1
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Marson NA, Gallio AE, Mandal SK, Laskowski RA, Raven EL. In silico prediction of heme binding in proteins. J Biol Chem 2024; 300:107250. [PMID: 38569935 PMCID: PMC11101860 DOI: 10.1016/j.jbc.2024.107250] [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: 01/19/2024] [Revised: 03/11/2024] [Accepted: 03/26/2024] [Indexed: 04/05/2024] Open
Abstract
The process of heme binding to a protein is prevalent in almost all forms of life to control many important biological properties, such as O2-binding, electron transfer, gas sensing or to build catalytic power. In these cases, heme typically binds tightly (irreversibly) to a protein in a discrete heme binding pocket, with one or two heme ligands provided most commonly to the heme iron by His, Cys or Tyr residues. Heme binding can also be used as a regulatory mechanism, for example in transcriptional regulation or ion channel control. When used as a regulator, heme binds more weakly, with different heme ligations and without the need for a discrete heme pocket. This makes the characterization of heme regulatory proteins difficult, and new approaches are needed to predict and understand the heme-protein interactions. We apply a modified version of the ProFunc bioinformatics tool to identify heme-binding sites in a test set of heme-dependent regulatory proteins taken from the Protein Data Bank and AlphaFold models. The potential heme binding sites identified can be easily visualized in PyMol and, if necessary, optimized with RosettaDOCK. We demonstrate that the methodology can be used to identify heme-binding sites in proteins, including in cases where there is no crystal structure available, but the methodology is more accurate when the quality of the structural information is high. The ProFunc tool, with the modification used in this work, is publicly available at https://www.ebi.ac.uk/thornton-srv/databases/profunc and can be readily adopted for the examination of new heme binding targets.
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Affiliation(s)
- Noa A Marson
- School of Chemistry, University of Bristol, Bristol, UK
| | | | | | - Roman A Laskowski
- European Bioinformatics Institute (EMBL-EBI), European Molecular Biology Laboratory, Wellcome Trust Genome Campus, Cambridge, UK
| | - Emma L Raven
- School of Chemistry, University of Bristol, Bristol, UK.
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2
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Ghorbani M, Wang ZJ, Chen X, Tiwari PB, Klauda JB, Brelidze TI. Chlorpromazine inhibits EAG1 channels by altering the coupling between the PAS, CNBH and pore domains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.23.581826. [PMID: 38464246 PMCID: PMC10925124 DOI: 10.1101/2024.02.23.581826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
EAG1 depolarization-activated potassium selective channels are important targets for treatment of cancer and neurological disorders. EAG1 channels are formed by a tetrameric subunit assembly with each subunit containing an N-terminal Per-Arnt-Sim (PAS) domain and C-terminal cyclic nucleotide-binding homology (CNBH) domain. The PAS and CNBH domains from adjacent subunits interact and form an intracellular tetrameric ring that regulates the EAG1 channel gating, including the movement of the voltage sensor domain (VSD) from closed to open states. Small molecule ligands can inhibit EAG1 channels by binding to their PAS domains. However, the allosteric pathways of this inhibition are not known. Here we show that chlorpromazine, a PAS domain small molecule binder, alters interactions between the PAS and CNBH domains and decreases the coupling between the intracellular tetrameric ring and the pore of the channel, while having little effect on the coupling between the PAS and VSD domains. In addition, chlorpromazine binding to the PAS domain did not alter Cole-Moore shift characteristic of EAG1 channels, further indicating that chlorpromazine has no effect on VSD movement from the deep closed to opened states. Our study provides a framework for understanding global pathways of EAG1 channel regulation by small molecule PAS domain binders.
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3
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Tiwari PB, Kamgar-Dayhoff P, Tiwari P, McKillop MI, Brelidze TI. Use of Surface Plasmon Resonance Technique for Studies of Inter-domain Interactions in Ion Channels. Methods Mol Biol 2024; 2796:105-118. [PMID: 38856898 PMCID: PMC11225882 DOI: 10.1007/978-1-0716-3818-7_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Ion channels are transmembrane proteins essential for cellular functions and are important drug targets. Surface plasmon resonance (SPR) is a powerful technique for investigating protein-protein and protein-small molecule ligand interactions. SPR has been underutilized for studies of ion channels, even though it could provide a wealth of information on the mechanisms of ion channel regulation and aid in ion channel drug discovery. Here we provide a detailed description of the use of SPR technology for investigating inter-domain interactions in KCNH potassium-selective and voltage-gated ion channels.
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Affiliation(s)
- Purushottam B Tiwari
- Department of Oncology, Georgetown University Medical Center, Washington, DC, USA
| | - Pareesa Kamgar-Dayhoff
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA
| | - Prakriti Tiwari
- Department of Oncology, Georgetown University Medical Center, Washington, DC, USA
- Department of Biology, College of Arts & Sciences, Georgetown University, Washington, DC, USA
| | - Maria I McKillop
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA
| | - Tinatin I Brelidze
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, USA.
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4
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Wang ZJ, Ghorbani M, Chen X, Tiwari PB, Klauda JB, Brelidze TI. Molecular mechanism of EAG1 channel inhibition by imipramine binding to the PAS domain. J Biol Chem 2023; 299:105391. [PMID: 37898402 PMCID: PMC10687071 DOI: 10.1016/j.jbc.2023.105391] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/17/2023] [Accepted: 10/19/2023] [Indexed: 10/30/2023] Open
Abstract
Ether-a-go-go (EAG) channels are key regulators of neuronal excitability and tumorigenesis. EAG channels contain an N-terminal Per-Arnt-Sim (PAS) domain that can regulate currents from EAG channels by binding small molecules. The molecular mechanism of this regulation is not clear. Using surface plasmon resonance and electrophysiology we show that a small molecule ligand imipramine can bind to the PAS domain of EAG1 channels and inhibit EAG1 currents via this binding. We further used a combination of molecular dynamics (MD) simulations, electrophysiology, and mutagenesis to investigate the molecular mechanism of EAG1 current inhibition by imipramine binding to the PAS domain. We found that Tyr71, located at the entrance to the PAS domain cavity, serves as a "gatekeeper" limiting access of imipramine to the cavity. MD simulations indicate that the hydrophobic electrostatic profile of the cavity facilitates imipramine binding and in silico mutations of hydrophobic cavity-lining residues to negatively charged glutamates decreased imipramine binding. Probing the PAS domain cavity-lining residues with site-directed mutagenesis, guided by MD simulations, identified D39 and R84 as residues essential for the EAG1 channel inhibition by imipramine binding to the PAS domain. Taken together, our study identified specific residues in the PAS domain that could increase or decrease EAG1 current inhibition by imipramine binding to the PAS domain. These findings should further the understanding of molecular mechanisms of EAG1 channel regulation by ligands and facilitate the development of therapeutic agents targeting these channels.
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Affiliation(s)
- Ze-Jun Wang
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Mahdi Ghorbani
- Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland, USA
| | - Xi Chen
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Purushottam B Tiwari
- Department of Oncology, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Jeffery B Klauda
- Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland, USA; Institute for Physical Science and Technology and Biophysics Graduate Program, University of Maryland, College Park, Maryland, USA.
| | - Tinatin I Brelidze
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, District of Columbia, USA.
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5
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Xing J, Gumerov VM, Zhulin IB. Origin and functional diversification of PAS domain, a ubiquitous intracellular sensor. SCIENCE ADVANCES 2023; 9:eadi4517. [PMID: 37647406 PMCID: PMC10468136 DOI: 10.1126/sciadv.adi4517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 07/28/2023] [Indexed: 09/01/2023]
Abstract
Signal perception is a key function in regulating biological activities and adapting to changing environments. Per-Arnt-Sim (PAS) domains are ubiquitous sensors found in diverse receptors in bacteria, archaea, and eukaryotes, but their origins, distribution across the tree of life, and extent of their functional diversity are not fully characterized. Here, we show that using sequence conservation and structural information, it is possible to propose specific and potential functions for a large portion of nearly 3 million PAS domains. Our analysis suggests that PAS domains originated in bacteria and were horizontally transferred to archaea and eukaryotes. We reveal that gas sensing via a heme cofactor evolved independently in several lineages, whereas redox and light sensing via flavin adenine dinucleotide and flavin mononucleotide cofactors have the same origin. The close relatedness of human PAS domains to those in bacteria provides an opportunity for drug design by exploring potential natural ligands and cofactors for bacterial homologs.
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Affiliation(s)
- Jiawei Xing
- Department of Microbiology, The Ohio State University, Columbus, OH, USA
- Translational Data Analytics Institute, The Ohio State University, Columbus, OH USA
| | - Vadim M. Gumerov
- Department of Microbiology, The Ohio State University, Columbus, OH, USA
- Translational Data Analytics Institute, The Ohio State University, Columbus, OH USA
| | - Igor B. Zhulin
- Department of Microbiology, The Ohio State University, Columbus, OH, USA
- Translational Data Analytics Institute, The Ohio State University, Columbus, OH USA
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6
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Rathod DC, Vaidya SM, Hopp MT, Kühl T, Imhof D. Shapes and Patterns of Heme-Binding Motifs in Mammalian Heme-Binding Proteins. Biomolecules 2023; 13:1031. [PMID: 37509066 PMCID: PMC10377097 DOI: 10.3390/biom13071031] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/30/2023] Open
Abstract
Heme is a double-edged sword. On the one hand, it has a pivotal role as a prosthetic group of hemoproteins in many biological processes ranging from oxygen transport and storage to miRNA processing. On the other hand, heme can transiently associate with proteins, thereby regulating biochemical pathways. During hemolysis, excess heme, which is released into the plasma, can bind to proteins and regulate their activity and function. The role of heme in these processes is under-investigated, with one problem being the lack of knowledge concerning recognition mechanisms for the initial association of heme with the target protein and the formation of the resulting complex. A specific heme-binding sequence motif is a prerequisite for such complex formation. Although numerous short signature sequences indicating a particular protein function are known, a comprehensive analysis of the heme-binding motifs (HBMs) which have been identified in proteins, concerning specific patterns and structural peculiarities, is missing. In this report, we focus on the evaluation of known mammalian heme-regulated proteins concerning specific recognition and structural patterns in their HBMs. The Cys-Pro dipeptide motifs are particularly emphasized because of their more frequent occurrence. This analysis presents a comparative insight into the sequence and structural anomalies observed during transient heme binding, and consequently, in the regulation of the relevant protein.
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Affiliation(s)
- Dhruv C Rathod
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany
| | - Sonali M Vaidya
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany
| | - Marie-T Hopp
- Department of Chemistry, Institute for Integrated Natural Sciences, University of Koblenz, D-56070 Koblenz, Germany
| | - Toni Kühl
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany
| | - Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany
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7
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Kim H, Moore CM, Mestre-Fos S, Hanna DA, Williams LD, Reddi AR, Torres MP. Depletion assisted hemin affinity (DAsHA) proteomics reveals an expanded landscape of heme-binding proteins in the human proteome. Metallomics 2023; 15:6994529. [PMID: 36669767 PMCID: PMC10022665 DOI: 10.1093/mtomcs/mfad004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
Heme b (iron protoporphyrin IX) plays important roles in biology as a metallocofactor and signaling molecule. However, the targets of heme signaling and the network of proteins that mediate the exchange of heme from sites of synthesis or uptake to heme dependent or regulated proteins are poorly understood. Herein, we describe a quantitative mass spectrometry (MS)-based chemoproteomics strategy to identify exchange labile hemoproteins in human embryonic kidney HEK293 cells that may be relevant to heme signaling and trafficking. The strategy involves depleting endogenous heme with the heme biosynthetic inhibitor succinylacetone (SA), leaving putative heme-binding proteins in their apo-state, followed by the capture of those proteins using hemin-agarose resin, and finally elution and identification by MS. By identifying only those proteins that interact with high specificity to hemin-agarose relative to control beaded agarose in an SA-dependent manner, we have expanded the number of proteins and ontologies that may be involved in binding and buffering labile heme or are targets of heme signaling. Notably, these include proteins involved in chromatin remodeling, DNA damage response, RNA splicing, cytoskeletal organization, and vesicular trafficking, many of which have been associated with heme through complementary studies published recently. Taken together, these results provide support for the emerging role of heme in an expanded set of cellular processes from genome integrity to protein trafficking and beyond.
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Affiliation(s)
- Hyojung Kim
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Courtney M Moore
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Santi Mestre-Fos
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - David A Hanna
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Loren Dean Williams
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Amit R Reddi
- Correspondence: Amit R. Reddi, School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Dr. Atlanta, GA 30033. E-mail:
| | - Matthew P Torres
- Correspondence: Matthew P. Torres, School of Biological Sciences, Georgia Institute of Technology, 950 Atlantic Dr. Atlanta, GA 30033. E-mail:
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8
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Wilkinson IVL, Bottlinger M, El Harraoui Y, Sieber SA. Profiling the Heme-Binding Proteomes of Bacteria Using Chemical Proteomics. Angew Chem Int Ed Engl 2023; 62:e202212111. [PMID: 36495310 DOI: 10.1002/anie.202212111] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022]
Abstract
Heme is a cofactor with myriad roles and essential to almost all living organisms. Beyond classical gas transport and catalytic functions, heme is increasingly appreciated as a tightly controlled signalling molecule regulating protein expression. However, heme acquisition, biosynthesis and regulation is poorly understood beyond a few model organisms, and the heme-binding proteome has not been fully characterised in bacteria. Yet as heme homeostasis is critical for bacterial survival, heme-binding proteins are promising drug targets. Herein we report a chemical proteomics method for global profiling of heme-binding proteins in live cells for the first time. Employing a panel of heme-based clickable and photoaffinity probes enabled the profiling of 32-54 % of the known heme-binding proteomes in Gram-positive and Gram-negative bacteria. This simple-to-implement profiling strategy could be interchangeably applied to different cell types and systems and fuel future research into heme biology.
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Affiliation(s)
- Isabel V L Wilkinson
- Centre for Functional Protein Assemblies, Technical University of Munich, Ernst-Otto-Fischer-Straße 8, 85748, Garching, Germany
| | - Max Bottlinger
- Centre for Functional Protein Assemblies, Technical University of Munich, Ernst-Otto-Fischer-Straße 8, 85748, Garching, Germany
| | - Yassmine El Harraoui
- Centre for Functional Protein Assemblies, Technical University of Munich, Ernst-Otto-Fischer-Straße 8, 85748, Garching, Germany
| | - Stephan A Sieber
- Centre for Functional Protein Assemblies, Technical University of Munich, Ernst-Otto-Fischer-Straße 8, 85748, Garching, Germany
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9
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Gessner G, Jamili M, Tomczyk P, Menche D, Schönherr R, Hoshi T, Heinemann SH. Extracellular hemin is a reverse use-dependent gating modifier of cardiac voltage-gated Na + channels. Biol Chem 2022; 403:1067-1081. [PMID: 36038266 DOI: 10.1515/hsz-2022-0194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/10/2022] [Indexed: 02/07/2023]
Abstract
Heme (Fe2+-protoporphyrin IX) is a well-known protein prosthetic group; however, heme and hemin (Fe3+-protoporphyrin IX) are also increasingly viewed as signaling molecules. Among the signaling targets are numerous ion channels, with intracellular-facing heme-binding sites modulated by heme and hemin in the sub-µM range. Much less is known about extracellular hemin, which is expected to be more abundant, in particular after hemolytic insults. Here we show that the human cardiac voltage-gated sodium channel hNaV1.5 is potently inhibited by extracellular hemin (IC 50 ≈ 80 nM), while heme, dimethylhemin, and protoporphyrin IX are ineffective. Hemin is selective for hNaV1.5 channels: hNaV1.2, hNaV1.4, hNaV1.7, and hNaV1.8 are insensitive to 1 µM hemin. Using domain chimeras of hNaV1.5 and rat rNaV1.2, domain II was identified as the critical determinant. Mutation N803G in the domain II S3/S4 linker largely diminished the impact of hemin on the cardiac channel. This profile is reminiscent of the interaction of some peptide voltage-sensor toxins with NaV channels. In line with a mechanism of select gating modifiers, the impact of hemin on NaV1.5 channels is reversely use dependent, compatible with an interaction of hemin and the voltage sensor of domain II. Extracellular hemin thus has potential to modulate the cardiac function.
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Affiliation(s)
- Guido Gessner
- Department of Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-Straße 2, D-07745 Jena, Germany
| | - Mahdi Jamili
- Department of Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-Straße 2, D-07745 Jena, Germany
| | - Pascal Tomczyk
- Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany
| | - Dirk Menche
- Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany
| | - Roland Schönherr
- Department of Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-Straße 2, D-07745 Jena, Germany
| | - Toshinori Hoshi
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - Stefan H Heinemann
- Department of Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-Straße 2, D-07745 Jena, Germany
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10
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Intracellular hemin is a potent inhibitor of the voltage-gated potassium channel Kv10.1. Sci Rep 2022; 12:14645. [PMID: 36030326 PMCID: PMC9420133 DOI: 10.1038/s41598-022-18975-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/23/2022] [Indexed: 11/08/2022] Open
Abstract
Heme, an iron-protoporphyrin IX complex, is a cofactor bound to various hemoproteins and supports a broad range of functions, such as electron transfer, oxygen transport, signal transduction, and drug metabolism. In recent years, there has been a growing recognition of heme as a non-genomic modulator of ion channel functions. Here, we show that intracellular free heme and hemin modulate human ether à go-go (hEAG1, Kv10.1) voltage-gated potassium channels. Application of hemin to the intracellular side potently inhibits Kv10.1 channels with an IC50 of about 4 nM under ambient and 63 nM under reducing conditions in a weakly voltage-dependent manner, favoring inhibition at resting potential. Functional studies on channel mutants and biochemical analysis of synthetic and recombinant channel fragments identified a heme-binding motif CxHx8H in the C-linker region of the Kv10.1 C terminus, with cysteine 541 and histidines 543 and 552 being important for hemin binding. Binding of hemin to the C linker may induce a conformational constraint that interferes with channel gating. Our results demonstrate that heme and hemin are endogenous modulators of Kv10.1 channels and could be exploited to modulate Kv10.1-mediated cellular functions.
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11
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Yuan Z, De La Cruz LK, Yang X, Wang B. Carbon Monoxide Signaling: Examining Its Engagement with Various Molecular Targets in the Context of Binding Affinity, Concentration, and Biologic Response. Pharmacol Rev 2022; 74:823-873. [PMID: 35738683 DOI: 10.1124/pharmrev.121.000564] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Carbon monoxide (CO) has been firmly established as an endogenous signaling molecule with a variety of pathophysiological and pharmacological functions, including immunomodulation, organ protection, and circadian clock regulation, among many others. In terms of its molecular mechanism(s) of action, CO is known to bind to a large number of hemoproteins with at least 25 identified targets, including hemoglobin, myoglobin, neuroglobin, cytochrome c oxidase, cytochrome P450, soluble guanylyl cyclase, myeloperoxidase, and some ion channels with dissociation constant values spanning the range of sub-nM to high μM. Although CO's binding affinity with a large number of targets has been extensively studied and firmly established, there is a pressing need to incorporate such binding information into the analysis of CO's biologic response in the context of affinity and dosage. Especially important is to understand the reservoir role of hemoglobin in CO storage, transport, distribution, and transfer. We critically review the literature and inject a sense of quantitative assessment into our analyses of the various relationships among binding affinity, CO concentration, target occupancy level, and anticipated pharmacological actions. We hope that this review presents a picture of the overall landscape of CO's engagement with various targets, stimulates additional research, and helps to move the CO field in the direction of examining individual targets in the context of all of the targets and the concentration of available CO. We believe that such work will help the further understanding of the relationship of CO concentration and its pathophysiological functions and the eventual development of CO-based therapeutics. SIGNIFICANCE STATEMENT: The further development of carbon monoxide (CO) as a therapeutic agent will significantly rely on the understanding of CO's engagement with therapeutically relevant targets of varying affinity. This review critically examines the literature by quantitatively analyzing the intricate relationships among targets, target affinity for CO, CO level, and the affinity state of carboxyhemoglobin and provide a holistic approach to examining the molecular mechanism(s) of action for CO.
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Affiliation(s)
- Zhengnan Yuan
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia
| | - Ladie Kimberly De La Cruz
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia
| | - Xiaoxiao Yang
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia
| | - Binghe Wang
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia
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12
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Conformation-sensitive antibody reveals an altered cytosolic PAS/CNBh assembly during hERG channel gating. Proc Natl Acad Sci U S A 2021; 118:2108796118. [PMID: 34716268 DOI: 10.1073/pnas.2108796118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 09/22/2021] [Indexed: 11/18/2022] Open
Abstract
The human ERG (hERG) K+ channel has a crucial function in cardiac repolarization, and mutations or channel block can give rise to long QT syndrome and catastrophic ventricular arrhythmias. The cytosolic assembly formed by the Per-Arnt-Sim (PAS) and cyclic nucleotide binding homology (CNBh) domains is the defining structural feature of hERG and related KCNH channels. However, the molecular role of these two domains in channel gating remains unclear. We have previously shown that single-chain variable fragment (scFv) antibodies can modulate hERG function by binding to the PAS domain. Here, we mapped the scFv2.12 epitope to a site overlapping with the PAS/CNBh domain interface using NMR spectroscopy and mutagenesis and show that scFv binding in vitro and in the cell is incompatible with the PAS interaction with CNBh. By generating a fluorescently labeled scFv2.12, we demonstrate that association with the full-length hERG channel is state dependent. We detect Förster resonance energy transfer (FRET) with scFv2.12 when the channel gate is open but not when it is closed. In addition, state dependence of scFv2.12 FRET signal disappears when the R56Q mutation, known to destabilize the PAS-CNBh interaction, is introduced in the channel. Altogether, these data are consistent with an extensive structural alteration of the PAS/CNBh assembly when the cytosolic gate opens, likely favoring PAS domain dissociation from the CNBh domain.
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13
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Gallio A, Fung SSP, Cammack-Najera A, Hudson AJ, Raven EL. Understanding the Logistics for the Distribution of Heme in Cells. JACS AU 2021; 1:1541-1555. [PMID: 34723258 PMCID: PMC8549057 DOI: 10.1021/jacsau.1c00288] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Indexed: 05/03/2023]
Abstract
Heme is essential for the survival of virtually all living systems-from bacteria, fungi, and yeast, through plants to animals. No eukaryote has been identified that can survive without heme. There are thousands of different proteins that require heme in order to function properly, and these are responsible for processes such as oxygen transport, electron transfer, oxidative stress response, respiration, and catalysis. Further to this, in the past few years, heme has been shown to have an important regulatory role in cells, in processes such as transcription, regulation of the circadian clock, and the gating of ion channels. To act in a regulatory capacity, heme needs to move from its place of synthesis (in mitochondria) to other locations in cells. But while there is detailed information on how the heme lifecycle begins (heme synthesis), and how it ends (heme degradation), what happens in between is largely a mystery. Here we summarize recent information on the quantification of heme in cells, and we present a discussion of a mechanistic framework that could meet the logistical challenge of heme distribution.
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Affiliation(s)
- Andrea
E. Gallio
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Simon S.-P. Fung
- Department
of Chemistry and Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, U.K.
| | - Ana Cammack-Najera
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Andrew J. Hudson
- Department
of Chemistry and Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, U.K.
| | - Emma L. Raven
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
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14
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Dent MR, DeMartino AW, Tejero J, Gladwin MT. Endogenous Hemoprotein-Dependent Signaling Pathways of Nitric Oxide and Nitrite. Inorg Chem 2021; 60:15918-15940. [PMID: 34313417 DOI: 10.1021/acs.inorgchem.1c01048] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Interdisciplinary research at the interface of chemistry, physiology, and biomedicine have uncovered pivotal roles of nitric oxide (NO) as a signaling molecule that regulates vascular tone, platelet aggregation, and other pathways relevant to human health and disease. Heme is central to physiological NO signaling, serving as the active site for canonical NO biosynthesis in nitric oxide synthase (NOS) enzymes and as the highly selective NO binding site in the soluble guanylyl cyclase receptor. Outside of the primary NOS-dependent biosynthetic pathway, other hemoproteins, including hemoglobin and myoglobin, generate NO via the reduction of nitrite. This auxiliary hemoprotein reaction unlocks a "second axis" of NO signaling in which nitrite serves as a stable NO reservoir. In this Forum Article, we highlight these NO-dependent physiological pathways and examine complex chemical and biochemical reactions that govern NO and nitrite signaling in vivo. We focus on hemoprotein-dependent reaction pathways that generate and consume NO in the presence of nitrite and consider intermediate nitrogen oxides, including NO2, N2O3, and S-nitrosothiols, that may facilitate nitrite-based signaling in blood vessels and tissues. We also discuss emergent therapeutic strategies that leverage our understanding of these key reaction pathways to target NO signaling and treat a wide range of diseases.
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Affiliation(s)
- Matthew R Dent
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Anthony W DeMartino
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Jesús Tejero
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Mark T Gladwin
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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15
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Wang X, An P, Gu Z, Luo Y, Luo J. Mitochondrial Metal Ion Transport in Cell Metabolism and Disease. Int J Mol Sci 2021; 22:ijms22147525. [PMID: 34299144 PMCID: PMC8305404 DOI: 10.3390/ijms22147525] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/06/2021] [Accepted: 07/13/2021] [Indexed: 12/19/2022] Open
Abstract
Mitochondria are vital to life and provide biological energy for other organelles and cell physiological processes. On the mitochondrial double layer membrane, there are a variety of channels and transporters to transport different metal ions, such as Ca2+, K+, Na+, Mg2+, Zn2+ and Fe2+/Fe3+. Emerging evidence in recent years has shown that the metal ion transport is essential for mitochondrial function and cellular metabolism, including oxidative phosphorylation (OXPHOS), ATP production, mitochondrial integrity, mitochondrial volume, enzyme activity, signal transduction, proliferation and apoptosis. The homeostasis of mitochondrial metal ions plays an important role in maintaining mitochondria and cell functions and regulating multiple diseases. In particular, channels and transporters for transporting mitochondrial metal ions are very critical, which can be used as potential targets to treat neurodegeneration, cardiovascular diseases, cancer, diabetes and other metabolic diseases. This review summarizes the current research on several types of mitochondrial metal ion channels/transporters and their functions in cell metabolism and diseases, providing strong evidence and therapeutic strategies for further insights into related diseases.
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Affiliation(s)
- Xuan Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; (X.W.); (P.A.)
| | - Peng An
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; (X.W.); (P.A.)
| | - Zhenglong Gu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA;
| | - Yongting Luo
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; (X.W.); (P.A.)
- Correspondence: (Y.L.); (J.L.)
| | - Junjie Luo
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; (X.W.); (P.A.)
- Correspondence: (Y.L.); (J.L.)
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16
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Dolzer J, Schröder K, Stengl M. Cyclic nucleotide-dependent ionic currents in olfactory receptor neurons of the hawkmoth Manduca sexta suggest pull-push sensitivity modulation. Eur J Neurosci 2021; 54:4804-4826. [PMID: 34128265 DOI: 10.1111/ejn.15346] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 06/02/2021] [Accepted: 06/04/2021] [Indexed: 11/27/2022]
Abstract
Olfactory receptor neurons (ORNs) of the hawkmoth Manduca sexta sensitize via cAMP- and adapt via cGMP-dependent mechanisms. Perforated patch clamp recordings distinguished 11 currents in these ORNs. Derivatives of cAMP and/or cGMP antagonistically affected three of five K+ currents and two non-specific cation currents. The Ca2+ -dependent K+ current IK(Ca 2+ ) and the sensitive pheromone-dependent K+ current IK(cGMP-) , which both express fast kinetics, were inhibited by 8bcGMP, while a slow K+ current, IK(cGMP+) , was activated by 8bcGMP. Furthermore, application of 8bcAMP blocked slowly activating, zero mV-reversing, non-specific cation currents, ILL and Icat(PKC?) , which remained activated in the presence of 8bcGMP. Their activations pull the membrane potential towards their 0-mV reversal potentials, in addition to increasing intracellular Ca2+ levels voltage- and ILL -dependently. Twenty minutes after application, 8bcGMP blocked a TEA-independent K+ current, IK(noTEA) , and a fast cation current, Icat(nRP) , which both shift the membrane potential to negative values. We conclude that conditions of sensitization are maintained at high levels of cAMP, via specific opening/closure of ion channels that allow for fast kinetics, hyperpolarized membrane potentials, and low intracellular Ca2+ levels. In contrast, adaptation is supported via cGMP, which antagonizes cAMP, opening Ca2+ -permeable channels with slow kinetics that stabilize depolarized resting potentials. The antagonistic modulation of peripheral sensory neurons by cAMP or cGMP is reminiscent of pull-push mechanisms of neuromodulation at central synapses underlying metaplasticity.
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Affiliation(s)
- Jan Dolzer
- Biologie, Tierphysiologie, Philipps-Universität Marburg, Marburg, Germany.,Institut für Zoologie, Universität Regensburg, Regensburg, Germany
| | - Katrin Schröder
- Animal Physiology/Neuroethology, Biology, FB 10, University of Kassel, Kassel, Germany
| | - Monika Stengl
- Biologie, Tierphysiologie, Philipps-Universität Marburg, Marburg, Germany.,Institut für Zoologie, Universität Regensburg, Regensburg, Germany.,Animal Physiology/Neuroethology, Biology, FB 10, University of Kassel, Kassel, Germany
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