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EswarKumar N, Yang CH, Tewary S, Peng WH, Chen GC, Yeh YQ, Yang HC, Ho MC. An integrative approach unveils a distal encounter site for rPTPε and phospho-Src complex formation. Structure 2023; 31:1567-1577.e5. [PMID: 37794594 DOI: 10.1016/j.str.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/10/2023] [Accepted: 09/07/2023] [Indexed: 10/06/2023]
Abstract
The structure determination of protein tyrosine phosphatase (PTP): phospho-protein complexes, which is essential to understand how specificity is achieved at the amino acid level, remains a significant challenge for protein crystallography and cryoEM due to the transient nature of binding interactions. Using rPTPεD1 and phospho-SrcKD as a model system, we have established an integrative workflow to address this problem, by means of which we generate a protein:phospho-protein complex model using predetermined protein structures, SAXS and pTyr-tailored MD simulations. Our model reveals transient protein-protein interactions between rPTPεD1 and phospho-SrcKD and is supported by three independent experimental validations. Measurements of the association rate between rPTPεD1 and phospho-SrcKD showed that mutations on the rPTPεD1: SrcKD complex interface disrupts these transient interactions, resulting in a reduction in protein-protein association rate and, eventually, phosphatase activity. This integrative approach is applicable to other PTP: phospho-protein complexes and the characterization of transient protein-protein interface interactions.
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Affiliation(s)
- Nadendla EswarKumar
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan; Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Cheng-Han Yang
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan; Department of Chemistry, Fu Jen Catholic University, New Taipei City 24205, Taiwan
| | - Sunilkumar Tewary
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan
| | - Wen-Hsin Peng
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan
| | - Guang-Chao Chen
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan
| | - Yi-Qi Yeh
- National Synchrotron Radiation Research Center, Hsin-Chu 300, Taiwan
| | - Hsiao-Ching Yang
- Department of Chemistry, Fu Jen Catholic University, New Taipei City 24205, Taiwan.
| | - Meng-Chiao Ho
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road Sec. 2, Nankang, Taipei 115, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan.
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Li J, Kumari T, Barazia A, Jha V, Jeong SY, Olson A, Kim M, Lee BK, Manickam V, Song Z, Clemens R, Razani B, Kim J, Dinauer MC, Cho J. Neutrophil DREAM promotes neutrophil recruitment in vascular inflammation. J Exp Med 2022; 219:e20211083. [PMID: 34751735 PMCID: PMC8719643 DOI: 10.1084/jem.20211083] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/21/2021] [Accepted: 10/19/2021] [Indexed: 01/02/2023] Open
Abstract
The interaction between neutrophils and endothelial cells is critical for the pathogenesis of vascular inflammation. However, the regulation of neutrophil adhesive function remains not fully understood. Intravital microscopy demonstrates that neutrophil DREAM promotes neutrophil recruitment to sites of inflammation induced by TNF-α but not MIP-2 or fMLP. We observe that neutrophil DREAM represses expression of A20, a negative regulator of NF-κB activity, and enhances expression of pro-inflammatory molecules and phosphorylation of IκB kinase (IKK) after TNF-α stimulation. Studies using genetic and pharmacologic approaches reveal that DREAM deficiency and IKKβ inhibition significantly diminish the ligand-binding activity of β2 integrins in TNF-α-stimulated neutrophils or neutrophil-like HL-60 cells. Neutrophil DREAM promotes degranulation through IKKβ-mediated SNAP-23 phosphorylation. Using sickle cell disease mice lacking DREAM, we show that hematopoietic DREAM promotes vaso-occlusive events in microvessels following TNF-α challenge. Our study provides evidence that targeting DREAM might be a novel therapeutic strategy to reduce excessive neutrophil recruitment in inflammatory diseases.
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Affiliation(s)
- Jing Li
- Department of Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, IL
| | - Tripti Kumari
- Division of Hematology, Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Andrew Barazia
- Department of Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, IL
| | - Vishwanath Jha
- Division of Hematology, Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Si-Yeon Jeong
- Department of Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, IL
| | - Amber Olson
- Division of Hematology, Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Mijeong Kim
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX
| | - Bum-Kyu Lee
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX
| | - Vijayprakash Manickam
- Division of Hematology, Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Zhimin Song
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Regina Clemens
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Babak Razani
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO
- John Cochran VA Medical Center, St. Louis, MO
| | - Jonghwan Kim
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX
| | - Mary C. Dinauer
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Jaehyung Cho
- Department of Pharmacology, University of Illinois at Chicago College of Medicine, Chicago, IL
- Division of Hematology, Department of Medicine, Washington University School of Medicine, St. Louis, MO
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
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Haworth AS, Brackenbury WJ. Emerging roles for multifunctional ion channel auxiliary subunits in cancer. Cell Calcium 2019; 80:125-140. [PMID: 31071485 PMCID: PMC6553682 DOI: 10.1016/j.ceca.2019.04.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/16/2019] [Accepted: 04/16/2019] [Indexed: 02/07/2023]
Abstract
Several superfamilies of plasma membrane channels which regulate transmembrane ion flux have also been shown to regulate a multitude of cellular processes, including proliferation and migration. Ion channels are typically multimeric complexes consisting of conducting subunits and auxiliary, non-conducting subunits. Auxiliary subunits modulate the function of conducting subunits and have putative non-conducting roles, further expanding the repertoire of cellular processes governed by ion channel complexes to processes such as transcellular adhesion and gene transcription. Given this expansive influence of ion channels on cellular behaviour it is perhaps no surprise that aberrant ion channel expression is a common occurrence in cancer. This review will focus on the conducting and non-conducting roles of the auxiliary subunits of various Ca2+, K+, Na+ and Cl- channels and the burgeoning evidence linking such auxiliary subunits to cancer. Several subunits are upregulated (e.g. Cavβ, Cavγ) and downregulated (e.g. Kvβ) in cancer, while other subunits have been functionally implicated as oncogenes (e.g. Navβ1, Cavα2δ1) and tumour suppressor genes (e.g. CLCA2, KCNE2, BKγ1) based on in vivo studies. The strengthening link between ion channel auxiliary subunits and cancer has exposed these subunits as potential biomarkers and therapeutic targets. However further mechanistic understanding is required into how these subunits contribute to tumour progression before their therapeutic potential can be fully realised.
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Affiliation(s)
- Alexander S Haworth
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK
| | - William J Brackenbury
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK.
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De novo variants in HK1 associated with neurodevelopmental abnormalities and visual impairment. Eur J Hum Genet 2019; 27:1081-1089. [PMID: 30778173 DOI: 10.1038/s41431-019-0366-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 12/15/2018] [Accepted: 02/02/2019] [Indexed: 12/18/2022] Open
Abstract
Hexokinase 1 (HK1) phosphorylates glucose to glucose-6-phosphate, the first rate-limiting step in glycolysis. Homozygous and heterozygous variants in HK1 have been shown to cause autosomal recessive non-spherocytic hemolytic anemia, autosomal recessive Russe type hereditary motor and sensory neuropathy, and autosomal dominant retinitis pigmentosa (adRP). We report seven patients from six unrelated families with a neurodevelopmental disorder associated with developmental delay, intellectual disability, structural brain abnormality, and visual impairments in whom we identified four novel, de novo missense variants in the N-terminal half of HK1. Hexokinase activity in red blood cells of two patients was normal, suggesting that the disease mechanism is not due to loss of hexokinase enzymatic activity.
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Zhang J, Li J, Craig TA, Kumar R, Gross ML. Hydrogen-Deuterium Exchange Mass Spectrometry Reveals Calcium Binding Properties and Allosteric Regulation of Downstream Regulatory Element Antagonist Modulator (DREAM). Biochemistry 2017. [PMID: 28627884 DOI: 10.1021/acs.biochem.7b00100] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Downstream regulatory element antagonist modulator (DREAM) is an EF-hand Ca2+-binding protein that also binds to a specific DNA sequence, downstream regulatory elements (DRE), and thereby regulates transcription in a calcium-dependent fashion. DREAM binds to DRE in the absence of Ca2+ but detaches from DRE under Ca2+ stimulation, allowing gene expression. The Ca2+ binding properties of DREAM and the consequences of the binding on protein structure are key to understanding the function of DREAM. Here we describe the application of hydrogen-deuterium exchange mass spectrometry (HDX-MS) and site-directed mutagenesis to investigate the Ca2+ binding properties and the subsequent conformational changes of full-length DREAM. We demonstrate that all EF-hands undergo large conformation changes upon calcium binding even though the EF-1 hand is not capable of binding to Ca2+. Moreover, EF-2 is a lower-affinity site compared to EF-3 and -4 hands. Comparison of HDX profiles between wild-type DREAM and two EF-1 mutated constructs illustrates that the conformational changes in the EF-1 hand are induced by long-range structural interactions. HDX analyses also reveal a conformational change in an N-terminal leucine-charged residue-rich domain (LCD) remote from Ca2+-binding EF-hands. This LCD domain is responsible for the direct interaction between DREAM and cAMP response element-binding protein (CREB) and regulates the recruitment of the co-activator, CREB-binding protein. These long-range interactions strongly suggest how conformational changes transmit the Ca2+ signal to CREB-mediated gene transcription.
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Affiliation(s)
- Jun Zhang
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Jing Li
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Theodore A Craig
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic , Rochester, Minnesota 55905, United States
| | - Rajiv Kumar
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic , Rochester, Minnesota 55905, United States
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States
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DREAM plays an important role in platelet activation and thrombogenesis. Blood 2016; 129:209-225. [PMID: 27903531 DOI: 10.1182/blood-2016-07-724419] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 11/23/2016] [Indexed: 01/18/2023] Open
Abstract
Downstream regulatory element antagonist modulator (DREAM), a transcriptional repressor, is known to modulate pain responses. However, it is unknown whether DREAM is expressed in anucleate platelets and plays a role in thrombogenesis. By using intravital microscopy with DREAM-null mice and their bone marrow chimeras, we demonstrated that both hematopoietic and nonhematopoietic cell DREAMs are required for platelet thrombus formation following laser-induced arteriolar injury. In a FeCl3-induced thrombosis model, we found that compared with wild-type (WT) control and nonhematopoietic DREAM knockout (KO) mice, DREAM KO control and hematopoietic DREAM KO mice showed a significant delay in time to occlusion. Tail bleeding time was prolonged in DREAM KO control mice, but not in WT or DREAM bone marrow chimeric mice. In vivo adoptive transfer experiments further indicated the importance of platelet DREAM in thrombogenesis. We found that DREAM deletion does not alter the ultrastructural features of platelets but significantly impairs platelet aggregation and adenosine triphosphate secretion induced by numerous agonists (collagen-related peptide, adenosine 5'-diphosphate, A23187, thrombin, or U46619). Biochemical studies revealed that platelet DREAM positively regulates phosphoinositide 3-kinase (PI3K) activity during platelet activation. Using DREAM-null platelets and PI3K isoform-specific inhibitors, we observed that platelet DREAM is important for α-granule secretion, Ca2+ mobilization, and aggregation through PI3K class Iβ (PI3K-Iβ). Genetic and pharmacological studies in human megakaryoblastic MEG-01 cells showed that DREAM is important for A23187-induced Ca2+ mobilization and its regulatory function requires Ca2+ binding and PI3K-Iβ activation. These results suggest that platelet DREAM regulates PI3K-Iβ activity and plays an important role during thrombus formation.
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Farfariello V, Iamshanova O, Germain E, Fliniaux I, Prevarskaya N. Calcium homeostasis in cancer: A focus on senescence. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1974-9. [PMID: 25764980 DOI: 10.1016/j.bbamcr.2015.03.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/25/2015] [Accepted: 03/01/2015] [Indexed: 01/01/2023]
Abstract
Senescence is one of the primary responses to the activation of oncoproteins or down-regulation of tumor suppressors in normal cells and is therefore considered as being anti-tumorigenic but the mechanisms controlling this process are still much unknown. Calcium (Ca²⁺) plays a major role in many cellular processes and calcium channels control many of the "hallmarks of cancer" but their involvement in tumor initiation is poorly understood and remains unclear. Therefore, in this article we review some striking senescence-associated characteristics and their potential regulation by Ca²⁺. The main aim is to produce plausible hypothesis on how calcium homeostasis may participate in cancer-related senescence. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.
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Affiliation(s)
- Valerio Farfariello
- Inserm U1003, Laboratory of Excellence, Ion Channels Science and Therapeutics, Equipe Labellisée par la Ligue Nationale Contre le Cancer, SIRIC ONCOLille, Université de Lille 1-Sciences et Technologies, Villeneuve d'Ascq, 59656, France
| | - Oksana Iamshanova
- Inserm U1003, Laboratory of Excellence, Ion Channels Science and Therapeutics, Equipe Labellisée par la Ligue Nationale Contre le Cancer, SIRIC ONCOLille, Université de Lille 1-Sciences et Technologies, Villeneuve d'Ascq, 59656, France
| | - Emmanuelle Germain
- Inserm U1003, Laboratory of Excellence, Ion Channels Science and Therapeutics, Equipe Labellisée par la Ligue Nationale Contre le Cancer, SIRIC ONCOLille, Université de Lille 1-Sciences et Technologies, Villeneuve d'Ascq, 59656, France
| | - Ingrid Fliniaux
- Inserm U1003, Laboratory of Excellence, Ion Channels Science and Therapeutics, Equipe Labellisée par la Ligue Nationale Contre le Cancer, SIRIC ONCOLille, Université de Lille 1-Sciences et Technologies, Villeneuve d'Ascq, 59656, France
| | - Natalia Prevarskaya
- Inserm U1003, Laboratory of Excellence, Ion Channels Science and Therapeutics, Equipe Labellisée par la Ligue Nationale Contre le Cancer, SIRIC ONCOLille, Université de Lille 1-Sciences et Technologies, Villeneuve d'Ascq, 59656, France
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Sullivan LS, Koboldt DC, Bowne SJ, Lang S, Blanton SH, Cadena E, Avery CE, Lewis RA, Webb-Jones K, Wheaton DH, Birch DG, Coussa R, Ren H, Lopez I, Chakarova C, Koenekoop RK, Garcia CA, Fulton RS, Wilson RK, Weinstock GM, Daiger SP. A dominant mutation in hexokinase 1 (HK1) causes retinitis pigmentosa. Invest Ophthalmol Vis Sci 2014; 55:7147-58. [PMID: 25190649 DOI: 10.1167/iovs.14-15419] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify the cause of retinitis pigmentosa (RP) in UTAD003, a large, six-generation Louisiana family with autosomal dominant retinitis pigmentosa (adRP). METHODS A series of strategies, including candidate gene screening, linkage exclusion, genome-wide linkage mapping, and whole-exome next-generation sequencing, was used to identify a mutation in a novel disease gene on chromosome 10q22.1. Probands from an additional 404 retinal degeneration families were subsequently screened for mutations in this gene. RESULTS Exome sequencing in UTAD003 led to identification of a single, novel coding variant (c.2539G>A, p.Glu847Lys) in hexokinase 1 (HK1) present in all affected individuals and absent from normal controls. One affected family member carries two copies of the mutation and has an unusually severe form of disease, consistent with homozygosity for this mutation. Screening of additional adRP probands identified four other families (American, Canadian, and Sicilian) with the same mutation and a similar range of phenotypes. The families share a rare 450-kilobase haplotype containing the mutation, suggesting a founder mutation among otherwise unrelated families. CONCLUSIONS We identified an HK1 mutation in five adRP families. Hexokinase 1 catalyzes phosphorylation of glucose to glucose-6-phosphate. HK1 is expressed in retina, with two abundant isoforms expressed at similar levels. The Glu847Lys mutation is located at a highly conserved position in the protein, outside the catalytic domains. We hypothesize that the effect of this mutation is limited to the retina, as no systemic abnormalities in glycolysis were detected. Prevalence of the HK1 mutation in our cohort of RP families is 1%.
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Affiliation(s)
- Lori S Sullivan
- Human Genetics Center, University of Texas Health Science Center, Houston, Texas, United States
| | - Daniel C Koboldt
- The Genome Institute at Washington University, St. Louis, Missouri, United States
| | - Sara J Bowne
- Human Genetics Center, University of Texas Health Science Center, Houston, Texas, United States
| | - Steven Lang
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, Florida, United States
| | - Susan H Blanton
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, Florida, United States
| | - Elizabeth Cadena
- Human Genetics Center, University of Texas Health Science Center, Houston, Texas, United States
| | - Cheryl E Avery
- Human Genetics Center, University of Texas Health Science Center, Houston, Texas, United States
| | - Richard A Lewis
- Departments of Ophthalmology, Medicine, Pediatrics, and Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States
| | - Kaylie Webb-Jones
- The Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Dianna H Wheaton
- The Retina Foundation of the Southwest, Dallas, Texas, United States
| | - David G Birch
- The Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Razck Coussa
- McGill Ocular Genetics Laboratory, Departments of Paediatric Surgery, Human Genetics, and Ophthalmology, McGill University Health Center, Montreal, Quebec, Canada
| | - Huanan Ren
- McGill Ocular Genetics Laboratory, Departments of Paediatric Surgery, Human Genetics, and Ophthalmology, McGill University Health Center, Montreal, Quebec, Canada
| | - Irma Lopez
- McGill Ocular Genetics Laboratory, Departments of Paediatric Surgery, Human Genetics, and Ophthalmology, McGill University Health Center, Montreal, Quebec, Canada
| | - Christina Chakarova
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Robert K Koenekoop
- McGill Ocular Genetics Laboratory, Departments of Paediatric Surgery, Human Genetics, and Ophthalmology, McGill University Health Center, Montreal, Quebec, Canada
| | - Charles A Garcia
- Department of Ophthalmology and Visual Sciences, University of Texas Health Science Center, Houston, Texas, United States
| | - Robert S Fulton
- The Genome Institute at Washington University, St. Louis, Missouri, United States
| | - Richard K Wilson
- The Genome Institute at Washington University, St. Louis, Missouri, United States
| | - George M Weinstock
- The Genome Institute at Washington University, St. Louis, Missouri, United States
| | - Stephen P Daiger
- Human Genetics Center, University of Texas Health Science Center, Houston, Texas, United States Department of Ophthalmology and Visual Sciences, University of Texas Health Science Center, Houston, Texas, United States
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Application of ANS fluorescent probes to identify hydrophobic sites on the surface of DREAM. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1472-80. [PMID: 24854592 DOI: 10.1016/j.bbapap.2014.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/01/2014] [Accepted: 05/12/2014] [Indexed: 11/23/2022]
Abstract
DREAM (calsenilin or KChIP-3) is a calcium sensor involved in regulation of diverse physiological processes by interactions with multiple intracellular partners including DNA, Kv4 channels, and presenilin, however the detailed mechanism of the recognition of the intracellular partners remains unclear. To identify the surface hydrophobic surfaces on apo and Ca(2+)DREAM as a possible interaction sites for target proteins and/or specific regulators of DREAM function the binding interactions of 1,8-ANS and 2,6-ANS with DREAM were characterized by fluorescence and docking studies. Emission intensity of ANS-DREAM complexes increases upon Ca(2+) association which is consistent with an overall decrease in surface polarity. The dissociation constants for ANS binding to apoDREAM and Ca(2+)DREAM were determined to be 195±20μM and 62±4μM, respectively. Fluorescence lifetime measurements indicate that two ANS molecules bind in two independent binding sites on DREAM monomer. One site is near the exiting helix of EF-4 and the second site is located in the hydrophobic crevice between EF-3 and EF-4. 1,8-ANS displacement studies using arachidonic acid demonstrate that the hydrophobic crevice between EF-3 and EF-4 serves as a binding site for fatty acids that modulate functional properties of Kv4 channel:KChIP complexes. Thus, the C-terminal hydrophobic crevice may be involved in DREAM interactions with small hydrophobic ligands as well as other intracellular proteins.
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Marden JH. Nature's inordinate fondness for metabolic enzymes: why metabolic enzyme loci are so frequently targets of selection. Mol Ecol 2013; 22:5743-64. [PMID: 24106889 DOI: 10.1111/mec.12534] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 09/11/2013] [Accepted: 09/17/2013] [Indexed: 01/01/2023]
Abstract
Metabolic enzyme loci were some of the first genes accessible for molecular evolution and ecology research. New technologies now make the whole genome, transcriptome or proteome readily accessible, allowing unbiased scans for loci exhibiting significant differences in allele frequency or expression level and associated with phenotypes and/or responses to natural selection. With surprising frequency and in many cases in proportions greater than chance relative to other genes, glycolysis and TCA cycle enzyme loci appear among the genes with significant associations in these studies. Hence, there is an ongoing need to understand the basis for fitness effects of metabolic enzyme polymorphisms. Allele-specific effects on the binding affinity and catalytic rate of individual enzymes are well known, but often of uncertain significance because metabolic control theory and in vivo studies indicate that many individual metabolic enzymes do not affect pathway flux rate. I review research, so far little used in evolutionary biology, showing that metabolic enzyme substrates affect signalling pathways that regulate cell and organismal biology, and that these enzymes have moonlighting functions. To date there is little knowledge of how alleles in natural populations affect these phenotypes. I discuss an example in which alleles of a TCA enzyme locus associate with differences in a signalling pathway and development, organismal performance, and ecological dynamics. Ultimately, understanding how metabolic enzyme polymorphisms map to phenotypes and fitness remains a compelling and ongoing need for gaining robust knowledge of ecological and evolutionary processes.
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Affiliation(s)
- James H Marden
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
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11
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Krasnov GS, Dmitriev AA, Lakunina VA, Kirpiy AA, Kudryavtseva AV. Targeting VDAC-bound hexokinase II: a promising approach for concomitant anti-cancer therapy. Expert Opin Ther Targets 2013; 17:1221-33. [DOI: 10.1517/14728222.2013.833607] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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