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Borges-Araújo L, Pereira GP, Valério M, Souza PCT. Assessing the Martini 3 protein model: A review of its path and potential. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2024; 1872:141014. [PMID: 38670324 DOI: 10.1016/j.bbapap.2024.141014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/13/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024]
Abstract
Coarse-grained (CG) protein models have become indispensable tools for studying many biological protein details, from conformational dynamics to the organization of protein macro-complexes, and even the interaction of proteins with other molecules. The Martini force field is one of the most widely used CG models for bio-molecular simulations, partly because of the enormous success of its protein model. With the recent release of a new and improved version of the Martini force field - Martini 3 - a new iteration of its protein model was also made available. The Martini 3 protein force field is an evolution of its Martini 2 counterpart, aimed at improving many of the shortcomings that had been previously identified. In this mini-review, we first provide a general overview of the model and then focus on the successful advances made in the short time since its release, many of which would not have been possible before. Furthermore, we discuss reported limitations, potential directions for model improvement and comment on what the likely future development and application avenues are.
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Affiliation(s)
- Luís Borges-Araújo
- Laboratoire de Biologie et Modélisation de la Cellule, CNRS, UMR 5239, Inserm, U1293, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France; Centre Blaise Pascal de Simulation et de Modélisation Numérique, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France
| | - Gilberto P Pereira
- Laboratoire de Biologie et Modélisation de la Cellule, CNRS, UMR 5239, Inserm, U1293, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France; Centre Blaise Pascal de Simulation et de Modélisation Numérique, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France
| | - Mariana Valério
- Laboratoire de Biologie et Modélisation de la Cellule, CNRS, UMR 5239, Inserm, U1293, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France; Centre Blaise Pascal de Simulation et de Modélisation Numérique, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France
| | - Paulo C T Souza
- Laboratoire de Biologie et Modélisation de la Cellule, CNRS, UMR 5239, Inserm, U1293, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France; Centre Blaise Pascal de Simulation et de Modélisation Numérique, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France.
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2
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Lihan M, Tajkhorshid E. Improved Highly Mobile Membrane Mimetic Model for Investigating Protein-Cholesterol Interactions. J Chem Inf Model 2024; 64:4822-4834. [PMID: 38844760 DOI: 10.1021/acs.jcim.4c00619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
Cholesterol (CHL) plays an integral role in modulating the function and activity of various mammalian membrane proteins. Due to the slow dynamics of lipids, conventional computational studies of protein-CHL interactions rely on either long-time scale atomistic simulations or coarse-grained approximations to sample the process. A highly mobile membrane mimetic (HMMM) has been developed to enhance lipid diffusion and thus used to facilitate the investigation of lipid interactions with peripheral membrane proteins and, with customized in silico solvents to replace phospholipid tails, with integral membrane proteins. Here, we report an updated HMMM model that is able to include CHL, a nonphospholipid component of the membrane, henceforth called HMMM-CHL. To this end, we had to optimize the effect of the customized solvents on CHL behavior in the membrane. Furthermore, the new solvent is compatible with simulations using force-based switching protocols. In the HMMM-CHL, both improved CHL dynamics and accelerated lipid diffusion are integrated. To test the updated model, we have applied it to the characterization of protein-CHL interactions in two membrane protein systems, the human β2-adrenergic receptor (β2AR) and the mitochondrial voltage-dependent anion channel 1 (VDAC-1). Our HMMM-CHL simulations successfully identified CHL binding sites and captured detailed CHL interactions in excellent consistency with experimental data as well as other simulation results, indicating the utility of the improved model in applications where an enhanced sampling of protein-CHL interactions is desired.
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Affiliation(s)
- Muyun Lihan
- Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Emad Tajkhorshid
- Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
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3
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Sajan SA, Gradisch R, Vogel FD, Coffey AJ, Salyakina D, Soler D, Jayakar P, Jayakar A, Bianconi SE, Cooper AH, Liu S, William N, Benkel-Herrenbrück I, Maiwald R, Heller C, Biskup S, Leiz S, Westphal DS, Wagner M, Clarke A, Stockner T, Ernst M, Kesari A, Krenn M. De novo variants in GABRA4 are associated with a neurological phenotype including developmental delay, behavioral abnormalities and epilepsy. Eur J Hum Genet 2024:10.1038/s41431-024-01600-3. [PMID: 38565639 DOI: 10.1038/s41431-024-01600-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 02/03/2024] [Accepted: 03/19/2024] [Indexed: 04/04/2024] Open
Abstract
Nine out of 19 genes encoding GABAA receptor subunits have been linked to monogenic syndromes characterized by seizures and developmental disorders. Previously, we reported the de novo variant p.(Thr300Ile) in GABRA4 in a patient with epilepsy and neurodevelopmental abnormalities. However, no new cases have been reported since then. Through an international collaboration, we collected molecular and phenotype data of individuals carrying de novo variants in GABRA4. Patients and their parents were investigated either by exome or genome sequencing, followed by targeted Sanger sequencing in some cases. All variants within the transmembrane domain, including the previously reported p.(Thr300Ile) variant, were characterized in silico and analyzed by molecular dynamics (MD) simulation studies. We identified three novel de novo missense variants in GABRA4 (NM_000809.4): c.797 C > T, p.(Pro266Leu), c.899 C > A, p.(Thr300Asn), and c.634 G > A, p.(Val212Ile). The p.(Thr300Asn) variant impacts the same codon as the previously reported variant p.(Thr300Ile) and likely arose post-zygotically as evidenced by sequencing oral mucosal cells. Overlapping phenotypes among affected individuals included developmental delay (4/4), epileptiform EEG abnormalities (3/4), attention deficits (3/4), seizures (2/4), autistic features (2/4) and structural brain abnormalities (2/4). MD simulations of the three variants within the transmembrane domain of the receptor indicate that sub-microsecond scale dynamics differ between wild-type and mutated subunits. Taken together, our findings further corroborate an association between GABRA4 and a neurological phenotype including variable neurodevelopmental, behavioral and epileptic abnormalities.
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Affiliation(s)
- Samin A Sajan
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Ralph Gradisch
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Florian D Vogel
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Alison J Coffey
- lllumina Clinical Services Laboratory, Illumina Inc., San Diego, CA, USA
| | - Daria Salyakina
- Personalized Medicine and Health Outcomes Research, Nicklaus Children's Hospital, Miami, FL, USA
| | - Diana Soler
- Personalized Medicine and Health Outcomes Research, Nicklaus Children's Hospital, Miami, FL, USA
| | - Parul Jayakar
- Division of Genetics and Metabolism, Nicklaus Children's Hospital, Miami, FL, USA
| | - Anuj Jayakar
- Department of Neurology, Division of Epilepsy, Nicklaus Children's Hospital, Miami, FL, USA
| | | | | | | | | | | | - Robert Maiwald
- Medizinisches Versorgungszentrum für Gerinnungsdiagnostik und Medizinische Genetik Köln, Köln, Germany
| | | | - Saskia Biskup
- Zentrum für Humangenetik, Tübingen, Germany
- Center for Genomics and Transcriptomics (CeGaT), Tübingen, Germany
| | - Steffen Leiz
- Division of Neuropediatrics, Klinikum Dritter Orden, Munich, Germany
| | - Dominik S Westphal
- Institute of Human Genetics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Department of Internal Medicine I, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Matias Wagner
- Institute of Human Genetics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Amy Clarke
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Thomas Stockner
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Margot Ernst
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Akanchha Kesari
- lllumina Clinical Services Laboratory, Illumina Inc., San Diego, CA, USA
| | - Martin Krenn
- Department of Neurology, Medical University of Vienna, Vienna, Austria.
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria.
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4
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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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5
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Naglekar A, Chattopadhyay A, Sengupta D. Palmitoylation of the Glucagon-like Peptide-1 Receptor Modulates Cholesterol Interactions at the Receptor-Lipid Microenvironment. J Phys Chem B 2023; 127:11000-11010. [PMID: 38111968 DOI: 10.1021/acs.jpcb.3c05930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
The G protein-coupled receptor (GPCR) superfamily of cell surface receptors has been shown to be functionally modulated by post-translational modifications. The glucagon-like peptide receptor-1 (GLP-1R), which is a drug target in diabetes and obesity, undergoes agonist-dependent palmitoyl tail conjugation. The palmitoylation in the C-terminal domain of GLP-1R has been suggested to modulate the receptor-lipid microenvironment. In this work, we have performed coarse-grain molecular dynamics simulations of palmitoylated and nonpalmitoylated GLP-1R to analyze the differential receptor-lipid interactions. Interestingly, the placement and dynamics of the C-terminal domain of GLP-1R are found to be directly dependent on the palmitoyl tail. We observe that both cholesterol and phospholipids interact with the receptor but display differential interactions in the presence and absence of the palmitoyl tail. We characterize important cholesterol-binding sites and validate sites that have been previously reported in experimentally resolved structures of the receptor. We show that the receptor acts like a conduit for cholesterol flip-flop by stabilizing cholesterol in the membrane core. Taken together, our work represents an important step in understanding the molecular effects of lipid modifications in GPCRs.
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Affiliation(s)
- Amit Naglekar
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Amitabha Chattopadhyay
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | - Durba Sengupta
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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6
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Vo ADP, Kim SK, Yang MY, Ondrus AE, Goddard WA. Fully activated structure of the sterol-bound Smoothened GPCR-Gi protein complex. Proc Natl Acad Sci U S A 2023; 120:e2300919120. [PMID: 38015850 PMCID: PMC10710022 DOI: 10.1073/pnas.2300919120] [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: 01/17/2023] [Accepted: 10/22/2023] [Indexed: 11/30/2023] Open
Abstract
Smoothened (SMO) is an oncoprotein and signal transducer in the Hedgehog signaling pathway that regulates cellular differentiation and embryogenesis. As a member of the Frizzled (Class F) family of G protein-coupled receptors (GPCRs), SMO biochemically and functionally interacts with Gi family proteins. However, key molecular features of fully activated, G protein-coupled SMO remain elusive. We present the atomistic structure of activated human SMO complexed with the heterotrimeric Gi protein and two sterol ligands, equilibrated at 310 K in a full lipid bilayer at physiological salt concentration and pH. In contrast to previous experimental structures, our equilibrated SMO complex exhibits complete breaking of the pi-cation interaction between R4516.32 and W5357.55, a hallmark of Class F receptor activation. The Gi protein couples to SMO at seven strong anchor points similar to those in Class A GPCRs: intracellular loop 1, intracellular loop 2, transmembrane helix 6, and helix 8. On the path to full activation, we find that the extracellular cysteine-rich domain (CRD) undergoes a dramatic tilt, following a trajectory suggested by positions of the CRD in active and inactive experimental SMO structures. Strikingly, a sterol ligand bound to a shallow transmembrane domain (TMD) site in the initial structure migrates to a deep TMD pocket found exclusively in activator-bound SMO complexes. Thus, our results indicate that SMO interacts with Gi prior to full activation to break the molecular lock, form anchors with Gi subunits, tilt the CRD, and facilitate migration of a sterol ligand in the TMD to an activated position.
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Affiliation(s)
- Amy-Doan P. Vo
- Materials and Process Simulation Center, Division of Chemistry & Chemical Engineering, California Institute of Technology, Pasadena, CA91125
| | - Soo-Kyung Kim
- Materials and Process Simulation Center, Division of Chemistry & Chemical Engineering, California Institute of Technology, Pasadena, CA91125
| | - Moon Young Yang
- Materials and Process Simulation Center, Division of Chemistry & Chemical Engineering, California Institute of Technology, Pasadena, CA91125
| | - Alison E. Ondrus
- Department of Chemistry, University of Illinois Chicago, Chicago, IL60607
- Department of Pharmaceutical Sciences, University of Illinois Chicago, Chicago, IL60607
| | - William A. Goddard
- Materials and Process Simulation Center, Division of Chemistry & Chemical Engineering, California Institute of Technology, Pasadena, CA91125
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7
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Kumari S, Mitra A, Bulusu G. Putative Role of Cholesterol in Shaping the Structural and Functional Dynamics of Smoothened (SMO). J Phys Chem B 2023; 127:9476-9495. [PMID: 37878627 DOI: 10.1021/acs.jpcb.3c02255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
The smoothened (SMO) receptor belongs to the superfamily of class F G protein-coupled receptors (GPCRs) and is a potential drug target in several types of cancer. It has two ligand binding sites, respectively, in the cysteine-rich domain (CRD) and the transmembrane domain (TMD). It has been shown that cholesterol is important for its activation and function. However, the molecular-level understanding of SMO dynamics in the presence of cholesterol has not been explored in sufficient detail. In this work, we have carried out atomistic molecular dynamics simulations totaling 3.6 μs to analyze the effect of cholesterol binding to TMD and/or CRD on the structure and dynamics of the SMO receptor. Our results show that the presence of cholesterol in the CRD and TMD, respectively, alters the conformational dynamics of SMO differently. We reported that the reorganization of the D-R-E network at the extracellular end of the TMD is important for the high activity of SMO. In general, the transmembrane helices 5, 6, and 7 and helix 8 are most affected, which, in turn, leads to changes in the CRD and intracellular cytoplasmic domain (ICD) dynamics patterns depending on the presence or absence of cholesterol in the CRD and/or the TMD. We have also reported that the interaction of membrane lipids with SMO is different in different SMO states. These results agree with the experimental structural observations and data of cholesterol-bound and unbound structures of SMO and add to our molecular understanding of the SMO-cholesterol interaction.
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Affiliation(s)
- Shweta Kumari
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad 500032, India
| | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad 500032, India
| | - Gopalakrishnan Bulusu
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad 500032, India
- IHub-Data, International Institute of Information Technology, Hyderabad 500032, India
- Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad 500046, India
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8
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Borges-Araújo L, Borges-Araújo AC, Ozturk TN, Ramirez-Echemendia DP, Fábián B, Carpenter TS, Thallmair S, Barnoud J, Ingólfsson HI, Hummer G, Tieleman DP, Marrink SJ, Souza PCT, Melo MN. Martini 3 Coarse-Grained Force Field for Cholesterol. J Chem Theory Comput 2023; 19:7387-7404. [PMID: 37796943 DOI: 10.1021/acs.jctc.3c00547] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Cholesterol plays a crucial role in biomembranes by regulating various properties, such as fluidity, rigidity, permeability, and organization of lipid bilayers. The latest version of the Martini model, Martini 3, offers significant improvements in interaction balance, molecular packing, and inclusion of new bead types and sizes. However, the release of the new model resulted in the need to reparameterize many core molecules, including cholesterol. Here, we describe the development and validation of a Martini 3 cholesterol model, addressing issues related to its bonded setup, shape, volume, and hydrophobicity. The proposed model mitigates some limitations of its Martini 2 predecessor while maintaining or improving the overall behavior.
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Affiliation(s)
- Luís Borges-Araújo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS & University of Lyon, 7 Passage du Vercors, Lyon F-69367, France
| | - Ana C Borges-Araújo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Tugba Nur Ozturk
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Daniel P Ramirez-Echemendia
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada, T2N 1N4
| | - Balázs Fábián
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue Straße 3, 60438 Frankfurt am Main, Germany
| | - Timothy S Carpenter
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Sebastian Thallmair
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany
| | - Jonathan Barnoud
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
- CiTIUS Intelligent Technologies Research Centre, University of Santiago de Compostela, Rúa de Jenaro de la Fuente, 15705 Santiago de Compostela, Spain
| | - Helgi I Ingólfsson
- Physical and Life Sciences (PLS) Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue Straße 3, 60438 Frankfurt am Main, Germany
- Institute of Biophysics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada, T2N 1N4
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Paulo C T Souza
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS & University of Lyon, 7 Passage du Vercors, Lyon F-69367, France
| | - Manuel N Melo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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9
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Kulshrestha A, Punnathanam SN, Roy R, Ayappa KG. Cholesterol catalyzes unfolding in membrane-inserted motifs of the pore forming protein cytolysin A. Biophys J 2023; 122:4068-4081. [PMID: 37740492 PMCID: PMC10598289 DOI: 10.1016/j.bpj.2023.09.005] [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: 05/07/2023] [Revised: 08/20/2023] [Accepted: 09/13/2023] [Indexed: 09/24/2023] Open
Abstract
Plasma membrane-induced protein folding and conformational transitions play a central role in cellular homeostasis. Several transmembrane proteins are folded in the complex lipid milieu to acquire a specific structure and function. Bacterial pore forming toxins (PFTs) are proteins expressed by a large class of pathogenic bacteria that exploit the plasma membrane environment to efficiently undergo secondary structure changes, oligomerize, and form transmembrane pores. Unregulated pore formation causes ion imbalance, leading to cell death and infection. Determining the free energy landscape of these membrane-driven-driven transitions remains a challenging problem. Although cholesterol recognition is required for lytic activity of several proteins in the PFT family of toxins, the regulatory role of cholesterol for the α-PFT, cytolysin A expressed by Escherichia coli remains unexplained. In a recent free energy computation, we showed that the β tongue, a critical membrane-inserted motif of the ClyA toxin, has an on-pathway partially unfolded intermediate that refolds into the helix-turn-helix motif of the pore state. To understand the molecular role played by cholesterol, we carry out string-method-based computations in membranes devoid of cholesterol, which reveals an increase of ∼30 times in the free energy barrier for the loss of β sheet secondary structure when compared with membranes containing cholesterol. Specifically, the tyrosine-cholesterol interaction was found to be critical to creating the unfolded intermediate. Cholesterol also increases the packing and hydrophobicity of the bilayer, resulting in enhanced interactions of the bound protein before complete membrane insertion. Our study illustrates that cholesterol is critical to catalyzing and stabilizing the membrane-inserted unfolded state of the β tongue motif of ClyA, opening up fresh insights into cholesterol-assisted unfolding of membrane proteins.
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Affiliation(s)
- Avijeet Kulshrestha
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India
| | - Sudeep N Punnathanam
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India
| | - Rahul Roy
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India; Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka, India
| | - K Ganapathy Ayappa
- Department of Chemical Engineering, Indian Institute of Science, Bangalore, Karnataka, India.
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10
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Ansell TB, Corey RA, Viti LV, Kinnebrew M, Rohatgi R, Siebold C, Sansom MS. The energetics and ion coupling of cholesterol transport through Patched1. SCIENCE ADVANCES 2023; 9:eadh1609. [PMID: 37611095 PMCID: PMC10446486 DOI: 10.1126/sciadv.adh1609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 07/24/2023] [Indexed: 08/25/2023]
Abstract
Patched1 (PTCH1) is a tumor suppressor protein of the mammalian Hedgehog (HH) signaling pathway, implicated in embryogenesis and tissue homeostasis. PTCH1 inhibits the G protein-coupled receptor Smoothened (SMO) via a debated mechanism involving modulating ciliary cholesterol accessibility. Using extensive molecular dynamics simulations and free energy calculations to evaluate cholesterol transport through PTCH1, we find an energetic barrier of ~15 to 20 kilojoule per mole for cholesterol export. In silico data are coupled to in vivo biochemical assays of PTCH1 mutants to probe coupling between cation binding sites, transmembrane motions, and PTCH1 activity. Using complementary simulations of Dispatched1, we find that transition between "inward-open" and solvent "occluded" states is accompanied by Na+-induced pinching of intracellular helical segments. Thus, our findings illuminate the energetics and ion coupling stoichiometries of PTCH1 transport mechanisms, whereby one to three Na+ or two to three K+ couple to cholesterol export, and provide the first molecular description of transitions between distinct transport states.
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Affiliation(s)
- T. Bertie Ansell
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Robin A. Corey
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
- School of Physiology, Pharmacology and Neuroscience, Bristol University, Bristol BS8 1TD, UK
| | - Lucrezia Vittoria Viti
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Maia Kinnebrew
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Mark S. P. Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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11
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Ray AP, Thakur N, Pour NG, Eddy MT. Dual mechanisms of cholesterol-GPCR interactions that depend on membrane phospholipid composition. Structure 2023; 31:836-847.e6. [PMID: 37236187 PMCID: PMC10330489 DOI: 10.1016/j.str.2023.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 02/25/2023] [Accepted: 05/01/2023] [Indexed: 05/28/2023]
Abstract
Cholesterol is a critical component of mammalian cell membranes and an allosteric modulator of G protein-coupled receptors (GPCRs), but divergent views exist on the mechanisms by which cholesterol influences receptor functions. Leveraging the benefits of lipid nanodiscs, i.e., quantitative control of lipid composition, we observe distinct impacts of cholesterol in the presence and absence of anionic phospholipids on the function-related conformational dynamics of the human A2A adenosine receptor (A2AAR). Direct receptor-cholesterol interactions drive activation of agonist-bound A2AAR in membranes containing zwitterionic phospholipids. Intriguingly, the presence of anionic lipids attenuates cholesterol's impact through direct interactions with the receptor, highlighting a more complex role for cholesterol that depends on membrane phospholipid composition. Targeted amino acid replacements at two frequently predicted cholesterol interaction sites showed distinct impacts of cholesterol at different receptor locations, demonstrating the ability to delineate different roles of cholesterol in modulating receptor signaling and maintaining receptor structural integrity.
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Affiliation(s)
- Arka Prabha Ray
- Department of Chemistry, University of Florida, 126 Sisler Hall, Gainesville, FL 32611, USA
| | - Naveen Thakur
- Department of Chemistry, University of Florida, 126 Sisler Hall, Gainesville, FL 32611, USA
| | - Niloofar Gopal Pour
- Department of Chemistry, University of Florida, 126 Sisler Hall, Gainesville, FL 32611, USA
| | - Matthew T Eddy
- Department of Chemistry, University of Florida, 126 Sisler Hall, Gainesville, FL 32611, USA.
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12
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Bansal PD, Dutta S, Shukla D. Activation mechanism of the human Smoothened receptor. Biophys J 2023; 122:1400-1413. [PMID: 36883002 PMCID: PMC10111369 DOI: 10.1016/j.bpj.2023.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 01/17/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Smoothened (SMO) is a membrane protein of the class F subfamily of G protein-coupled receptors (GPCRs) and maintains homeostasis of cellular differentiation. SMO undergoes conformational change during activation, transmitting the signal across the membrane, making it amenable to bind to its intracellular signaling partner. Receptor activation has been studied at length for class A receptors, but the mechanism of class F receptor activation remains unknown. Agonists and antagonists bound to SMO at sites in the transmembrane domain (TMD) and the cysteine-rich domain have been characterized, giving a static view of the various conformations SMO adopts. Although the structures of the inactive and active SMO outline the residue-level transitions, a kinetic view of the overall activation process remains unexplored for class F receptors. We describe SMO's activation process in atomistic detail by performing 300 μs of molecular dynamics simulations and combining it with Markov state model theory. A molecular switch, conserved across class F and analogous to the activation-mediating D-R-Y motif in class A receptors, is observed to break during activation. We also show that this transition occurs in a stage-wise movement of the transmembrane helices: TM6 first, followed by TM5. To see how modulators affect SMO activity, we simulated agonist and antagonist-bound SMO. We observed that agonist-bound SMO has an expanded hydrophobic tunnel in SMO's core TMD, whereas antagonist-bound SMO shrinks this tunnel, further supporting the hypothesis that cholesterol travels through a tunnel inside Smoothened to activate it. In summary, this study elucidates the distinct activation mechanism of class F GPCRs and shows that SMO's activation process rearranges the core TMD to open a hydrophobic conduit for cholesterol transport.
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Affiliation(s)
- Prateek D Bansal
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Soumajit Dutta
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois; Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois; Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, Illinois.
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13
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Isu UH, Badiee SA, Khodadadi E, Moradi M. Cholesterol in Class C GPCRs: Role, Relevance, and Localization. MEMBRANES 2023; 13:301. [PMID: 36984688 PMCID: PMC10056374 DOI: 10.3390/membranes13030301] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/21/2023] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
G-protein coupled receptors (GPCRs), one of the largest superfamilies of cell-surface receptors, are heptahelical integral membrane proteins that play critical roles in virtually every organ system. G-protein-coupled receptors operate in membranes rich in cholesterol, with an imbalance in cholesterol level within the vicinity of GPCR transmembrane domains affecting the structure and/or function of many GPCRs, a phenomenon that has been linked to several diseases. These effects of cholesterol could result in indirect changes by altering the mechanical properties of the lipid environment or direct changes by binding to specific sites on the protein. There are a number of studies and reviews on how cholesterol modulates class A GPCRs; however, this area of study is yet to be explored for class C GPCRs, which are characterized by a large extracellular region and often form constitutive dimers. This review highlights specific sites of interaction, functions, and structural dynamics involved in the cholesterol recognition of the class C GPCRs. We summarize recent data from some typical family members to explain the effects of membrane cholesterol on the structural features and functions of class C GPCRs and speculate on their corresponding therapeutic potential.
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14
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Pezeshkian W, Grünewald F, Narykov O, Lu S, Arkhipova V, Solodovnikov A, Wassenaar TA, Marrink SJ, Korkin D. Molecular architecture and dynamics of SARS-CoV-2 envelope by integrative modeling. Structure 2023; 31:492-503.e7. [PMID: 36870335 DOI: 10.1016/j.str.2023.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 11/15/2022] [Accepted: 02/07/2023] [Indexed: 03/06/2023]
Abstract
Despite tremendous efforts, the exact structure of SARS-CoV-2 and related betacoronaviruses remains elusive. SARS-CoV-2 envelope is a key structural component of the virion that encapsulates viral RNA. It is composed of three structural proteins, spike, membrane (M), and envelope, which interact with each other and with the lipids acquired from the host membranes. Here, we developed and applied an integrative multi-scale computational approach to model the envelope structure of SARS-CoV-2 with near atomistic detail, focusing on studying the dynamic nature and molecular interactions of its most abundant, but largely understudied, M protein. The molecular dynamics simulations allowed us to test the envelope stability under different configurations and revealed that the M dimers agglomerated into large, filament-like, macromolecular assemblies with distinct molecular patterns. These results are in good agreement with current experimental data, demonstrating a generic and versatile approach to model the structure of a virus de novo.
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Affiliation(s)
- Weria Pezeshkian
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, the Netherlands; Niels Bohr International Academy, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - Fabian Grünewald
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, the Netherlands
| | - Oleksandr Narykov
- Department of Computer Science, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | - Senbao Lu
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | | | | | - Tsjerk A Wassenaar
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, the Netherlands; Institute for Life Science and Technology, Hanze University of Applied Sciences, 9747AS Groningen, the Netherlands
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, the Netherlands.
| | - Dmitry Korkin
- Department of Computer Science, Worcester Polytechnic Institute, Worcester, MA 01609, USA; Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA 01609, USA.
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15
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Ansell TB, Corey RA, Viti LV, Kinnebrew M, Rohatgi R, Siebold C, Sansom MSP. The Energetics and Ion Coupling of Cholesterol Transport Through Patched1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.14.528445. [PMID: 36824746 PMCID: PMC9949057 DOI: 10.1101/2023.02.14.528445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Patched1 (PTCH1) is the principal tumour suppressor protein of the mammalian Hedgehog (HH) signalling pathway, implicated in embryogenesis and tissue homeostasis. PTCH1 inhibits the Class F G protein-coupled receptor Smoothened (SMO) via a debated mechanism involving modulating accessible cholesterol levels within ciliary membranes. Using extensive molecular dynamics (MD) simulations and free energy calculations to evaluate cholesterol transport through PTCH1, we find an energetic barrier of ~15-20 kJ mol -1 for cholesterol export. In simulations we identify cation binding sites within the PTCH1 transmembrane domain (TMD) which may provide the energetic impetus for cholesterol transport. In silico data are coupled to in vivo biochemical assays of PTCH1 mutants to probe coupling between transmembrane motions and PTCH1 activity. Using complementary simulations of Dispatched1 (DISP1) we find that transition between 'inward-open' and solvent 'occluded' states is accompanied by Na + induced pinching of intracellular helical segments. Thus, our findings illuminate the energetics and ion-coupling stoichiometries of PTCH1 transport mechanisms, whereby 1-3 Na + or 2-3 K + couple to cholesterol export, and provide the first molecular description of transitions between distinct transport states.
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Affiliation(s)
- T. Bertie Ansell
- Department of Biochemistry, South Parks Road, Oxford, OX1 3QU, UK
| | - Robin A. Corey
- Department of Biochemistry, South Parks Road, Oxford, OX1 3QU, UK
| | - Lucrezia Vittoria Viti
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Maia Kinnebrew
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
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16
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Tzortzini E, Corey RA, Kolocouris A. Comparative Study of Receptor-, Receptor State-, and Membrane-Dependent Cholesterol Binding Sites in A 2A and A 1 Adenosine Receptors Using Coarse-Grained Molecular Dynamics Simulations. J Chem Inf Model 2023; 63:928-949. [PMID: 36637988 DOI: 10.1021/acs.jcim.2c01181] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
We used coarse-grained molecular dynamics (CG MD) simulations to study protein-cholesterol interactions for different activation states of the A2A adenosine receptor (A2AR) and the A1 adenosine receptor (A1R) and predict new cholesterol binding sites indicating amino acid residues with a high residence time in three biologically relevant membranes. Compared to 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)-cholesterol and POPC-phosphatidylinositol-bisphosphate (PIP2)-cholesterol, the plasma mimetic membrane best described the cholesterol binding sites previously detected for the inactive state of A2AR and revealed the binding sites with long-lasting amino acid residues. We observed that using the plasma mimetic membrane and plotting residues with cholesterol residence time ≥2 μs, our CG MD simulations captured most obviously the cholesterol-protein interactions. For the inactive A2AR, we identified one more binding site in which cholesterol is bound to residues with a long residence time compared to the previously detected, for the active A1R, three binding sites, and for the inactive A1R, two binding sites. We calculated that for the active states, cholesterol binds to residues with a much longer residence time compared to the inactive state for both A2AR and A1R. The stability of the identified binding sites to A1R or A2AR with CG MD simulations was additionally investigated with potential of mean force calculations using umbrella sampling. We observed that the binding sites with residues to which cholesterol has a long residence time in A2AR have shallow binding free energy minima compared to the related binding sites in A1R, suggesting a stronger binding for cholesterol to A1R. The differences in binding sites in which cholesterol is stabilized and interacts with residues with a long residence time between active and inactive states of A1R and A2AR can be important for differences in functional activity and orthosteric agonist or antagonist affinity and can be used for the design of allosteric modulators, which can bind through lipid pathways. We observed a stronger binding for cholesterol to A1R (i.e., generally higher association rates) compared to A2AR, which remains to be demonstrated. For the active states, cholesterol binds to residues with much longer residence times compared to the inactive state for both A2AR and A1R. Taken together, binding sites of active A1R may be considered as promising allosteric targets.
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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, Panepistimiopolis-Zografou, 15771Athens, Greece
| | - Robin A Corey
- Department of Biochemistry, University of Oxford, OxfordOX1 3QU, United Kingdom
| | - Antonios Kolocouris
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, 15771Athens, Greece
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17
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Keller F, Alavizargar A, Wedlich-Söldner R, Heuer A. The impact of bilayer composition on the dimerization properties of the Slg1 stress sensor TMD from a multiscale analysis. Phys Chem Chem Phys 2023; 25:1299-1309. [PMID: 36533706 DOI: 10.1039/d2cp03497b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The impact of mutual interactions between the transmembrane domains of membrane proteins and lipids on bilayer properties has gained major attraction. Most simulation studies of membranes rely on the Martini force field, which has proven extremely helpful in providing molecular insights into realistic systems. Accordingly, an evaluation of the accuracy of the Martini force field is crucial to be able to correctly interpret the reported data. In this study, we combine atomistic and coarse-grained Martini simulations to investigate the properties of transmembrane domains (TMDs) in a model yeast membrane. The results show that the TMD binding state (monomeric and dimeric with positive or negative crossing angle) and the membrane composition significantly influence the properties around the TMDs and change TMD-TMD and TMD-lipid affinities. Furthermore, ergosterol (ERG) exhibits a strong affinity to TMD dimers. Importantly, the right-handed TMD dimer configuration is stabilized via TMD-TMD contacts by the addition of asymmetric anionic phosphatidylserine (PS). The coarse-grained simulations corroborate many of these findings, with two notable exceptions: a systematic overestimation of TMD-ERG interaction and lack of stabilization of the right-handed TMD dimers with the addition of PS.
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Affiliation(s)
- Fabian Keller
- Institut für Physikalische Chemie, Corrensstraße 28, Münster, Germany.
| | | | | | - Andreas Heuer
- Institut für Physikalische Chemie, Corrensstraße 28, Münster, Germany.
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18
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Roy A, Patra SK. Lipid Raft Facilitated Receptor Organization and Signaling: A Functional Rheostat in Embryonic Development, Stem Cell Biology and Cancer. Stem Cell Rev Rep 2023; 19:2-25. [PMID: 35997871 DOI: 10.1007/s12015-022-10448-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2022] [Indexed: 01/29/2023]
Abstract
Molecular views of plasma membrane organization and dynamics are gradually changing over the past fifty years. Dynamics of plasma membrane instigate several signaling nexuses in eukaryotic cells. The striking feature of plasma membrane dynamics is that, it is internally transfigured into various subdomains of clustered macromolecules. Lipid rafts are nanoscale subdomains, enriched with cholesterol and sphingolipids, reside as floating entity mostly on the exoplasmic leaflet of the lipid bilayer. In terms of functionality, lipid rafts are unique among other membrane subdomains. Herein, advances on the roles of lipid rafts in cellular physiology and homeostasis are discussed, precisely, on how rafts dynamically harbor signaling proteins, including GPCRs, catalytic receptors, and ionotropic receptors within it and orchestrate multiple signaling pathways. In the developmental proceedings signaling are designed for patterning of overall organism and they differ from the somatic cell physiology and signaling of fully developed organisms. Some of the developmental signals are characteristic in maintenance of stemness and activated during several types of tumor development and cancer progression. The harmony between extracellular signaling and lineage specific transcriptional programs are extremely important for embryonic development. The roles of plasma membrane lipid rafts mediated signaling in lineage specificity, early embryonic development, stem cell maintenance are emerging. In view of this, we have highlighted and analyzed the roles of lipid rafts in receptor organization, cell signaling, and gene expression during embryonic development; from pre-implantation through the post-implantation phase, in stem cell and cancer biology.
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Affiliation(s)
- Ankan Roy
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, Odisha, 769008, India
| | - Samir Kumar Patra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, Odisha, 769008, India.
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19
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Mohole M, Sengupta D, Chattopadhyay A. Synergistic and Competitive Lipid Interactions in the Serotonin 1A Receptor Microenvironment. ACS Chem Neurosci 2022; 13:3403-3415. [PMID: 36351047 DOI: 10.1021/acschemneuro.2c00422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The interaction of lipids with G-protein-coupled receptors (GPCRs) has been shown to modulate and dictate several aspects of GPCR organization and function. Diverse lipid interaction sites have been identified from structural biology, bioinformatics, and molecular dynamics studies. For example, multiple cholesterol interaction sites have been identified in the serotonin1A receptor, along with distinct and overlapping sphingolipid interaction sites. How these lipids interact with each other and what is the resultant effect on the receptor is still not clear. In this work, we have analyzed lipid-lipid crosstalk at the receptor of the serotonin1A receptor embedded in a membrane bilayer that mimics the neuronal membrane composition by long coarse-grain simulations. Using a set of similarity coefficients, we classified lipids that bind at the receptor together as synergistic cobinding, and those that bind individually as competitive. Our results show that certain lipids interact with the serotonin1A receptor in synergy with each other. Not surprisingly, the ganglioside GM1 and cholesterol show a synergistic cobinding, along with the relatively uncommon GM1-phosphatidylethanolamine (PE) and cholesterol-PE synergy. In contrast, certain lipid pairs such as cholesterol and sphingomyelin appear to be in competition at several sites, despite their coexistence in lipid nanodomains. In addition, we observed intralipid competition between two lipid tails, with the receptor exhibiting increased interactions with the unsaturated lipid tails. We believe our work represents an important step in understanding the diversity of GPCR-lipid interactions and exploring synergistic cobinding and competition in natural membranes.
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Affiliation(s)
- Madhura Mohole
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune411 008, India.,Academy of Scientific and Innovative Research, Ghaziabad201 002, India
| | - Durba Sengupta
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune411 008, India.,Academy of Scientific and Innovative Research, Ghaziabad201 002, India
| | - Amitabha Chattopadhyay
- Academy of Scientific and Innovative Research, Ghaziabad201 002, India.,CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad500 007, India
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20
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Kumari S, Mitra A, Bulusu G. Structural dynamics of Smoothened (SMO) in the ciliary membrane and its interaction with membrane lipids. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183946. [PMID: 35483421 DOI: 10.1016/j.bbamem.2022.183946] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 03/22/2022] [Accepted: 04/18/2022] [Indexed: 06/14/2023]
Abstract
The Smoothened receptor (SMO, a 7 pass transmembrane domain, Class F GPCR family protein) plays a crucial role in the Hedgehog (HH) signaling pathway, which is involved in embryonic development and is implicated in various types of cancer throughout the animal kingdom. In the absence of HH signaling, SMO is inhibited by Patched 1 (PTC1; a 12 pass transmembrane domain protein), which is localized in the primary cilia. HH binding leads to the dislocation of PTC1 from the cilia, thus making way for SMO to localize in the primary cilia, as an essential prerequisite for its activation. We have carried out MARTINI coarse-grained molecular dynamics simulations of SMO in POPC and in ciliary membrane models, respectively, to study the interactions of SMO with cholesterol and other lipid molecules in the ciliary membrane, and to gain molecular-level insights into the role of the primary cilia in shaping the functional dynamics of SMO. We are able to identify the interaction of membrane cholesterols with definite sites and domains within SMO and relate them with known cholesterol-binding sequence and structure motifs. We show that cholesterol interactions with the transmembrane domain TMD, unlike those with the cysteine-rich domain (CRD) and the intracellular domain (ICD), are through residues belonging to known cholesterol-binding motifs. Notably, a few persistent interactions of cholesterol with lower TM cholesterol-binding domains are governed by the presence of multiple cholesterol-binding motifs. These analyses have also helped to identify and define a strict cholesterol consensus motif (CCM), which may well steer cholesterol into the hitherto identified binding sites within the TMD of SMO. We have also reported the interaction of phosphatidylinositol 4-phosphate with the intracellular region of transmembrane (TM) helices (TM1, TM3, TM4, and TM5), intracellular loop1, helix8, and Arg/Lys clusters of the ICD. Structural analysis of SMO domains shows significant changes in the CRD and ICD, during the course of the simulation. Further detailed analysis of the dynamics of the TMD reveals the movements of TM5, TM6, and TM7, linked with the helix8, which are possibly involved in shaping the conformational disposition of the ICD. The movement of these TM helices could possibly be a consequence of interactions involving the extracellular domain and extracellular loops. In addition, our analysis also shows that phosphatidylinositol-4-phosphate (PI4P), along with some ICD cholesterols, are implicated in anchoring SMO in the membrane.
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Affiliation(s)
- Shweta Kumari
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad 500 032, India
| | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad 500 032, India
| | - Gopalakrishnan Bulusu
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad 500 032, India; Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad 500 046, India.
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21
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Erkan‐Candag H, Clarke A, Tiapko O, Gsell MAF, Stockner T, Groschner K. Diacylglycerols interact with the L2 lipidation site in TRPC3 to induce a sensitized channel state. EMBO Rep 2022; 23:e54276. [PMID: 35604352 PMCID: PMC9253791 DOI: 10.15252/embr.202154276] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 04/11/2022] [Accepted: 04/25/2022] [Indexed: 11/09/2022] Open
Abstract
Coordination of lipids within transient receptor potential canonical channels (TRPCs) is essential for their Ca2+ signaling function. Single particle cryo-EM studies identified two lipid interaction sites, designated L1 and L2, which are proposed to accommodate diacylglycerols (DAGs). To explore the role of L1 and L2 in TRPC3 function, we combined structure-guided mutagenesis and electrophysiological recording with molecular dynamics (MD) simulations. MD simulations indicate rapid DAG accumulation within both L1 and L2 upon its availability within the plasma membrane. Electrophysiological experiments using a photoswitchable DAG-probe reveal potentiation of TRPC3 currents during repetitive activation by DAG. Importantly, initial DAG exposure generates a subsequently sensitized channel state that is associated with significantly faster activation kinetics. TRPC3 sensitization is specifically promoted by mutations within L2, with G652A exhibiting sensitization at very low levels of active DAG. We demonstrate the ability of TRPC3 to adopt a closed state conformation that features partial lipidation of L2 sites by DAG and enables fast activation of the channel by the phospholipase C-DAG pathway.
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Affiliation(s)
- Hazel Erkan‐Candag
- Gottfried‐Schatz‐Research‐Center – BiophysicsMedical University of GrazGrazAustria
| | - Amy Clarke
- Institute of PharmacologyMedical University of ViennaViennaAustria
| | - Oleksandra Tiapko
- Gottfried‐Schatz‐Research‐Center – BiophysicsMedical University of GrazGrazAustria
| | - Mathias AF Gsell
- Gottfried‐Schatz‐Research‐Center – BiophysicsMedical University of GrazGrazAustria
| | - Thomas Stockner
- Institute of PharmacologyMedical University of ViennaViennaAustria
| | - Klaus Groschner
- Gottfried‐Schatz‐Research‐Center – BiophysicsMedical University of GrazGrazAustria
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22
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Lee AG. The role of cholesterol binding in the control of cholesterol by the Scap–Insig system. EUROPEAN BIOPHYSICS JOURNAL 2022; 51:385-399. [PMID: 35717507 PMCID: PMC9233655 DOI: 10.1007/s00249-022-01606-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 05/26/2022] [Accepted: 06/05/2022] [Indexed: 12/02/2022]
Abstract
Scap and Insig, two proteins embedded in the membrane of the endoplasmic reticulum (ER), regulate the synthesis of cholesterol in animal cells by forming a dimer in the presence of high concentrations of cholesterol. Cryo-electron microscopic structures for the Scap–Insig dimer show a sterol-binding site at the dimer interface, but none of the structures include cholesterol itself. Here, a molecular docking approach developed to characterise cholesterol binding to the transmembrane (TM) regions of membrane proteins is used to characterise cholesterol binding to sites on the TM surface of the dimer and to the interfacial binding site. Binding of cholesterol is also observed at sites on the extra-membranous luminal domains of Scap, but the properties of these sites suggest that they will be unoccupied in vivo. Comparing the structure of Scap in the dimer with that predicted by AlphaFold for monomeric Scap suggests that dimer formation could result in relocation of TM helix 7 of Scap and of the loop between TM6 and 7, and that this could be the key change on Scap that signals that there is a high concentration of cholesterol in the ER.
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Affiliation(s)
- Anthony G Lee
- School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
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23
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Clarke A, Groschner K, Stockner T. Exploring TRPC3 Interaction with Cholesterol through Coarse-Grained Molecular Dynamics Simulations. Biomolecules 2022; 12:biom12070890. [PMID: 35883446 PMCID: PMC9313397 DOI: 10.3390/biom12070890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/21/2022] [Accepted: 06/23/2022] [Indexed: 02/04/2023] Open
Abstract
Transient receptor potential canonical 3 (TRPC3) channel belongs to the superfamily of transient receptor potential (TRP) channels which mediate Ca2+ influx into the cell. These channels constitute essential elements of cellular signalling and have been implicated in a wide range of diseases. TRPC3 is primarily gated by lipids and its surface expression has been shown to be dependent on cholesterol, yet a comprehensive exploration of its interaction with this lipid has thus far not emerged. Here, through 80 µs of coarse-grained molecular dynamics simulations, we show that cholesterol interacts with multiple elements of the transmembrane machinery of TRPC3. Through our approach, we identify an annular binding site for cholesterol on the pre-S1 helix and a non-annular site at the interface between the voltage-sensor-like domain and pore domains. Here, cholesterol interacts with exposed polar residues and possibly acts to stabilise the domain interface.
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Affiliation(s)
- Amy Clarke
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstr., 13A, 1090 Vienna, Austria;
| | - Klaus Groschner
- Gottfried Schatz Research Center, Division of Biophysics, Medical University of Graz, 8010 Graz, Austria;
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstr., 13A, 1090 Vienna, Austria;
- Correspondence:
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24
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Marrink SJ, Monticelli L, Melo MN, Alessandri R, Tieleman DP, Souza PCT. Two decades of Martini: Better beads, broader scope. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2022. [DOI: 10.1002/wcms.1620] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Siewert J. Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials University of Groningen Groningen The Netherlands
| | - Luca Monticelli
- Molecular Microbiology and Structural Biochemistry (MMSB ‐ UMR 5086) CNRS & University of Lyon Lyon France
| | - Manuel N. Melo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa Oeiras Portugal
| | - Riccardo Alessandri
- Pritzker School of Molecular Engineering University of Chicago Chicago Illinois USA
| | - D. Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences University of Calgary Alberta Canada
| | - Paulo C. T. Souza
- Molecular Microbiology and Structural Biochemistry (MMSB ‐ UMR 5086) CNRS & University of Lyon Lyon France
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25
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Kinnebrew M, Woolley RE, Ansell TB, Byrne EFX, Frigui S, Luchetti G, Sircar R, Nachtergaele S, Mydock-McGrane L, Krishnan K, Newstead S, Sansom MSP, Covey DF, Siebold C, Rohatgi R. Patched 1 regulates Smoothened by controlling sterol binding to its extracellular cysteine-rich domain. SCIENCE ADVANCES 2022; 8:eabm5563. [PMID: 35658032 PMCID: PMC9166294 DOI: 10.1126/sciadv.abm5563] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 04/15/2022] [Indexed: 05/06/2023]
Abstract
Smoothened (SMO) transduces the Hedgehog (Hh) signal across the plasma membrane in response to accessible cholesterol. Cholesterol binds SMO at two sites: one in the extracellular cysteine-rich domain (CRD) and a second in the transmembrane domain (TMD). How these two sterol-binding sites mediate SMO activation in response to the ligand Sonic Hedgehog (SHH) remains unknown. We find that mutations in the CRD (but not the TMD) reduce the fold increase in SMO activity triggered by SHH. SHH also promotes the photocrosslinking of a sterol analog to the CRD in intact cells. In contrast, sterol binding to the TMD site boosts SMO activity regardless of SHH exposure. Mutational and computational analyses show that these sites are in allosteric communication despite being 45 angstroms apart. Hence, sterols function as both SHH-regulated orthosteric ligands at the CRD and allosteric ligands at the TMD to regulate SMO activity and Hh signaling.
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Affiliation(s)
- Maia Kinnebrew
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Rachel E. Woolley
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - Eamon F. X. Byrne
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Sara Frigui
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Giovanni Luchetti
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Ria Sircar
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Sigrid Nachtergaele
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Laurel Mydock-McGrane
- Department of Developmental Biology, Washington School of Medicine, St. Louis, MO, USA
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington School of Medicine, St. Louis, MO, USA
| | - Simon Newstead
- Department of Biochemistry, University of Oxford, Oxford, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, UK
| | | | - Douglas F. Covey
- Department of Developmental Biology, Washington School of Medicine, St. Louis, MO, USA
- Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA, USA
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26
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Zimmermann MT. Molecular Modeling is an Enabling Approach to Complement and Enhance Channelopathy Research. Compr Physiol 2022; 12:3141-3166. [PMID: 35578963 DOI: 10.1002/cphy.c190047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Hundreds of human membrane proteins form channels that transport necessary ions and compounds, including drugs and metabolites, yet details of their normal function or how function is altered by genetic variants to cause diseases are often unknown. Without this knowledge, researchers are less equipped to develop approaches to diagnose and treat channelopathies. High-resolution computational approaches such as molecular modeling enable researchers to investigate channelopathy protein function, facilitate detailed hypothesis generation, and produce data that is difficult to gather experimentally. Molecular modeling can be tailored to each physiologic context that a protein may act within, some of which may currently be difficult or impossible to assay experimentally. Because many genomic variants are observed in channelopathy proteins from high-throughput sequencing studies, methods with mechanistic value are needed to interpret their effects. The eminent field of structural bioinformatics integrates techniques from multiple disciplines including molecular modeling, computational chemistry, biophysics, and biochemistry, to develop mechanistic hypotheses and enhance the information available for understanding function. Molecular modeling and simulation access 3D and time-dependent information, not currently predictable from sequence. Thus, molecular modeling is valuable for increasing the resolution with which the natural function of protein channels can be investigated, and for interpreting how genomic variants alter them to produce physiologic changes that manifest as channelopathies. © 2022 American Physiological Society. Compr Physiol 12:3141-3166, 2022.
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Affiliation(s)
- Michael T Zimmermann
- Bioinformatics Research and Development Laboratory, Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.,Clinical and Translational Sciences Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.,Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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27
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Song W, Corey RA, Ansell TB, Cassidy CK, Horrell MR, Duncan AL, Stansfeld PJ, Sansom MSP. PyLipID: A Python Package for Analysis of Protein-Lipid Interactions from Molecular Dynamics Simulations. J Chem Theory Comput 2022; 18:1188-1201. [PMID: 35020380 PMCID: PMC8830038 DOI: 10.1021/acs.jctc.1c00708] [Citation(s) in RCA: 60] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Indexed: 12/11/2022]
Abstract
Lipids play important modulatory and structural roles for membrane proteins. Molecular dynamics simulations are frequently used to provide insights into the nature of these protein-lipid interactions. Systematic comparative analysis requires tools that provide algorithms for objective assessment of such interactions. We introduce PyLipID, a Python package for the identification and characterization of specific lipid interactions and binding sites on membrane proteins from molecular dynamics simulations. PyLipID uses a community analysis approach for binding site detection, calculating lipid residence times for both the individual protein residues and the detected binding sites. To assist structural analysis, PyLipID produces representative bound lipid poses from simulation data, using a density-based scoring function. To estimate residue contacts robustly, PyLipID uses a dual-cutoff scheme to differentiate between lipid conformational rearrangements while bound from full dissociation events. In addition to the characterization of protein-lipid interactions, PyLipID is applicable to analysis of the interactions of membrane proteins with other ligands. By combining automated analysis, efficient algorithms, and open-source distribution, PyLipID facilitates the systematic analysis of lipid interactions from large simulation data sets of multiple species of membrane proteins.
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Affiliation(s)
- Wanling Song
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
- Rahko,
Clifton House, 46 Clifton
Terrace, Finsbury Park, London N4 3JP, United Kingdom
| | - Robin A. Corey
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - T. Bertie Ansell
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - C. Keith Cassidy
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Michael R. Horrell
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Anna L. Duncan
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Phillip J. Stansfeld
- School
of Life Sciences & Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Mark S. P. Sansom
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
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28
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Zhong C, Wang B. Regulation of Cholesterol Binding to the Receptor Patched1 by its interactions With the Ligand Sonic Hedgehog (Shh). Front Mol Biosci 2022; 9:831891. [PMID: 35187087 PMCID: PMC8847689 DOI: 10.3389/fmolb.2022.831891] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/11/2022] [Indexed: 01/17/2023] Open
Abstract
The Hedgehog (Hh) signaling pathway is essential in cell development and regeneration, which is activated by the ligand Sonic hedgehog (Shh). The binding of Shh to its receptor Patched1 (PTCH1) releases the inhibitory effect on the downstream protein Smoothened (SMO), a G-protein-coupled-receptor (GPCR) protein. Cholesterol was supposed to function as a secondary messenger between PTCH1 and SMO. However, the molecular mechanism of this regulation process is still unclear. Therefore, microsecond coarse-grained molecular dynamics simulations were performed to investigate the protein-lipid interactions of the PTCH1 monomer and dimer-Shh complex. It was observed that the binding of cholesterols to the monomer is more stable than that to the dimer-Shh complex. It is regulated by the enrichment of Ganglioside lipids around proteins and the conformation of Y446, a residue in the sterol-sensing domain (SSD). The regulation of Shh on the dynamics of PTCH1 was further analyzed to explore the allosteric communication pathways between the Shh and the SSD. Our study provides structural and dynamic details of an additional perspective on the regulation of Hh signaling pathway through the lipid micro-environments of PTCH1.
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Affiliation(s)
- Changqing Zhong
- Centre for Informational Biology, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Beibei Wang
- Centre for Advanced Materials Research, Advanced Institute of Natural Sciences, Beijing Normal University at Zhuhai, Zhuhai, China
- *Correspondence: Beibei Wang,
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29
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Kolokouris D, Kalenderoglou IE, Kolocouris A. Inside and Out of the Pore: Comparing Interactions and Molecular Dynamics of Influenza A M2 Viroporin Complexes in Standard Lipid Bilayers. J Chem Inf Model 2021; 61:5550-5568. [PMID: 34714655 DOI: 10.1021/acs.jcim.1c00264] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ion channels located at viral envelopes (viroporins) have a critical function for the replication of infectious viruses and are important drug targets. Over the last decade, the number and duration of molecular dynamics (MD) simulations of the influenza A M2 ion channel owing to the increased computational efficiency. Here, we aimed to define the system setup and simulation conditions for the correct description of the protein-pore and the protein-lipid interactions for influenza A M2 in comparison with experimental data. We performed numerous MD simulations of the influenza A M2 protein in complex with adamantane blockers in standard lipid bilayers using OPLS2005 and CHARMM36 (C36) force fields. We explored the effect of varying the M2 construct (M2(22-46) and M2(22-62)), the lipid buffer size and type (stiffer DMPC or softer POPC with or without 20% cholesterol), the simulation time, the H37 protonation site (Nδ or Νε), the conformational state of the W41 channel gate, and M2's cholesterol binding sites (BSs). We report that the 200 ns MD with M2(22-62) (having Nε Η37) in the 20 Å lipid buffer with the C36 force field accurately describe: (a) the M2 pore structure and interactions inside the pore, that is, adamantane channel blocker location, water clathrate structure, and water or chloride anion blockage/passage from the M2 pore in the presence of a channel blocker and (b) interactions between M2 and the membrane environment as reflected by the calculation of the M2 bundle tilt, folding of amphipathic helices, and cholesterol BSs. Strikingly, we also observed that the C36 1 μs MD simulations using M2(22-62) embedded in a 20 Å POPC:cholesterol (5:1) scrambled membrane produced frequent interactions with cholesterol, which when combined with computational kinetic analysis, revealed the experimentally observed BSs of cholesterol and suggested three similarly long-interacting positions in the top leaflet that have previously not been observed experimentally. These findings promise to be useful for other viroporin systems.
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Affiliation(s)
- Dimitrios Kolokouris
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, Athens 15771, Greece
| | - Iris E Kalenderoglou
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, Athens 15771, Greece
| | - Antonios Kolocouris
- Laboratory of Medicinal Chemistry, Section of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis-Zografou, Athens 15771, Greece
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30
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NanoBRET and NanoBiT/BRET-Based Ligand Binding Assays Permit Quantitative Assessment of Small Molecule Ligand Binding to Smoothened. Methods Mol Biol 2021. [PMID: 34562254 DOI: 10.1007/978-1-0716-1701-4_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Smoothened (SMO) is a G protein-coupled receptor (GPCR) that mediates Hedgehog (Hh) signaling. SMO activity is regulated following the binding of Hh to the transmembrane protein Patched. Overactive SMO signaling is oncogenic, and hence this receptor is a target for several marketed drugs. However, development of new SMO ligands has been hampered by the fact that current radioligand and fluorescence-based binding assays are not high-throughput scalable. Here, we demonstrate two Nanoluciferase (Nluc) bioluminescence resonance energy transfer-based ligand binding assays (NanoBRET and NanoBiT/BRET) which provide a sensitive and high-throughput-compatible tool in drug screening efforts. In the described assays, SMO is N-terminally tagged either with full-length nanoluciferase or the partial HiBiT sequence, and subsequently binding of BODIPY-cyclopamine is assessed by quantifying resonance energy transfer between the receptor and the fluorescent ligand. Additionally, the assay allows performing competition binding experiments using commercially available SMO ligands, such as the SMO agonist SAG1.3.
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31
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Mechanisms of Smoothened Regulation in Hedgehog Signaling. Cells 2021; 10:cells10082138. [PMID: 34440907 PMCID: PMC8391454 DOI: 10.3390/cells10082138] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/05/2021] [Accepted: 08/16/2021] [Indexed: 12/21/2022] Open
Abstract
The seven-transmembrane protein, Smoothened (SMO), has shown to be critical for the hedgehog (HH) signal transduction on the cell membrane (and the cilium in vertebrates). SMO is subjected to multiple types of post-translational regulations, including phosphorylation, ubiquitination, and sumoylation, which alter SMO intracellular trafficking and cell surface accumulation. Recently, SMO is also shown to be regulated by small molecules, such as oxysterol, cholesterol, and phospholipid. The activity of SMO must be very well balanced by these different mechanisms in vivo because the malfunction of SMO will not only cause developmental defects in early stages, but also induce cancers in late stages. Here, we discuss the activation and inactivation of SMO by different mechanisms to better understand how SMO is regulated by the graded HH signaling activity that eventually governs distinct development outcomes.
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32
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Sejdiu BI, Tieleman DP. ProLint: a web-based framework for the automated data analysis and visualization of lipid-protein interactions. Nucleic Acids Res 2021; 49:W544-W550. [PMID: 34038536 PMCID: PMC8262751 DOI: 10.1093/nar/gkab409] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/25/2021] [Accepted: 05/24/2021] [Indexed: 12/18/2022] Open
Abstract
The functional activity of membrane proteins is carried out in a complex lipid environment. Increasingly, it is becoming clear that lipids are an important player in regulating or generally modulating their activity. A routinely used method to gain insight into this interplay between lipids and proteins are Molecular Dynamics (MD) simulations, since they allow us to study interactions at atomic or near-atomic detail as a function of time. A major bottleneck, however, is analyzing and visualizing lipid-protein interactions, which, in practice, is a time-demanding task. Here, we present ProLint (www.prolint.ca), a webserver that completely automates analysis of MD generated files and visualization of lipid-protein interactions. Analysis is modular allowing users to select their preferred method, and visualization is entirely interactive through custom built applications that enable a detailed qualitative and quantitative exploration of lipid-protein interactions. ProLint also includes a database of published MD results that have been processed through the ProLint workflow and can be visualized by anyone regardless of their level of experience with MD. The automated analysis, feature-rich visualization, database integration, and open-source distribution with an easy to install process, will allow ProLint to become a routine workflow in lipid-protein interaction studies.
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Affiliation(s)
- Besian I Sejdiu
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Alberta T2N 1N4, Canada
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Alberta T2N 1N4, Canada
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33
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The structural biology of canonical Wnt signalling. Biochem Soc Trans 2021; 48:1765-1780. [PMID: 32725184 PMCID: PMC7458405 DOI: 10.1042/bst20200243] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/04/2020] [Accepted: 07/07/2020] [Indexed: 12/17/2022]
Abstract
The Wnt signalling pathways are of great importance in embryonic development and oncogenesis. Canonical and non-canonical Wnt signalling pathways are known, with the canonical (or β-catenin dependent) pathway being perhaps the best studied of these. While structural knowledge of proteins and interactions involved in canonical Wnt signalling has accumulated over the past 20 years, the pace of discovery has increased in recent years, with the structures of several key proteins and assemblies in the pathway being released. In this review, we provide a brief overview of canonical Wnt signalling, followed by a comprehensive overview of currently available X-ray, NMR and cryoEM data elaborating the structures of proteins and interactions involved in canonical Wnt signalling. While the volume of structures available is considerable, numerous gaps in knowledge remain, particularly a comprehensive understanding of the assembly of large multiprotein complexes mediating key aspects of pathway, as well as understanding the structure and activation of membrane receptors in the pathway. Nonetheless, the presently available data affords considerable opportunities for structure-based drug design efforts targeting canonical Wnt signalling.
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34
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Lee AG. Interfacial binding sites for cholesterol on GABA A receptors and competition with neurosteroids. Biophys J 2021; 120:2710-2722. [PMID: 34022235 DOI: 10.1016/j.bpj.2021.05.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/06/2021] [Accepted: 05/13/2021] [Indexed: 01/17/2023] Open
Abstract
γ-Aminobutyric acid type A (GABAA) receptors in the brain are located in the outer membranes of brain cells where the concentration of cholesterol is high. Of the 25 available high-resolution structures available for GABAA receptors, none were determined in the presence of cholesterol, but four include resolved molecules of cholesterol hemisuccinate (CHS). Here, a molecular docking procedure is used to sweep the transmembrane (TM) surfaces of the receptors for cholesterol binding sites. Cholesterol docking poses determined in this way match 89% of the resolved CHS when CHS molecules deemed unlikely to represent typical bound cholesterols are excluded. The receptors are pentameric, and their TM surfaces consist of a set of five facets, each including pairs of TM helices from two adjacent subunits. Each facet contains hydrophobic hollows running from one side of the membrane to the other, within which are six potential binding sites for cholesterol, three on each side of the membrane. High-resolution structures of GABAA receptors with bound neurosteroids show that neurosteroids bind in these cholesterol binding sites, so the binding of neurosteroids and cholesterol will be competitive.
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Affiliation(s)
- Anthony G Lee
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom.
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35
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Statins repress hedgehog signaling in medulloblastoma with no bone toxicities. Oncogene 2021; 40:2258-2272. [PMID: 33649536 DOI: 10.1038/s41388-021-01701-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/30/2021] [Accepted: 02/05/2021] [Indexed: 02/06/2023]
Abstract
The Hedgehog (Hh) pathway plays an indispensable role in bone development and genetic activation of the pathway results in medulloblastoma (MB), the most common malignant brain tumor in children. Inhibitors of Hh pathway (such as vismodegib and sonedigib), which are used to treat MB, cause irreversible defects in bone growth in young children. Cholesterol is required for the activation of the Hh pathway, and statins, inhibitors of cholesterol biosynthesis, suppress MB growth by repressing Hh signaling in tumor cells. Here, we investigate the role of cholesterol biosynthesis in the proliferation and Hh signaling in chondrocytes, and examine the bone development in mice after statin treatment. Statins significantly inhibited MB growth in young mice, but caused no defects in bone development. Conditional deletion of NADP steroid dehydrogenase-like (NSDHL), an enzyme necessary for cholesterol biosynthesis, suppressed cholesterol synthesis in chondrocytes, and disrupted the growth plate in mouse femur and tibia, indicating the important function of intracellular cholesterol in bone development. Hh pathway activation and the proliferation of chondrocytes were inhibited by statin treatment in vitro; however, statins did not impair bone growth in vivo due to insufficient penetration into the bone. Our studies reveal a critical role of cholesterol in bone development, and support the utilization of statins for treatment of MB as well as other Hh pathway-associated malignancies.
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36
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Lemel L, Nieścierowicz K, García-Fernández MD, Darré L, Durroux T, Busnelli M, Pezet M, Rébeillé F, Jouhet J, Mouillac B, Domene C, Chini B, Cherezov V, Moreau CJ. The ligand-bound state of a G protein-coupled receptor stabilizes the interaction of functional cholesterol molecules. J Lipid Res 2021; 62:100059. [PMID: 33647276 PMCID: PMC8050779 DOI: 10.1016/j.jlr.2021.100059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 02/11/2021] [Indexed: 12/30/2022] Open
Abstract
Cholesterol is a major component of mammalian plasma membranes that not only affects the physical properties of the lipid bilayer but also is the function of many membrane proteins including G protein-coupled receptors. The oxytocin receptor (OXTR) is involved in parturition and lactation of mammals and in their emotional and social behaviors. Cholesterol acts on OXTR as an allosteric modulator inducing a high-affinity state for orthosteric ligands through a molecular mechanism that has yet to be determined. Using the ion channel-coupled receptor technology, we developed a functional assay of cholesterol modulation of G protein-coupled receptors that is independent of intracellular signaling pathways and operational in living cells. Using this assay, we discovered a stable binding of cholesterol molecules to the receptor when it adopts an orthosteric ligand-bound state. This stable interaction preserves the cholesterol-dependent activity of the receptor in cholesterol-depleted membranes. This mechanism was confirmed using time-resolved FRET experiments on WT OXTR expressed in CHO cells. Consequently, a positive cross-regulation sequentially occurs in OXTR between cholesterol and orthosteric ligands.
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Affiliation(s)
- Laura Lemel
- Univ. Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | | | | | - Leonardo Darré
- Functional Genomics Laboratory and Biomolecular Simulations Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Thierry Durroux
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Marta Busnelli
- CNR, Institute of Neuroscience, U28 and NeuroMI Center for Neuroscience, University of Milano-Bicocca, Vedano al Lambro (MB), Italy
| | - Mylène Pezet
- Institute for Advanced Biosciences, Inserm U 1209, CNRS UMR 5309, Grenoble Alpes University, Grenoble, France
| | - Fabrice Rébeillé
- Laboratoire de Physiologie Cellulaire Végétale, Univ. Grenoble Alpes, CNRS, CEA, INRAE, Grenoble, France
| | - Juliette Jouhet
- Laboratoire de Physiologie Cellulaire Végétale, Univ. Grenoble Alpes, CNRS, CEA, INRAE, Grenoble, France
| | - Bernard Mouillac
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Carmen Domene
- Department of Chemistry, University of Bath, Bath, United Kingdom; Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Bice Chini
- CNR, Institute of Neuroscience, U28 and NeuroMI Center for Neuroscience, University of Milano-Bicocca, Vedano al Lambro (MB), Italy
| | - Vadim Cherezov
- Bridge Institute, Department of Chemistry, University of Southern California, Los Angeles, CA, USA
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Zhang T, Hu W, Chen W. Plasma Membrane Integrates Biophysical and Biochemical Regulation to Trigger Immune Receptor Functions. Front Immunol 2021; 12:613185. [PMID: 33679752 PMCID: PMC7933204 DOI: 10.3389/fimmu.2021.613185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 01/06/2021] [Indexed: 11/23/2022] Open
Abstract
Plasma membrane provides a biophysical and biochemical platform for immune cells to trigger signaling cascades and immune responses against attacks from foreign pathogens or tumor cells. Mounting evidence suggests that the biophysical-chemical properties of this platform, including complex compositions of lipids and cholesterols, membrane tension, and electrical potential, could cooperatively regulate the immune receptor functions. However, the molecular mechanism is still unclear because of the tremendous compositional complexity and spatio-temporal dynamics of the plasma membrane. Here, we review the recent significant progress of dynamical regulation of plasma membrane on immune receptors, including T cell receptor, B cell receptor, Fc receptor, and other important immune receptors, to proceed mechano-chemical sensing and transmembrane signal transduction. We also discuss how biophysical-chemical cues couple together to dynamically tune the receptor’s structural conformation or orientation, distribution, and organization, thereby possibly impacting their in-situ ligand binding and related signal transduction. Moreover, we propose that electrical potential could potentially induce the biophysical-chemical coupling change, such as lipid distribution and membrane tension, to inevitably regulate immune receptor activation.
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Affiliation(s)
- Tongtong Zhang
- Department of Hepatobiliary and Pancreatic Surgery, The Center for Integrated Oncology and Precision Medicine, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Hu
- Department of Cell Biology and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Chen
- Department of Cell Biology and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory for Biomedical Engineering of Ministry of Education, State Key Laboratory for Modern Optical Instrumentation, College of Biomedical Engineering and Instrument Science, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China
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38
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Martin LJ, Banister SD, Bowen MT. Understanding the complex pharmacology of cannabidiol: Mounting evidence suggests a common binding site with cholesterol. Pharmacol Res 2021; 166:105508. [PMID: 33610721 DOI: 10.1016/j.phrs.2021.105508] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/28/2021] [Accepted: 02/16/2021] [Indexed: 12/19/2022]
Abstract
Cannabidiol is claimed to bind to a large number of protein targets based on in vitro assays. This suggests opportunities for a wide range of therapeutic applications. On the other hand, the existence of phytochemical 'nuisance compounds' suggests some measure of caution - these compounds are capable of altering membrane biophysical properties and changing protein function without directly contacting a binding site. Like cannabidiol, cholesterol alters membrane properties, but it also binds directly to membrane proteins through abundant cholesterol recognition sites. We present the evidence that cannabidiol and cholesterol may bind to the same site on some proteins. As a starting point for further research, we also used blind docking to show that cannabidiol binds to a cholesterol binding site on the CB1 receptor. Elucidation of the mechanism(s) of action of cannabidiol will assist the prioritisation of in vitro hits across targets, improve the success rate of medicinal chemistry campaigns, and ultimately benefit patient populations by focusing resources on programs with the most translational potential.
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Affiliation(s)
- Lewis J Martin
- The University of Sydney, Brain and Mind Centre, The Lambert Initiative for Cannabinoid Therapeutics, Sydney, NSW, Australia; The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia; The University of Sydney, Faculty of Science, School of Psychology, NSW, Australia
| | - Samuel D Banister
- The University of Sydney, Brain and Mind Centre, The Lambert Initiative for Cannabinoid Therapeutics, Sydney, NSW, Australia; The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia
| | - Michael T Bowen
- The University of Sydney, Brain and Mind Centre, The Lambert Initiative for Cannabinoid Therapeutics, Sydney, NSW, Australia; The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia; The University of Sydney, Faculty of Science, School of Psychology, NSW, Australia.
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39
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Agostino M, Pohl SÖG. Activation barriers in Class F G protein-coupled receptors revealed by umbrella sampling simulations. Org Biomol Chem 2020; 18:9816-9825. [PMID: 33290484 DOI: 10.1039/d0ob02175j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Class F G protein-coupled receptors (GPCRs) include Smoothened and the ten Frizzled receptors, which are major cell membrane receptors in the Hedgehog and Wnt signalling pathways respectively and of enormous interest in embryonic development and as therapeutic targets in cancer. Recent crystal structures of Smoothened provide the opportunity to investigate the structural biology of Class F GPCRs in more detail, in turn, informing the development of therapeutics. A key question in this area is how one receptor may trigger distinct pathways - particularly relevant for Wnt signalling, in which signals may be transduced from a Frizzled via Dishevelled or G proteins, depending on the context. In this study, we employ adiabatic biased molecular dynamics and umbrella sampling to investigate the activation of Smoothened and Frizzled-7 in both the native state and bound to endogenous ligands, as well as how the clinically used Smoothened antagonist vismodegib alters this signalling. The results highlight key energetic barriers in the activation of these receptors, and the molecular features of the receptors mediating these barriers, demonstrating our approach as a robust means of investigating signalling through these receptors.
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Affiliation(s)
- Mark Agostino
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute (CHIRI), and Curtin Institute for Computation, Curtin University, Bentley, Western Australia, Australia.
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40
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Data analysis of molecular dynamics simulation trajectories of β-sitosterol, sonidegib and cholesterol in smoothened protein with the CHARMM36 force field. Data Brief 2020; 33:106350. [PMID: 33083505 PMCID: PMC7554031 DOI: 10.1016/j.dib.2020.106350] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 02/07/2023] Open
Abstract
Inactivation of smoothened protein (SMO) by the antagonists in SHH-driven cancer types is essential for inhibition of cancer progression. This article presents molecular dynamics (MD) trajectories of water solution of three protein-ligand complexes smoothened-β-sitosterol (SMO-BST), smoothened-sonidegib (SMO-SNG) and smoothened-cholesterol (SMO-CLR) using CHARMM36 and SPC/E water model combination. Additionally, the work presents the topologies and trajectories of GROMACS files that were employed to analyse the protein-ligand interaction types (PyContact) and binding energy calculation (g_mmpbsa). The data demonstrated that equilibrated models of SMO-SNG and SMO-CLR complexes showed crucial residues that almost similar for interaction and contribution energy as previously reported in laboratory setup (in vitro). Initial simulations confirmed the role of ARG451 and TRP535 in the dynamic regulation of SMO. These data then were used as a reference for understanding the molecular dynamics of SMO-BST complex and thus predicted its mechanism of action.
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41
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Pantelopulos GA, Panahi A, Straub JE. Impact of Cholesterol Concentration and Lipid Phase on Structure and Fluctuation of Amyloid Precursor Protein. J Phys Chem B 2020; 124:10173-10185. [PMID: 33135883 PMCID: PMC7958706 DOI: 10.1021/acs.jpcb.0c07615] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Elevated levels of cellular cholesterol have been identified as one factor contributing to the onset of Alzheimer's disease (AD). Specific interaction between cholesterol and the amyloid precursor protein (APP), investigated via NMR experiments and computational studies, has been proposed to play a critical role in the processing of APP by secretases and the biogenesis of amyloid-β (Aβ) protein. We present all-atom molecular dynamics simulations of the 40-residue congener of the C-terminal domain of APP, C9916-55 (C99), in cholesterol-enriched DMPC lipid bilayers. We investigated the effect of cholesterol concentration on the conformational ensemble of wild-type C99 and C99-cholesterol associations at the low pH of endosomal environments, at which residues E22 and D23 are neutral. C99 was also characterized in liquid ordered domains for Dutch (E22Q) and Iowa (D23N) Familial AD mutants at low pH and for the wild-type sequence using protonation states characteristic of neutral pH. Our results reproduce the equilibrium constant of past NMR characterizations of the C99-cholesterol interaction but are not consistent with the C99-cholesterol binding hypothesis. We find that the lifetimes of both DMPC and cholesterol complexed with C99 display a power-law distribution of residence lifetimes. Longer-lived C99-DMPC and C99-cholesterol complexes are primarily stabilized by salt bridges and hydrogen bonds of lysine amines to phosphate and hydroxyl groups. Nevertheless, specific interfaces for C99-cholesterol association which are not present for DMPC can be identified. Changes to C99-cholesterol interfaces are found to depend on C99 tilt angle and orientation of the juxtamembrane domain of C99 containing residues E22 and D23. These observations support a more nuanced view of the C99-cholesterol interaction than has previously been suggested. We propose that cholesterol modulates the conformation and activity of C99 and other small transmembrane proteins indirectly through induction of the liquid ordered phase and directly through hydrogen bonding. This suggests a critical role for membrane heterogeneity introduced by cholesterol in modulating the structural ensemble of C99 and the production of Aβ.
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Affiliation(s)
- George A Pantelopulos
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Afra Panahi
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - John E Straub
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
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42
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Qiu T, Cao J, Chen W, Wang J, Wang Y, Zhao L, Liu M, He L, Wu G, Li H, Gu H. 24-Dehydrocholesterol reductase promotes the growth of breast cancer stem-like cells through the Hedgehog pathway. Cancer Sci 2020; 111:3653-3664. [PMID: 32713162 PMCID: PMC7540995 DOI: 10.1111/cas.14587] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/17/2020] [Accepted: 07/20/2020] [Indexed: 12/19/2022] Open
Abstract
Cholesterol is a risk factor for breast cancer. However, it is still unclear whether the cholesterol biosynthesis pathway plays any significant role in breast carcinogenesis. 24-Dehydrocholesterol reductase (DHCR24) is a key enzyme in the cholesterol synthesis pathway. Although DHCR24 is reported to have different functions in different cancers, it is not clear whether DHCR24 is involved in breast cancer. In this study, we found that DHCR24 expression was higher in breast cancer especially in luminal and HER2 positive breast cancer tissues compared with normal breast. Changes in DHCR24 expression altered cellular cholesterol content without affecting the adherent growth of breast cancer cells. However, DHCR24 knockdown reduced whereas DHCR24 overexpression enhanced breast cancer stem-like cell populations such as mammosphere and aldehyde dehydrogenase positive cell numbers. In addition, DHCR24 overexpression increased the expression of the Hedgehog pathway-regulated genes. Treating DHCR24 overexpressing breast cancer cell lines with the Hedgehog pathway inhibitor GANT61 blocked DHCR24-induced mammosphere growth and increased mRNA levels of the Hedgehog regulated genes. Furthermore, expression of a constitutively activated mutant of Smoothened, a key hedgehog signal transducer, rescued the decreases in mammosphere growth and Hedgehog regulated gene expression induced by knockdown of DHCR24. These results indicate that DHCR24 promotes the growth of breast cancer stem-like cells in part through enhancing the Hedgehog signaling pathway. Our data suggest that cholesterol contribute to breast carcinogenesis by enhancing Hedgehog signaling and cancer stem-like cell populations. Enzymes including DHCR24 involved in cholesterol biosynthesis should be considered as potential treatment targets for breast cancer.
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Affiliation(s)
- Ting Qiu
- Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Jiawei Cao
- Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Wanzhou Chen
- Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Jieyi Wang
- Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Yaqi Wang
- Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Lingjie Zhao
- Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Min Liu
- Department of Orthopedics, Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Licai He
- Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Guang Wu
- Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Hongzhi Li
- Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Haihua Gu
- Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
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43
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Lee AG. Interfacial Binding Sites for Cholesterol on Kir, Kv, K 2P, and Related Potassium Channels. Biophys J 2020; 119:35-47. [PMID: 32553129 PMCID: PMC7335934 DOI: 10.1016/j.bpj.2020.05.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/06/2020] [Accepted: 05/27/2020] [Indexed: 12/30/2022] Open
Abstract
Inwardly rectifying, voltage-gated, two-pore domain, and related K+ channels are located in eukaryotic membranes rich in cholesterol. Here, molecular docking is used to detect specific binding sites ("hot spots") for cholesterol on K+ channels with characteristics that match those of known cholesterol binding sites. The transmembrane surfaces of all available high-resolution structures for K+ channels were swept for potential binding sites. Cholesterol poses were found to be located largely in hollows between protein ridges. A comparison between cholesterol poses and resolved phospholipids suggests that not all cholesterol molecules binding to the transmembrane surface of a K+ channel will result in displacement of a phospholipid molecule from the surface. Competition between cholesterol binding and binding of anionic phospholipids essential for activity could explain some of the effects of cholesterol on channel function.
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Affiliation(s)
- Anthony G Lee
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom.
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44
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Chua NK, Coates HW, Brown AJ. Squalene monooxygenase: a journey to the heart of cholesterol synthesis. Prog Lipid Res 2020; 79:101033. [DOI: 10.1016/j.plipres.2020.101033] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/21/2020] [Accepted: 04/24/2020] [Indexed: 02/07/2023]
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45
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The Glycosphingolipid GM3 Modulates Conformational Dynamics of the Glucagon Receptor. Biophys J 2020; 119:300-313. [PMID: 32610088 PMCID: PMC7376093 DOI: 10.1016/j.bpj.2020.06.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/27/2020] [Accepted: 06/09/2020] [Indexed: 12/12/2022] Open
Abstract
The extracellular domain (ECD) of class B1 G-protein-coupled receptors (GPCRs) plays a central role in signal transduction and is uniquely positioned to sense both the extracellular and membrane environments. Although recent studies suggest a role for membrane lipids in the modulation of class A and class F GPCR signaling properties, little is known about the effect of lipids on class B1 receptors. In this study, we employed multiscale molecular dynamics simulations to access the dynamics of the glucagon receptor (GCGR) ECD in the presence of native-like membrane bilayers. Simulations showed that the ECD could move about a hinge region formed by residues Q122–E126 to adopt both closed and open conformations relative to the transmembrane domain. ECD movements were modulated by binding of the glycosphingolipid GM3. These large-scale fluctuations in ECD conformation may affect the ligand binding and receptor activation properties. We also identify a unique phosphatidylinositol (4,5)-bisphosphate (PIP2) interaction profile near intracellular loop (ICL) 2/TM3 at the G-protein-coupling interface, suggesting a mechanism of engaging G-proteins that may have a distinct dependence on PIP2 compared with class A GPCRs. Given the structural conservation of class B1 GPCRs, the modulatory effects of GM3 and PIP2 on GCGR may be conserved across these receptors, offering new insights into potential therapeutic targeting.
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46
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Qi X, Li X. Mechanistic Insights into the Generation and Transduction of Hedgehog Signaling. Trends Biochem Sci 2020; 45:397-410. [PMID: 32311334 PMCID: PMC7174405 DOI: 10.1016/j.tibs.2020.01.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/19/2020] [Accepted: 01/23/2020] [Indexed: 12/23/2022]
Abstract
Cell differentiation and proliferation require Hedgehog (HH) signaling and aberrant HH signaling causes birth defects or cancers. In this signaling pathway, the N-terminally palmitoylated and C-terminally cholesterylated HH ligand is secreted into the extracellular space with help of the Dispatched-1 (DISP1) and Scube2 proteins. The Patched-1 (PTCH1) protein releases its inhibition of the oncoprotein Smoothened (SMO) after binding the HH ligand, triggering downstream signaling events. In this review, we discuss the recent structural and biochemical studies on four major components of the HH pathway: the HH ligand, DISP1, PTCH1, and SMO. This research provides mechanistic insights into how HH signaling is generated and transduced from the cell surface into the intercellular space and will aid in facilitating the treatment of HH-related diseases.
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Affiliation(s)
- Xiaofeng Qi
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Xiaochun Li
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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47
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Duncan AL, Corey RA, Sansom MSP. Defining how multiple lipid species interact with inward rectifier potassium (Kir2) channels. Proc Natl Acad Sci U S A 2020. [PMID: 32213593 DOI: 10.5281/zenodo.3634884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023] Open
Abstract
Protein-lipid interactions are a key element of the function of many integral membrane proteins. These potential interactions should be considered alongside the complexity and diversity of membrane lipid composition. Inward rectifier potassium channel (Kir) Kir2.2 has multiple interactions with plasma membrane lipids: Phosphatidylinositol (4, 5)-bisphosphate (PIP2) activates the channel; a secondary anionic lipid site has been identified, which augments the activation by PIP2; and cholesterol inhibits the channel. Molecular dynamics simulations are used to characterize in molecular detail the protein-lipid interactions of Kir2.2 in a model of the complex plasma membrane. Kir2.2 has been simulated with multiple, functionally important lipid species. From our simulations we show that PIP2 interacts most tightly at the crystallographic interaction sites, outcompeting other lipid species at this site. Phosphatidylserine (PS) interacts at the previously identified secondary anionic lipid interaction site, in a PIP2 concentration-dependent manner. There is interplay between these anionic lipids: PS interactions are diminished when PIP2 is not present in the membrane, underlining the need to consider multiple lipid species when investigating protein-lipid interactions.
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Affiliation(s)
- Anna L Duncan
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Robin A Corey
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
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48
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Defining how multiple lipid species interact with inward rectifier potassium (Kir2) channels. Proc Natl Acad Sci U S A 2020; 117:7803-7813. [PMID: 32213593 PMCID: PMC7149479 DOI: 10.1073/pnas.1918387117] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Ion channels form pores that allow for the selective transport of ions across cell membranes, generating electrical signals in response to a variety of signals. Inward rectifier potassium (Kir) channels in particular are regulated by direct interactions with the complex mixture of lipids that are present in eukaryotic cell membranes. However, the molecular details of these concurrent lipid interactions with Kir channels are not clear and difficult to access via experimental methods. Here, we simulate the Kir2.2 channel in a complex lipid mixture to explore how anionic phospholipids and cholesterol dynamically organize around the membrane protein. In particular we demonstrate a synergy between binding interactions of different anionic phospholipid species which are known to activate Kir channels. Protein–lipid interactions are a key element of the function of many integral membrane proteins. These potential interactions should be considered alongside the complexity and diversity of membrane lipid composition. Inward rectifier potassium channel (Kir) Kir2.2 has multiple interactions with plasma membrane lipids: Phosphatidylinositol (4, 5)-bisphosphate (PIP2) activates the channel; a secondary anionic lipid site has been identified, which augments the activation by PIP2; and cholesterol inhibits the channel. Molecular dynamics simulations are used to characterize in molecular detail the protein–lipid interactions of Kir2.2 in a model of the complex plasma membrane. Kir2.2 has been simulated with multiple, functionally important lipid species. From our simulations we show that PIP2 interacts most tightly at the crystallographic interaction sites, outcompeting other lipid species at this site. Phosphatidylserine (PS) interacts at the previously identified secondary anionic lipid interaction site, in a PIP2 concentration-dependent manner. There is interplay between these anionic lipids: PS interactions are diminished when PIP2 is not present in the membrane, underlining the need to consider multiple lipid species when investigating protein–lipid interactions.
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49
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Centi A, Dutta A, Parekh SH, Bereau T. Inserting Small Molecules across Membrane Mixtures: Insight from the Potential of Mean Force. Biophys J 2020; 118:1321-1332. [PMID: 32075746 DOI: 10.1016/j.bpj.2020.01.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/05/2020] [Accepted: 01/27/2020] [Indexed: 11/29/2022] Open
Abstract
Small solutes have been shown to alter the lateral organization of cell membranes and reconstituted phospholipid bilayers; however, the mechanisms by which these changes happen are still largely unknown. Traditionally, both experiment and simulation studies have been restricted to testing only a few compounds at a time, failing to identify general molecular descriptors or chemical properties that would allow extrapolating beyond the subset of considered solutes. In this work, we probe the competing energetics of inserting a solute in different membrane environments by means of the potential of mean force. We show that these calculations can be used as a computationally efficient proxy to establish whether a solute will stabilize or destabilize domain phase separation. Combined with umbrella-sampling simulations and coarse-grained molecular dynamics simulations, we are able to screen solutes across a wide range of chemistries and polarities. Our results indicate that for the system under consideration, preferential partitioning and therefore effectiveness in altering membrane phase separation are strictly linked to the location of insertion in the bilayer (i.e., midplane or interface). Our approach represents a fast and simple tool for obtaining structural and thermodynamic insight into the partitioning of small molecules between lipid domains and its relation to phase separation, ultimately providing a platform for identifying the key determinants of this process.
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Affiliation(s)
- Alessia Centi
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Arghya Dutta
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Sapun H Parekh
- Max Planck Institute for Polymer Research, Mainz, Germany; Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas
| | - Tristan Bereau
- Max Planck Institute for Polymer Research, Mainz, Germany.
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50
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Sejdiu BI, Tieleman DP. Lipid-Protein Interactions Are a Unique Property and Defining Feature of G Protein-Coupled Receptors. Biophys J 2020; 118:1887-1900. [PMID: 32272057 DOI: 10.1016/j.bpj.2020.03.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/06/2020] [Accepted: 03/11/2020] [Indexed: 12/19/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are membrane-bound proteins that depend on their lipid environment to carry out their physiological function. Combined efforts from many theoretical and experimental studies on the lipid-protein interaction profile of several GPCRs hint at an intricate relationship of these receptors with their surrounding membrane environment, with several lipids emerging as particularly important. Using coarse-grained molecular dynamics simulations, we explore the lipid-protein interaction profiles of 28 different GPCRs, spanning different levels of classification and conformational states and totaling to 1 ms of simulation time. We find a close relationship with lipids for all GPCRs simulated, in particular, cholesterol and phosphatidylinositol phosphate (PIP) lipids, but the number, location, and estimated strength of these interactions is dependent on the specific GPCR as well as its conformational state. Although both cholesterol and PIP lipids bind specifically to GPCRs, they utilize distinct mechanisms. Interactions with PIP lipids are mediated by charge-charge interactions with intracellular loop residues and stabilized by one or both of the transmembrane helices linked by the loop. Interactions with cholesterol, on the other hand, are mediated by a hydrophobic environment, usually made up of residues from more than one helix, capable of accommodating its ring structure and stabilized by interactions with aromatic and charged/polar residues. Cholesterol binding to GPCRs occurs in a small number of sites, some of which (like the binding site on the extracellular side of transmembrane 6/7) are shared among many class A GPCRs. Combined with a thorough investigation of the local membrane structure, our results provide a detailed picture of GPCR-lipid interactions. Additionally, we provide an accompanying website to interactively explore the lipid-protein interaction profile of all GPCRs simulated to facilitate analysis and comparison of our data.
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Affiliation(s)
- Besian I Sejdiu
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
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