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Beverley KM, Barbera N, Levitan I. Dual pattern of cholesterol-induced decoupling of residue-residue interactions of Kir2.2. J Struct Biol 2024; 216:108091. [PMID: 38641256 DOI: 10.1016/j.jsb.2024.108091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 03/28/2024] [Accepted: 04/09/2024] [Indexed: 04/21/2024]
Abstract
Cholesterol is a negative regulator of a variety of ion channels. We have previously shown that cholesterol suppresses Kir2.2 channels via residue-residue uncoupling on the inter-subunit interfaces within the close state of the channels (3JYC). In this study, we extend this analysis to the other known structure of Kir2.2 that is closer to the open state of Kir2.2 channels (3SPI) and provide additional analysis of the residue distances between the uncoupled residues and cholesterol binding domains in the two conformation states of the channels. We found that the general phenomenon of cholesterol binding leading to uncoupling between specific residues is conserved in both channel states but the specific pattern of the uncoupling residues is distinct between the two states and implies different mechanisms. Specifically, we found that cholesterol binding in the 3SPI state results in an uncoupling of residues in three distinct regions; the transmembrane domain, membrane-cytosolic interface, and the cytosolic domain, with the first two regions forming an envelope around PI(4,5)P2 and cholesterol binding sites and the distal region overlapping with the subunit-subunit interface characterized in our previous study of the disengaged state. We also found that this uncoupling is dependent upon the number of cholesterol molecules bound to the channel. We further generated a mutant channel Kir2.2P187V with a single point mutation in a residue proximal to the PI(4,5)P2 binding site, which is predicted to be uncoupled from other residues in its vicinity upon cholesterol binding and found that this mutation abrogates the sensitivity of Kir2.2 to cholesterol changes in the membrane. These findings suggest that cholesterol binding to this conformation state of Kir2.2 channels may destabilize the PI(4,5)P2 interactions with the channels while in the disengaged state the destabilization occurs where the subunits interact. These findings give insight into the structural mechanistic basis for the functional effects of cholesterol binding to the Kir2.2 channel.
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Affiliation(s)
- Katie M Beverley
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
| | - Nicolas Barbera
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA; Center for Public Health Genomics, Department of Biomedical Engineering, School of Engineering &Applied Science, University of Virginia, Charlottesville, VA 22904, USA
| | - Irena Levitan
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
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2
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Beverley KM, Levitan I. Cholesterol regulation of mechanosensitive ion channels. Front Cell Dev Biol 2024; 12:1352259. [PMID: 38333595 PMCID: PMC10850386 DOI: 10.3389/fcell.2024.1352259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/17/2024] [Indexed: 02/10/2024] Open
Abstract
The purpose of this review is to evaluate the role of cholesterol in regulating mechanosensitive ion channels. Ion channels discussed in this review are sensitive to two types of mechanical signals, fluid shear stress and/or membrane stretch. Cholesterol regulates the channels primarily in two ways: 1) indirectly through localizing the channels into cholesterol-rich membrane domains where they interact with accessory proteins and/or 2) direct binding of cholesterol to the channel at specified putative binding sites. Cholesterol may also regulate channel function via changes of the biophysical properties of the membrane bilayer. Changes in cholesterol affect both mechanosensitivity and basal channel function. We focus on four mechanosensitive ion channels in this review Piezo, Kir2, TRPV4, and VRAC channels. Piezo channels were shown to be regulated by auxiliary proteins that enhance channel function in high cholesterol domains. The direct binding mechanism was shown in Kir2.1 and TRPV4 where cholesterol inhibits channel function. Finally, cholesterol regulation of VRAC was attributed to changes in the physical properties of lipid bilayer. Additional studies should be performed to determine the physiological implications of these sterol effects in complex cellular environments.
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Affiliation(s)
- Katie M. Beverley
- Division of Pulmonary, Critical Care, Sleep, and Allergy, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Irena Levitan
- Division of Pulmonary, Critical Care, Sleep, and Allergy, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
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3
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Steck TL, Ali Tabei SM, Lange Y. Estimating the Cholesterol Affinity of Integral Membrane Proteins from Experimental Data. Biochemistry 2024; 63:19-26. [PMID: 38099740 PMCID: PMC10765374 DOI: 10.1021/acs.biochem.3c00567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/29/2023] [Accepted: 11/29/2023] [Indexed: 01/03/2024]
Abstract
The cholesterol affinities of many integral plasma membrane proteins have been estimated by molecular computation. However, these values lack experimental confirmation. We therefore developed a simple mathematical model to extract sterol affinity constants and stoichiometries from published isotherms for the dependence of the activity of such proteins on the membrane cholesterol concentration. The binding curves for these proteins are sigmoidal, with strongly lagged thresholds attributable to competition for the cholesterol by bilayer phospholipids. The model provided isotherms that matched the experimental data using published values for the sterol association constants and stoichiometries of the phospholipids. Three oligomeric transporters were found to bind cholesterol without cooperativity, with dimensionless association constants of 35 for Kir3.4* and 100 for both Kir2 and a GAT transporter. (The corresponding ΔG° values were -8.8, -11.4, and -11.4 kJ/mol, respectively). These association constants are significantly lower than those for the phospholipids, which range from ∼100 to 6000. The BK channel, the nicotinic acetylcholine receptor, and the M192I mutant of Kir3.4* appear to bind multiple cholesterol molecules cooperatively (n = 2 or 4), with subunit affinities of 563, 950, and 700, respectively. The model predicts that the three less avid transporters are approximately half-saturated in their native plasma membranes; hence, they are sensitive to variations in cholesterol in vivo. The more avid proteins would be nearly saturated in vivo. The method can be applied to any integral protein or other ligands in any bilayer for which there are reasonable estimates of the sterol affinities and stoichiometries of the phospholipids.
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Affiliation(s)
- Theodore L. Steck
- Department
of Biochemistry and Molecular Biology, University
of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - S. M. Ali Tabei
- Department
of Physics, University of Northern Iowa, Cedar Falls, Iowa 50614, United States
| | - Yvonne Lange
- Department
of Pathology, Rush University Medical Center, Chicago, Illinois 60612, United States
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4
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Polk FD, Hakim MA, Silva JF, Behringer EJ, Pires PW. Endothelial K IR2 channel dysfunction in aged cerebral parenchymal arterioles. Am J Physiol Heart Circ Physiol 2023; 325:H1360-H1372. [PMID: 37801044 PMCID: PMC10907073 DOI: 10.1152/ajpheart.00279.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/07/2023]
Abstract
Aging is associated with cognitive decline via incompletely understood mechanisms. Cerebral microvascular dysfunction occurs in aging, particularly impaired endothelium-mediated dilation. Parenchymal arterioles are bottlenecks of the cerebral microcirculation, and dysfunction causes a mismatch in nutrient demand and delivery, leaving neurons at risk. Extracellular nucleotides elicit parenchymal arteriole dilation by activating endothelial purinergic receptors (P2Y), leading to opening of K+ channels, including inwardly-rectifying K+ channels (KIR2). These channels amplify hyperpolarizing signals, resulting in dilation. However, it remains unknown if endothelial P2Y and KIR2 signaling are altered in brain parenchymal arterioles during aging. We hypothesized that aging impairs endothelial P2Y and KIR2 function in parenchymal arterioles. We observed reduced dilation to the purinergic agonist 2-methyl-S-ADP (1 µM) in arterioles from Aged (>24-month-old) mice when compared to Young (4-6 months of age) despite similar hyperpolarization in endothelial cells tubes. No differences were observed in vasodilation or endothelial cell hyperpolarization to activation of small- and intermediate-conductance Ca2+-activated K+ channels (KCa2.3 / KCa3.1) by NS309. Hyperpolarization to 15 mM [K+]E was smaller in Aged than Young mice, despite a paradoxical increased dilation in Aged arterioles to 15 mM [K+]E that was unchanged by endothelium removal. KIR2 Inhibition attenuated vasodilatory responses to 15 mM [K+]E and 1 µM 2-me-S-ADP in both Young and Aged arterioles. Further, we observed a significant increase in myogenic tone in Aged parenchymal arterioles, which was not enhanced by endothelium removal. We conclude that aging impairs endothelial KIR2 channel function in the cerebral microcirculation with possible compensation by smooth muscle cells.
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Affiliation(s)
- Felipe D Polk
- Department of Physiology, University of Arizona, Tucson, Arizona, United States
| | - Md A Hakim
- Loma Linda University, Loma Linda, CA, United States
| | - Josiane F Silva
- Physiology, University of Arizona, Tucson, Arizona, United States
| | - Erik J Behringer
- Basic Sciences, Loma Linda University, Loma Linda, CA, United States
| | - Paulo W Pires
- Physiology, University of Arizona, Tucson, AZ, United States
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Fancher IS, Levitan I. Membrane Cholesterol Interactions with Proteins in Hypercholesterolemia-Induced Endothelial Dysfunction. Curr Atheroscler Rep 2023; 25:535-541. [PMID: 37418067 PMCID: PMC10471518 DOI: 10.1007/s11883-023-01127-w] [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] [Accepted: 06/23/2023] [Indexed: 07/08/2023]
Abstract
PURPOSE OF REVIEW The goal of this review is to highlight work identifying mechanisms driving hypercholesterolemia-mediated endothelial dysfunction. We specifically focus on cholesterol-protein interactions and address specific questions related to the impact of hypercholesterolemia on cellular cholesterol and vascular endothelial function. We describe key approaches used to determine the effects of cholesterol-protein interactions in mediating endothelial dysfunction under dyslipidemic conditions. RECENT FINDINGS The benefits of removing the cholesterol surplus on endothelial function in models of hypercholesterolemia is clear. However, specific mechanisms driving cholesterol-induced endothelial dysfunction need to be determined. In this review, we detail the latest findings describing cholesterol-mediated endothelial dysfunction, highlighting our studies indicating that cholesterol suppresses endothelial Kir2.1 channels as a major underlying mechanism. The findings detailed in this review support the targeting of cholesterol-induced suppression of proteins in restoring endothelial function in dyslipidemic conditions. The identification of similar mechanisms regarding other cholesterol-endothelial protein interactions is warranted.
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Affiliation(s)
- Ibra S. Fancher
- Department of Kinesiology and Applied Physiology, College of Health Sciences, University of Delaware, Newark, DE USA
| | - Irena Levitan
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, IL USA
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Dobi D, Loberto N, Bassi R, Pistocchi A, Lunghi G, Tamanini A, Aureli M. Cross-talk between CFTR and sphingolipids in cystic fibrosis. FEBS Open Bio 2023; 13:1601-1614. [PMID: 37315117 PMCID: PMC10476574 DOI: 10.1002/2211-5463.13660] [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: 04/07/2023] [Revised: 06/06/2023] [Accepted: 06/12/2023] [Indexed: 06/16/2023] Open
Abstract
Cystic fibrosis (CF) is the most common inherited, life-limiting disorder in Caucasian populations. It is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR), which lead to an impairment of protein expression and/or function. CFTR is a chloride/bicarbonate channel expressed at the apical surface of epithelial cells of different organs. Nowadays, more than 2100 CFTR genetic variants have been described, but not all of them cause CF. However, around 80-85% of the patients worldwide are characterized by the presence, at least in one allele, of the mutation F508del. CFTR mutations cause aberrant hydration and secretion of mucus in hollow organs. In the lungs, this condition favors bacterial colonization, allowing the development of chronic infections that lead to the onset of the CF lung disease, which is the main cause of death in patients. In recent years, evidence has reported that CFTR loss of function is responsible for alterations in a particular class of bioactive lipids, called sphingolipids (SL). SL are ubiquitously present in eukaryotic cells and are mainly asymmetrically located within the external leaflet of the plasma membrane, where they organize specific platforms capable of segregating a selected number of proteins. CFTR is associated with these platforms that are fundamental for its functioning. Considering the importance of SL in CFTR homeostasis, we attempt here to provide a critical overview of the literature to determine the role of these lipids in channel stability and activity, and whether their modulation in CF could be a target for new therapeutic approaches.
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Affiliation(s)
- Dorina Dobi
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
| | - Nicoletta Loberto
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
| | - Rosaria Bassi
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
| | - Anna Pistocchi
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
| | - Giulia Lunghi
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
| | - Anna Tamanini
- Section of Clinical Biochemistry, Department of Neurosciences, Biomedicine and MovementUniversity of VeronaItaly
| | - Massimo Aureli
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
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Ferreira G, Santander A, Cardozo R, Chavarría L, Domínguez L, Mujica N, Benítez M, Sastre S, Sobrevia L, Nicolson GL. Nutrigenomics of inward rectifier potassium channels. Biochim Biophys Acta Mol Basis Dis 2023:166803. [PMID: 37406972 DOI: 10.1016/j.bbadis.2023.166803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023]
Abstract
Inwardly rectifying potassium (Kir) channels play a key role in maintaining the resting membrane potential and supporting potassium homeostasis. There are many variants of Kir channels, which are usually tetramers in which the main subunit has two trans-membrane helices attached to two N- and C-terminal cytoplasmic tails with a pore-forming loop in between that contains the selectivity filter. These channels have domains that are strongly modulated by molecules present in nutrients found in different diets, such as phosphoinositols, polyamines and Mg2+. These molecules can impact these channels directly or indirectly, either allosterically by modulation of enzymes or via the regulation of channel expression. A particular type of these channels is coupled to cell metabolism and inhibited by ATP (KATP channels, essential for insulin release and for the pathogenesis of metabolic diseases like diabetes mellitus). Genomic changes in Kir channels have a significant impact on metabolism, such as conditioning the nutrients and electrolytes that an individual can take. Thus, the nutrigenomics of ion channels is an important emerging field in which we are attempting to understand how nutrients and diets can affect the activity and expression of ion channels and how genomic changes in such channels may be the basis for pathological conditions that limit nutrition and electrolyte intake. In this contribution we briefly review Kir channels, discuss their nutrigenomics, characterize how different components in the diet affect their function and expression, and suggest how their genomic changes lead to pathological phenotypes that affect diet and electrolyte intake.
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Affiliation(s)
- Gonzalo Ferreira
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay.
| | - Axel Santander
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Romina Cardozo
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Luisina Chavarría
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Lucía Domínguez
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Nicolás Mujica
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Milagros Benítez
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Santiago Sastre
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo CP 11800, Uruguay
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; Medical School (Faculty of Medicine), Sao Paulo State University (UNESP), Brazil; University of Queensland, Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, 4029, Queensland, Australia; Tecnologico de Monterrey, Eutra, The Institute for Obesity Research (IOR), School of Medicine and Health Sciences, Monterrey, Nuevo León, Mexico
| | - Garth L Nicolson
- Department of Molecular Pathology, The Institute for Molecular Medicine, Huntington Beach, CA, USA
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8
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Tzortzini E, Kolocouris A. Molecular Biophysics of Class A G Protein Coupled Receptors-Lipids Interactome at a Glance-Highlights from the A 2A Adenosine Receptor. Biomolecules 2023; 13:957. [PMID: 37371538 DOI: 10.3390/biom13060957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/25/2023] [Accepted: 05/28/2023] [Indexed: 06/29/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are embedded in phospholipid membrane bilayers with cholesterol representing 34% of the total lipid content in mammalian plasma membranes. Membrane lipids interact with GPCRs structures and modulate their function and drug-stimulated signaling through conformational selection. It has been shown that anionic phospholipids form strong interactions between positively charged residues in the G protein and the TM5-TM6-TM 7 cytoplasmic interface of class A GPCRs stabilizing the signaling GPCR-G complex. Cholesterol with a high content in plasma membranes can be identified in more specific sites in the transmembrane region of GPCRs, such as the Cholesterol Consensus Motif (CCM) and Cholesterol Recognition Amino Acid Consensus (CRAC) motifs and other receptor dependent and receptor state dependent sites. Experimental biophysical methods, atomistic (AA) MD simulations and coarse-grained (CG) molecular dynamics simulations have been applied to investigate these interactions. We emphasized here the impact of phosphatidyl inositol-4,5-bisphosphate (PtdIns(4,5)P2 or PIP2), a minor phospholipid component and of cholesterol on the function-related conformational equilibria of the human A2A adenosine receptor (A2AR), a representative receptor in class A GPCR. Several GPCRs of class A interacted with PIP2 and cholesterol and in many cases the mechanism of the modulation of their function remains unknown. This review provides a helpful comprehensive overview for biophysics that enter the field of GPCRs-lipid systems.
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Affiliation(s)
- Efpraxia Tzortzini
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - Antonios Kolocouris
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, 15771 Athens, Greece
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9
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Davis MJ, Earley S, Li YS, Chien S. Vascular mechanotransduction. Physiol Rev 2023; 103:1247-1421. [PMID: 36603156 PMCID: PMC9942936 DOI: 10.1152/physrev.00053.2021] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 01/07/2023] Open
Abstract
This review aims to survey the current state of mechanotransduction in vascular smooth muscle cells (VSMCs) and endothelial cells (ECs), including their sensing of mechanical stimuli and transduction of mechanical signals that result in the acute functional modulation and longer-term transcriptomic and epigenetic regulation of blood vessels. The mechanosensors discussed include ion channels, plasma membrane-associated structures and receptors, and junction proteins. The mechanosignaling pathways presented include the cytoskeleton, integrins, extracellular matrix, and intracellular signaling molecules. These are followed by discussions on mechanical regulation of transcriptome and epigenetics, relevance of mechanotransduction to health and disease, and interactions between VSMCs and ECs. Throughout this review, we offer suggestions for specific topics that require further understanding. In the closing section on conclusions and perspectives, we summarize what is known and point out the need to treat the vasculature as a system, including not only VSMCs and ECs but also the extracellular matrix and other types of cells such as resident macrophages and pericytes, so that we can fully understand the physiology and pathophysiology of the blood vessel as a whole, thus enhancing the comprehension, diagnosis, treatment, and prevention of vascular diseases.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Scott Earley
- Department of Pharmacology, University of Nevada, Reno, Nevada
| | - Yi-Shuan Li
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
- Department of Medicine, University of California, San Diego, California
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10
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Marlow B, Kuenze G, Meiler J, Koehler Leman J. Docking cholesterol to integral membrane proteins with Rosetta. PLoS Comput Biol 2023; 19:e1010947. [PMID: 36972273 PMCID: PMC10042369 DOI: 10.1371/journal.pcbi.1010947] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/14/2023] [Indexed: 03/29/2023] Open
Abstract
Lipid molecules such as cholesterol interact with the surface of integral membrane proteins (IMP) in a mode different from drug-like molecules in a protein binding pocket. These differences are due to the lipid molecule's shape, the membrane's hydrophobic environment, and the lipid's orientation in the membrane. We can use the recent increase in experimental structures in complex with cholesterol to understand protein-cholesterol interactions. We developed the RosettaCholesterol protocol consisting of (1) a prediction phase using an energy grid to sample and score native-like binding poses and (2) a specificity filter to calculate the likelihood that a cholesterol interaction site may be specific. We used a multi-pronged benchmark (self-dock, flip-dock, cross-dock, and global-dock) of protein-cholesterol complexes to validate our method. RosettaCholesterol improved sampling and scoring of native poses over the standard RosettaLigand baseline method in 91% of cases and performs better regardless of benchmark complexity. On the β2AR, our method found one likely-specific site, which is described in the literature. The RosettaCholesterol protocol quantifies cholesterol binding site specificity. Our approach provides a starting point for high-throughput modeling and prediction of cholesterol binding sites for further experimental validation.
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Affiliation(s)
- Brennica Marlow
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Georg Kuenze
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - Julia Koehler Leman
- Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, New York, United States of America
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11
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Rezende L, Couto NFD, Fernandes-Braga W, Epshtein Y, Alvarez-Leite JI, Levitan I, Andrade LDO. OxLDL induces membrane structure rearrangement leading to biomechanics alteration and migration deficiency in macrophage. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - BIOMEMBRANES 2022; 1864:183951. [PMID: 35504320 DOI: 10.1016/j.bbamem.2022.183951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 11/30/2022]
Abstract
Cholesterol sequestration from plasma membrane has been shown to induce lipid packing disruption, causing actin cytoskeleton reorganization and polymerization, increasing cell stiffness and inducing lysosomal exocytosis in non-professional phagocytes. Similarly, oxidized form of low-density lipoprotein (oxLDL) has also been shown to disrupt lipid organization and packing in endothelial cells, leading to biomechanics alterations that interfere with membrane injury and repair. For macrophages, much is known about oxLDL effects in cell activation, cytokine production and foam cell formation. However, little is known about its impact in the organization of macrophage membrane structured domains and cellular mechanics, the focus of the present study. Treatment of bone marrow-derived macrophages (BMDM) with oxLDL not only altered membrane structure, and potentially the distribution of raft domains, but also induced actin rearrangement, diffuse integrin distribution and cell shrinkage, similarly to observed upon treatment of these cells with MβCD. Those alterations led to decreased migration efficiency. For both treatments, higher co-localization of actin cytoskeleton and GM1 was observed, indicating a similar mechanism of action involving raft-like domain dynamics. Lastly, like MβCD treatment, oxLDL also induced lysosomal spreading in BMDM. We propose that OxLDL induced re-organization of membrane/cytoskeleton complex in macrophages can be attributed to the insertion of oxysterols into the membrane, which lead to changes in lipid organization and disruption of membrane structure, similar to the effect of cholesterol depletion by MβCD treatment. These results indicate that oxLDL can induce physical alterations in the complex membrane/cytoskeleton of macrophages, leading to significant biomechanical changes that compromise cell behavior.
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Affiliation(s)
- Luisa Rezende
- Department of Morphology/Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Natalia Fernanda Do Couto
- Department of Morphology/Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; Department of Medicine, University of Illinois at Chicago, Chicago, USA
| | - Weslley Fernandes-Braga
- Department of Biochemistry and Immunology/Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Yulia Epshtein
- Department of Medicine, University of Illinois at Chicago, Chicago, USA
| | | | - Irena Levitan
- Department of Medicine, University of Illinois at Chicago, Chicago, USA
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12
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Barbera N, Granados ST, Vanoye CG, Abramova TV, Kulbak D, Ahn SJ, George AL, Akpa BS, Levitan I. Cholesterol-induced suppression of Kir2 channels is mediated by decoupling at the inter-subunit interfaces. iScience 2022; 25:104329. [PMID: 35602957 PMCID: PMC9120057 DOI: 10.1016/j.isci.2022.104329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/29/2022] [Accepted: 04/26/2022] [Indexed: 12/29/2022] Open
Abstract
Cholesterol is a major regulator of multiple types of ion channels. Although there is increasing information about cholesterol binding sites, the molecular mechanisms through which cholesterol binding alters channel function are virtually unknown. In this study, we used a combination of Martini coarse-grained simulations, a network theory-based analysis, and electrophysiology to determine the effect of cholesterol on the dynamic structure of the Kir2.2 channel. We found that increasing membrane cholesterol reduced the likelihood of contact between specific regions of the cytoplasmic and transmembrane domains of the channel, most prominently at the subunit-subunit interfaces of the cytosolic domains. This decrease in contact was mediated by pairwise interactions of specific residues and correlated to the stoichiometry of cholesterol binding events. The predictions of the model were tested by site-directed mutagenesis of two identified residues-V265 and H222-and high throughput electrophysiology.
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Affiliation(s)
- Nicolas Barbera
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60611, USA
| | - Sara T. Granados
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60611, USA
| | - Carlos Guillermo Vanoye
- Department of Pharmacology; Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Tatiana V. Abramova
- Department of Pharmacology; Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Danielle Kulbak
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60611, USA
| | - Sang Joon Ahn
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60611, USA
| | - Alfred L. George
- Department of Pharmacology; Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Belinda S. Akpa
- Division of Biosciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA
- Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Irena Levitan
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60611, USA
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13
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Abstract
Cholesterol is one of the main components found in plasma membranes and is involved in lipid-dependent signaling enabled by integral membrane proteins such as inwardly rectifying potassium (Kir) channels. Similar to other ion channels, most of the Kir channels are down-regulated by cholesterol. One of the very few notable exceptions is Kir3.4, which is up-regulated by this important lipid. Here, we discovered and characterized a molecular switch that controls the impact (up-regulation vs. down-regulation) of cholesterol on Kir3.4. Our results provide a detailed molecular mechanism of tunable cholesterol regulation of a potassium channel. Cholesterol decreases the activity of the majority of ion channels while increasing the activity of only a few, yet it remains unclear how. Here, we used the inwardly rectifying potassium channel Kir3.4, which is up-regulated by cholesterol, as a tool to address this question. Employing mutagenesis and electrophysiology, we discovered a molecular switch that controls the impact of cholesterol on the channel. Through a single point mutation at position 182 in the transmembrane domain of Kir3.4, we converted the cholesterol-driven up-regulation of the channel into down-regulation. Microseconds-long coarse-grained and atomistic molecular dynamics simulations revealed that the effect of the point mutation propagated toward the selectivity filter of the channel whose conformation controls the conductance of the channel. Planar lipid bilayer experiments validated these results, showing that although cholesterol up-regulated Kir3.4 by increasing its open probability, cholesterol down-regulated the mutant by decreasing its conductance. Further studies underscored the role of mutation-specific alterations of cholesterol distribution in proximity to the channel in cholesterol’s impact on channel activity, highlighting the role of subtle molecular differences in determining how cholesterol distributes around proteins and affects their function.
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14
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Sancho M, Fletcher J, Welsh DG. Inward Rectifier Potassium Channels: Membrane Lipid-Dependent Mechanosensitive Gates in Brain Vascular Cells. Front Cardiovasc Med 2022; 9:869481. [PMID: 35419431 PMCID: PMC8995785 DOI: 10.3389/fcvm.2022.869481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Cerebral arteries contain two primary and interacting cell types, smooth muscle (SMCs) and endothelial cells (ECs), which are each capable of sensing particular hemodynamic forces to set basal tone and brain perfusion. These biomechanical stimuli help confer tone within arterial networks upon which local neurovascular stimuli function. Tone development is intimately tied to arterial membrane potential (VM) and changes in intracellular [Ca2+] driven by voltage-gated Ca2+ channels (VGCCs). Arterial VM is in turn set by the dynamic interplay among ion channel species, the strongly inward rectifying K+ (Kir) channel being of special interest. Kir2 channels possess a unique biophysical signature in that they strongly rectify, display negative slope conductance, respond to elevated extracellular K+ and are blocked by micromolar Ba2+. While functional Kir2 channels are expressed in both smooth muscle and endothelium, they lack classic regulatory control, thus are often viewed as a simple background conductance. Recent literature has provided new insight, with two membrane lipids, phosphatidylinositol 4,5-bisphosphate (PIP2) and cholesterol, noted to (1) stabilize Kir2 channels in a preferred open or closed state, respectively, and (2) confer, in association with the cytoskeleton, caveolin-1 (Cav1) and syntrophin, hemodynamic sensitivity. It is these aspects of vascular Kir2 channels that will be the primary focus of this review.
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Affiliation(s)
- Maria Sancho
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
- Department of Physiology, Faculty of Medicine, Universidad Complutense de Madrid, Madrid, Spain
- *Correspondence: Maria Sancho,
| | - Jacob Fletcher
- Department of Physiology and Pharmacology, Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | - Donald G. Welsh
- Department of Physiology and Pharmacology, Robarts Research Institute, University of Western Ontario, London, ON, Canada
- Donald G. Welsh,
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15
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Borcik CG, Eason IR, Yekefallah M, Amani R, Han R, Vanderloop BH, Wylie BJ. A Cholesterol Dimer Stabilizes the Inactivated State of an Inward-Rectifier Potassium Channel. Angew Chem Int Ed Engl 2022; 61:e202112232. [PMID: 34985791 PMCID: PMC8957755 DOI: 10.1002/anie.202112232] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Indexed: 12/15/2022]
Abstract
Cholesterol oligomers reside in multiple membrane protein X-ray crystal structures. Yet, there is no direct link between these oligomers and a biological function. Here we present the structural and functional details of a cholesterol dimer that stabilizes the inactivated state of an inward-rectifier potassium channel KirBac1.1. K+ efflux assays confirm that high cholesterol concentration reduces K+ conductance. We then determine the structure of the cholesterol-KirBac1.1 complex using Xplor-NIH simulated annealing calculations driven by solid-state NMR distance measurements. These calculations identified an α-α cholesterol dimer docked to a cleft formed by adjacent subunits of the homotetrameric protein. We compare these results to coarse grain molecular dynamics simulations. This is one of the first examples of a cholesterol oligomer performing a distinct biological function and structural characterization of a conserved promiscuous lipid binding region.
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Affiliation(s)
- Collin G Borcik
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Isaac R Eason
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Maryam Yekefallah
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Reza Amani
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Ruixian Han
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Boden H Vanderloop
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Benjamin J Wylie
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
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16
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Borcik CG, Eason IR, Yekefallah M, Amani R, Han R, Vanderloop BH, Wylie BJ. A Cholesterol Dimer Stabilizes the Inactivated State of an Inward‐Rectifier Potassium Channel. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Collin G. Borcik
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
| | - Isaac R. Eason
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
| | - Maryam Yekefallah
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
| | - Reza Amani
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
| | - Ruixian Han
- Department of Biochemistry University of Wisconsin-Madison Madison WI 53706 USA
| | - Boden H. Vanderloop
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
| | - Benjamin J. Wylie
- Department of Chemistry and Biochemistry Texas Tech University Lubbock TX 79409 USA
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17
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Suresh P, London E. Using cyclodextrin-induced lipid substitution to study membrane lipid and ordered membrane domain (raft) function in cells. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183774. [PMID: 34534531 PMCID: PMC9128603 DOI: 10.1016/j.bbamem.2021.183774] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/30/2021] [Accepted: 09/08/2021] [Indexed: 02/03/2023]
Abstract
Methods for efficient cyclodextrin-induced lipid exchange have been developed in our lab. These make it possible to almost completely replace the lipids in the outer leaflet of artificial membranes or the plasma membranes of living cells with exogenous lipids. Lipid replacement/substitution allows detailed studies of how lipid composition and asymmetry influence the structure and function of membrane domains and membrane proteins. In this review, we both summarize progress on cyclodextrin exchange in cells, mainly by the use of methyl-alpha cyclodextrin to exchange phospholipids and sphingolipids, and discuss the issues to consider when carrying out lipid exchange experiments upon cells. Issues that impact interpretation of lipid exchange are also discussed. This includes how overly naïve interpretation of how lipid exchange-induced changes in domain formation can impact protein function.
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18
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Ahn SJ, Fancher IS, Granados ST, Do Couto NF, Hwang CL, Phillips SA, Levitan I. Cholesterol-Induced Suppression of Endothelial Kir Channels Is a Driver of Impairment of Arteriolar Flow-Induced Vasodilation in Humans. Hypertension 2022; 79:126-138. [PMID: 34784737 PMCID: PMC8845492 DOI: 10.1161/hypertensionaha.121.17672] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Dyslipidemia-induced endothelial dysfunction is an important factor in the progression of cardiovascular disease; however, the underlying mechanisms are unclear. Our recent studies demonstrated that flow-induced vasodilation (FIV) is regulated by inwardly rectifying K+ channels (Kir2.1) in resistance arteries. Furthermore, we showed that hypercholesterolemia inhibits Kir2.1-dependent vasodilation. In this study, we introduced 2 new mouse models: (1) endothelial-specific deletion of Kir2.1 to demonstrate the role of endothelial Kir2.1 in FIV and (2) cholesterol-insensitive Kir2.1 mutant to determine the Kir2.1 regulation in FIV under hypercholesterolemia. FIV was significantly reduced in endothelial-specific Kir2.1 knock-out mouse mesenteric arteries compared with control groups. In cholesterol-insensitive Kir2.1 mutant mice, Kir2.1 currents were not affected by cyclodextrin and FIV was restored in cells and arteries, respectively, with a hypercholesterolemic background. To extend our observations to humans, 16 healthy subjects were recruited with LDL (low-density lipoprotein)-cholesterol ranging from 51 to 153 mg/dL and FIV was assessed in resistance arteries isolated from gluteal adipose. Resistance arteries from participants with >100 mg/dL LDL (high-LDL) exhibited reduced FIV as compared with those participants with <100 mg/dL LDL (low-LDL). A significant negative correlation was observed between LDL cholesterol and FIV in high-LDL. Expressing dominant-negative Kir2.1 in endothelium blunted FIV in arteries from low-LDL but had no further effect on FIV in arteries from high-LDL. The Kir2.1-dependent vasodilation more negatively correlated to LDL cholesterol in high-LDL. Overexpressing wild-type Kir2.1 in endothelium fully recovered FIV in arteries from participants with high-LDL. Our data suggest that cholesterol-induced suppression of Kir2.1 is a major mechanism underlying endothelial dysfunction in hypercholesterolemia.
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Affiliation(s)
- Sang Joon Ahn
- Department of Medicine, Division of Pulmonary, Critical Care, Allergy and Sleep, College of Medicine, University of Illinois at Chicago
| | - Ibra S. Fancher
- Department of Medicine, Division of Pulmonary, Critical Care, Allergy and Sleep, College of Medicine, University of Illinois at Chicago,Department of Kinesiology and Applied Physiology, University of Delaware
| | - Sara T. Granados
- Department of Medicine, Division of Pulmonary, Critical Care, Allergy and Sleep, College of Medicine, University of Illinois at Chicago
| | - Natalia F. Do Couto
- Department of Medicine, Division of Pulmonary, Critical Care, Allergy and Sleep, College of Medicine, University of Illinois at Chicago,Department of Physical Therapy, College of Applied Health Science, University of Illinois at Chicago
| | - Chueh-Lung Hwang
- Department of Physical Therapy, College of Applied Health Science, University of Illinois at Chicago
| | - Shane A. Phillips
- Department of Physical Therapy, College of Applied Health Science, University of Illinois at Chicago
| | - Irena Levitan
- Department of Medicine, Division of Pulmonary, Critical Care, Allergy and Sleep, College of Medicine, University of Illinois at Chicago
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19
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Martinière A, Zelazny E. Membrane nanodomains and transport functions in plant. PLANT PHYSIOLOGY 2021; 187:1839-1855. [PMID: 35235669 PMCID: PMC8644385 DOI: 10.1093/plphys/kiab312] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/16/2021] [Indexed: 05/25/2023]
Abstract
Far from a homogeneous environment, biological membranes are highly structured with lipids and proteins segregating in domains of different sizes and dwell times. In addition, membranes are highly dynamics especially in response to environmental stimuli. Understanding the impact of the nanoscale organization of membranes on cellular functions is an outstanding question. Plant channels and transporters are tightly regulated to ensure proper cell nutrition and signaling. Increasing evidence indicates that channel and transporter nano-organization within membranes plays an important role in these regulation mechanisms. Here, we review recent advances in the field of ion, water, but also hormone transport in plants, focusing on protein organization within plasma membrane nanodomains and its cellular and physiological impacts.
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Affiliation(s)
| | - Enric Zelazny
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
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20
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Kir Channel Molecular Physiology, Pharmacology, and Therapeutic Implications. Handb Exp Pharmacol 2021; 267:277-356. [PMID: 34345939 DOI: 10.1007/164_2021_501] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
For the past two decades several scholarly reviews have appeared on the inwardly rectifying potassium (Kir) channels. We would like to highlight two efforts in particular, which have provided comprehensive reviews of the literature up to 2010 (Hibino et al., Physiol Rev 90(1):291-366, 2010; Stanfield et al., Rev Physiol Biochem Pharmacol 145:47-179, 2002). In the past decade, great insights into the 3-D atomic resolution structures of Kir channels have begun to provide the molecular basis for their functional properties. More recently, computational studies are beginning to close the time domain gap between in silico dynamic and patch-clamp functional studies. The pharmacology of these channels has also been expanding and the dynamic structural studies provide hope that we are heading toward successful structure-based drug design for this family of K+ channels. In the present review we focus on placing the physiology and pharmacology of this K+ channel family in the context of atomic resolution structures and in providing a glimpse of the promising future of therapeutic opportunities.
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21
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Alvira-Iraizoz F, Gillard BT, Lin P, Paterson A, Pauža AG, Ali MA, Alabsi AH, Burger PA, Hamadi N, Adem A, Murphy D, Greenwood MP. Multiomic analysis of the Arabian camel (Camelus dromedarius) kidney reveals a role for cholesterol in water conservation. Commun Biol 2021; 4:779. [PMID: 34163009 PMCID: PMC8222267 DOI: 10.1038/s42003-021-02327-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 06/06/2021] [Indexed: 02/05/2023] Open
Abstract
The Arabian camel (Camelus dromedarius) is the most important livestock animal in arid and semi-arid regions and provides basic necessities to millions of people. In the current context of climate change, there is renewed interest in the mechanisms that enable camelids to survive in arid conditions. Recent investigations described genomic signatures revealing evolutionary adaptations to desert environments. We now present a comprehensive catalogue of the transcriptomes and proteomes of the dromedary kidney and describe how gene expression is modulated as a consequence of chronic dehydration and acute rehydration. Our analyses suggested an enrichment of the cholesterol biosynthetic process and an overrepresentation of categories related to ion transport. Thus, we further validated differentially expressed genes with known roles in water conservation which are affected by changes in cholesterol levels. Our datasets suggest that suppression of cholesterol biosynthesis may facilitate water retention in the kidney by indirectly facilitating the AQP2-mediated water reabsorption.
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Affiliation(s)
- Fernando Alvira-Iraizoz
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK.
| | - Benjamin T Gillard
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Panjiao Lin
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Alex Paterson
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Audrys G Pauža
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Mahmoud A Ali
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, AL Ain, United Arab Emirates
| | - Ammar H Alabsi
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Pamela A Burger
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, Vetmeduni Vienna, Vienna, Austria
| | - Naserddine Hamadi
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi, United Arab Emirates
| | - Abdu Adem
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, AL Ain, United Arab Emirates.
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates.
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
| | - Michael P Greenwood
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, UK
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22
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Lasunción MA, Martínez-Botas J, Martín-Sánchez C, Busto R, Gómez-Coronado D. Cell cycle dependence on the mevalonate pathway: Role of cholesterol and non-sterol isoprenoids. Biochem Pharmacol 2021; 196:114623. [PMID: 34052188 DOI: 10.1016/j.bcp.2021.114623] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 12/16/2022]
Abstract
The mevalonate pathway is responsible for the synthesis of isoprenoids, including sterols and other metabolites that are essential for diverse biological functions. Cholesterol, the main sterol in mammals, and non-sterol isoprenoids are in high demand by rapidly dividing cells. As evidence of its importance, many cell signaling pathways converge on the mevalonate pathway and these include those involved in proliferation, tumor-promotion, and tumor-suppression. As well as being a fundamental building block of cell membranes, cholesterol plays a key role in maintaining their lipid organization and biophysical properties, and it is crucial for the function of proteins located in the plasma membrane. Importantly, cholesterol and other mevalonate derivatives are essential for cell cycle progression, and their deficiency blocks different steps in the cycle. Furthermore, the accumulation of non-isoprenoid mevalonate derivatives can cause DNA replication stress. Identification of the mechanisms underlying the effects of cholesterol and other mevalonate derivatives on cell cycle progression may be useful in the search for new inhibitors, or the repurposing of preexisting cholesterol biosynthesis inhibitors to target cancer cell division. In this review, we discuss the dependence of cell division on an active mevalonate pathway and the role of different mevalonate derivatives in cell cycle progression.
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Affiliation(s)
- Miguel A Lasunción
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
| | - Javier Martínez-Botas
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain
| | - Covadonga Martín-Sánchez
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain
| | - Rebeca Busto
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain
| | - Diego Gómez-Coronado
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
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23
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Marlow B, Kuenze G, Li B, Sanders CR, Meiler J. Structural determinants of cholesterol recognition in helical integral membrane proteins. Biophys J 2021; 120:1592-1604. [PMID: 33640379 DOI: 10.1016/j.bpj.2021.02.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 01/12/2021] [Accepted: 02/08/2021] [Indexed: 12/20/2022] Open
Abstract
Cholesterol is an integral component of mammalian membranes. It has been shown to modulate membrane fluidity and dynamics and alter integral membrane protein function. However, understanding the molecular mechanisms of how cholesterol impacts protein function is complicated by limited and conflicting structural data. Because of the nature of the crystallization and cryo-EM structure determination, it is difficult to distinguish between specific and biologically relevant interactions and a nonspecific association. The only widely recognized search algorithm for cholesterol-integral-membrane-protein interaction sites is sequence based, i.e., searching for the so-called "Cholesterol Recognition/interaction Amino acid Consensus" motif. Although these motifs are present in numerous integral membrane proteins, there is inconclusive evidence to support their necessity or sufficiency for cholesterol binding. Here, we leverage the increasing number of experimental cholesterol-integral-membrane-protein structures to systematically analyze putative interaction sites based on their spatial arrangement and evolutionary conservation. This analysis creates three-dimensional representations of general cholesterol interaction sites that form clusters across multiple integral membrane protein classes. We also classify cholesterol-integral-membrane-protein interaction sites as either likely-specific or nonspecific. Information gleaned from our characterization will eventually enable a structure-based approach to predict and design cholesterol-integral-membrane-protein interaction sites.
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Affiliation(s)
- Brennica Marlow
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee
| | - Georg Kuenze
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Department of Chemistry, Vanderbilt University, Nashville, Tennessee; Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - Bian Li
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee
| | - Charles R Sanders
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Department of Biochemistry, Vanderbilt University, Nashville, Tennessee
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee; Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee; Department of Chemistry, Vanderbilt University, Nashville, Tennessee; Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany.
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24
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Chong J, De Vecchis D, Hyman AJ, Povstyan OV, Ludlow MJ, Shi J, Beech DJ, Kalli AC. Modeling of full-length Piezo1 suggests importance of the proximal N-terminus for dome structure. Biophys J 2021; 120:1343-1356. [PMID: 33582137 PMCID: PMC8105715 DOI: 10.1016/j.bpj.2021.02.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/22/2021] [Accepted: 02/03/2021] [Indexed: 01/22/2023] Open
Abstract
Piezo1 forms a mechanically activated calcium-permeable nonselective cation channel that is functionally important in many cell types. Structural data exist for C-terminal regions, but we lack information about N-terminal regions and how the entire channel interacts with the lipid bilayer. Here, we use computational approaches to predict the three-dimensional structure of the full-length Piezo1 and simulate it in an asymmetric membrane. A number of novel insights are suggested by the model: 1) Piezo1 creates a trilobed dome in the membrane that extends beyond the radius of the protein, 2) Piezo1 changes the lipid environment in its vicinity via preferential interactions with cholesterol and phosphatidylinositol 4,5-bisphosphate (PIP2) molecules, and 3) cholesterol changes the depth of the dome and PIP2 binding preference. In vitro alteration of cholesterol concentration inhibits Piezo1 activity in a manner complementing some of our computational findings. The data suggest the importance of N-terminal regions of Piezo1 for dome structure and membrane cholesterol and PIP2 interactions.
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Affiliation(s)
- Jiehan Chong
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Dario De Vecchis
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Adam J Hyman
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Oleksandr V Povstyan
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Melanie J Ludlow
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Jian Shi
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
| | - David J Beech
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom.
| | - Antreas C Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.
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25
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Structural Stringency and Optimal Nature of Cholesterol Requirement in the Function of the Serotonin1A Receptor. J Membr Biol 2020; 253:445-457. [DOI: 10.1007/s00232-020-00138-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/04/2020] [Indexed: 12/11/2022]
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26
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Direct and indirect cholesterol effects on membrane proteins with special focus on potassium channels. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158706. [DOI: 10.1016/j.bbalip.2020.158706] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 03/19/2020] [Accepted: 03/30/2020] [Indexed: 12/16/2022]
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Shrivastava S, Paila YD, Kombrabail M, Krishnamoorthy G, Chattopadhyay A. Role of Cholesterol and Its Immediate Biosynthetic Precursors in Membrane Dynamics and Heterogeneity: Implications for Health and Disease. J Phys Chem B 2020; 124:6312-6320. [DOI: 10.1021/acs.jpcb.0c04338] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Sandeep Shrivastava
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Yamuna Devi Paila
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Mamata Kombrabail
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
| | - G. Krishnamoorthy
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
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Sancho M, Welsh DG. K IR channels in the microvasculature: Regulatory properties and the lipid-hemodynamic environment. CURRENT TOPICS IN MEMBRANES 2020; 85:227-259. [PMID: 32402641 DOI: 10.1016/bs.ctm.2020.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Basal tone and perfusion control is set in cerebral arteries by the sensing of pressure and flow, key hemodynamic stimuli. These forces establish a contractile foundation within arterial networks upon which local neurovascular stimuli operate. This fundamental process is intimately tied to arterial VM and the rise in cytosolic [Ca2+] by the graded opening of voltage-operated Ca2+ channels. Arterial VM is in turn controlled by a dynamic interaction among several resident ion channels, KIR being one of particular significance. As the name suggests, KIR displays strong inward rectification, retains a small outward component, potentiated by extracellular K+ and blocked by micromolar Ba2+. Cerebrovascular KIR is unique from other K+ currents as it is present in both smooth muscle and endothelium yet lacking in classical regulatory modulation. Such observations have fostered the view that KIR is nothing more than a background conductance, activated by extracellular K+ and which passively facilitates dilation. Recent work in cell model systems has; however, identified two membrane lipids, phosphatidylinositol 4,5-bisphosphate (PIP2) and cholesterol, that interact with KIR2.x, to stabilize the channel in the preferred open or silent state, respectively. Translating this unique form of regulation, recent studies have demonstrated that specific lipid-protein interactions enable unique KIR populations to sense distinct hemodynamic stimuli and set basal tone. This review summarizes the current knowledge of vascular KIR channels and how the lipid and hemodynamic impact their activity.
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Affiliation(s)
- Maria Sancho
- Robarts Research Institute and the Department of Physiology & Pharmacology, University of Western Ontario, London, ON, Canada
| | - Donald G Welsh
- Robarts Research Institute and the Department of Physiology & Pharmacology, University of Western Ontario, London, ON, Canada.
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Abstract
Cystic Fibrosis (CF) is the most common life-shortening genetic disease among Caucasians, resulting from mutations in the gene encoding the Cystic Fibrosis Transmembrane conductance Regulator (CFTR). While work to understand this protein has resulted in new treatment strategies, it is important to emphasize that CFTR exists within a complex lipid bilayer — a concept largely overlooked when performing structural and functional studies. In this review we discuss cellular lipid imbalances in CF, mechanisms by which lipids affect membrane protein activity, and the specific impact of detergents and lipids on CFTR function. In this review, Cottrill et al. discuss how the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) interacts with the membrane into which it is inserted. They summarize recent insight into the ways lipids are imbalanced in CF epithelia and how the lipid environment affects CFTR.
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Barbera NA, Minke B, Levitan I. Comparative docking analysis of cholesterol analogs to ion channels to discriminate between stereospecific binding vs. stereospecific response. Channels (Austin) 2020; 13:136-146. [PMID: 31033379 PMCID: PMC6527060 DOI: 10.1080/19336950.2019.1606670] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cholesterol is a major component of the membrane and a key regulator of many ion channels. Multiple studies showed that cholesterol regulates ion channels in a stereospecific manner, with cholesterol but not its chiral isomers having a functional effect. This stereospecificity has been universally attributed to the specificity of cholesterol binding, with the assumption that only native cholesterol binds to the channels whereas its isomers do not. In this study, we challenge this paradigm by docking analyses of cholesterol and its chiral isomers to five ion channels whose response to cholesterol was shown to be stereospecific, Kir2.2, KirBac1.1, TRPV1, GABAA and BK. The analysis is performed using AutoDock Vina to predict the binding poses and energies of the sterols to the channels and identify amino acids interacting with the sterol molecules. We found that for every ion channel tested herein all three sterols showed similar binding poses and significant overlap in the set of the amino acids that comprise the predicted binding sites, along with similar energetic favorability to these overlapping sites. We also found, however, that specific orientations of the three sterols within the binding sites of the channels are distinct, so that a subset of the interacting amino acids is unique to each sterol. We propose therefore, that contrary to previous thought, stereospecific effects of cholesterol should be attributed not to the lack of binding of the stereoisomers but to specific, unique interactions between the cholesterol molecule and the residues within the binding sites of the channels.
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Affiliation(s)
- Nicolas A Barbera
- a Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine , University of Illinois at Chicago , Chicago , IL , USA.,b Department of Chemical Engineering , University of Illinois at Chicago , Chicago , USA
| | - Baruch Minke
- c Department of Medical Neurobiology, and the Edmond and Lily Safra Center for Brain Sciences (ELSC), Faculty of Medicine , the Hebrew University , Jerusalem , Israel
| | - Irena Levitan
- a Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine , University of Illinois at Chicago , Chicago , IL , USA
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Meza U, Delgado-Ramírez M, Romero-Méndez C, Sánchez-Armass S, Rodríguez-Menchaca AA. Functional marriage in plasma membrane: Critical cholesterol level-optimal protein activity. Br J Pharmacol 2020; 177:2456-2465. [PMID: 32060896 DOI: 10.1111/bph.15027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/14/2020] [Accepted: 02/06/2020] [Indexed: 12/13/2022] Open
Abstract
In physiology, homeostasis refers to the condition where a system exhibits an optimum functional level. In contrast, any variation from this optimum is considered as a dysfunctional or pathological state. In this review, we address the proposal that a critical cholesterol level in the plasma membrane is required for the proper functioning of transmembrane proteins. Thus, membrane cholesterol depletion or enrichment produces a loss or gain of direct cholesterol-protein interaction and/or changes in the physical properties of the plasma membrane, which affect the basal or optimum activity of transmembrane proteins. Whether or not this functional switching is a generalized mechanism exhibited for all transmembrane proteins, or if it works just for an exclusive group of them, is an open question and an attractive subject to explore at a basic, pharmacological and clinical level.
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Affiliation(s)
- Ulises Meza
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - Mayra Delgado-Ramírez
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - Catalina Romero-Méndez
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - Sergio Sánchez-Armass
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - Aldo A Rodríguez-Menchaca
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
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Fancher IS, Levitan I. Endothelial inwardly-rectifying K + channels as a key component of shear stress-induced mechanotransduction. CURRENT TOPICS IN MEMBRANES 2020; 85:59-88. [PMID: 32402645 DOI: 10.1016/bs.ctm.2020.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
It has been recognized for decades that fluid shear stress plays a major role in vascular function. Acting on the endothelium shear stress induces vasorelaxation of resistance arteries and plays a major role in the propensity of the major arteries to atherosclerosis. Many elements of shear-induced signaling have been identified yet we are just beginning to decipher the roles that mechanosensitive ion channels may play in the signaling pathways initiated by shear stress. Endothelial inwardly-rectifying K+ channels were identified as potential primary mechanosensors in the late 1980s yet until our recent works, highlighted in the forthcoming chapter, the functional effect of a shear-activated K+ current was completely unknown. In this chapter, we present the physiological effects of shear stress in arteries in health and disease and highlight the most prevalent of today's investigated mechanosensitive ion channels. Ultimately, we focus on Kir2.1 channels and discuss in detail our findings regarding the downstream signaling events that are induced by shear-activated endothelial Kir2.1 channels. Most importantly, we examine our findings regarding hypercholesterolemia-induced inhibition of Kir channel shear-sensitivity and the impact on endothelial function in the context of flow (shear)-mediated vasodilation and atherosclerosis.
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Affiliation(s)
- Ibra S Fancher
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, IL, United States.
| | - Irena Levitan
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, IL, United States
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Kever L, Cherezova A, Zenin V, Negulyaev Y, Komissarchik Y, Semenova S. Downregulation of TRPV6 channel activity by cholesterol depletion in Jurkat T cell line. Cell Biol Int 2019; 43:965-975. [DOI: 10.1002/cbin.11185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/21/2019] [Accepted: 05/25/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Lyudmila Kever
- Laboratory of Ionic Mechanisms of Cell SignalingInstitute of Cytology of the Russian Academy of ScienceTikhoretsky ave. 4 194064 Saint‐Petersburg Russia
| | - Alena Cherezova
- Laboratory of Ionic Mechanisms of Cell SignalingInstitute of Cytology of the Russian Academy of ScienceTikhoretsky ave. 4 194064 Saint‐Petersburg Russia
- Department of PhysiologyMedical College of Georgia, Augusta University1120 15th Street 30912 Augusta GA USA
| | - Valery Zenin
- Laboratory of Ionic Mechanisms of Cell SignalingInstitute of Cytology of the Russian Academy of ScienceTikhoretsky ave. 4 194064 Saint‐Petersburg Russia
| | - Yuri Negulyaev
- Laboratory of Ionic Mechanisms of Cell SignalingInstitute of Cytology of the Russian Academy of ScienceTikhoretsky ave. 4 194064 Saint‐Petersburg Russia
| | - Yan Komissarchik
- Laboratory of Ionic Mechanisms of Cell SignalingInstitute of Cytology of the Russian Academy of ScienceTikhoretsky ave. 4 194064 Saint‐Petersburg Russia
| | - Svetlana Semenova
- Laboratory of Ionic Mechanisms of Cell SignalingInstitute of Cytology of the Russian Academy of ScienceTikhoretsky ave. 4 194064 Saint‐Petersburg Russia
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Sancho M, Fabris S, Hald BO, Brett SE, Sandow SL, Poepping TL, Welsh DG. Membrane Lipid-K
IR
2.x Channel Interactions Enable Hemodynamic Sensing in Cerebral Arteries. Arterioscler Thromb Vasc Biol 2019; 39:1072-1087. [DOI: 10.1161/atvbaha.119.312493] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Objective—
Inward rectifying K
+
(K
IR
) channels are present in cerebral arterial smooth muscle and endothelial cells, a tandem arrangement suggestive of a dynamic yet undiscovered role for this channel. This study defined whether distinct pools of cerebral arterial K
IR
channels were uniquely modulated by membrane lipids and hemodynamic stimuli.
Approach and Results—
A Ba
2+
-sensitive K
IR
current was isolated in smooth muscle and endothelial cells of rat cerebral arteries; molecular analyses subsequently confirmed K
IR
2.1/K
IR
2.2 mRNA and protein expression in both cells. Patch-clamp electrophysiology next demonstrated that each population of K
IR
channels was sensitive to key membrane lipids and hemodynamic stimuli. In this regard, endothelial K
IR
was sensitive to phosphatidylinositol 4,5-bisphosphate content, with depletion impairing the ability of laminar shear stress to activate this channel pool. In contrast, smooth muscle K
IR
was sensitive to membrane cholesterol content, with sequestration blocking the ability of pressure to inhibit channel activity. The idea that membrane lipids help confer shear stress and pressure sensitivity of K
IR
channels was confirmed in intact arteries using myography. Virtual models integrating structural/electrical observations reconceptualized K
IR
as a dynamic regulator of membrane potential working in concert with other currents to set basal tone across a range of shear stresses and intravascular pressures.
Conclusions—
The data show for the first time that specific membrane lipid-K
IR
interactions enable unique channel populations to sense hemodynamic stimuli and drive vasomotor responses to set basal perfusion in the cerebral circulation.
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Affiliation(s)
- Maria Sancho
- From the Department of Physiology and Pharmacology, Robarts Research Institute (M.S., S.F., S.E.B., D.G.W.), University of Western Ontario, London, Canada
| | - Sergio Fabris
- From the Department of Physiology and Pharmacology, Robarts Research Institute (M.S., S.F., S.E.B., D.G.W.), University of Western Ontario, London, Canada
| | - Bjorn O. Hald
- Department of Neuroscience, Translational Neurobiology, University of Copenhagen, Denmark (B.O.H.)
| | - Suzanne E. Brett
- From the Department of Physiology and Pharmacology, Robarts Research Institute (M.S., S.F., S.E.B., D.G.W.), University of Western Ontario, London, Canada
| | - Shaun L. Sandow
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Queensland, Australia (S.L.S.)
| | - Tamie L. Poepping
- Department of Physics and Astronomy (T.L.P.), University of Western Ontario, London, Canada
| | - Donald G. Welsh
- From the Department of Physiology and Pharmacology, Robarts Research Institute (M.S., S.F., S.E.B., D.G.W.), University of Western Ontario, London, Canada
- Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada (D.G.W.)
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Effect of sterol structure on ordered membrane domain (raft) stability in symmetric and asymmetric vesicles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:1112-1122. [PMID: 30904407 DOI: 10.1016/j.bbamem.2019.03.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 12/16/2022]
Abstract
Sterol structure influences liquid ordered domains in membranes, and the dependence of biological functions on sterol structure can help identify processes dependent on ordered domains. In this study we compared the effect of sterol structure on ordered domain formation in symmetric vesicles composed of mixtures of sphingomyelin, 1, 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and cholesterol, and in asymmetric vesicles in which sphingomyelin was introduced into the outer leaflet of vesicles composed of DOPC and cholesterol. In most cases, sterol behavior was similar in symmetric and asymmetric vesicles, with ordered domains most strongly stabilized by 7-dehydrocholesterol (7DHC) and cholesterol, stabilized to a moderate degree by lanosterol, epicholesterol and desmosterol, and very little if at all by 4-cholesten-3-one. However, in asymmetric vesicles desmosterol stabilized ordered domain almost as well as cholesterol, and to a much greater degree than epicholesterol, so that the ability to support ordered domains decreased in the order 7-DHC > cholesterol > desmosterol > lanosterol > epicholesterol > 4-cholesten-3-one. This contrasts with values for intermediate stabilizing sterols in symmetric vesicles in which the ranking was cholesterol > lanosterol ~ desmosterol ~ epicholesterol or prior studies in which the ranking was cholesterol ~ epicholesterol > lanosterol ~ desmosterol. The reasons for these differences are discussed. Based on these results, we re-evaluated our prior studies in cells and conclude that endocytosis levels and bacterial uptake are even more closely correlated with the ability of sterols to form ordered domains than previously thought, and do not necessarily require that a sterol have a 3β-OH group.
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36
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Zhang L, Zhao L, Ouyang PK, Chen P. Insight into the role of cholesterol in modulation of morphology and mechanical properties of CHO-K1 cells: An in situ AFM study. Front Chem Sci Eng 2019. [DOI: 10.1007/s11705-018-1775-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Barbera N, Levitan I. Chiral Specificity of Cholesterol Orientation Within Cholesterol Binding Sites in Inwardly Rectifying K+ Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1115:77-95. [DOI: 10.1007/978-3-030-04278-3_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Morales-Lázaro SL, Rosenbaum T. Cholesterol as a Key Molecule That Regulates TRPV1 Channel Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1135:105-117. [DOI: 10.1007/978-3-030-14265-0_6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Rosenhouse-Dantsker A. Cholesterol Binding Sites in Inwardly Rectifying Potassium Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1135:119-138. [DOI: 10.1007/978-3-030-14265-0_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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40
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Bukiya AN, Dopico AM. Regulation of BK Channel Activity by Cholesterol and Its Derivatives. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1115:53-75. [DOI: 10.1007/978-3-030-04278-3_3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Zakany F, Pap P, Papp F, Kovacs T, Nagy P, Peter M, Szente L, Panyi G, Varga Z. Determining the target of membrane sterols on voltage-gated potassium channels. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:312-325. [PMID: 30553843 DOI: 10.1016/j.bbalip.2018.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/30/2018] [Accepted: 12/12/2018] [Indexed: 12/18/2022]
Abstract
Cholesterol, an essential lipid component of cellular plasma membranes, regulates fluidity, mechanical integrity, raft structure and may specifically interact with membrane proteins. Numerous effects on ion channels by cholesterol, including changes in current amplitude, voltage dependence and gating kinetics, have been reported. We have previously described such changes in the voltage-gated potassium channel Kv1.3 of lymphocytes by cholesterol and its analog 7-dehydrocholesterol (7DHC). In voltage-gated channels membrane depolarization induces movement of the voltage sensor domains (VSD), which is transmitted by a coupling mechanism to the pore domain (PD) to open the channel. Here, we investigated whether cholesterol effects were mediated by the VSD to the pore or the PD was the direct target. Specificity was tested by comparing Kv1.3 and Kv10.1 channels having different VSD-PD coupling mechanisms. Current recordings were performed with two-electrode voltage-clamp fluorometry, where movement of the VSDs was monitored by attaching fluorophores to external cysteine residues introduced in the channel sequence. Loading the membrane with cholesterol or 7DHC using methyl-β-cyclodextrin induced changes in the steady-state and kinetic parameters of the ionic currents while leaving fluorescence parameters mostly unaffected in both channels. Non-stationary noise analysis revealed that reduction of single channel conductance rather than that of open probability caused the observed current decrease. Furthermore, confocal laser scanning and stimulated emission depletion microscopy demonstrated significant changes in the distribution of these ion channels in response to sterol loading. Our results indicate that sterol-induced effects on ion channel gating directly target the pore and do not act via the VSD.
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Affiliation(s)
- Florina Zakany
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary
| | - Pal Pap
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary; MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary
| | - Ferenc Papp
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary; MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary
| | - Tamas Kovacs
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary
| | - Peter Nagy
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary
| | - Maria Peter
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences, Temesvari Krt. 62, Szeged H-6726, Hungary
| | - Lajos Szente
- CycloLab Cyclodextrin R & D Laboratory Ltd., Illatos u. 7, Budapest H-1097, Hungary
| | - Gyorgy Panyi
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary; MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary
| | - Zoltan Varga
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary; MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, Egyetem ter 1, Debrecen H-4032, Hungary.
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42
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Nikouee A, Uchida K, Moench I, Lopatin AN. Cholesterol Protects Against Acute Stress-Induced T-Tubule Remodeling in Mouse Ventricular Myocytes. Front Physiol 2018; 9:1516. [PMID: 30483142 PMCID: PMC6240595 DOI: 10.3389/fphys.2018.01516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/09/2018] [Indexed: 12/28/2022] Open
Abstract
Efficient excitation-contraction coupling in ventricular myocytes depends critically on the presence of the t-tubular network. It has been recently demonstrated that cholesterol, a major component of the lipid bilayer, plays an important role in long-term maintenance of the integrity of t-tubular system although mechanistic understanding of underlying processes is essentially lacking. Accordingly, in this study we investigated the contribution of membrane cholesterol to t-tubule remodeling in response to acute hyposmotic stress. Experiments were performed using isolated left ventricular cardiomyocytes from adult mice. Depletion and restoration of membrane cholesterol was achieved by applying methyl-β-cyclodextrin (MβCD) and water soluble cholesterol (WSC), respectively, and t-tubule remodeling in response to acute hyposmotic stress was assessed using fluorescent dextran trapping assay and by measuring t-tubule dependent IK1 tail current (IK1,tail). The amount of dextran trapped in t-tubules sealed in response to stress was significantly increased when compared to control cells, and reintroduction of cholesterol to cells treated with MβCD restored the amount of trapped dextran to control values. Alternatively, application of WSC to normal cells significantly reduced the amount of trapped dextran further suggesting the protective effect of cholesterol. Importantly, modulation of membrane cholesterol (without osmotic stress) led to significant changes in various parameters of IK1, tail strongly suggesting significant but essentially hidden remodeling of t-tubules prior to osmotic stress. Results of this study demonstrate that modulation of the level of membrane cholesterol has significant effects on the susceptibility of cardiac t-tubules to acute hyposmotic stress.
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Affiliation(s)
- Azadeh Nikouee
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Keita Uchida
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Ian Moench
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Anatoli N Lopatin
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
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43
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Zhang B, Paffett ML, Naik JS, Jernigan NL, Walker BR, Resta TC. Cholesterol Regulation of Pulmonary Endothelial Calcium Homeostasis. CURRENT TOPICS IN MEMBRANES 2018; 82:53-91. [PMID: 30360783 DOI: 10.1016/bs.ctm.2018.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cholesterol is a key structural component and regulator of lipid raft signaling platforms critical for cell function. Such regulation may involve changes in the biophysical properties of lipid microdomains or direct protein-sterol interactions that alter the function of ion channels, receptors, enzymes, and membrane structural proteins. Recent studies have implicated abnormal membrane cholesterol levels in mediating endothelial dysfunction that is characteristic of pulmonary hypertensive disorders, including that resulting from long-term exposure to hypoxia. Endothelial dysfunction in this setting is characterized by impaired pulmonary endothelial calcium entry and an associated imbalance that favors production vasoconstrictor and mitogenic factors that contribute to pulmonary hypertension. Here we review current knowledge of cholesterol regulation of pulmonary endothelial Ca2+ homeostasis, focusing on the role of membrane cholesterol in mediating agonist-induced Ca2+ entry and its components in the normal and hypertensive pulmonary circulation.
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Affiliation(s)
- Bojun Zhang
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | - Michael L Paffett
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | - Jay S Naik
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | - Nikki L Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | - Benjimen R Walker
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | - Thomas C Resta
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States.
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Barbera N, Ayee MAA, Akpa BS, Levitan I. Molecular Dynamics Simulations of Kir2.2 Interactions with an Ensemble of Cholesterol Molecules. Biophys J 2018; 115:1264-1280. [PMID: 30205899 PMCID: PMC6170799 DOI: 10.1016/j.bpj.2018.07.041] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 07/12/2018] [Accepted: 07/31/2018] [Indexed: 11/16/2022] Open
Abstract
Cholesterol is a major regulator of multiple types of ion channels, but the specific mechanisms and the dynamics of its interactions with the channels are not well understood. Kir2 channels were shown to be sensitive to cholesterol through direct interactions with "cholesterol-sensitive" regions on the channel protein. In this work, we used Martini coarse-grained simulations to analyze the long (μs) timescale dynamics of cholesterol with Kir2.2 channels embedded into a model membrane containing POPC phospholipid with 30 mol% cholesterol. This approach allows us to simulate the dynamic, unbiased migration of cholesterol molecules from the lipid membrane environment to the protein surface of Kir2.2 and explore the favorability of cholesterol interactions at both surface sites and recessed pockets of the channel. We found that the cholesterol environment surrounding Kir channels forms a complex milieu of different short- and long-term interactions, with multiple cholesterol molecules concurrently interacting with the channel. Furthermore, utilizing principles from network theory, we identified four discrete cholesterol-binding sites within the previously identified cholesterol-sensitive region that exist depending on the conformational state of the channel-open or closed. We also discovered that a twofold decrease in the cholesterol level of the membrane, which we found earlier to increase Kir2 activity, results in a site-specific decrease of cholesterol occupancy at these sites in both the open and closed states: cholesterol molecules at the deepest of these discrete sites shows no change in occupancy at different cholesterol levels, whereas the remaining sites showed a marked decrease in occupancy.
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Affiliation(s)
- Nicolas Barbera
- Department of Chemical Engineering; Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Manuela A A Ayee
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Belinda S Akpa
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, North Carolina.
| | - Irena Levitan
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois.
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Jaipuria G, Ukmar-Godec T, Zweckstetter M. Challenges and approaches to understand cholesterol-binding impact on membrane protein function: an NMR view. Cell Mol Life Sci 2018; 75:2137-2151. [PMID: 29520423 PMCID: PMC11105689 DOI: 10.1007/s00018-018-2789-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 02/16/2018] [Accepted: 02/27/2018] [Indexed: 01/27/2023]
Abstract
Experimental evidence for a direct role of lipids in determining the structure, dynamics, and function of membrane proteins leads to the term 'functional lipids'. In particular, the sterol molecule cholesterol modulates the activity of many membrane proteins. The precise nature of cholesterol-binding sites and the consequences of modulation of local membrane micro-viscosity by cholesterol, however, is often unknown. Here, we review the current knowledge of the interaction of cholesterol with transmembrane proteins, with a special focus on structural aspects of the interaction derived from nuclear magnetic resonance approaches. We highlight examples of the importance of cholesterol modulation of membrane protein function, discuss the specificity of cholesterol binding, and review the proposed binding motifs from a molecular perspective. We conclude with a short perspective on what could be future trends in research efforts targeted towards a better understanding of cholesterol/membrane protein interactions.
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Affiliation(s)
- Garima Jaipuria
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
| | - Tina Ukmar-Godec
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany.
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany.
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
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46
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Jackson WF. Boosting the signal: Endothelial inward rectifier K + channels. Microcirculation 2018; 24. [PMID: 27652592 DOI: 10.1111/micc.12319] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/12/2016] [Indexed: 12/19/2022]
Abstract
Endothelial cells express a diverse array of ion channels including members of the strong inward rectifier family composed of KIR 2 subunits. These two-membrane spanning domain channels are modulated by their lipid environment, and exist in macromolecular signaling complexes with receptors, protein kinases and other ion channels. Inward rectifier K+ channel (KIR ) currents display a region of negative slope conductance at membrane potentials positive to the K+ equilibrium potential that allows outward current through the channels to be activated by membrane hyperpolarization, permitting KIR to amplify hyperpolarization induced by other K+ channels and ion transporters. Increases in extracellular K+ concentration activate KIR allowing them to sense extracellular K+ concentration and transduce this change into membrane hyperpolarization. These properties position KIR to participate in the mechanism of action of hyperpolarizing vasodilators and contribute to cell-cell conduction of hyperpolarization along the wall of microvessels. The expression of KIR in capillaries in electrically active tissues may allow KIR to sense extracellular K+ , contributing to functional hyperemia. Understanding the regulation of expression and function of microvascular endothelial KIR will improve our understanding of the control of blood flow in the microcirculation in health and disease and may provide new targets for the development of therapeutics in the future.
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Affiliation(s)
- William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
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Affiliation(s)
- Nhat-Tu Le
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX
| | - Jun-Ichi Abe
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX
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48
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Fancher IS, Ahn SJ, Adamos C, Osborn C, Oh MJ, Fang Y, Reardon CA, Getz GS, Phillips SA, Levitan I. Hypercholesterolemia-Induced Loss of Flow-Induced Vasodilation and Lesion Formation in Apolipoprotein E-Deficient Mice Critically Depend on Inwardly Rectifying K + Channels. J Am Heart Assoc 2018; 7:e007430. [PMID: 29502106 PMCID: PMC5866319 DOI: 10.1161/jaha.117.007430] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 01/17/2018] [Indexed: 01/14/2023]
Abstract
BACKGROUND Hypercholesterolemia-induced decreased availability of nitric oxide (NO) is a major factor in cardiovascular disease. We previously established that cholesterol suppresses endothelial inwardly rectifying K+ (Kir) channels and that Kir2.1 is an upstream mediator of flow-induced NO production. Therefore, we tested the hypothesis that suppression of Kir2.1 is responsible for hypercholesterolemia-induced inhibition of flow-induced NO production and flow-induced vasodilation (FIV). We also tested the role of Kir2.1 in the development of atherosclerotic lesions. METHODS AND RESULTS Kir2.1 currents are significantly suppressed in microvascular endothelial cells exposed to acetylated-low-density lipoprotein or isolated from apolipoprotein E-deficient (Apoe-/- ) mice and rescued by cholesterol depletion. Genetic deficiency of Kir2.1 on the background of hypercholesterolemic Apoe-/- mice, Kir2.1+/-/Apoe-/- exhibit the same blunted FIV and flow-induced NO response as Apoe-/- or Kir2.1+/- alone, but while FIV in Apoe-/- mice can be rescued by cholesterol depletion, in Kir2.1+/-/Apoe-/- mice cholesterol depletion has no effect on FIV. Endothelial-specific overexpression of Kir2.1 in arteries from Apoe-/- and Kir2.1+/-/Apoe-/- mice results in full rescue of FIV and NO production in Apoe-/- mice with and without the addition of a high-fat diet. Conversely, endothelial-specific expression of dominant-negative Kir2.1 results in the opposite effect. Kir2.1+/-/Apoe-/- mice also show increased lesion formation, particularly in the atheroresistant area of descending aorta. CONCLUSIONS We conclude that hypercholesterolemia-induced reduction in FIV is largely attributable to cholesterol suppression of Kir2.1 function via the loss of flow-induced NO production, whereas the stages downstream of flow-induced Kir2.1 activation appear to be mostly intact. Kir2.1 channels also have an atheroprotective role.
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MESH Headings
- Animals
- Aorta/metabolism
- Aorta/pathology
- Aortic Diseases/genetics
- Aortic Diseases/metabolism
- Aortic Diseases/pathology
- Aortic Diseases/physiopathology
- Atherosclerosis/genetics
- Atherosclerosis/metabolism
- Atherosclerosis/pathology
- Atherosclerosis/physiopathology
- Cells, Cultured
- Cholesterol/blood
- Disease Models, Animal
- Endothelial Cells/metabolism
- Endothelial Cells/pathology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiopathology
- Hypercholesterolemia/genetics
- Hypercholesterolemia/metabolism
- Hypercholesterolemia/pathology
- Hypercholesterolemia/physiopathology
- Male
- Mesenteric Arteries/metabolism
- Mesenteric Arteries/physiopathology
- Mice, Inbred C57BL
- Mice, Knockout, ApoE
- Nitric Oxide/metabolism
- Plaque, Atherosclerotic
- Potassium Channels, Inwardly Rectifying/deficiency
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
- Signal Transduction
- Vasodilation
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Affiliation(s)
- Ibra S Fancher
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, IL
- Department of Physical Therapy, University of Illinois at Chicago, IL
| | - Sang Joon Ahn
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, IL
| | - Crystal Adamos
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, IL
- Department of Physical Therapy, University of Illinois at Chicago, IL
| | - Catherine Osborn
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, IL
| | - Myung-Jin Oh
- Section of Pulmonary and Critical Care, Department of Medicine, University of Chicago, IL
| | - Yun Fang
- Section of Pulmonary and Critical Care, Department of Medicine, University of Chicago, IL
| | | | | | - Shane A Phillips
- Department of Physical Therapy, University of Illinois at Chicago, IL
| | - Irena Levitan
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, IL
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Delgado-Ramírez M, Sánchez-Armass S, Meza U, Rodríguez-Menchaca AA. Regulation of Kv7.2/Kv7.3 channels by cholesterol: Relevance of an optimum plasma membrane cholesterol content. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1242-1251. [PMID: 29474891 DOI: 10.1016/j.bbamem.2018.02.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 02/14/2018] [Accepted: 02/16/2018] [Indexed: 12/18/2022]
Abstract
Kv7.2/Kv7.3 channels are the molecular correlate of the M-current, which stabilizes the membrane potential and controls neuronal excitability. Previous studies have shown the relevance of plasma membrane lipids on both M-currents and Kv7.2/Kv7.3 channels. Here, we report the sensitive modulation of Kv7.2/Kv7.3 channels by membrane cholesterol level. Kv7.2/Kv7.3 channels transiently expressed in HEK-293 cells were significantly inhibited by decreasing the cholesterol level in the plasma membrane by three different pharmacological strategies: methyl-β-cyclodextrin (MβCD), Filipin III, and cholesterol oxidase treatment. Surprisingly, Kv7.2/Kv7.3 channels were also inhibited by membrane cholesterol loading with the MβCD/cholesterol complex. Depletion or enrichment of plasma membrane cholesterol differentially affected the biophysical parameters of the macroscopic Kv7.2/Kv7.3 currents. These results indicate a complex mechanism of Kv7.2/Kv7.3 channels modulation by membrane cholesterol. We propose that inhibition of Kv7.2/Kv7.3 channels by membrane cholesterol depletion involves a loss of a direct cholesterol-channel interaction. However, the inhibition of Kv7.2/Kv7.3 channels by membrane cholesterol enrichment could include an additional direct cholesterol-channel interaction, or changes in the physical properties of the plasma membrane. In summary, our results indicate that an optimum cholesterol level in the plasma membrane is required for the proper functioning of Kv7.2/Kv7.3 channels.
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Affiliation(s)
- Mayra Delgado-Ramírez
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP 78210, Mexico
| | - Sergio Sánchez-Armass
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP 78210, Mexico
| | - Ulises Meza
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP 78210, Mexico.
| | - Aldo A Rodríguez-Menchaca
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP 78210, Mexico.
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50
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Fantini J, J. Barrantes F. How membrane lipids control the 3D structure and function of receptors. AIMS BIOPHYSICS 2018. [DOI: 10.3934/biophy.2018.1.22] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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