disaccharide, regardless of the order in which β-galactosidase and neuraminidase are applied. Moreover, glycosidase digestion results show that α-N-Acetylgalactosamindase (nagalase) lacks endoglycosidic function and only cleaves the DBP O-glycan once it has been trimmed down to a GalNAc-Thr monosaccharide-precluding the possibility of this enzyme removing the O-glycan trisaccharide from cancer-patient DBP in vivo.
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Kenche H, Ye ZW, Vedagiri K, Richards DM, Gao XH, Tew KD, Townsend DM, Blumental-Perry A. Adverse Outcomes Associated with Cigarette Smoke Radicals Related to Damage to Protein-disulfide Isomerase. J Biol Chem 2016; 291:4763-78. [PMID: 26728460 DOI: 10.1074/jbc.m115.712331] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 12/19/2022] Open
Abstract
Identification of factors contributing to the development of chronic obstructive pulmonary disease (COPD) is crucial for developing new treatments. An increase in the levels of protein-disulfide isomerase (PDI), a multifaceted endoplasmic reticulum resident chaperone, has been demonstrated in human smokers, presumably as a protective adaptation to cigarette smoke (CS) exposure. We found a similar increase in the levels of PDI in the murine model of COPD. We also found abnormally high levels (4-6 times) of oxidized and sulfenilated forms of PDI in the lungs of murine smokers compared with non-smokers. PDI oxidation progressively increases with age. We begin to delineate the possible role of an increased ratio of oxidized PDI in the age-related onset of COPD by investigating the impact of exposure to CS radicals, such as acrolein (AC), hydroxyquinones (HQ), peroxynitrites (PN), and hydrogen peroxide, on their ability to induce unfolded protein response (UPR) and their effects on the structure and function of PDIs. Exposure to AC, HQ, PN, and CS resulted in cysteine and tyrosine nitrosylation leading to an altered three-dimensional structure of the PDI due to a decrease in helical content and formation of a more random coil structure, resulting in protein unfolding, inhibition of PDI reductase and isomerase activity in vitro and in vivo, and subsequent induction of endoplasmic reticulum stress response. Addition of glutathione prevented the induction of UPR, and AC and HQ induced structural changes in PDI. Exposure to PN and glutathione resulted in conjugation of PDI possibly at active site tyrosine residues. The findings presented here propose a new role of PDI in the pathogenesis of COPD and its age-dependent onset.
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Affiliation(s)
- Harshavardhan Kenche
- From the Anderson Cancer Institute, Memorial Health University Medical Center, Savannah, Georgia 31404
| | - Zhi-Wei Ye
- the College of Pharmacy, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kokilavani Vedagiri
- From the Anderson Cancer Institute, Memorial Health University Medical Center, Savannah, Georgia 31404
| | - Dylan M Richards
- From the Anderson Cancer Institute, Memorial Health University Medical Center, Savannah, Georgia 31404
| | - Xing-Huang Gao
- Genetics, Case Western Reserve University, Cleveland, Ohio 44106, and
| | - Kenneth D Tew
- the College of Pharmacy, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Danyelle M Townsend
- the College of Pharmacy, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Anna Blumental-Perry
- From the Anderson Cancer Institute, Memorial Health University Medical Center, Savannah, Georgia 31404, the Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia 31404, the Departments of Surgery and
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Rehder DS, Gundberg CM, Booth SL, Borges CR. Gamma-carboxylation and fragmentation of osteocalcin in human serum defined by mass spectrometry. Mol Cell Proteomics 2015; 14:1546-55. [PMID: 25855755 DOI: 10.1074/mcp.m114.047621] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Indexed: 11/06/2022] Open
Abstract
Serum osteocalcin (Oc) concentration is a highly specific measure of bone turnover, but its circulating proteoform(s) have not been well defined. Based on immunological methods, the major forms are thought to be the intact polypeptide and a large N-terminal-mid molecule fragment for which there is no consensus on the precise sequence. Vitamin K-dependent gamma (γ)-carboxylated variants of Oc are also found in circulation but there have been no methods that can define how many of the three potential γ-carboxyglutamic acid (Gla) residues are γ-carboxylated or provide their relative abundances. Recent reports that uncarboxylated and partially γ-carboxylated Oc forms have hormonal function underscore the need for precise evaluation of Oc at all three potential γ-carboxylation sites. Herein, mass spectrometric immunoassay (MSIA) was used to provide qualitative and semiquantitative (relative percent abundance) information on Oc molecular variants as they exist in individual plasma and serum samples. Following verification that observable Oc proteoforms were accurately assigned and not simply ex vivo artifacts, MALDI-MSIA and ESI-MSIA were used to assess the relative abundance of Oc truncation and γ-carboxylation, respectively, in plasma from 130 patients enrolled in vitamin K supplementation trials. Human Oc was found to circulate in over a dozen truncated forms with each of these displaying anywhere from 0-3 Gla residues. The relative abundance of truncated forms was consistent and unaffected by vitamin K supplementation. In contrast, when compared with placebo, vitamin K supplementation dramatically increased the fractional abundance of Oc with three Gla residues, corresponding to a decrease in the fractional abundance of Oc with zero Gla residues. These findings unequivocally document that increased vitamin K intake reduces the uncarboxylated form of Oc. Several reports of a positive effect of vitamin K intake on insulin sensitivity in humans have shown that un- or undercarboxylation of Oc, unlike in mice, is not associated with insulin resistance. Analyses similar to those described here will be useful to understand the functional significance of Oc γ-carboxylation in human health and disease.
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Affiliation(s)
- Douglas S Rehder
- From the ‡The Biodesign Institute at Arizona State University, Tempe, Arizona
| | - Caren M Gundberg
- ¶Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut
| | - Sarah L Booth
- ‖Jean Mayer USDA Human Nutrition Center on Aging at Tufts University, Boston, Massachusetts
| | - Chad R Borges
- From the ‡The Biodesign Institute at Arizona State University, Tempe, Arizona; §Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona;
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Klomsiri C, Rogers LC, Soito L, McCauley AK, King SB, Nelson KJ, Poole LB, Daniel LW. Endosomal H2O2 production leads to localized cysteine sulfenic acid formation on proteins during lysophosphatidic acid-mediated cell signaling. Free Radic Biol Med 2014; 71:49-60. [PMID: 24657741 PMCID: PMC4064372 DOI: 10.1016/j.freeradbiomed.2014.03.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/10/2014] [Accepted: 03/14/2014] [Indexed: 12/17/2022]
Abstract
Lysophosphatidic acid (LPA) is a growth factor for many cells including prostate and ovarian cancer-derived cell lines. LPA stimulates H2O2 production which is required for growth. However, there are significant gaps in our understanding of the spatial and temporal regulation of H2O2-dependent signaling and the way in which signals are transmitted following receptor activation. Herein, we describe the use of two reagents, DCP-Bio1 and DCP-Rho1, to evaluate the localization of active protein oxidation after LPA stimulation by detection of nascent protein sulfenic acids. We found that LPA stimulation causes internalization of LPA receptors into early endosomes that contain NADPH oxidase components and are sites of H2O2 generation. DCP-Rho1 allowed visualization of sulfenic acid formation, indicative of active protein oxidation, which was stimulated by LPA and decreased by an LPA receptor antagonist. Protein oxidation sites colocalized with LPAR1 and the endosomal marker EEA1. Concurrent with the generation of these redox signaling-active endosomes (redoxosomes) is the H2O2- and NADPH oxidase-dependent oxidation of Akt2 and PTP1B detected using DCP-Bio1. These new approaches therefore enable detection of active, H2O2-dependent protein oxidation linked to cell signaling processes. DCP-Rho1 may be a particularly useful protein oxidation imaging agent enabling spatial resolution due to the transient nature of the sulfenic acid intermediate it detects.
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Affiliation(s)
- Chananat Klomsiri
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
| | - LeAnn C Rogers
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
| | - Laura Soito
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
| | - Anita K McCauley
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA.
| | - S Bruce King
- Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109, USA.
| | - Kimberly J Nelson
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
| | - Leslie B Poole
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
| | - Larry W Daniel
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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9
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Furdui CM, Poole LB. Chemical approaches to detect and analyze protein sulfenic acids. MASS SPECTROMETRY REVIEWS 2014; 33:126-46. [PMID: 24105931 PMCID: PMC3946320 DOI: 10.1002/mas.21384] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 04/03/2013] [Accepted: 04/04/2013] [Indexed: 05/08/2023]
Abstract
Orchestration of many processes relying on intracellular signal transduction is recognized to require the generation of hydrogen peroxide as a second messenger, yet relatively few molecular details of how this oxidant acts to regulate protein function are currently understood. This review describes emerging chemical tools and approaches that can be applied to study protein oxidation in biological systems, with a particular emphasis on a key player in protein redox regulation, cysteine sulfenic acid. While sulfenic acids (within purified proteins or simple mixtures) are detectable by physical approaches like X-ray crystallography, nuclear magnetic resonance and mass spectrometry, the propensity of these moieties to undergo further modification in complex biological systems has necessitated the development of chemical probes, reporter groups and analytical approaches to allow for their selective detection and quantification. Provided is an overview of techniques that are currently available for the study of sulfenic acids, and some of the biologically meaningful data that have been collected using such approaches.
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Affiliation(s)
- Cristina M. Furdui
- Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
| | - Leslie B. Poole
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
- Correspondence to: Leslie B. Poole, Department of Biochemistry, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157; ; telephone: 336-716-6711
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10
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Pang HB, Braun GB, She ZG, Kotamraju VR, Sugahara KN, Teesalu T, Ruoslahti E. A free cysteine prolongs the half-life of a homing peptide and improves its tumor-penetrating activity. J Control Release 2013; 175:48-53. [PMID: 24345789 DOI: 10.1016/j.jconrel.2013.12.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 11/26/2013] [Accepted: 12/05/2013] [Indexed: 11/16/2022]
Abstract
The accessibility of extravascular tumor tissue to drugs is critical for therapeutic efficacy. We previously described a tumor-targeting peptide (iRGD) that elicits active transport of drugs and macromolecules (covalently coupled or co-administered) across the vascular wall into tumor tissue. Short peptides (iRGD is a 9-amino acid cyclic peptide) generally have a plasma half-life measured in minutes. Since short half-life limits the window of activity obtained with a bolus injection of iRGD, we explored to extend the half-life of the peptide. We show here that addition of a cysteine residue prolongs the plasma half-life of iRGD and increases the accumulation of the peptide in tumors. This modification prolongs the activity of iRGD in inducing macromolecular extravasation and leads to greater drug accumulation in tumors than is obtained with the unmodified peptide. This effect is mediated by covalent binding of iRGD to plasma albumin through a disulfide bond. Our study provides a simple strategy to improve peptide pharmacokinetics and activity. Applied to RGD, it provides a means to increase the entry of therapeutic agents into tumors.
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Affiliation(s)
- Hong-Bo Pang
- Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Gary B Braun
- Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Zhi-Gang She
- Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Venkata R Kotamraju
- Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Kazuki N Sugahara
- Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA; Department of Surgery, Columbia University, College of Physicians and Surgeons, New York, NY, USA
| | - Tambet Teesalu
- Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA; Laboratory of Cancer Biology, Centre of Excellence for Translational Medicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu 50411, Estonia
| | - Erkki Ruoslahti
- Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA; Center for Nanomedicine, University of California Santa Barbara, Santa Barbara, CA 93106-9610, USA; Department of Cell, Molecular and Developmental Biology, Bio II, Rm. #3119, University of California Santa Barbara, Santa Barbara, CA 93106-9610, USA.
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11
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Freeman F, Adesina IT, La JL, Lee JY, Poplawski AA. Conformers of cysteine and cysteine sulfenic acid and mechanisms of the reaction of cysteine sulfenic acid with 5,5-dimethyl-1,3-cyclohexanedione (dimedone). J Phys Chem B 2013; 117:16000-12. [PMID: 24274619 DOI: 10.1021/jp409022m] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Equilibrium and molecular structures, relative energies of conformers of gaseous cysteine (Cys, C, Cys-SH) and gaseous cysteine sulfenic acid (Cys-SOH), and the mechanisms of the reaction of Cys-SOH with 3-hydroxy-5,5-dimethyl-2-cyclohexen-1-one, the enol tautomer of 5,5-dimethyl-1,3-cyclohexadione (dimedone), have been studied using BD(T), CCSD(T), and QCISD(T) with the cc-pVTZ basis set and using MP2 and the density functionals B3LYP, B3PW91, PBE1PBE, PBEh1PBE, M062X, CAM-B3LYP, and WB97XD with the 6-311+G(d,p) basis set. The structures of the six lowest energy conformers of gaseous Cys-SOH are compared with the six lowest energy conformers of gaseous cysteine (Cys-SH). The relative stability of the six lowest energy conformers of Cys-SH and Cys-SOH are influenced by the interplay among many factors including dispersive effects, electronic effects, electrostatic interactions, hydrogen bonds, inductive effects, and noncovalent interactions. The mechanism of the addition of the lowest energy conformer of cysteine sulfenic acid (Cys-SOH) to dimedone may proceed through a six-membered ring transition state structure and through cyclic hydrogen-bonded transition state structures with one water molecule (8-membered ring), with two water molecules (10-membered ring), and with three water molecules (12-membered ring). Inclusion of one and two water molecules in the transition state structures lowers the activation barrier, whereas inclusion of a third water molecule raises the activation barrier.
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Affiliation(s)
- Fillmore Freeman
- Department of Chemistry, University of California, Irvine , Irvine, California 92697, United States
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12
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Yassine H, Borges CR, Schaab MR, Billheimer D, Stump C, Reaven P, Lau SS, Nelson R. Mass spectrometric immunoassay and MRM as targeted MS-based quantitative approaches in biomarker development: potential applications to cardiovascular disease and diabetes. Proteomics Clin Appl 2013; 7:528-40. [PMID: 23696124 DOI: 10.1002/prca.201200028] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 02/04/2013] [Accepted: 03/30/2013] [Indexed: 12/29/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is an important risk factor for cardiovascular disease (CVD)--the leading cause of death in the United States. Yet not all subjects with T2DM are at equal risk for CVD complications; the challenge lies in identifying those at greatest risk. Therapies directed toward treating conventional risk factors have failed to significantly reduce this residual risk in T2DM patients. Thus newer targets and markers are needed for the development and testing of novel therapies. Herein we review two complementary MS-based approaches--mass spectrometric immunoassay (MSIA) and MS/MS as MRM--for the analysis of plasma proteins and PTMs of relevance to T2DM and CVD. Together, these complementary approaches allow for high-throughput monitoring of many PTMs and the absolute quantification of proteins near the low picomolar range. In this review article, we discuss the clinical relevance of the high density lipoprotein (HDL) proteome and Apolipoprotein A-I PTMs to T2DM and CVD as well as provide illustrative MSIA and MRM data on HDL proteins from T2DM patients to provide examples of how these MS approaches can be applied to gain new insight regarding cardiovascular risk factors. Also discussed are the reproducibility, interpretation, and limitations of each technique with an emphasis on their capacities to facilitate the translation of new biomarkers into clinical practice.
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Affiliation(s)
- Hussein Yassine
- Department of Medicine, University of Southern California, Los Angeles, CA, USA
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Luanpitpong S, Chanvorachote P, Stehlik C, Tse W, Callery PS, Wang L, Rojanasakul Y. Regulation of apoptosis by Bcl-2 cysteine oxidation in human lung epithelial cells. Mol Biol Cell 2013; 24:858-69. [PMID: 23363601 PMCID: PMC3596255 DOI: 10.1091/mbc.e12-10-0747] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Bcl-2 interacts with ERK to suppress apoptosis. Hydrogen peroxide disrupts the interaction through Bcl-2 cysteine oxidation, which promotes apoptosis. These findings provide a novel redox regulatory mechanism that controls apoptosis via Bcl-2 cysteine oxidation, which could aid in the understanding of pathogenesis under oxidative stress conditions. Hydrogen peroxide is a key mediator of oxidative stress known to be important in various cellular processes, including apoptosis. B-cell lymphoma-2 (Bcl-2) is an oxidative stress–responsive protein and a key regulator of apoptosis; however, the underlying mechanisms of oxidative regulation of Bcl-2 are not well understood. The present study investigates the direct effect of H2O2 on Bcl-2 cysteine oxidation as a potential mechanism of apoptosis regulation. Exposure of human lung epithelial cells to H2O2 induces apoptosis concomitant with cysteine oxidation and down-regulation of Bcl-2. Inhibition of Bcl-2 oxidation by antioxidants or by site-directed mutagenesis of Bcl-2 at Cys-158 and Cys-229 abrogates the effects of H2O2 on Bcl-2 and apoptosis. Immunoprecipitation and confocal microscopic studies show that Bcl-2 interacts with mitogen-activated protein kinase (extracellular signal-regulated kinase 1/2 [ERK1/2]) to suppress apoptosis and that this interaction is modulated by cysteine oxidation of Bcl-2. The H2O2-induced Bcl-2 cysteine oxidation interferes with Bcl-2 and ERK1/2 interaction. Mutation of the cysteine residues inhibits the disruption of Bcl-2–ERK complex, as well as the induction of apoptosis by H2O2. Taken together, these results demonstrate the critical role of Bcl-2 cysteine oxidation in the regulation of apoptosis through ERK signaling. This new finding reveals crucial redox regulatory mechanisms that control the antiapoptotic function of Bcl-2.
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Affiliation(s)
- Sudjit Luanpitpong
- Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506, USA
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Kumar V, Calamaras TD, Haeussler D, Colucci WS, Cohen RA, McComb ME, Pimentel D, Bachschmid MM. Cardiovascular redox and ox stress proteomics. Antioxid Redox Signal 2012; 17:1528-59. [PMID: 22607061 PMCID: PMC3448941 DOI: 10.1089/ars.2012.4706] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
SIGNIFICANCE Oxidative post-translational modifications (OPTMs) have been demonstrated as contributing to cardiovascular physiology and pathophysiology. These modifications have been identified using antibodies as well as advanced proteomic methods, and the functional importance of each is beginning to be understood using transgenic and gene deletion animal models. Given that OPTMs are involved in cardiovascular pathology, the use of these modifications as biomarkers and predictors of disease has significant therapeutic potential. Adequate understanding of the chemistry of the OPTMs is necessary to determine what may occur in vivo and which modifications would best serve as biomarkers. RECENT ADVANCES By using mass spectrometry, advanced labeling techniques, and antibody identification, OPTMs have become accessible to a larger proportion of the scientific community. Advancements in instrumentation, database search algorithms, and processing speed have allowed MS to fully expand on the proteome of OPTMs. In addition, the role of enzymatically reversible OPTMs has been further clarified in preclinical models. CRITICAL ISSUES The identification of OPTMs suffers from limitations in analytic detection based on the methodology, instrumentation, sample complexity, and bioinformatics. Currently, each type of OPTM requires a specific strategy for identification, and generalized approaches result in an incomplete assessment. FUTURE DIRECTIONS Novel types of highly sensitive MS instrumentation that allow for improved separation and detection of modified proteins and peptides have been crucial in the discovery of OPTMs and biomarkers. To further advance the identification of relevant OPTMs in advanced search algorithms, standardized methods for sample processing and depository of MS data will be required.
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Affiliation(s)
- Vikas Kumar
- Vascular Biology Section, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118, USA
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Oran PE, Jarvis JW, Borges CR, Sherma ND, Nelson RW. Mass spectrometric immunoassay of intact insulin and related variants for population proteomics studies. Proteomics Clin Appl 2011; 5:454-9. [PMID: 21656909 DOI: 10.1002/prca.201000112] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 02/24/2011] [Accepted: 03/03/2011] [Indexed: 11/10/2022]
Abstract
PURPOSE The purpose of the work presented herein was to develop a high-throughput assay for the quantification of human insulin in plasma samples while simultaneously detecting, with high mass accuracy, any additional variant forms of insulin that might be present in each sample. EXPERIMENTAL DESIGN A mass spectrometric immunoassay (MSIA) was designed in which anti-human insulin antibodies were immobilized to commercially available mass spectrometric immunoassay pipette tips and used to capture insulin and related protein variants from human plasma. RESULTS Standard curves for insulin exhibited linearity (average R(2) for three days of analysis=0.99) and assay concentration limits of detection and limits of quantification for insulin were found to be 1 and 15 pM, respectively. Estimated coefficient of variations for inter-day experiments (n=3 days) were <8%. Simultaneously, the assay was shown to detect and identify insulin metabolites and synthetic insulin analogs (e.g. Lantus). Notably, insulin variants not known to exist in plasma were detected in diabetics. CONCLUSIONS AND CLINICAL RELEVANCE This introductory study sets a foundation toward the screening of large populations to investigate insulin isoforms, isoform frequencies, and their quantification.
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Affiliation(s)
- Paul E Oran
- Molecular Biomarkers, The Biodesign Institute at Arizona State University, Tempe, AZ 85287, USA
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Jacob C, Ba LA. Open Season for Hunting and Trapping Post-translational Cysteine Modifications in Proteins and Enzymes. Chembiochem 2011; 12:841-4. [DOI: 10.1002/cbic.201100068] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Indexed: 11/06/2022]
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Seo YH, Carroll KS. Quantification of protein sulfenic acid modifications using isotope-coded dimedone and iododimedone. Angew Chem Int Ed Engl 2011; 50:1342-5. [PMID: 21290508 DOI: 10.1002/anie.201007175] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Indexed: 11/06/2022]
Affiliation(s)
- Young Ho Seo
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, 49109, USA
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Seo YH, Carroll KS. Quantification of Protein Sulfenic Acid Modifications Using Isotope-Coded Dimedone and Iododimedone. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201007175] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kettenhofen NJ, Wood MJ. Formation, reactivity, and detection of protein sulfenic acids. Chem Res Toxicol 2010; 23:1633-46. [PMID: 20845928 DOI: 10.1021/tx100237w] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
It has become clear in recent decades that the post-translational modification of protein cysteine residues is a crucial regulatory event in biology. Evidence supports the reversible oxidation of cysteine thiol groups as a mechanism of redox-based signal transduction, while the accumulation of proteins with irreversible thiol oxidations is a hallmark of stress-induced cellular damage. The initial formation of cysteine-sulfenic acid (SOH) derivatives, along with the reactive properties of this functional group, serves as a crossroads whereby the local redox environment may dictate the progression of either regulatory or pathological outcomes. Protein-SOH are established as transient intermediates in the formation of more stable cysteine oxidation products both under basal conditions and in response to several redox-active extrinsic compounds. This review details both direct and multistep chemical routes proposed to generate protein-SOH, the spectrum of secondary reactions that may follow their initial formation and the arsenal of experimental tools available for their detection. Pioneering studies that have provided a framework for our current understanding of protein-SOH as well as state-of-the-art proteomic strategies designed for global assessments of this post-translational modification are highlighted.
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Affiliation(s)
- Nicholas J Kettenhofen
- Department of Environmental Toxicology, University of California, Davis, California 95616, USA
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