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Li S, Liu T, Li K, Bai X, Xi K, Chai X, Mi L, Li J. Spectrins and human diseases. Transl Res 2022; 243:78-88. [PMID: 34979321 DOI: 10.1016/j.trsl.2021.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/27/2021] [Accepted: 12/28/2021] [Indexed: 11/18/2022]
Abstract
Spectrin, as one of the major components of a plasma membrane-associated cytoskeleton, is a cytoskeletal protein composed of the modular structure of α and β subunits. The spectrin-based skeleton is essential for preserving the integrity and mechanical characteristics of the cell membrane. Moreover, spectrin regulates a variety of cell processes including cell apoptosis, cell adhesion, cell spreading, and cell cycle. Dysfunction of spectrins is implicated in various human diseases including hemolytic anemia, neurodegenerative diseases, ataxia, heart diseases, and cancers. Here, we briefly discuss spectrins function as well as the clinical manifestations and currently known molecular mechanisms of human diseases related to spectrins, highlighting that strategies for targeting regulation of spectrins function may provide new avenues for therapeutic intervention for these diseases.
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Affiliation(s)
- Shan Li
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Ting Liu
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Kejing Li
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Xinyi Bai
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Kewang Xi
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Xiaojing Chai
- Central Laboratory, The First Hospital of Lanzhou University, Gansu, China
| | - Leyuan Mi
- The First School of Clinical Medicine, Lanzhou University, Gansu, China; Clinical Laboratory Center, Gansu Provincial Maternity and Child Care Hospital, Gansu, China
| | - Juan Li
- Gansu Key Laboratory of Genetic Study of Hematopathy, The First Hospital of Lanzhou University, Gansu, China; Central Laboratory, The First Hospital of Lanzhou University, Gansu, China.
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2
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Wonkam A, Adadey SM, Schrauwen I, Aboagye ET, Wonkam-Tingang E, Esoh K, Popel K, Manyisa N, Jonas M, deKock C, Nembaware V, Cornejo Sanchez DM, Bharadwaj T, Nasir A, Everard JL, Kadlubowska MK, Nouel-Saied LM, Acharya A, Quaye O, Amedofu GK, Awandare GA, Leal SM. Exome sequencing of families from Ghana reveals known and candidate hearing impairment genes. Commun Biol 2022; 5:369. [PMID: 35440622 PMCID: PMC9019055 DOI: 10.1038/s42003-022-03326-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 03/25/2022] [Indexed: 12/15/2022] Open
Abstract
We investigated hearing impairment (HI) in 51 families from Ghana with at least two affected members that were negative for GJB2 pathogenic variants. DNA samples from 184 family members underwent whole-exome sequencing (WES). Variants were found in 14 known non-syndromic HI (NSHI) genes [26/51 (51.0%) families], five genes that can underlie either syndromic HI or NSHI [13/51 (25.5%)], and one syndromic HI gene [1/51 (2.0%)]. Variants in CDH23 and MYO15A contributed the most to HI [31.4% (16/51 families)]. For DSPP, an autosomal recessive mode of inheritance was detected. Post-lingual expression was observed for a family segregating a MARVELD2 variant. To our knowledge, seven novel candidate HI genes were identified (13.7%), with six associated with NSHI (INPP4B, CCDC141, MYO19, DNAH11, POTEI, and SOX9); and one (PAX8) with Waardenburg syndrome. MYO19 and DNAH11 were replicated in unrelated Ghanaian probands. Six of the novel genes were expressed in mouse inner ear. It is known that Pax8-/- mice do not respond to sound, and depletion of Sox9 resulted in defective vestibular structures and abnormal utricle development. Most variants (48/60; 80.0%) have not previously been associated with HI. Identifying seven candidate genes in this study emphasizes the potential of novel HI genes discovery in Africa.
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Affiliation(s)
- Ambroise Wonkam
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa.
- McKusick-Nathans Institute and Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Samuel Mawuli Adadey
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Elvis Twumasi Aboagye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Edmond Wonkam-Tingang
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Kevin Esoh
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Kalinka Popel
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Noluthando Manyisa
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Mario Jonas
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Carmen deKock
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Victoria Nembaware
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town, 7925, South Africa
| | - Diana M Cornejo Sanchez
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Thashi Bharadwaj
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Abdul Nasir
- Department of Molecular Science and Technology, Ajou University, Suwon-si, Republic of Korea
| | - Jenna L Everard
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Magda K Kadlubowska
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Liz M Nouel-Saied
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Anushree Acharya
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA
| | - Osbourne Quaye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Geoffrey K Amedofu
- Department of Eye, Ear, Nose, and Throat, School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, LG 54, Ghana
| | - Suzanne M Leal
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Centre, New York, NY, 10032, USA.
- Taub Institute for Alzheimer's Disease and the Aging Brain, Columbia University Medical Centre, New York, NY, 10032, USA.
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3
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Creighton BA, Afriyie S, Ajit D, Casingal CR, Voos KM, Reger J, Burch AM, Dyne E, Bay J, Huang JK, Anton ES, Fu MM, Lorenzo DN. Giant ankyrin-B mediates transduction of axon guidance and collateral branch pruning factor sema 3A. eLife 2021; 10:69815. [PMID: 34812142 PMCID: PMC8610419 DOI: 10.7554/elife.69815] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 11/04/2021] [Indexed: 01/19/2023] Open
Abstract
Variants in the high confident autism spectrum disorder (ASD) gene ANK2 target both ubiquitously expressed 220 kDa ankyrin-B and neurospecific 440 kDa ankyrin-B (AnkB440) isoforms. Previous work showed that knock-in mice expressing an ASD-linked Ank2 variant yielding a truncated AnkB440 product exhibit ectopic brain connectivity and behavioral abnormalities. Expression of this variant or loss of AnkB440 caused axonal hyperbranching in vitro, which implicated AnkB440 microtubule bundling activity in suppressing collateral branch formation. Leveraging multiple mouse models, cellular assays, and live microscopy, we show that AnkB440 also modulates axon collateral branching stochastically by reducing the number of F-actin-rich branch initiation points. Additionally, we show that AnkB440 enables growth cone (GC) collapse in response to chemorepellent factor semaphorin 3 A (Sema 3 A) by stabilizing its receptor complex L1 cell adhesion molecule/neuropilin-1. ASD-linked ANK2 variants failed to rescue Sema 3A-induced GC collapse. We propose that impaired response to repellent cues due to AnkB440 deficits leads to axonal targeting and branch pruning defects and may contribute to the pathogenicity of ANK2 variants.
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Affiliation(s)
- Blake A Creighton
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Simone Afriyie
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Deepa Ajit
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Cristine R Casingal
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Kayleigh M Voos
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Joan Reger
- National Institute of Neurological Disorders and Stroke (NINDS), Bethesda, United States.,Department of Biology and Center for Cell Reprogramming, Georgetown University, Washington, United States
| | - April M Burch
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Eric Dyne
- National Institute of Neurological Disorders and Stroke (NINDS), Bethesda, United States
| | - Julia Bay
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Jeffrey K Huang
- Department of Biology and Center for Cell Reprogramming, Georgetown University, Washington, United States
| | - E S Anton
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Meng-Meng Fu
- National Institute of Neurological Disorders and Stroke (NINDS), Bethesda, United States
| | - Damaris N Lorenzo
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Carolina Institute for Developmental Disabilities, Chapel Hill, United States
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4
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Cousin MA, Creighton BA, Breau KA, Spillmann RC, Torti E, Dontu S, Tripathi S, Ajit D, Edwards RJ, Afriyie S, Bay JC, Harper KM, Beltran AA, Munoz LJ, Falcon Rodriguez L, Stankewich MC, Person RE, Si Y, Normand EA, Blevins A, May AS, Bier L, Aggarwal V, Mancini GMS, van Slegtenhorst MA, Cremer K, Becker J, Engels H, Aretz S, MacKenzie JJ, Brilstra E, van Gassen KLI, van Jaarsveld RH, Oegema R, Parsons GM, Mark P, Helbig I, McKeown SE, Stratton R, Cogne B, Isidor B, Cacheiro P, Smedley D, Firth HV, Bierhals T, Kloth K, Weiss D, Fairley C, Shieh JT, Kritzer A, Jayakar P, Kurtz-Nelson E, Bernier RA, Wang T, Eichler EE, van de Laar IMBH, McConkie-Rosell A, McDonald MT, Kemppainen J, Lanpher BC, Schultz-Rogers LE, Gunderson LB, Pichurin PN, Yoon G, Zech M, Jech R, Winkelmann J, Beltran AS, Zimmermann MT, Temple B, Moy SS, Klee EW, Tan QKG, Lorenzo DN. Pathogenic SPTBN1 variants cause an autosomal dominant neurodevelopmental syndrome. Nat Genet 2021; 53:1006-1021. [PMID: 34211179 PMCID: PMC8273149 DOI: 10.1038/s41588-021-00886-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 05/14/2021] [Indexed: 12/22/2022]
Abstract
SPTBN1 encodes βII-spectrin, the ubiquitously expressed β-spectrin that forms micrometer-scale networks associated with plasma membranes. Mice deficient in neuronal βII-spectrin have defects in cortical organization, developmental delay and behavioral deficiencies. These phenotypes, while less severe, are observed in haploinsufficient animals, suggesting that individuals carrying heterozygous SPTBN1 variants may also show measurable compromise of neural development and function. Here we identify heterozygous SPTBN1 variants in 29 individuals with developmental, language and motor delays; mild to severe intellectual disability; autistic features; seizures; behavioral and movement abnormalities; hypotonia; and variable dysmorphic facial features. We show that these SPTBN1 variants lead to effects that affect βII-spectrin stability, disrupt binding to key molecular partners, and disturb cytoskeleton organization and dynamics. Our studies define SPTBN1 variants as the genetic basis of a neurodevelopmental syndrome, expand the set of spectrinopathies affecting the brain and underscore the critical role of βII-spectrin in the central nervous system.
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Affiliation(s)
- Margot A Cousin
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA.
| | - Blake A Creighton
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Keith A Breau
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Rebecca C Spillmann
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | | | - Sruthi Dontu
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Swarnendu Tripathi
- Bioinformatics Research and Development Laboratory, Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Deepa Ajit
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Reginald J Edwards
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Simone Afriyie
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Julia C Bay
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kathryn M Harper
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Alvaro A Beltran
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Human Pluripotent Stem Cell Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Lorena J Munoz
- Human Pluripotent Stem Cell Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Liset Falcon Rodriguez
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | | | - Yue Si
- GeneDx, Gaithersburg, MD, USA
| | | | | | - Alison S May
- Department of Neurology, Columbia University, New York, NY, USA
| | - Louise Bier
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
| | - Vimla Aggarwal
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
- Laboratory of Personalized Genomic Medicine, Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Grazia M S Mancini
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | | | - Kirsten Cremer
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Jessica Becker
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Hartmut Engels
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Stefan Aretz
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | | | - Eva Brilstra
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Koen L I van Gassen
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | | | - Renske Oegema
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | | | - Paul Mark
- Spectrum Health Medical Genetics, Grand Rapids, MI, USA
| | - Ingo Helbig
- Division of Neurology, Departments of Neurology and Pediatrics, The Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Sarah E McKeown
- Division of Neurology, Departments of Neurology and Pediatrics, The Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Robert Stratton
- Genetics, Driscoll Children's Hospital, Corpus Christi, TX, USA
| | - Benjamin Cogne
- Service de Génétique Médicale, CHU Nantes, Nantes, France
- Université de Nantes, CNRS, INSERM, L'Institut du Thorax, Nantes, France
| | - Bertrand Isidor
- Service de Génétique Médicale, CHU Nantes, Nantes, France
- Université de Nantes, CNRS, INSERM, L'Institut du Thorax, Nantes, France
| | - Pilar Cacheiro
- William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Damian Smedley
- William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Helen V Firth
- Department of Clinical Genetics, Cambridge University Hospitals, Cambridge, UK
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katja Kloth
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Deike Weiss
- Neuropediatrics, Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Cecilia Fairley
- Division of Medical Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
| | - Joseph T Shieh
- Division of Medical Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Amy Kritzer
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | | | - Evangeline Kurtz-Nelson
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - Raphael A Bernier
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - Tianyun Wang
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Ingrid M B H van de Laar
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Allyn McConkie-Rosell
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | - Marie T McDonald
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | - Jennifer Kemppainen
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Brendan C Lanpher
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Laura E Schultz-Rogers
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | - Lauren B Gunderson
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Pavel N Pichurin
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Grace Yoon
- Divisions of Clinical/Metabolic Genetics and Neurology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
| | - Robert Jech
- Department of Neurology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Juliane Winkelmann
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Lehrstuhl für Neurogenetik, Technische Universität München, Munich, Germany
- Munich Cluster for Systems Neurology, SyNergy, Munich, Germany
| | - Adriana S Beltran
- Human Pluripotent Stem Cell Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Michael T Zimmermann
- Bioinformatics Research and Development Laboratory, Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA
- Clinical and Translational Sciences Institute, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Brenda Temple
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Sheryl S Moy
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Queenie K-G Tan
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | - Damaris N Lorenzo
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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5
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Rosenfeld JA, Xiao R, Bekheirnia MR, Kanani F, Parker MJ, Koenig MK, van Haeringen A, Ruivenkamp C, Rosmaninho-Salgado J, Almeida PM, Sá J, Basto JP, Palen E, Oetjens KF, Burrage LC, Xia F, Liu P, Eng CM, Yang Y, Posey JE, Lee BH. Heterozygous variants in SPTBN1 cause intellectual disability and autism. Am J Med Genet A 2021; 185:2037-2045. [PMID: 33847457 PMCID: PMC11182376 DOI: 10.1002/ajmg.a.62201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 02/26/2021] [Accepted: 03/24/2021] [Indexed: 11/09/2022]
Abstract
Spectrins are common components of cytoskeletons, binding to cytoskeletal elements and the plasma membrane, allowing proper localization of essential membrane proteins, signal transduction, and cellular scaffolding. Spectrins are assembled from α and β subunits, encoded by SPTA1 and SPTAN1 (α) and SPTB, SPTBN1, SPTBN2, SPTBN4, and SPTBN5 (β). Pathogenic variants in various spectrin genes are associated with erythroid cell disorders (SPTA1, SPTB) and neurologic disorders (SPTAN1, SPTBN2, and SPTBN4), but no phenotypes have been definitively associated with variants in SPTBN1 or SPTBN5. Through exome sequencing and case matching, we identified seven unrelated individuals with heterozygous SPTBN1 variants: two with de novo missense variants and five with predicted loss-of-function variants (found to be de novo in two, while one was inherited from a mother with a history of learning disabilities). Common features include global developmental delays, intellectual disability, and behavioral disturbances. Autistic features (4/6) and epilepsy (2/7) or abnormal electroencephalogram without overt seizures (1/7) were present in a subset. Identification of loss-of-function variants suggests a haploinsufficiency mechanism, but additional functional studies are required to fully elucidate disease pathogenesis. Our findings support the essential roles of SPTBN1 in human neurodevelopment and expand the knowledge of human spectrinopathy disorders.
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Affiliation(s)
- Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Rui Xiao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Mir Reza Bekheirnia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Renal Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Farah Kanani
- Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - Michael J. Parker
- The Wellcome Centre for Ethics and Humanities/Ethox Centre, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Mary K. Koenig
- Department of Pediatrics, University of Texas Health Science Center, Houston, Texas, 77030, USA
| | - Arie van Haeringen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Claudia Ruivenkamp
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Joana Rosmaninho-Salgado
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Pedro M. Almeida
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Joaquim Sá
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Jorge Pinto Basto
- Molecular Diagnostics and Clinical Genomics, CGC Genetics, Porto, Portugal
| | - Emily Palen
- Autism & Developmental Medicine Institute, Geisinger, Danville, Pennsylvania, 17822, USA
| | - Kathryn F. Oetjens
- Autism & Developmental Medicine Institute, Geisinger, Danville, Pennsylvania, 17822, USA
| | - Lindsay C. Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Texas Children’s Hospital, Houston, Texas, 77030, USA
| | - Fan Xia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Christine M. Eng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | | | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Jennifer E. Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Brendan H. Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
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6
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Yang P, Yang Y, Sun P, Tian Y, Gao F, Wang C, Zong T, Li M, Zhang Y, Yu T, Jiang Z. βII spectrin (SPTBN1): biological function and clinical potential in cancer and other diseases. Int J Biol Sci 2021; 17:32-49. [PMID: 33390831 PMCID: PMC7757025 DOI: 10.7150/ijbs.52375] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 10/22/2020] [Indexed: 12/16/2022] Open
Abstract
βII spectrin, the most common isoform of non-erythrocyte spectrin, is a cytoskeleton protein present in all nucleated cells. Interestingly, βII spectrin is essential for the development of various organs such as nerve, epithelium, inner ear, liver and heart. The functions of βII spectrin include not only establishing and maintaining the cell structure but also regulating a variety of cellular functions, such as cell apoptosis, cell adhesion, cell spreading and cell cycle regulation. Notably, βII spectrin dysfunction is associated with embryonic lethality and the DNA damage response. More recently, the detection of altered βII spectrin expression in tumors indicated that βII spectrin might be involved in the development and progression of cancer. Its mutations and disorders could result in developmental disabilities and various diseases. The versatile roles of βII spectrin in disease have been examined in an increasing number of studies; nonetheless, the exact mechanisms of βII spectrin are still poorly understood. Thus, we summarize the structural features and biological roles of βII spectrin and discuss its molecular mechanisms and functions in development, homeostasis, regeneration and differentiation. This review highlight the potential effects of βII spectrin dysfunction in cancer and other diseases, outstanding questions for the future investigation of therapeutic targets. The investigation of the regulatory mechanism of βII spectrin signal inactivation and recovery may bring hope for future therapy of related diseases.
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Affiliation(s)
- Panyu Yang
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Yanyan Yang
- Department of Immunology, Basic Medicine School, Qingdao University, No. 308 Ningxia Road, Qingdao 266071, People's Republic of China
| | - Pin Sun
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Yu Tian
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Fang Gao
- Department of Physical Medicine and Rehabiliation, The Affiliated Hospital of Qingdao University, Qingdao, Shandong Province, China
| | - Chen Wang
- Department of Physical Medicine and Rehabiliation, The Affiliated Hospital of Qingdao University, Qingdao, Shandong Province, China
| | - Tingyu Zong
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Min Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, No. 38 Dengzhou Road, Qingdao 266021, People's Republic of China
| | - Ying Zhang
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Tao Yu
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, Qingdao 266000, China.,Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, No. 38 Dengzhou Road, Qingdao 266021, People's Republic of China
| | - Zhirong Jiang
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, Qingdao 266000, China
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7
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Barbarino F, Wäschenbach L, Cavalho-Lemos V, Dillenberger M, Becker K, Gohlke H, Cortese-Krott MM. Targeting spectrin redox switches to regulate the mechanoproperties of red blood cells. Biol Chem 2020; 402:317-331. [PMID: 33544503 DOI: 10.1515/hsz-2020-0293] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/17/2020] [Indexed: 12/16/2022]
Abstract
The mechanical properties of red blood cells (RBCs) are fundamental for their physiological role as gas transporters. RBC flexibility and elasticity allow them to survive the hemodynamic changes in the different regions of the vascular tree, to dynamically contribute to the flow thereby decreasing vascular resistance, and to deform during the passage through narrower vessels. RBC mechanoproperties are conferred mainly by the structural characteristics of their cytoskeleton, which consists predominantly of a spectrin scaffold connected to the membrane via nodes of actin, ankyrin and adducin. Changes in redox state and treatment with thiol-targeting molecules decrease the deformability of RBCs and affect the structure and stability of the spectrin cytoskeleton, indicating that the spectrin cytoskeleton may contain redox switches. In this perspective review, we revise current knowledge about the structural and functional characterization of spectrin cysteine redox switches and discuss the current lines of research aiming to understand the role of redox regulation on RBC mechanical properties. These studies may provide novel functional targets to modulate RBC function, blood viscosity and flow, and tissue perfusion in disease conditions.
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Affiliation(s)
- Frederik Barbarino
- Myocardial Infarction Research Laboratory, Department of Cardiology, Pulmonology, and Vascular Medicine, Medical Faculty, Heinrich Heine University, Postfach 128, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
| | - Lucas Wäschenbach
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
| | - Virginia Cavalho-Lemos
- Myocardial Infarction Research Laboratory, Department of Cardiology, Pulmonology, and Vascular Medicine, Medical Faculty, Heinrich Heine University, Postfach 128, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
| | - Melissa Dillenberger
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, D-35392, Giessen, Germany
| | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, D-35392, Giessen, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
- John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
| | - Miriam M Cortese-Krott
- Myocardial Infarction Research Laboratory, Department of Cardiology, Pulmonology, and Vascular Medicine, Medical Faculty, Heinrich Heine University, Postfach 128, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
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8
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Complementary mesoscale dynamics of spectrin and acto-myosin shape membrane territories during mechanoresponse. Nat Commun 2020; 11:5108. [PMID: 33037189 PMCID: PMC7547731 DOI: 10.1038/s41467-020-18825-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 09/11/2020] [Indexed: 11/08/2022] Open
Abstract
The spectrin-based membrane skeleton is a major component of the cell cortex. While expressed by all metazoans, its dynamic interactions with the other cortex components, including the plasma membrane or the acto-myosin cytoskeleton, are poorly understood. Here, we investigate how spectrin re-organizes spatially and dynamically under the membrane during changes in cell mechanics. We find spectrin and acto-myosin to be spatially distinct but cooperating during mechanical challenges, such as cell adhesion and contraction, or compression, stretch and osmolarity fluctuations, creating a cohesive cortex supporting the plasma membrane. Actin territories control protrusions and contractile structures while spectrin territories concentrate in retractile zones and low-actin density/inter-contractile regions, acting as a fence that organize membrane trafficking events. We unveil here the existence of a dynamic interplay between acto-myosin and spectrin necessary to support a mesoscale organization of the lipid bilayer into spatially-confined cortical territories during cell mechanoresponse.
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9
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Barbosa S, Greville-Heygate S, Bonnet M, Godwin A, Fagotto-Kaufmann C, Kajava AV, Laouteouet D, Mawby R, Wai HA, Dingemans AJ, Hehir-Kwa J, Willems M, Capri Y, Mehta SG, Cox H, Goudie D, Vansenne F, Turnpenny P, Vincent M, Cogné B, Lesca G, Hertecant J, Rodriguez D, Keren B, Burglen L, Gérard M, Putoux A, Cantagrel V, Siquier-Pernet K, Rio M, Banka S, Sarkar A, Steeves M, Parker M, Clement E, Moutton S, Tran Mau-Them F, Piton A, de Vries BB, Guille M, Debant A, Schmidt S, Baralle D, Baralle D. Opposite Modulation of RAC1 by Mutations in TRIO Is Associated with Distinct, Domain-Specific Neurodevelopmental Disorders. Am J Hum Genet 2020; 106:338-355. [PMID: 32109419 PMCID: PMC7058823 DOI: 10.1016/j.ajhg.2020.01.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/27/2020] [Indexed: 12/13/2022] Open
Abstract
The Rho-guanine nucleotide exchange factor (RhoGEF) TRIO acts as a key regulator of neuronal migration, axonal outgrowth, axon guidance, and synaptogenesis by activating the GTPase RAC1 and modulating actin cytoskeleton remodeling. Pathogenic variants in TRIO are associated with neurodevelopmental diseases, including intellectual disability (ID) and autism spectrum disorders (ASD). Here, we report the largest international cohort of 24 individuals with confirmed pathogenic missense or nonsense variants in TRIO. The nonsense mutations are spread along the TRIO sequence, and affected individuals show variable neurodevelopmental phenotypes. In contrast, missense variants cluster into two mutational hotspots in the TRIO sequence, one in the seventh spectrin repeat and one in the RAC1-activating GEFD1. Although all individuals in this cohort present with developmental delay and a neuro-behavioral phenotype, individuals with a pathogenic variant in the seventh spectrin repeat have a more severe ID associated with macrocephaly than do most individuals with GEFD1 variants, who display milder ID and microcephaly. Functional studies show that the spectrin and GEFD1 variants cause a TRIO-mediated hyper- or hypo-activation of RAC1, respectively, and we observe a striking correlation between RAC1 activation levels and the head size of the affected individuals. In addition, truncations in TRIO GEFD1 in the vertebrate model X. tropicalis induce defects that are concordant with the human phenotype. This work demonstrates distinct clinical and molecular disorders clustering in the GEFD1 and seventh spectrin repeat domains and highlights the importance of tight control of TRIO-RAC1 signaling in neuronal development.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Diana Baralle
- Wessex Clinical Genetics, University Hospital Southampton National Health Service Foundation Trust, Southampton SO16 5YA, UK; Human Development and Health, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
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10
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Mechanical Unfolding of Spectrin Repeats Induces Water-Molecule Ordering. Biophys J 2020; 118:1076-1089. [PMID: 32027822 DOI: 10.1016/j.bpj.2020.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 12/24/2019] [Accepted: 01/02/2020] [Indexed: 02/07/2023] Open
Abstract
Mechanical processes are involved at many stages of the development of living cells, and often external forces applied to a biomolecule result in its unfolding. Although our knowledge of the unfolding mechanisms and the magnitude of the forces involved has evolved, the role that water molecules play in the mechanical unfolding of biomolecules has not yet been fully elucidated. To this end, we investigated with steered molecular dynamics simulations the mechanical unfolding of dystrophin's spectrin repeat 1 and related the changes in the protein's structure to the ordering of the surrounding water molecules. Our results indicate that upon mechanically induced unfolding of the protein, the solvent molecules become more ordered and increase their average number of hydrogen bonds. In addition, the unfolded structures originating from mechanical pulling expose an increasing amount of the hydrophobic residues to the solvent molecules, and the uncoiled regions adapt a convex surface with a small radius of curvature. As a result, the solvent molecules reorganize around the protein's small protrusions in structurally ordered waters that are characteristic of the so-called "small-molecule regime," which allows water to maintain a high hydrogen bond count at the expense of an increased structural order. We also determined that the response of water to structural changes in the protein is localized to the specific regions of the protein that undergo unfolding. These results indicate that water plays an important role in the mechanically induced unfolding of biomolecules. Our findings may prove relevant to the ever-growing interest in understanding macromolecular crowding in living cells and their effects on protein folding, and suggest that the hydration layer may be exploited as a means for short-range allosteric communication.
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11
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Goodman SR, Johnson D, Youngentob SL, Kakhniashvili D. The Spectrinome: The Interactome of a Scaffold Protein Creating Nuclear and Cytoplasmic Connectivity and Function. Exp Biol Med (Maywood) 2019; 244:1273-1302. [PMID: 31483159 DOI: 10.1177/1535370219867269] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We provide a review of Spectrin isoform function in the cytoplasm, the nucleus, the cell surface, and in intracellular signaling. We then discuss the importance of Spectrin’s E2/E3 chimeric ubiquitin conjugating and ligating activity in maintaining cellular homeostasis. Finally we present spectrin isoform subunit specific human diseases. We have created the Spectrinome, from the Human Proteome, Human Reactome and Human Atlas data and demonstrated how it can be a useful tool in visualizing and understanding spectrins myriad of cellular functions.Impact statementSpectrin was for the first 12 years after its discovery thought to be found only in erythrocytes. In 1981, Goodman and colleagues1found that spectrin-like molecules were ubiquitously found in non-erythroid cells leading to a great multitude of publications over the next thirty eight years. The discovery of multiple spectrin isoforms found associated with every cellular compartment, and representing 2-3% of cellular protein, has brought us to today’s understanding that spectrin is a scaffolding protein, with its own E2/E3 chimeric ubiquitin conjugating ligating activity that is involved in virtually every cellular function. We cover the history, localized functions of spectrin isoforms, human diseases caused by mutations, and provide the spectrinome: a useful tool for understanding the myriad of functions for one of the most important proteins in all eukaryotic cells.
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Affiliation(s)
- Steven R Goodman
- Department of Pediatrics, Memphis Institute of Regenerative Medicine, The University of Tennessee Health Science Center, Memphis, TN 38103
| | - Daniel Johnson
- Department of Pediatrics, Memphis Institute of Regenerative Medicine, The University of Tennessee Health Science Center, Memphis, TN 38103
| | - Steven L Youngentob
- Department of Anatomy and Neurobiology, Memphis Institute of Regenerative Medicine, The University of Tennessee Health Science Center, Memphis, TN 38103
| | - David Kakhniashvili
- Department of Pediatrics, Memphis Institute of Regenerative Medicine, The University of Tennessee Health Science Center, Memphis, TN 38103
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12
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Berger SL, Leo-Macias A, Yuen S, Khatri L, Pfennig S, Zhang Y, Agullo-Pascual E, Caillol G, Zhu MS, Rothenberg E, Melendez-Vasquez CV, Delmar M, Leterrier C, Salzer JL. Localized Myosin II Activity Regulates Assembly and Plasticity of the Axon Initial Segment. Neuron 2018; 97:555-570.e6. [PMID: 29395909 PMCID: PMC5805619 DOI: 10.1016/j.neuron.2017.12.039] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 08/24/2017] [Accepted: 12/22/2017] [Indexed: 01/08/2023]
Abstract
The axon initial segment (AIS) is the site of action potential generation and a locus of activity-dependent homeostatic plasticity. A multimeric complex of sodium channels, linked via a cytoskeletal scaffold of ankyrin G and beta IV spectrin to submembranous actin rings, mediates these functions. The mechanisms that specify the AIS complex to the proximal axon and underlie its plasticity remain poorly understood. Here we show phosphorylated myosin light chain (pMLC), an activator of contractile myosin II, is highly enriched in the assembling and mature AIS, where it associates with actin rings. MLC phosphorylation and myosin II contractile activity are required for AIS assembly, and they regulate the distribution of AIS components along the axon. pMLC is rapidly lost during depolarization, destabilizing actin and thereby providing a mechanism for activity-dependent structural plasticity of the AIS. Together, these results identify pMLC/myosin II activity as a common link between AIS assembly and plasticity.
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Affiliation(s)
- Stephen L Berger
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | | | - Stephanie Yuen
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Latika Khatri
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Sylvia Pfennig
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Yanqing Zhang
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | | | - Ghislaine Caillol
- Aix Marseille Université, CNRS, INP UMR7051, 13344 Cedex 15, Marseille, France
| | - Min-Sheng Zhu
- Model Animal Research Center and MOE Key Laboratory of Model Animal and Disease Study, Nanjing University, Nanjing 210061, China
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
| | - Carmen V Melendez-Vasquez
- Department of Biological Sciences, Hunter College, New York, NY 10065, USA; Department of Molecular, Cellular, and Developmental Biology, The Graduate Center, The City University of New York, NY 10016, USA
| | - Mario Delmar
- Division of Cardiology, NYU School of Medicine, New York, NY 10016, USA
| | | | - James L Salzer
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
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13
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Lu Y, Zhou D, King R, Zhu S, Simpson CL, Jones BC, Zhang W, Geisert EE, Lu L. The genetic dissection of Myo7a gene expression in the retinas of BXD mice. Mol Vis 2018; 24:115-126. [PMID: 29430167 PMCID: PMC5802760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 01/31/2018] [Indexed: 11/16/2022] Open
Abstract
Purpose Usher syndrome (US) is characterized by a loss of vision due to retinitis pigmentosa (RP) and deafness. US has three clinical subtypes, but even within each subtype, the severity varies. Myosin VIIA, coded by Myo7a, has been identified as one of the causal genes of US. This study aims to identify pathways and other genes through which Myo7a interacts to affect the presentation of US symptoms. Methods In this study, we used the retinal tissue of BXD recombinant inbred (RI) mice to examine the expression of Myo7a and perform genetic mapping. Expression quantitative trait locus (eQTL), single nucleotide polymorphism (SNP), and gene correlation analysis were performed using GeneNetwork. Gene set enrichment analysis was performed using WebGestalt, and gene network construction was performed using the Gene Cohesion Analysis Tool. Results We found Myo7a to be cis-regulated, with varied levels of expression across BXD strains. Here, we propose a genetic network with 40 genes whose expression is highly correlated with Myo7a. Among these genes, six have been linked to retinal diseases, three to deafness, and five share a transcription factor with Myo7a. Gene ontology and pathway analysis revealed a strong connection among ion channel activity, Myo7a, and US. Conclusions Although Myo7a is a causal gene of US type I, this gene works with many other genes and pathways to affect the severity of US. Many of the genes found in the genetic network, pathways, and gene ontology categories of Myo7a are related to either deafness or blindness. Further investigation is needed to examine the specific relationships between these genes, which may assist in the treatment of US.
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Affiliation(s)
- Ye Lu
- Department of Ophthalmology, The First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou, China
| | - Diana Zhou
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Rebecca King
- Department of Ophthalmology and Emory Eye Center, Emory University, Atlanta, GA
| | - Shuang Zhu
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, TX
| | - Claire L. Simpson
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Byron C. Jones
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Wenbo Zhang
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, TX
| | - Eldon E. Geisert
- Department of Ophthalmology and Emory Eye Center, Emory University, Atlanta, GA
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
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14
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Derbala MH, Guo AS, Mohler PJ, Smith SA. The role of βII spectrin in cardiac health and disease. Life Sci 2017; 192:278-285. [PMID: 29128512 DOI: 10.1016/j.lfs.2017.11.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 11/02/2017] [Accepted: 11/07/2017] [Indexed: 02/07/2023]
Abstract
Spectrins are large, flexible proteins comprised of α-β dimers that are connected head-to-head to form the canonical heterotetrameric spectrin structure. Spectrins were initially believed to be exclusively found in human erythrocytic membrane and are highly conserved among different species. βII spectrin, the most common isoform of non-erythrocytic spectrin, is found in all nucleated cells and forms larger macromolecular complexes with ankyrins and actins. Not only is βII spectrin a central cytoskeletal scaffolding protein involved in preserving cell structure but it has also emerged as a critical protein required for distinct physiologic functions such as posttranslational localization of crucial membrane proteins and signal transduction. In the heart, βII spectrin plays a vital role in maintaining normal cardiac membrane excitability and proper cardiac development during embryogenesis. Mutations in βII spectrin genes have been strongly linked with the development of serious cardiac disorders such as congenital arrhythmias, heart failure, and possibly sudden cardiac death. This review focuses on our current knowledge of the role βII spectrin plays in the cardiovascular system in health and disease and the potential future clinical implications.
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Affiliation(s)
- Mohamed H Derbala
- Dorothy M. Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA.
| | - Aaron S Guo
- Dorothy M. Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Peter J Mohler
- Dorothy M. Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA; Department of Internal Medicine (Division of Cardiology), The Ohio State University College of Medicine, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Sakima A Smith
- Dorothy M. Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA; Department of Internal Medicine (Division of Cardiology), The Ohio State University College of Medicine, Columbus, OH, USA
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15
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Nelson AD, Jenkins PM. Axonal Membranes and Their Domains: Assembly and Function of the Axon Initial Segment and Node of Ranvier. Front Cell Neurosci 2017; 11:136. [PMID: 28536506 PMCID: PMC5422562 DOI: 10.3389/fncel.2017.00136] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/21/2017] [Indexed: 12/19/2022] Open
Abstract
Neurons are highly specialized cells of the nervous system that receive, process and transmit electrical signals critical for normal brain function. Here, we review the intricate organization of axonal membrane domains that facilitate rapid action potential conduction underlying communication between complex neuronal circuits. Two critical excitable domains of vertebrate axons are the axon initial segment (AIS) and the nodes of Ranvier, which are characterized by the high concentrations of voltage-gated ion channels, cell adhesion molecules and specialized cytoskeletal networks. The AIS is located at the proximal region of the axon and serves as the site of action potential initiation, while nodes of Ranvier, gaps between adjacent myelin sheaths, allow rapid propagation of the action potential through saltatory conduction. The AIS and nodes of Ranvier are assembled by ankyrins, spectrins and their associated binding partners through the clustering of membrane proteins and connection to the underlying cytoskeleton network. Although the AIS and nodes of Ranvier share similar protein composition, their mechanisms of assembly are strikingly different. Here we will cover the mechanisms of formation and maintenance of these axonal excitable membrane domains, specifically highlighting the similarities and differences between them. We will also discuss recent advances in super resolution fluorescence imaging which have elucidated the arrangement of the submembranous axonal cytoskeleton revealing a surprising structural organization necessary to maintain axonal organization and function. Finally, human mutations in axonal domain components have been associated with a growing number of neurological disorders including severe cognitive dysfunction, epilepsy, autism, neurodegenerative diseases and psychiatric disorders. Overall, this review highlights the assembly, maintenance and function of axonal excitable domains, particularly the AIS and nodes of Ranvier, and how abnormalities in these processes may contribute to disease.
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Affiliation(s)
- Andrew D Nelson
- Department of Pharmacology, University of Michigan Medical SchoolAnn Arbor, MI, USA
| | - Paul M Jenkins
- Department of Pharmacology, University of Michigan Medical SchoolAnn Arbor, MI, USA.,Department of Psychiatry, University of Michigan Medical SchoolAnn Arbor, MI, USA
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16
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Delalande O, Czogalla A, Hubert JF, Sikorski A, Le Rumeur E. Dystrophin and Spectrin, Two Highly Dissimilar Sisters of the Same Family. Subcell Biochem 2017; 82:373-403. [PMID: 28101868 DOI: 10.1007/978-3-319-49674-0_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Dystrophin and Spectrin are two proteins essential for the organization of the cytoskeleton and for the stabilization of membrane cells. The comparison of these two sister proteins, and with the dystrophin homologue utrophin, enables us to emphasise that, despite a similar topology with common subdomains and a common structural basis of a three-helix coiled-coil, they show a large range of dissimilarities in terms of genetics, cell expression and higher level structural organisation. Interactions with cellular partners, including proteins and membrane phospholipids, also show both strikingly similar and very different behaviours. The differences between dystrophin and spectrin are also illustrated by the large variety of pathological anomalies emerging from the dysfunction or the absence of these proteins, showing that they are keystones in their function of providing a scaffold that sustains cell structure.
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Affiliation(s)
- Olivier Delalande
- Institut de Génétique et Développement de Rennes, UMR CNRS 6290, Université de Rennes 1, Rennes, France.
| | - Aleksander Czogalla
- Biotechnology Faculty, Department of Cytobiochemistry, University of Wrocław, ul. joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Jean-François Hubert
- Institut de Génétique et Développement de Rennes, UMR CNRS 6290, Université de Rennes 1, Rennes, France
| | - Aleksander Sikorski
- Biotechnology Faculty, Department of Cytobiochemistry, University of Wrocław, ul. joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Elisabeth Le Rumeur
- Institut de Génétique et Développement de Rennes, UMR CNRS 6290, Université de Rennes 1, Rennes, France
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Mujoo K, Hunt CR, Pandita TK. Nuclear functions of β2-Spectrin in genomic stability. Aging (Albany NY) 2016; 8:3151-3152. [PMID: 27978509 PMCID: PMC5270656 DOI: 10.18632/aging.101147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Indexed: 11/25/2022]
Affiliation(s)
- Kalpana Mujoo
- Department of Radiation Oncology, Weill Cornell Medical College, The Methodist Hospital Research Institute, Houston, TX 77030, . USA
| | - Clayton R Hunt
- Department of Radiation Oncology, Weill Cornell Medical College, The Methodist Hospital Research Institute, Houston, TX 77030, . USA
| | - Tej K Pandita
- Department of Radiation Oncology, Weill Cornell Medical College, The Methodist Hospital Research Institute, Houston, TX 77030, . USA
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Identification of adducin-binding residues on the cytoplasmic domain of erythrocyte membrane protein, band 3. Biochem J 2016; 473:3147-58. [PMID: 27435097 DOI: 10.1042/bcj20160328] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/19/2016] [Indexed: 12/26/2022]
Abstract
Two major complexes form structural bridges that connect the erythrocyte membrane to its underlying spectrin-based cytoskeleton. Although the band 3-ankyrin bridge may account for most of the membrane-to-cytoskeleton interactions, the linkage between the cytoplasmic domain of band 3 (cdb3) and adducin has also been shown to be critical to membrane integrity. In the present paper, we demonstrate that adducin, a major component of the spectrin-actin junctional complex, binds primarily to residues 246-264 of cdb3, and mutation of two exposed glutamic acid residues within this sequence completely abrogates both α- and β-adducin binding. Because these residues are located next to the ankyrin-binding site on cdb3, it seems unlikely that band 3 can bind ankyrin and adducin concurrently, reducing the chances of an association between the ankyrin and junctional complexes that would significantly compromise erythrocyte membrane integrity. We also demonstrate that adducin binds the kidney isoform of cdb3, a spliceoform that lacks the first 65 amino acids of erythrocyte cdb3, including the central strand of a large β-pleated sheet. Because kidney cdb3 is not known to bind any of the common peripheral protein partners of erythrocyte cdb3, including ankyrin, protein 4.1, glyceraldehyde-3-phosphate dehydrogenase, aldolase, and phosphofructokinase, retention of this affinity for adducin was unexpected.
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Axon Initial Segment Cytoskeleton: Architecture, Development, and Role in Neuron Polarity. Neural Plast 2016; 2016:6808293. [PMID: 27493806 PMCID: PMC4967436 DOI: 10.1155/2016/6808293] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 05/22/2016] [Indexed: 12/28/2022] Open
Abstract
The axon initial segment (AIS) is a specialized structure in neurons that resides in between axonal and somatodendritic domains. The localization of the AIS in neurons is ideal for its two major functions: it serves as the site of action potential firing and helps to maintain neuron polarity. It has become increasingly clear that the AIS cytoskeleton is fundamental to AIS functions. In this review, we discuss current understanding of the AIS cytoskeleton with particular interest in its unique architecture and role in maintenance of neuron polarity. The AIS cytoskeleton is divided into two parts, submembrane and cytoplasmic, based on localization, function, and molecular composition. Recent studies using electron and subdiffraction fluorescence microscopy indicate that submembrane cytoskeletal components (ankyrin G, βIV-spectrin, and actin filaments) form a sophisticated network in the AIS that is conceptually similar to the polygonal/triangular network of erythrocytes, with some important differences. Components of the AIS cytoplasmic cytoskeleton (microtubules, actin filaments, and neurofilaments) reside deeper within the AIS shaft and display structural features distinct from other neuronal domains. We discuss how the AIS submembrane and cytoplasmic cytoskeletons contribute to different aspects of AIS polarity function and highlight recent advances in understanding their AIS cytoskeletal assembly and stability.
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Ortega E, Manso JA, Buey RM, Carballido AM, Carabias A, Sonnenberg A, de Pereda JM. The Structure of the Plakin Domain of Plectin Reveals an Extended Rod-like Shape. J Biol Chem 2016; 291:18643-62. [PMID: 27413182 DOI: 10.1074/jbc.m116.732909] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Indexed: 11/06/2022] Open
Abstract
Plakins are large multi-domain proteins that interconnect cytoskeletal structures. Plectin is a prototypical plakin that tethers intermediate filaments to membrane-associated complexes. Most plakins contain a plakin domain formed by up to nine spectrin repeats (SR1-SR9) and an SH3 domain. The plakin domains of plectin and other plakins harbor binding sites for junctional proteins. We have combined x-ray crystallography with small angle x-ray scattering (SAXS) to elucidate the structure of the plakin domain of plectin, extending our previous analysis of the SR1 to SR5 region. Two crystal structures of the SR5-SR6 region allowed us to characterize its uniquely wide inter-repeat conformational variability. We also report the crystal structures of the SR7-SR8 region, refined to 1.8 Å, and the SR7-SR9 at lower resolution. The SR7-SR9 region, which is conserved in all other plakin domains, forms a rigid segment stabilized by uniquely extensive inter-repeat contacts mediated by unusually long helices in SR8 and SR9. Using SAXS we show that in solution the SR3-SR6 and SR7-SR9 regions are rod-like segments and that SR3-SR9 of plectin has an extended shape with a small central kink. Other plakins, such as bullous pemphigoid antigen 1 and microtubule and actin cross-linking factor 1, are likely to have similar extended plakin domains. In contrast, desmoplakin has a two-segment structure with a central flexible hinge. The continuous versus segmented structures of the plakin domains of plectin and desmoplakin give insight into how different plakins might respond to tension and transmit mechanical signals.
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Affiliation(s)
- Esther Ortega
- From the Instituto de Biología Molecular y Celular del Cancer, Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain
| | - José A Manso
- From the Instituto de Biología Molecular y Celular del Cancer, Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain
| | - Rubén M Buey
- From the Instituto de Biología Molecular y Celular del Cancer, Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain, the Metabolic Engineering Group, Department of Microbiology and Genetics, University of Salamanca, Salamanca, 37007, Spain, and
| | - Ana M Carballido
- From the Instituto de Biología Molecular y Celular del Cancer, Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain
| | - Arturo Carabias
- From the Instituto de Biología Molecular y Celular del Cancer, Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain
| | - Arnoud Sonnenberg
- the Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - José M de Pereda
- From the Instituto de Biología Molecular y Celular del Cancer, Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain,
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22
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An Adaptable Spectrin/Ankyrin-Based Mechanism for Long-Range Organization of Plasma Membranes in Vertebrate Tissues. CURRENT TOPICS IN MEMBRANES 2015; 77:143-84. [PMID: 26781832 DOI: 10.1016/bs.ctm.2015.10.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Ankyrins are membrane-associated proteins that together with their spectrin partners are responsible for micron-scale organization of vertebrate plasma membranes, including those of erythrocytes, excitable membranes of neurons and heart, lateral membrane domains of columnar epithelial cells, and striated muscle. Ankyrins coordinate functionally related membrane transporters and cell adhesion proteins (15 protein families identified so far) within plasma membrane compartments through independently evolved interactions of intrinsically disordered sequences with a highly conserved peptide-binding groove formed by the ANK repeat solenoid. Ankyrins are coupled to spectrins, which are elongated organelle-sized proteins that form mechanically resilient arrays through cross-linking by specialized actin filaments. In addition to protein interactions, cellular targeting and assembly of spectrin/ankyrin domains also critically depend on palmitoylation of ankyrin-G by aspartate-histidine-histidine-cysteine 5/8 palmitoyltransferases, as well as interaction of beta-2 spectrin with phosphoinositide lipids. These lipid-dependent spectrin/ankyrin domains are not static but are locally dynamic and determine membrane identity through opposing endocytosis of bulk lipids as well as specific proteins. A partnership between spectrin, ankyrin, and cell adhesion molecules first emerged in bilaterians over 500 million years ago. Ankyrin and spectrin may have been recruited to plasma membranes from more ancient roles in organelle transport. The basic bilaterian spectrin-ankyrin toolkit markedly expanded in vertebrates through gene duplications combined with variation in unstructured intramolecular regulatory sequences as well as independent evolution of ankyrin-binding activity by ion transporters involved in action potentials and calcium homeostasis. In addition, giant vertebrate ankyrins with specialized roles in axons acquired new coding sequences by exon shuffling. We speculate that early axon initial segments and epithelial lateral membranes initially were based on spectrin-ankyrin-cell adhesion molecule assemblies and subsequently served as "incubators," where ion transporters independently acquired ankyrin-binding activity through positive selection.
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Jenkins PM, He M, Bennett V. Dynamic spectrin/ankyrin-G microdomains promote lateral membrane assembly by opposing endocytosis. SCIENCE ADVANCES 2015; 1:e1500301. [PMID: 26523289 PMCID: PMC4624203 DOI: 10.1126/sciadv.1500301] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Current physical models for plasma membranes emphasize dynamic 10- to 300-nm compartments at thermodynamic equilibrium but subject to thermal fluctuations. However, epithelial lateral membranes contain micrometer-sized domains defined by an underlying membrane skeleton composed of spectrin and its partner ankyrin-G. We demonstrate that these spectrin/ankyrin-G domains exhibit local microtubule-dependent movement on a time scale of minutes and encounter most of the lateral membranes within an hour. Spectrin/ankyrin-G domains exclude clathrin and clathrin-dependent cargo, and inhibit both receptor-mediated and bulk endocytosis. Moreover, inhibition of endocytosis fully restores lateral membrane height in spectrin- or ankyrin-G-depleted cells. These findings support a non-equilibrium cellular-scale model for epithelial lateral membranes, where spectrin/ankyrin-G domains actively patrol the plasma membrane, analogous to "window washers," and promote columnar morphology by blocking membrane uptake.
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Affiliation(s)
- Paul M. Jenkins
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Meng He
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Vann Bennett
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
- Howard Hughes Medical Institute, Durham, NC 27710, USA
- Corresponding author. E-mail:
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24
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Brown JW, Bullitt E, Sriswasdi S, Harper S, Speicher DW, McKnight CJ. The Physiological Molecular Shape of Spectrin: A Compact Supercoil Resembling a Chinese Finger Trap. PLoS Comput Biol 2015; 11:e1004302. [PMID: 26067675 PMCID: PMC4466138 DOI: 10.1371/journal.pcbi.1004302] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 04/27/2015] [Indexed: 01/29/2023] Open
Abstract
The primary, secondary, and tertiary structures of spectrin are reasonably well defined, but the structural basis for the known dramatic molecular shape change, whereby the molecular length can increase three-fold, is not understood. In this study, we combine previously reported biochemical and high-resolution crystallographic data with structural mass spectroscopy and electron microscopic data to derive a detailed, experimentally-supported quaternary structure of the spectrin heterotetramer. In addition to explaining spectrin’s physiological resting length of ~55-65 nm, our model provides a mechanism by which spectrin is able to undergo a seamless three-fold extension while remaining a linear filament, an experimentally observed property. According to the proposed model, spectrin’s quaternary structure and mechanism of extension is similar to a Chinese Finger Trap: at shorter molecular lengths spectrin is a hollow cylinder that extends by increasing the pitch of each spectrin repeat, which decreases the internal diameter. We validated our model with electron microscopy, which demonstrated that, as predicted, spectrin is hollow at its biological resting length of ~55-65 nm. The model is further supported by zero-length chemical crosslink data indicative of an approximately 90 degree bend between adjacent spectrin repeats. The domain-domain interactions in our model are entirely consistent with those present in the prototypical linear antiparallel heterotetramer as well as recently reported inter-strand chemical crosslinks. The model is consistent with all known physical properties of spectrin, and upon full extension our Chinese Finger Trap Model reduces to the ~180-200 nm molecular model currently in common use. Spectrins are cytoskeletal and scaffolding proteins ubiquitously expressed in essentially all cell-types. Despite unequivocal evidence for a short physiological length of ~55–65 nm at rest, spectrin is typically represented as an extended ~200 nm molecule that is implied based on crystallographic structures of a number of tandem repeats. Here, we incorporate previously reported biochemical and crystallographic data with structural mass spectroscopy and electron microscopic data to derive a detailed, experimentally-supported quaternary structure of the physiological compact form of spectrin. In addition to explaining spectrin’s physiological resting length (~55–65 nm), our model provides a mechanism by which spectrin can undergo a seamless three-fold extension, which is an experimentally observed property that is responsible for restoration of cell shape after mechanical deformation.
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Affiliation(s)
- Jeffrey W. Brown
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Internal Medicine Residency Program, University of Pittsburgh Medical Center, UPMC Montefiore Hospital, Pittsburgh, Pennsylvania, United States of America
| | - Esther Bullitt
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Sira Sriswasdi
- Center for Systems and Computational Biology, and Molecular and Cellular Oncogenesis Program, the Wistar Institute, Philadelphia, Pennsylvania, United States of America
- Genomics and Computational Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sandra Harper
- Center for Systems and Computational Biology, and Molecular and Cellular Oncogenesis Program, the Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - David W. Speicher
- Center for Systems and Computational Biology, and Molecular and Cellular Oncogenesis Program, the Wistar Institute, Philadelphia, Pennsylvania, United States of America
- Genomics and Computational Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - C. James McKnight
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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J. D'Souza RC, Knittle AM, Nagaraj N, van Dinther M, Choudhary C, ten Dijke P, Mann M, Sharma K. Time-resolved dissection of early phosphoproteome and ensuing proteome changes in response to TGF-. Sci Signal 2014; 7:rs5. [DOI: 10.1126/scisignal.2004856] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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26
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He M, Abdi KM, Bennett V. Ankyrin-G palmitoylation and βII-spectrin binding to phosphoinositide lipids drive lateral membrane assembly. J Cell Biol 2014; 206:273-88. [PMID: 25049274 PMCID: PMC4107783 DOI: 10.1083/jcb.201401016] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 06/17/2014] [Indexed: 12/22/2022] Open
Abstract
Ankyrin-G and βII-spectrin colocalize at sites of cell-cell contact in columnar epithelial cells and promote lateral membrane assembly. This study identifies two critical inputs from lipids that together provide a rationale for how ankyrin-G and βII-spectrin selectively localize to Madin-Darby canine kidney (MDCK) cell lateral membranes. We identify aspartate-histidine-histidine-cysteine 5/8 (DHHC5/8) as ankyrin-G palmitoyltransferases required for ankyrin-G lateral membrane localization and for assembly of lateral membranes. We also find that βII-spectrin functions as a coincidence detector that requires recognition of both ankyrin-G and phosphoinositide lipids for its lateral membrane localization. DHHC5/8 and βII-spectrin colocalize with ankyrin-G in micrometer-scale subdomains within the lateral membrane that are likely sites for palmitoylation of ankyrin-G. Loss of either DHHC5/8 or ankyrin-G-βII-spectrin interaction or βII-spectrin-phosphoinositide recognition through its pleckstrin homology domain all result in failure to build the lateral membrane. In summary, we identify a functional network connecting palmitoyltransferases DHHC5/8 with ankyrin-G, ankyrin-G with βII-spectrin, and βII-spectrin with phosphoinositides that is required for the columnar morphology of MDCK epithelial cells.
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Affiliation(s)
- Meng He
- Department of Pharmacology and Cancer Biology, Department of Cell Biology, Department of Biochemistry, and Department of Neurobiology, Duke University Medical Center, Durham, NC 27710
| | - Khadar M Abdi
- Department of Pharmacology and Cancer Biology, Department of Cell Biology, Department of Biochemistry, and Department of Neurobiology, Duke University Medical Center, Durham, NC 27710
| | - Vann Bennett
- Department of Pharmacology and Cancer Biology, Department of Cell Biology, Department of Biochemistry, and Department of Neurobiology, Duke University Medical Center, Durham, NC 27710Department of Pharmacology and Cancer Biology, Department of Cell Biology, Department of Biochemistry, and Department of Neurobiology, Duke University Medical Center, Durham, NC 27710 Howard Hughes Medical Institute, Durham, NC 27710
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27
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Nicolas A, Delalande O, Hubert JF, Le Rumeur E. The spectrin family of proteins: A unique coiled-coil fold for various molecular surface properties. J Struct Biol 2014; 186:392-401. [DOI: 10.1016/j.jsb.2014.03.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/12/2014] [Accepted: 03/14/2014] [Indexed: 01/11/2023]
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28
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Spectrin and phospholipids - the current picture of their fascinating interplay. Cell Mol Biol Lett 2014; 19:158-79. [PMID: 24569979 PMCID: PMC6276000 DOI: 10.2478/s11658-014-0185-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 02/19/2014] [Indexed: 12/02/2022] Open
Abstract
The spectrin-based membrane skeleton is crucial for the mechanical stability and resilience of erythrocytes. It mainly contributes to membrane integrity, protein organization and trafficking. Two transmembrane protein macro-complexes that are linked together by spectrin tetramers play a crucial role in attaching the membrane skeleton to the cell membrane, but they are not exclusive. Considerable experimental data have shown that direct interactions between spectrin and membrane lipids are important for cell membrane cohesion. Spectrin is a multidomain, multifunctional protein with several distinctive structural regions, including lipid-binding sites within CH tandem domains, a PH domain, and triple helical segments, which are excellent examples of ligand specificity hidden in a regular repetitive structure, as recently shown for the ankyrin-sensitive lipid-binding domain of beta spectrin. In this review, we summarize the state of knowledge about interactions between spectrin and membrane lipids.
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29
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Machnicka B, Czogalla A, Hryniewicz-Jankowska A, Bogusławska DM, Grochowalska R, Heger E, Sikorski AF. Spectrins: a structural platform for stabilization and activation of membrane channels, receptors and transporters. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:620-34. [PMID: 23673272 DOI: 10.1016/j.bbamem.2013.05.002] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/25/2013] [Accepted: 05/06/2013] [Indexed: 12/22/2022]
Abstract
This review focuses on structure and functions of spectrin as a major component of the membrane skeleton. Recent advances on spectrin function as an interface for signal transduction mediation and a number of data concerning interaction of spectrin with membrane channels, adhesion molecules, receptors and transporters draw a picture of multifaceted protein. Here, we attempted to show the current depiction of multitask role of spectrin in cell physiology. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- Beata Machnicka
- University of Zielona Góra, Faculty of Biological Sciences, Poland
| | | | | | | | | | - Elżbieta Heger
- University of Zielona Góra, Faculty of Biological Sciences, Poland
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30
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Autore F, Pfuhl M, Quan X, Williams A, Roberts RG, Shanahan CM, Fraternali F. Large-scale modelling of the divergent spectrin repeats in nesprins: giant modular proteins. PLoS One 2013; 8:e63633. [PMID: 23671687 PMCID: PMC3646009 DOI: 10.1371/journal.pone.0063633] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 04/09/2013] [Indexed: 11/29/2022] Open
Abstract
Nesprin-1 and nesprin-2 are nuclear envelope (NE) proteins characterized by a common structure of an SR (spectrin repeat) rod domain and a C-terminal transmembrane KASH [Klarsicht-ANC-Syne-homology] domain and display N-terminal actin-binding CH (calponin homology) domains. Mutations in these proteins have been described in Emery-Dreifuss muscular dystrophy and attributed to disruptions of interactions at the NE with nesprins binding partners, lamin A/C and emerin. Evolutionary analysis of the rod domains of the nesprins has shown that they are almost entirely composed of unbroken SR-like structures. We present a bioinformatical approach to accurate definition of the boundaries of each SR by comparison with canonical SR structures, allowing for a large-scale homology modelling of the 74 nesprin-1 and 56 nesprin-2 SRs. The exposed and evolutionary conserved residues identify important pbs for protein-protein interactions that can guide tailored binding experiments. Most importantly, the bioinformatics analyses and the 3D models have been central to the design of selected constructs for protein expression. 1D NMR and CD spectra have been performed of the expressed SRs, showing a folded, stable, high content α-helical structure, typical of SRs. Molecular Dynamics simulations have been performed to study the structural and elastic properties of consecutive SRs, revealing insights in the mechanical properties adopted by these modules in the cell.
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Affiliation(s)
- Flavia Autore
- Randall Division of Cell and Molecular Biophysics, School of Physical Sciences and Engineering, King's College London, London, United Kingdom
- Division of Cardiovascular Medicine, BHF Centre of Research Excellence, King's College London, London, United Kingdom
| | - Mark Pfuhl
- Randall Division of Cell and Molecular Biophysics, School of Physical Sciences and Engineering, King's College London, London, United Kingdom
| | - Xueping Quan
- Randall Division of Cell and Molecular Biophysics, School of Physical Sciences and Engineering, King's College London, London, United Kingdom
| | - Aisling Williams
- Randall Division of Cell and Molecular Biophysics, School of Physical Sciences and Engineering, King's College London, London, United Kingdom
- Division of Cardiovascular Medicine, BHF Centre of Research Excellence, King's College London, London, United Kingdom
| | - Roland G. Roberts
- Division of Medical and Molecular Genetics, Kings College London, Guy's Hospital, London, United Kingdom
| | - Catherine M. Shanahan
- Division of Cardiovascular Medicine, BHF Centre of Research Excellence, King's College London, London, United Kingdom
| | - Franca Fraternali
- Randall Division of Cell and Molecular Biophysics, School of Physical Sciences and Engineering, King's College London, London, United Kingdom
- The Thomas Young Centre for Theory and Simulation of Materials, London, United Kingdom
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31
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He M, Tseng WC, Bennett V. A single divergent exon inhibits ankyrin-B association with the plasma membrane. J Biol Chem 2013; 288:14769-79. [PMID: 23569209 PMCID: PMC3663501 DOI: 10.1074/jbc.m113.465328] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Vertebrate ankyrin-B and ankyrin-G exhibit divergent subcellular localization and function despite their high sequence and structural similarity and common origin from a single ancestral gene at the onset of chordate evolution. Previous studies of ankyrin family diversity have focused on the C-terminal regulatory domain. Here, we identify an ankyrin-B-specific linker peptide connecting the ankyrin repeat domain to the ZU52-UPA module that inhibits binding of ankyrin-B to membrane protein partners E-cadherin and neurofascin 186 and prevents association of ankyrin-B with epithelial lateral membranes as well as neuronal plasma membranes. The residues of the ankyrin-B linker required for autoinhibition are encoded by a small exon that is highly divergent between ankyrin family members but conserved in the ankyrin-B lineage. We show that the ankyrin-B linker suppresses activity of the ANK repeat domain through an intramolecular interaction, likely with a groove on the surface of the ANK repeat solenoid, thereby regulating the affinities between ankyrin-B and its binding partners. These results provide a simple evolutionary explanation for how ankyrin-B and ankyrin-G have acquired striking differences in their plasma membrane association while maintaining overall high levels of sequence similarity.
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Affiliation(s)
- Meng He
- Department of Pharmacology and Cancer Biology, Duke University, Medical Center, Durham, North Carolina 27710, USA
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32
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Dai L, Lidie KB, Chen Q, Adelsberger JW, Zheng X, Huang D, Yang J, Lempicki RA, Rehman T, Dewar RL, Wang Y, Hornung RL, Canizales KA, Lockett SJ, Lane HC, Imamichi T. IL-27 inhibits HIV-1 infection in human macrophages by down-regulating host factor SPTBN1 during monocyte to macrophage differentiation. J Exp Med 2013; 210:517-34. [PMID: 23460728 PMCID: PMC3600911 DOI: 10.1084/jem.20120572] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 01/31/2013] [Indexed: 02/06/2023] Open
Abstract
The susceptibility of macrophages to HIV-1 infection is modulated during monocyte differentiation. IL-27 is an anti-HIV cytokine that also modulates monocyte activation. In this study, we present new evidence that IL-27 promotes monocyte differentiation into macrophages that are nonpermissive for HIV-1 infection. Although IL-27 treatment does not affect expression of macrophage differentiation markers or macrophage biological functions, it confers HIV resistance by down-regulating spectrin β nonerythrocyte 1 (SPTBN1), a required host factor for HIV-1 infection. IL-27 down-regulates SPTBN1 through a TAK-1-mediated MAPK signaling pathway. Knockdown of SPTBN1 strongly inhibits HIV-1 infection of macrophages; conversely, overexpression of SPTBN1 markedly increases HIV susceptibility of IL-27-treated macrophages. Moreover, we demonstrate that SPTBN1 associates with HIV-1 gag proteins. Collectively, our results underscore the ability of IL-27 to protect macrophages from HIV-1 infection by down-regulating SPTBN1, thus indicating that SPTBN1 is an important host target to reduce HIV-1 replication in one major element of the viral reservoir.
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Affiliation(s)
- Lue Dai
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Kristy B. Lidie
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Qian Chen
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Joseph W. Adelsberger
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Xin Zheng
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - DaWei Huang
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Jun Yang
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Richard A. Lempicki
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Tauseef Rehman
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Robin L. Dewar
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Yanmei Wang
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Ronald L. Hornung
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Kelsey A. Canizales
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Stephen J. Lockett
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - H. Clifford Lane
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Tomozumi Imamichi
- Applied and Developmental Directorate and Advanced Technology Program Directorate, Science Applications International Corporation-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
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Bennett V, Lorenzo DN. Spectrin- and Ankyrin-Based Membrane Domains and the Evolution of Vertebrates. CURRENT TOPICS IN MEMBRANES 2013; 72:1-37. [DOI: 10.1016/b978-0-12-417027-8.00001-5] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Vishwanatha KS, Wang YP, Keutmann HT, Mains RE, Eipper BA. Structural organization of the nine spectrin repeats of Kalirin. Biochemistry 2012; 51:5663-73. [PMID: 22738176 DOI: 10.1021/bi300583s] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Sequence analysis suggests that KALRN, a Rho GDP/GTP exchange factor genetically linked to schizophrenia, could contain as many as nine tandem spectrin repeats (SRs). We expressed and purified fragments of Kalirin containing from one to five putative SRs to determine whether they formed nested structures that could endow Kalirin with the flexible rodlike properties characteristic of spectrin and dystrophin. Far-UV circular dichroism studies indicated that Kalirin contains nine SRs. On the basis of thermal denaturation, sensitivity to chemical denaturants, and the solubility of pairs of repeats, the nine SRs of Kalirin form nested structures. Modeling studies confirmed this conclusion and identified an exposed loop in SR5; consistent with the modeling, this loop was extremely labile to proteolytic cleavage. Analysis of a direpeat fragment (SR4:5) encompassing the region of Kalirin known to interact with NOS2, DISC-1, PAM, and Arf6 identified this as the least stable region. Analytical ultracentrifugation indicated that SR1:3, SR4:6, and SR7:9 were monomers and adopted an extended conformation. Gel filtration suggested that ΔKal7, a natural isoform that includes SR5:9, was monomeric and was not more extended than SR5:9. Similarly, the nine SRs of Kal7, which was also monomeric, were not more extended than SR5:9. The rigidity and flexibility of the nine SRs of Kal7, which separate its essential N-terminal Sec14p domain from its catalytic domain, play an essential role in its contribution to the formation and function of dendritic spines.
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Affiliation(s)
- K S Vishwanatha
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030, USA
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Legrand B, Giudice E, Nicolas A, Delalande O, Le Rumeur E. Computational study of the human dystrophin repeats: interaction properties and molecular dynamics. PLoS One 2011; 6:e23819. [PMID: 21901138 PMCID: PMC3162007 DOI: 10.1371/journal.pone.0023819] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 07/26/2011] [Indexed: 01/16/2023] Open
Abstract
Dystrophin is a large protein involved in the rare genetic disease Duchenne muscular dystrophy (DMD). It functions as a mechanical linker between the cytoskeleton and the sarcolemma, and is able to resist shear stresses during muscle activity. In all, 75% of the dystrophin molecule consists of a large central rod domain made up of 24 repeat units that share high structural homology with spectrin-like repeats. However, in the absence of any high-resolution structure of these repeats, the molecular basis of dystrophin central domain's functions has not yet been deciphered. In this context, we have performed a computational study of the whole dystrophin central rod domain based on the rational homology modeling of successive and overlapping tandem repeats and the analysis of their surface properties. Each tandem repeat has very specific surface properties that make it unique. However, the repeats share enough electrostatic-surface similarities to be grouped into four separate clusters. Molecular dynamics simulations of four representative tandem repeats reveal specific flexibility or bending properties depending on the repeat sequence. We thus suggest that the dystrophin central rod domain is constituted of seven biologically relevant sub-domains. Our results provide evidence for the role of the dystrophin central rod domain as a scaffold platform with a wide range of surface features and biophysical properties allowing it to interact with its various known partners such as proteins and membrane lipids. This new integrative view is strongly supported by the previous experimental works that investigated the isolated domains and the observed heterogeneity of the severity of dystrophin related pathologies, especially Becker muscular dystrophy.
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Affiliation(s)
- Baptiste Legrand
- Université de Rennes 1, Rennes, France
- Equipe RMN-ILP, Faculté de médecine, UMR CNRS 6026, Rennes, France
- Université Européenne de Bretagne, Rennes, France
| | - Emmanuel Giudice
- Université de Rennes 1, Rennes, France
- Equipe SDM, UMR CNRS 6026, Rennes, France
- Université Européenne de Bretagne, Rennes, France
| | - Aurélie Nicolas
- Université de Rennes 1, Rennes, France
- Equipe RMN-ILP, Faculté de médecine, UMR CNRS 6026, Rennes, France
- Université Européenne de Bretagne, Rennes, France
| | - Olivier Delalande
- Université de Rennes 1, Rennes, France
- Equipe RMN-ILP, Faculté de médecine, UMR CNRS 6026, Rennes, France
- Université Européenne de Bretagne, Rennes, France
| | - Elisabeth Le Rumeur
- Université de Rennes 1, Rennes, France
- Equipe RMN-ILP, Faculté de médecine, UMR CNRS 6026, Rennes, France
- Université Européenne de Bretagne, Rennes, France
- * E-mail:
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Sarkis J, Hubert JF, Legrand B, Robert E, Chéron A, Jardin J, Hitti E, Le Rumeur E, Vié V. Spectrin-like repeats 11-15 of human dystrophin show adaptations to a lipidic environment. J Biol Chem 2011; 286:30481-30491. [PMID: 21712383 DOI: 10.1074/jbc.m111.243881] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dystrophin is essential to skeletal muscle function and confers resistance to the sarcolemma by interacting with cytoskeleton and membrane. In the present work, we characterized the behavior of dystrophin 11-15 (DYS R11-15), five spectrin-like repeats from the central domain of human dystrophin, with lipids. DYS R11-15 displays an amphiphilic character at the liquid/air interface while maintaining its secondary α-helical structure. The interaction of DYS R11-15 with small unilamellar vesicles (SUVs) depends on the lipid nature, which is not the case with large unilamellar vesicles (LUVs). In addition, switching from anionic SUVs to anionic LUVs suggests the lipid packing as a crucial factor for the interaction of protein and lipid. The monolayer model and the modulation of surface pressure aim to mimic the muscle at work (i.e. dynamic changes of muscle membrane during contraction and relaxation) (high and low surface pressure). Strikingly, the lateral pressure modifies the protein organization. Increasing the lateral pressure leads the proteins to be organized in a regular network. Nevertheless, a different protein conformation after its binding to monolayer is revealed by trypsin proteolysis. Label-free quantification by nano-LC/MS/MS allowed identification of the helices in repeats 12 and 13 involved in the interaction with anionic SUVs. These results, combined with our previous studies, indicate that DYS R11-15 constitutes the only part of dystrophin that interacts with anionic as well as zwitterionic lipids and adapts its interaction and organization depending on lipid packing and lipid nature. We provide strong experimental evidence for a physiological role of the central domain of dystrophin in sarcolemma scaffolding through modulation of lipid-protein interactions.
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Affiliation(s)
- Joe Sarkis
- Université Européenne de Bretagne, 35000 Rennes, France; UMR-CNRS 6026-IFR 140, Equipe RMN-Interactions Lipides Protéines, Faculté de Médecine, CS 34317, 35043 Rennes, France; UMR-CNRS 6251, Institut de Physique de Rennes, Université de Rennes 1, 35042 Rennes, France
| | - Jean-François Hubert
- Université Européenne de Bretagne, 35000 Rennes, France; UMR-CNRS 6026-IFR 140, Equipe RMN-Interactions Lipides Protéines, Faculté de Médecine, CS 34317, 35043 Rennes, France
| | - Baptiste Legrand
- Université Européenne de Bretagne, 35000 Rennes, France; UMR-CNRS 6026-IFR 140, Equipe RMN-Interactions Lipides Protéines, Faculté de Médecine, CS 34317, 35043 Rennes, France
| | - Estelle Robert
- Université Européenne de Bretagne, 35000 Rennes, France; UMR-CNRS 6251, Institut de Physique de Rennes, Université de Rennes 1, 35042 Rennes, France
| | - Angélique Chéron
- Université Européenne de Bretagne, 35000 Rennes, France; UMR-CNRS 6026-IFR 140, Equipe RMN-Interactions Lipides Protéines, Faculté de Médecine, CS 34317, 35043 Rennes, France
| | - Julien Jardin
- Université Européenne de Bretagne, 35000 Rennes, France; Institut National de la Recherche Agronomique (INRA), AGROCAMPUS-OUEST, UMR 1253, Science et Technologie du Lait et de l'Oeuf, 35042 Rennes, France
| | - Eric Hitti
- Université Européenne de Bretagne, 35000 Rennes, France; Laboratoire Traitement du Signal et de l'Image (LTSI), INSERM 642, 35042 Rennes, France
| | - Elisabeth Le Rumeur
- Université Européenne de Bretagne, 35000 Rennes, France; UMR-CNRS 6026-IFR 140, Equipe RMN-Interactions Lipides Protéines, Faculté de Médecine, CS 34317, 35043 Rennes, France
| | - Véronique Vié
- Université Européenne de Bretagne, 35000 Rennes, France; UMR-CNRS 6251, Institut de Physique de Rennes, Université de Rennes 1, 35042 Rennes, France.
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Crystal structure of a rigid four-spectrin-repeat fragment of the human desmoplakin plakin domain. J Mol Biol 2011; 409:800-12. [PMID: 21536047 DOI: 10.1016/j.jmb.2011.04.046] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 04/14/2011] [Accepted: 04/16/2011] [Indexed: 12/17/2022]
Abstract
The plakin protein family serves to connect cell-cell and cell-matrix adhesion molecules to the intermediate filament cytoskeleton. Desmoplakin (DP) is an integral part of desmosomes, where it links desmosomal cadherins to the intermediate filaments. The 1056-amino-acid N-terminal region of DP contains a plakin domain common to members of the plakin family. Plakin domains contain multiple copies of spectrin repeats (SRs). We determined the crystal structure of a fragment of DP, residues 175-630, consisting of four SRs and an inserted SH3 domain. The four repeats form an elongated, rigid structure. The SH3 domain is present in a loop between two helices of an SR and interacts extensively with the preceding SR in a manner that appears to limit inter-repeat flexibility. The intimate intramolecular association of the SH3 domain with the preceding SR is also observed in plectin, another plakin protein, but not in α-spectrin, suggesting that the SH3 domain of plakins contributes to the stability and rigidity of this subfamily of SR-containing proteins.
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Song Y, Antoniou C, Memic A, Kay BK, Fung LWM. Apparent structural differences at the tetramerization region of erythroid and nonerythroid beta spectrin as discriminated by phage displayed scFvs. Protein Sci 2011; 20:867-79. [PMID: 21412925 DOI: 10.1002/pro.617] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 01/25/2011] [Accepted: 02/28/2011] [Indexed: 01/26/2023]
Abstract
We have screened a human immunoglobulin single-chain variable fragment (scFv) phage library against the C-terminal tetramerization regions of erythroid and nonerythroid beta spectrin (βI-C1 and βII-C1, respectively) to explore the structural uniqueness of erythroid and nonerythroid β-spectrin isoforms. We have identified interacting scFvs, with clones "G5" and "A2" binding only to βI-C1, and clone "F11" binding only to βII-C1. The K(d) values, estimated by competitive enzyme-linked immunosorbent assay, of these scFvs with their target spectrin proteins were 0.1-0.3 μM. A more quantitative K(d) value from isothermal titration calorimetry experiments with the recombinant G5 and βI-C1 was 0.15 μM. The α-spectrin fragments (model proteins), αI-N1 and αII-N1, competed with the βI-C1, or βII-C1, binding scFvs, with inhibitory concentration (IC(50) ) values of ∼50 μM for αI-N1, and ∼0.5 μM for αII-N1. Our predicted structures of βI-C1 and βII-C1 suggest that the Helix B' of the C-terminal partial domain of βI differs from that of βII. Consequently, an unstructured region downstream of Helix B' in βI may interact specifically with the unstructured, complementarity determining region H1 of G5 or A2 scFv. The corresponding region in βII was helical, and βII did not bind G5 scFv. Our results suggest that it is possible for cellular proteins to differentially associate with the C-termini of different β-spectrin isoforms to regulate α- and β-spectrin association to form functional spectrin tetramers, and may sort β-spectrin isoforms to their specific cellular localizations.
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Affiliation(s)
- Yuanli Song
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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Mirza A, Sagathevan M, Sahni N, Choi L, Menhart N. A biophysical map of the dystrophin rod. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:1796-809. [DOI: 10.1016/j.bbapap.2010.03.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 03/16/2010] [Accepted: 03/24/2010] [Indexed: 11/26/2022]
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Manno S, Mohandas N, Takakuwa Y. ATP-dependent mechanism protects spectrin against glycation in human erythrocytes. J Biol Chem 2010; 285:33923-9. [PMID: 20724481 DOI: 10.1074/jbc.m110.126896] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human erythrocytes are continuously exposed to glucose, which reacts with the amino terminus of the β-chain of hemoglobin (Hb) to form glycated Hb, HbA1c, levels of which increase with the age of the circulating cell. In contrast to extensive insights into glycation of hemoglobin, little is known about glycation of erythrocyte membrane proteins. In the present study, we explored the conditions under which glucose and ribose can glycate spectrin, both on the intact membrane and in solution and the functional consequences of spectrin glycation. Although purified spectrin could be readily glycated, membrane-associated spectrin could be glycated only after ATP depletion and consequent translocation of phosphatidylserine (PS) from the inner to the outer lipid monolayer. Glycation of membrane-associated spectrin led to a marked decrease in membrane deformability. We further observed that only PS-binding spectrin repeats are glycated. We infer that the absence of glycation in situ is the consequence of the interaction of the target lysine and arginine residues with PS and thus is inaccessible for glycation. The reduced membrane deformability after glycation in the absence of ATP is likely the result of the inability of the glycated spectrin repeats to undergo the obligatory unfolding as a consequence of interhelix cross-links. We thus postulate that through the use of an ATP-driven phospholipid translocase (flippase), erythrocytes have evolved a protective mechanism against spectrin glycation and thus maintain their optimal membrane function during their long circulatory life span.
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Affiliation(s)
- Sumie Manno
- Department of Biochemistry, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku-Ku, Tokyo 162-8666, Japan
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Baines AJ. The spectrin-ankyrin-4.1-adducin membrane skeleton: adapting eukaryotic cells to the demands of animal life. PROTOPLASMA 2010; 244:99-131. [PMID: 20668894 DOI: 10.1007/s00709-010-0181-1] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 07/05/2010] [Indexed: 05/29/2023]
Abstract
The cells in animals face unique demands beyond those encountered by their unicellular eukaryotic ancestors. For example, the forces engendered by the movement of animals places stresses on membranes of a different nature than those confronting free-living cells. The integration of cells into tissues, as well as the integration of tissue function into whole animal physiology, requires specialisation of membrane domains and the formation of signalling complexes. With the evolution of mammals, the specialisation of cell types has been taken to an extreme with the advent of the non-nucleated mammalian red blood cell. These and other adaptations to animal life seem to require four proteins--spectrin, ankyrin, 4.1 and adducin--which emerged during eumetazoan evolution. Spectrin, an actin cross-linking protein, was probably the earliest of these, with ankyrin, adducin and 4.1 only appearing as tissues evolved. The interaction of spectrin with ankyrin is probably a prerequisite for the formation of tissues; only with the advent of vertebrates did 4.1 acquires the ability to bind spectrin and actin. The latter activity seems to allow the spectrin complex to regulate the cell surface accumulation of a wide variety of proteins. Functionally, the spectrin-ankyrin-4.1-adducin complex is implicated in the formation of apical and basolateral domains, in aspects of membrane trafficking, in assembly of certain signalling and cell adhesion complexes and in providing stability to otherwise mechanically fragile cell membranes. Defects in this complex are manifest in a variety of hereditary diseases, including deafness, cardiac arrhythmia, spinocerebellar ataxia, as well as hereditary haemolytic anaemias. Some of these proteins also function as tumor suppressors. The spectrin-ankyrin-4.1-adducin complex represents a remarkable system that underpins animal life; it has been adapted to many different functions at different times during animal evolution.
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Affiliation(s)
- Anthony J Baines
- School of Biosciences and Centre for Biomedical Informatics, University of Kent, Canterbury, CT2 7NJ, UK.
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Czogalla A, Sikorski AF. Do we already know how spectrin attracts ankyrin? Cell Mol Life Sci 2010; 67:2679-83. [PMID: 20411297 PMCID: PMC11115695 DOI: 10.1007/s00018-010-0371-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 03/30/2010] [Accepted: 04/01/2010] [Indexed: 10/19/2022]
Abstract
The interaction of ankyrin and spectrin yields the major anchor between the membrane skeleton and the lipid bilayer. It is critical for red cell deformability and stability, and it is also involved in the cellular localization of several proteins, in cell differentiation, and in neuron activity. Therefore, its nature is of great interest, and recently, several researchers have had varying degrees of success in elucidating the structural basis of ankyrin-spectrin recognition. In this short paper, we briefly summarize the data obtained and compare the resulting conclusions.
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Affiliation(s)
- Aleksander Czogalla
- Research and Development Centre Novasome Sp. z o.o., 51-423 Wrocław, Poland.
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Chang Z, Ling C, Yamashita M, Welham NV. Microarray-driven validation of reference genes for quantitative real-time polymerase chain reaction in a rat vocal fold model of mucosal injury. Anal Biochem 2010; 406:214-21. [PMID: 20670610 DOI: 10.1016/j.ab.2010.07.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 07/20/2010] [Accepted: 07/20/2010] [Indexed: 02/06/2023]
Abstract
Relative quantification by normalization against a stably expressed reference gene is a widely used data analysis method in microarray and quantitative real-time polymerase chain reaction (qRT-PCR) platforms; however, recent evidence suggests that many commonly utilized reference genes are unstable in certain experimental systems and situations. The primary aim of this study, therefore, was to screen and identify stably expressed reference genes in a well-established rat model of vocal fold mucosal injury. We selected and evaluated the expression stability of nine candidate reference genes. Ablim1, Sptbn1, and Wrnip1 were identified as stably expressed in a model-specific microarray dataset and were further validated as suitable reference genes in an independent qRT-PCR experiment using 2(-DeltaCT) and pairwise comparison-based (geNorm) analyses. Parallel analysis of six commonly used reference genes identified Sdha as the only stably expressed candidate in this group. Sdha, Sptbn1, and the geometric mean of Sdha and Sptbn1 each provided accurate normalization of target gene Tgfb1; Gapdh, the least stable candidate gene in our dataset, provided inaccurate normalization and an invalid experimental result. The stable reference genes identified here are suitable for accurate normalization of target gene expression in vocal fold mucosal injury experiments.
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Affiliation(s)
- Zhen Chang
- Division of Otolaryngology, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
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Mazock GH, Das A, Base C, Dubreuil RR. Transgene rescue identifies an essential function for Drosophila beta spectrin in the nervous system and a selective requirement for ankyrin-2-binding activity. Mol Biol Cell 2010; 21:2860-8. [PMID: 20573981 PMCID: PMC2921109 DOI: 10.1091/mbc.e10-03-0180] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The Gal4-UAS system was used to overexpress or knock down β spectrin with dsRNA in a variety of Drosophila tissues. Unexpectedly, overexpression in most tissues tested was lethal, whereas knockdown failed to produce a detectable phenotype in the same tissues. The lethality of a β spectrin mutation was rescued by expression of β spectrin in neurons. The protein spectrin is ubiquitous in animal cells and is believed to play important roles in cell shape and membrane stability, cell polarity, and endomembrane traffic. Experiments here were undertaken to identify sites of essential β spectrin function in Drosophila and to determine whether spectrin and ankyrin function are strictly linked to one another. The Gal4-UAS system was used to drive tissue-specific overexpression of a β spectrin transgene or to knock down β spectrin expression with dsRNA. The results show that 1) overexpression of β spectrin in most of the cell types studied was lethal; 2) knockdown of β spectrin in most tissues had no detectable effect on growth or viability of the organism; and 3) nervous system-specific expression of a UAS-β spectrin transgene was sufficient to overcome the lethality of a loss-of-function β spectrin mutation. Thus β spectrin expression in other cells was not required for development of fertile adult males, although females lacking nonneuronal spectrin were sterile. Previous data indicated that binding of the DAnk1 isoform of ankyrin to spectrin was partially dispensable for viability. Domain swap experiments here uncovered a different requirement for neuronal DAnk2 binding to spectrin and establish that DAnk2-binding is critical for β spectrin function in vivo.
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Affiliation(s)
- G Harper Mazock
- Department of Biological Sciences and Laboratory for Molecular Biology, University of Illinois at Chicago, Chicago, IL 60607, USA
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Dystrophin: more than just the sum of its parts. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:1713-22. [PMID: 20472103 DOI: 10.1016/j.bbapap.2010.05.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 04/30/2010] [Accepted: 05/03/2010] [Indexed: 01/05/2023]
Abstract
Dystrophin is one of a number of large cytoskeleton associated proteins that connect between various cytoskeletal elements and often are tethered to the membrane through other transmembrane protein complexes. These cytolinker proteins often provide structure and support to the cells where they are expressed, and mutations in genes encoding these proteins frequently gives rise to disease. Dystrophin is no exception in any of these respects, providing connections between a transmembrane complex known as the dystrophin-glycoprotein complex and the underlying cytoskeleton. The most established connection and possibly the most important is that to F-actin, but more recently evidence has been forthcoming of connections to membrane phospholipids, intermediate filaments and microtubules. Moreover it is becoming increasingly clear that the multiple spectrin-like repeats in the centre of the molecule, that had hitherto been thought to be largely redundant, harbour binding activities that have a significant impact on dystrophin functionality. This functionality is particularly apparent when assessed by the ability to rescue the dystrophic phenotype in mdx mice. This review will focus on the relatively neglected but functionally vital coiled-coil region of dystrophin, highlighting the structural relationships and interactions of the coiled-coil region and providing new insights into the functional role of this region.
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Mehboob S, Song Y, Witek M, Long F, Santarsiero BD, Johnson ME, Fung LWM. Crystal structure of the nonerythroid alpha-spectrin tetramerization site reveals differences between erythroid and nonerythroid spectrin tetramer formation. J Biol Chem 2010; 285:14572-84. [PMID: 20228407 DOI: 10.1074/jbc.m109.080028] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We have solved the crystal structure of a segment of nonerythroid alpha-spectrin (alphaII) consisting of the first 147 residues to a resolution of 2.3 A. We find that the structure of this segment is generally similar to a corresponding segment from erythroid alpha-spectrin (alphaI) but exhibits unique differences with functional significance. Specific features include the following: (i) an irregular and frayed first helix (Helix C'); (ii) a helical conformation in the junction region connecting Helix C' with the first structural domain (D1); (iii) a long A(1)B(1) loop in D1; and (iv) specific inter-helix hydrogen bonds/salt bridges that stabilize D1. Our findings suggest that the hydrogen bond networks contribute to structural domain stability, and thus rigidity, in alphaII, and the lack of such hydrogen bond networks in alphaI leads to flexibility in alphaI. We have previously shown the junction region connecting Helix C' to D1 to be unstructured in alphaI (Park, S., Caffrey, M. S., Johnson, M. E., and Fung, L. W. (2003) J. Biol. Chem. 278, 21837-21844) and now find it to be helical in alphaII, an important difference for alpha-spectrin association with beta-spectrin in forming tetramers. Homology modeling and molecular dynamics simulation studies of the structure of the tetramerization site, a triple helical bundle of partial domain helices, show that mutations in alpha-spectrin will affect Helix C' structural flexibility and/or the junction region conformation and may alter the equilibrium between spectrin dimers and tetramers in cells. Mutations leading to reduced levels of functional tetramers in cells may potentially lead to abnormal neuronal functions.
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Affiliation(s)
- Shahila Mehboob
- Center for Pharmaceutical Biotechnology, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
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Crystal structure and functional interpretation of the erythrocyte spectrin tetramerization domain complex. Blood 2010; 115:4843-52. [PMID: 20197550 DOI: 10.1182/blood-2010-01-261396] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
As the principal component of the membrane skeleton, spectrin confers integrity and flexibility to red cell membranes. Although this network involves many interactions, the most common hemolytic anemia mutations that disrupt erythrocyte morphology affect the spectrin tetramerization domains. Although much is known clinically about the resulting conditions (hereditary elliptocytosis and pyropoikilocytosis), the detailed structural basis for spectrin tetramerization and its disruption by hereditary anemia mutations remains elusive. Thus, to provide further insights into spectrin assembly and tetramer site mutations, a crystal structure of the spectrin tetramerization domain complex has been determined. Architecturally, this complex shows striking resemblance to multirepeat spectrin fragments, with the interacting tetramer site region forming a central, composite repeat. This structure identifies conformational changes in alpha-spectrin that occur upon binding to beta-spectrin, and it reports the first structure of the beta-spectrin tetramerization domain. Analysis of the interaction surfaces indicates an extensive interface dominated by hydrophobic contacts and supplemented by electrostatic complementarity. Analysis of evolutionarily conserved residues suggests additional surfaces that may form important interactions. Finally, mapping of hereditary anemia-related mutations onto the structure demonstrate that most, but not all, local hereditary anemia mutations map to the interacting domains. The potential molecular effects of these mutations are described.
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Abstract
Maintenance of membrane integrity and organization in the metazoan cell is accomplished through intracellular tethering of membrane proteins to an extensive, flexible protein network. Spectrin, the principal component of this network, is anchored to membrane proteins through the adaptor protein ankyrin. To elucidate the atomic basis for this interaction, we determined a crystal structure of human betaI-spectrin repeats 13 to 15 in complex with the ZU5-ANK domain of human ankyrin R. The structure reveals the role of repeats 14 to 15 in binding, the electrostatic and hydrophobic contributions along the interface, and the necessity for a particular orientation of the spectrin repeats. Using structural and biochemical data as a guide, we characterized the individual proteins and their interactions by binding and thermal stability analyses. In addition to validating the structural model, these data provide insight into the nature of some mutations associated with cell morphology defects, including those found in human diseases such as hereditary spherocytosis and elliptocytosis. Finally, analysis of the ZU5 domain suggests it is a versatile protein-protein interaction module with distinct interaction surfaces. The structure represents not only the first of a spectrin fragment in complex with its binding partner, but also that of an intermolecular complex involving a ZU5 domain.
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La-Borde PJ, Stabach PR, Simonović I, Morrow JS, Simonović M. Ankyrin recognizes both surface character and shape of the 14-15 di-repeat of beta-spectrin. Biochem Biophys Res Commun 2010; 392:490-4. [PMID: 20079712 DOI: 10.1016/j.bbrc.2010.01.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Accepted: 01/12/2010] [Indexed: 11/18/2022]
Abstract
The spectrin-based cytoskeleton is critical for cell stability, membrane organization and membrane protein trafficking. At its core is the high-affinity complex between beta-spectrin and ankyrin. Defects in either of these proteins may cause hemolytic disease, developmental disorders, neurologic disease, and cancer. Crystal structures of the minimal recognition motifs of ankyrin and beta-spectrin have been determined and distinct recognition mechanisms proposed. One focused on the complementary surface charges of the minimal recognition motifs, whereas the other identified an unusual kink between beta-spectrin repeats and suggested a conformation-sensitive binding surface. Using isothermal titration calorimetry and site-directed mutagenesis, we demonstrate the primacy of the inter-repeat kink as the critical determinant underlying spectrin's ankyrin affinity. The clinical implications of this are discussed in light of recognized linker mutations and polymorphisms in the beta-spectrins.
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Affiliation(s)
- Penelope J La-Borde
- University of Illinois at Chicago, Department of Biochemistry and Molecular Genetics, 900 S. Ashland Ave., MBRB 1170, Chicago, IL 60607, USA
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