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Mykhailenko O, Korinek M, Ivanauskas L, Bezruk I, Myhal A, Petrikaitė V, El-Shazly M, Lin GH, Lin CY, Yen CH, Chen BH, Georgiyants V, Hwang TL. Qualitative and Quantitative Analysis of Ukrainian Iris Species: A Fresh Look on Their Antioxidant Content and Biological Activities. Molecules 2020; 25:molecules25194588. [PMID: 33050063 PMCID: PMC7582944 DOI: 10.3390/molecules25194588] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/23/2020] [Accepted: 10/02/2020] [Indexed: 01/13/2023] Open
Abstract
The major groups of antioxidant compounds (isoflavonoids, xanthones, hydroxycinnamic acids) in the rhizome methanol extracts of four Ukrainian Iris sp. (Iris pallida, Iris hungarica, Iris sibirica, and Iris variegata) were qualitatively and quantitatively analyzed using HPLC-DAD and UPLC-MS/MS. Gallic acid, caffeic acid, mangiferin, tectoridin, irigenin, iristectorigenin B, irisolidone, 5,6-dihydroxy-7,8,3',5'-tetramethoxyisoflavone, irisolidone-7-O-β-d-glucopyranoside, germanaism B, and nigricin were recognized by comparing their UV/MS spectra, chromatographic retention time (tR) with those of standard reference compounds. I. hungarica and I. variegata showed the highest total amount of phenolic compounds. Germanaism B was the most abundant component in the rhizomes of I. variegata (7.089 ± 0.032 mg/g) and I. hungarica (6.285 ± 0.030 mg/g). The compound analyses showed good calibration curve linearity (r2 > 0.999) and low detection and quantifications limit. These results validated the method for its use in the simultaneous quantitative evaluation of phenolic compounds in the studied Iris sp. I. hungarica and I. variegata rhizomes exhibited antioxidant activity, as demonstrated by the HPLC-ABTS system and NRF2 expression assay and anti-inflammatory activity on respiratory burst in human neutrophils. Moreover, the extracts showed anti-allergic and cytotoxic effects against cancer cells. Anti-coronavirus 229E and lipid formation activities were also evaluated. In summary, potent antioxidant marker compounds were identified in the examined Iris sp.
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Affiliation(s)
- Olha Mykhailenko
- Department of Pharmaceutical Chemistry, National University of Pharmacy, 4-Valentinivska st., 61168 Kharkiv, Ukraine; (O.M.); (I.B.); (A.M.)
| | - Michal Korinek
- Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (M.K.); (B.-H.C.)
- Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Research Center for Chinese Herbal Medicine, Research Center for Food and Cosmetic Safety, and Graduate Institute of Health Industry Technology, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 33302, Taiwan
| | - Liudas Ivanauskas
- Department of Analytical and Toxicological Chemistry, Lithuanian University of Health Sciences, A. Mickevičiaus g. 9, LT 44307 Kaunas, Lithuania;
| | - Ivan Bezruk
- Department of Pharmaceutical Chemistry, National University of Pharmacy, 4-Valentinivska st., 61168 Kharkiv, Ukraine; (O.M.); (I.B.); (A.M.)
| | - Artem Myhal
- Department of Pharmaceutical Chemistry, National University of Pharmacy, 4-Valentinivska st., 61168 Kharkiv, Ukraine; (O.M.); (I.B.); (A.M.)
| | - Vilma Petrikaitė
- Laboratory of Drug Targets Histopathology, Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 13, LT-50162 Kaunas, Lithuania;
- Institute of Physiology and Pharmacology, Faculty of Medicine, Lithuanian University of Health Sciences, Mickeviciaus g. 9, LT-44307 Kaunas, Lithuania
- Institute of Biotechnology, Life Sciences Centre, Vilnius University, Saulėtekio al. 7, LT-10257 Vilnius, Lithuania
| | - Mohamed El-Shazly
- Department of Pharmaceutical Biology, Faculty of Pharmacy and Biotechnology, the German University in Cairo, Cairo 11835, Egypt;
- Department of Pharmacognosy, Faculty of Pharmacy, Ain Shams University, African Union Organization Street, Abbassia, Cairo 11566, Egypt
| | - Guan-Hua Lin
- Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; (G.-H.L.); (C.-Y.L.)
| | - Chia-Yi Lin
- Department of Biochemistry and Molecular Biology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; (G.-H.L.); (C.-Y.L.)
| | - Chia-Hung Yen
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Bing-Hung Chen
- Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (M.K.); (B.-H.C.)
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
- The Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Victoriya Georgiyants
- Department of Pharmaceutical Chemistry, National University of Pharmacy, 4-Valentinivska st., 61168 Kharkiv, Ukraine; (O.M.); (I.B.); (A.M.)
- Correspondence: (V.G.); (T.-L.H.); Tel.: +380572-67-91-97 (V.G.); +886-3-2118800 (ext. 5523) (T.-L.H.)
| | - Tsong-Long Hwang
- Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Research Center for Chinese Herbal Medicine, Research Center for Food and Cosmetic Safety, and Graduate Institute of Health Industry Technology, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 33302, Taiwan
- Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan
- Chinese Herbal Medicine Research Team, Healthy Aging Research Center, Chang Gung University, Taoyuan 33302, Taiwan
- Correspondence: (V.G.); (T.-L.H.); Tel.: +380572-67-91-97 (V.G.); +886-3-2118800 (ext. 5523) (T.-L.H.)
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Peng W, Grobe W, Walgenbach-Brünagel G, Flicker S, Yu C, Sylvester M, Allam JP, Oldenburg J, Garbi N, Valenta R, Novak N. Distinct Expression and Function of FcεRII in Human B Cells and Monocytes. THE JOURNAL OF IMMUNOLOGY 2017; 198:3033-3044. [DOI: 10.4049/jimmunol.1601028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 02/14/2017] [Indexed: 01/25/2023]
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Korinek M, Chen KM, Jiang YH, El-Shazly M, Stocker J, Chou CK, Hwang TL, Wu YC, Chen BH, Chang FR. Anti-allergic potential of Typhonium blumei: Inhibition of degranulation via suppression of PI3K/PLCγ2 phosphorylation and calcium influx. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2016; 23:1706-1715. [PMID: 27912872 DOI: 10.1016/j.phymed.2016.10.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 07/07/2016] [Accepted: 10/22/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Typhonium blumei Nicolson & Sivadasan (Araceae) is a traditional Chinese medicinal herb possessing detumescent, detoxifying, and anti-inflammatory activities. It is used in Taiwan as a folk medicine to treat cancer and inflammatory diseases. Typhonium blumei is usually not distinguished from Typhonium roxburghii Schott and they are commonly used interchangeably. PURPOSE To evaluate and compare the anti-allergic and anti-inflammatory properties of T. blumei and T. roxburghii, their composition profiles and molecular basis of the anti-allergic effect. METHODS The methanolic plant extracts were partitioned with different solvents to obtain the nonpolar fractions. The anti-allergic activity of the nonpolar fractions was assessed by A23187- and antigen-induced degranulation assays using RBL-2H3 mast cells. Several molecular targets were investigated: FcεRI receptor expression by flow cytometry, calcium influx by live cells imaging fluorescent microscopy, cytokines mRNA expression by RT-PCR, and protein expression by Western blotting. The anti-inflammatory activity was evaluated using superoxide anion and elastase release assays in human neutrophils. TLC, NMR and GC-MS analyses were conducted to evaluate the chemical composition of the fractions. RESULTS The nonpolar fractions of both Typhonium species showed potent inhibitory activity in A23187-induced degranulation assay in RBL-2H3 cells. They also inhibited superoxide production and elastase release in human neutrophils. T. blumei nonpolar fractions inhibited antigen-induced β-hexosaminidase and histamine release. The nonpolar fractions of T. blumei significantly inhibited calcium influx upon activation with either A23187 or an antigen. The fractions did not affect FcεRI receptor expression, mRNA level of IL-4 and MCP-1 cytokine production or MAPK proteins expression, but did suppress the calcium signaling pathway via PI3K/PLCγ2. The active fractions were rich in fatty acids with palmitic, linoleic and α-linolenic acids identified as the major fatty acids in both plants. The content of omega-3 unsaturated fatty acids was higher in T. roxburghii nonpolar fractions compared to T. blumei. CONCLUSION Both species possess potent anti-allergic and anti-inflammatory activities. The inhibition of degranulation in mast cells was attributed to calcium influx modulation. The obtained results support the traditional use of T. blumei in the treatment of inflammatory diseases as well as its substitution with T. roxburghii.
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Affiliation(s)
- Michal Korinek
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Kuan-Ming Chen
- Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Yu-Han Jiang
- Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Mohamed El-Shazly
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, Ain-Shams University, Cairo 11566, Egypt.
| | - Joel Stocker
- Education Center for Humanities and Social Sciences, National Yang Ming University, Taipei 112, Taiwan.
| | - Chon-Kit Chou
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Tsong-Long Hwang
- Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; Research Center for Industry of Human Ecology and Graduate Institute of Health Industry Technology, Chang Gung University of Science and Technology, Taoyuan 333, Taiwan; Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan.
| | - Yang-Chang Wu
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan; School of Pharmacy, College of Pharmacy, China Medical University, Taichung 404, Taiwan; Chinese Medicine Research and Development Center, China Medical University Hospital, Taichung 404, Taiwan; Center for Molecular Medicine, China Medical University Hospital, Taichung 404, Taiwan.
| | - Bing-Hung Chen
- Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 807, Taiwan; The Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
| | - Fang-Rong Chang
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan; Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan.
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Effects of a Moderately Lower Temperature on the Proliferation and Degranulation of Rat Mast Cells. J Immunol Res 2016; 2016:8439594. [PMID: 27195304 PMCID: PMC4852356 DOI: 10.1155/2016/8439594] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/28/2016] [Indexed: 01/26/2023] Open
Abstract
Mast cells are traditionally considered as key effector cells in IgE-mediated allergic diseases. However, the roles of mast cells have also been implicated in diverse physiological and pathological processes. Mast cells are distributed in various organs and tissues of various species. Some of the organs and tissues, such as testis, skin, and the upper part of the respiratory tract, have a temperature that is lower than the body's core temperature. The purpose of the present study was to investigate the effects of a lower temperature on the proliferation and degranulation of rat mast cells. Here, we demonstrate that cell growth was retarded at 35°C compared to 37°C for both rat peritoneal mast cells (RPMC) and RBL-2H3, a rat mast cell line. Furthermore, RPMC became more susceptible to degranulation at 35°C compared to 37°C. In contrast, degranulation of RBL-2H3 was not as sensitive to temperature change as RPMC. The functionality of mast cells in unique organs with a lower temperature warrants further analysis.
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Sutton BJ, Davies AM. Structure and dynamics of IgE-receptor interactions: FcεRI and CD23/FcεRII. Immunol Rev 2015; 268:222-35. [DOI: 10.1111/imr.12340] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Brian J. Sutton
- Randall Division of Cell and Molecular Biophysics; King's College London; London UK
- Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma; London UK
| | - Anna M. Davies
- Randall Division of Cell and Molecular Biophysics; King's College London; London UK
- Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma; London UK
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Abstract
Immunoglobulins recognize and clear microbial pathogens and toxins through the coupling of variable region specificity to Fc-triggered cellular activation. These proinflammatory activities are regulated, thus avoiding the pathogenic sequelae of uncontrolled inflammation by modulating the composition of the Fc-linked glycan. Upon sialylation, the affinities for Fcγ receptors are reduced, whereas those for alternative cellular receptors, such as dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN)/CD23, are increased. We demonstrate that sialylation induces significant structural alterations in the Cγ2 domain and propose a model that explains the observed changes in ligand specificity and biological activity. By analogy to related complexes formed by IgE and its evolutionarily related Fc receptors, we conclude that this mechanism is general for the modulation of antibody-triggered immune responses, characterized by a shift between an "open" activating conformation and a "closed" anti-inflammatory state of antibody Fc fragments. This common mechanism has been targeted by pathogens to avoid host defense and offers targets for therapeutic intervention in allergic and autoimmune disorders.
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Wachholz PA, Dearman RJ, Kimber I. Detection of Allergen-Specific IgE Antibody Responses. J Immunotoxicol 2012; 1:189-99. [PMID: 18958652 DOI: 10.1080/15476910490919140] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Allergen-specific IgE production is the central event in the pathogenesis of atopic disorders and increases in specific IgE serum antibodies are an indicator of immediate hypersensitivity responses in humans and in animal models of allergy. Consequently, accurate and user-friendly methods are needed to measure serum levels of allergen-specific IgE. This review examines historical and recent developments in in vivo and in vitro methods for the detection of allergen-specific IgE in humans and in animal models. Routinely, in vitro methods such as enzyme-linked immunosorbant assays or radioallergosorbant tests and in vivo methods such as the skin prick test (SPT) for humans and the passive cutaneous anaphylaxis assay (PCA) used in animals are utilized to detect allergen-specific IgE. While in vivo assays are usually more accurate than in vitro assays since they provide a functional readout of IgE activity, they are relatively costly and require considerable expertise. On the other hand in vitro assays are limited by the fact that the amount of allergen-specific serum IgG exceeds IgE antibody by several orders of magnitude, resulting in competition for allergen binding. Consequently, methods that use allergen as a direct capture step are limited by the availability of free allergen binding sites for IgE. In order to circumvent this problem, in vitro methods usually require prior depletion of IgG or use high amounts of allergen in order to facilitate availability of free binding sites for IgE detection. Clearly, these approaches are limited for small sample volumes and allergens that are in short supply. New methods such as protein microarray could potentially overcome this problem by providing high allergen concentrations in a relatively small reaction volume. Currently, in vitro methods are rarely used in isolation for prognosis but are used primarily to complement the information obtained from in vivo assays. With the emergence of new technologies it is conceivable that in vitro assays may in the future replace in vivo assays, however until then in vivo assays remain the gold standard of allergen-specific IgE detection.
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Affiliation(s)
- Petra A Wachholz
- Syngenta Central Toxicology Laboratory, Cheshire, United Kingdom
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Crystal structure of IgE bound to its B-cell receptor CD23 reveals a mechanism of reciprocal allosteric inhibition with high affinity receptor FcεRI. Proc Natl Acad Sci U S A 2012; 109:12686-91. [PMID: 22802656 DOI: 10.1073/pnas.1207278109] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The role of IgE in allergic disease mechanisms is performed principally through its interactions with two receptors, FcεRI on mast cells and basophils, and CD23 (FcεRII) on B cells. The former mediates allergic hypersensitivity, the latter regulates IgE levels, and both receptors, also expressed on antigen-presenting cells, contribute to allergen uptake and presentation to the immune system. We have solved the crystal structure of the soluble lectin-like "head" domain of CD23 (derCD23) bound to a subfragment of IgE-Fc consisting of the dimer of Cε3 and Cε4 domains (Fcε3-4). One CD23 head binds to each heavy chain at the interface between the two domains, explaining the known 2:1 stoichiometry and suggesting mechanisms for cross-linking membrane-bound trimeric CD23 by IgE, or membrane IgE by soluble trimeric forms of CD23, both of which may contribute to the regulation of IgE synthesis by B cells. The two symmetrically located binding sites are distant from the single FcεRI binding site, which lies at the opposite ends of the Cε3 domains. Structural comparisons with both free IgE-Fc and its FcεRI complex reveal not only that the conformational changes in IgE-Fc required for CD23 binding are incompatible with FcεRI binding, but also that the converse is true. The two binding sites are allosterically linked. We demonstrate experimentally the reciprocal inhibition of CD23 and FcεRI binding in solution and suggest that the mutual exclusion of receptor binding allows IgE to function independently through its two receptors.
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Conrad DH, Ford JW, Sturgill JL, Gibb DR. CD23: an overlooked regulator of allergic disease. Curr Allergy Asthma Rep 2007; 7:331-7. [PMID: 17697638 DOI: 10.1007/s11882-007-0050-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Given the importance of immunoglobulin (Ig) E in mediating type I hypersensitivity, inhibiting IgE production would be a general way of controlling allergic disease. The low-affinity IgE receptor (FceRII or CD23) has long been proposed to be a natural regulator of IgE synthesis. In vivo research supporting this concept includes the observation that mice lacking CD23 have increased IgE production whereas mice overexpressing CD23 show strongly suppressed IgE responses. In addition, the finding that mice injected with monoclonal antibody directed against the coiled-coil stalk of CD23 have enhanced soluble CD23 release and increased IgE production demonstrates that full-length, trimeric CD23 is responsible for initiating an IgE inhibitory signal. The recent identification of ADAM10 (a disintegrin and metalloprotease) as the CD23 metalloprotease provides an alternative approach for designing therapies to combat allergic disease. Current data suggest that stabilizing cell-surface CD23 would be a natural means to decrease IgE synthesis and thus control type I hypersensitivity.
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Affiliation(s)
- Daniel H Conrad
- Department of Microbiology and Immunology, Virginia Commonwealth University, PO Box 980678, Richmond, VA 23298, USA.
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Lantsman K, Tombes RM. CaMK-II oligomerization potential determined using CFP/YFP FRET. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1746:45-54. [PMID: 16185778 DOI: 10.1016/j.bbamcr.2005.08.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Revised: 08/16/2005] [Accepted: 08/16/2005] [Indexed: 11/25/2022]
Abstract
Members of the Ca(2+)/calmodulin-dependent protein kinase II (CaMK-II) family are encoded throughout the animal kingdom by up to four genes (alpha, beta, gamma, and delta). Over three dozen known CaMK-II splice variants assemble into approximately 12-subunit oligomers with catalytic domains facing out from a central core. In this study, the catalytic domain of alpha, beta, and delta CaMK-IIs was replaced with cyan (CFP) or yellow fluorescent protein (YFP) for fluorescence resonance energy transfer (FRET) studies. FRET, when normalized to total CFP and YFP, reproducibly yielded values which reflected oligomerization preference, inter-subunit spacing, and localization. FRET occurred when individual CFP and YFP-linked CaMK-IIs were co-expressed, but not when they were expressed separately and then mixed. All hetero-oligomers exhibited FRET values that were averages of their homo-oligomeric parents, indicating no oligomeric preference or restriction. FRET for CaMK-II homo-oligomers was inversely proportional to the variable region length. FPs were monomerized (Leu221 to Lys221) for this study, thus eliminating any potential artifact caused by FP-CaMK-II aggregates. Our results indicate that alpha, beta, and delta CaMK-IIs can freely hetero-oligomerize and that increased variable region lengths place amino termini further apart, potentially influencing the rate of inter-subunit autophosphorylation.
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Affiliation(s)
- Konstantin Lantsman
- Department of Biology and Biochemistry, Virginia Commonwealth University, Richmond, VA 23284-2012, USA
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Abstract
In the year 2003 there was a 17% increase in the number of publications citing work performed using optical biosensor technology compared with the previous year. We collated the 962 total papers for 2003, identified the geographical regions where the work was performed, highlighted the instrument types on which it was carried out, and segregated the papers by biological system. In this overview, we spotlight 13 papers that should be on everyone's 'must read' list for 2003 and provide examples of how to identify and interpret high-quality biosensor data. Although we still find that the literature is replete with poorly performed experiments, over-interpreted results and a general lack of understanding of data analysis, we are optimistic that these shortcomings will be addressed as biosensor technology continues to mature.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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Kilmon MA, Shelburne AE, Chan-Li Y, Holmes KL, Conrad DH. CD23 Trimers Are Preassociated on the Cell Surface Even in the Absence of Its Ligand, IgE. THE JOURNAL OF IMMUNOLOGY 2004; 172:1065-73. [PMID: 14707080 DOI: 10.4049/jimmunol.172.2.1065] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Allergic disease is mediated by high levels of allergen-specific IgE. IgE binding to CD23, the low affinity receptor for IgE, results in a negative feedback signal leading to a decrease in IgE production. Previous studies have shown that CD23 associates as an oligomer and that cooperative binding of at least two lectin domains is required for high affinity IgE binding to CD23. We have previously shown that cooperative binding is required for regulation of IgE production. This study describes the production of several mAbs that bind the stalk region of murine CD23. One of the Abs, 19G5, inhibited the IgE/CD23 interaction at 37 degrees C, but not at 4 degrees C. Analysis of the binding properties of these Abs revealed that CD23 dissociates at high temperatures, such as 37 degrees C; however, the N terminus is constitutively associated, indicating partial, rather than complete, dissociation. A novel finding was that the stalk region, previously thought to mediate trimer association, was not required for oligomerization. These data reveal important information about the structure of CD23 that may be useful in modulating IgE production.
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Affiliation(s)
- Michelle A Kilmon
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA 23298, USA
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