1
|
Hossain MNB, Adnan A. Mechanical characterization of spectrin at the molecular level. Sci Rep 2024; 14:16631. [PMID: 39025938 PMCID: PMC11258356 DOI: 10.1038/s41598-024-67500-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 07/11/2024] [Indexed: 07/20/2024] Open
Abstract
Spectrin, a large cytoskeletal protein, consists of a heterodimeric structure comprising α and β subunits. Here, we have studied the mechanics of spectrin filament as a major constituent of dendrites and dendritic spines. Given the intricate biological details and compact biological construction of spectrin, we've developed a constitutive model of spectrin that describes its continuous deformation over three distinct stages and it's progressive failure mechanisms. Our model closely predicts both the force at which uncoiling begins and the ultimate force at which spectrin fails, measuring approximately 93 ~ 100 pN. Remarkably, our predicted failure force closely matches the findings from AFM experiments focused on the uncoiling of spectrin repeats, which reported a force of 90 pN. Our theoretical model proposes a plausible pathway for the potential failure of dendrites and the intricate connection between strain and strain rate. These findings deepen our understanding of how spectrin can contribute to traumatic brain injury risk analysis.
Collapse
Affiliation(s)
- Md Nahian Bin Hossain
- Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington (UTA), Arlington, TX, USA
| | - Ashfaq Adnan
- Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington (UTA), Arlington, TX, USA.
| |
Collapse
|
2
|
Lorenzo DN, Edwards RJ, Slavutsky AL. Spectrins: molecular organizers and targets of neurological disorders. Nat Rev Neurosci 2023; 24:195-212. [PMID: 36697767 PMCID: PMC10598481 DOI: 10.1038/s41583-022-00674-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2022] [Indexed: 01/26/2023]
Abstract
Spectrins are cytoskeletal proteins that are expressed ubiquitously in the mammalian nervous system. Pathogenic variants in SPTAN1, SPTBN1, SPTBN2 and SPTBN4, four of the six genes encoding neuronal spectrins, cause neurological disorders. Despite their structural similarity and shared role as molecular organizers at the cell membrane, spectrins vary in expression, subcellular localization and specialization in neurons, and this variation partly underlies non-overlapping disease presentations across spectrinopathies. Here, we summarize recent progress in discerning the local and long-range organization and diverse functions of neuronal spectrins. We provide an overview of functional studies using mouse models, which, together with growing human genetic and clinical data, are helping to illuminate the aetiology of neurological spectrinopathies. These approaches are all critical on the path to plausible therapeutic solutions.
Collapse
Affiliation(s)
- Damaris N Lorenzo
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Reginald J Edwards
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Anastasia L Slavutsky
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
3
|
Giri RP, Mukhopadhyay MK, Sanyal MK, Bose D, Chakrabarti A, Quan P, Bu W, Lin B. Structural Flexibility of Proteins Dramatically Alters Membrane Stability─A Novel Aspect of Lipid-Protein Interaction. J Phys Chem Lett 2022; 13:11430-11437. [PMID: 36468973 DOI: 10.1021/acs.jpclett.2c02971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Protein isoforms are structural variants with changes in the overall flexibility predominantly at the tertiary level. For membrane associated proteins, such structural flexibility or rigidity affects membrane stability by playing modulatory roles in lipid-protein interaction. Herein, we investigate the protein chain flexibility mediated changes in the mechanistic behavior of phospholipid model membranes in the presence of two well-known isoforms, erythroid (ER) and nonerythroid (NER) spectrin. We show dramatic alterations of membrane elasticity and stability induced by spectrin in the Langmuir monolayers of phosphatidylocholine (PC) and phosphatidylethanolamine (PE) by a combination of isobaric relaxation, surface pressure-area isotherm, X-ray scattering, and microscopy measurements. The NER spectrin drives all monolayers to possess an approximately equal stability, and that required 25-fold increase and 5-fold decrease of stability in PC and PE monolayers, respectively. The untilting transition of the PC membrane in the presence of NER spectrin observed in X-ray measurements can explain better membrane packing and stability.
Collapse
Affiliation(s)
- Rajendra P Giri
- Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, Kolkata, 700064, West Bengal, India
- Institute for Experimental and Applied Physics, Kiel University, 24118Kiel, Germany
| | - Mrinmay K Mukhopadhyay
- Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, Kolkata, 700064, West Bengal, India
| | - Milan K Sanyal
- Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, Kolkata, 700064, West Bengal, India
| | - Dipayan Bose
- Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, Kolkata, 700064, West Bengal, India
| | - Abhijit Chakrabarti
- Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, Kolkata, 700064, West Bengal, India
- School of Biological Sciences, Ramakrishna Mission Vivekananda Educational & Research Institute, Narendrapur, Kolkata700103, India
| | - Peiyu Quan
- NSF's ChemMatCARS, Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois60637, United States
| | - Wei Bu
- NSF's ChemMatCARS, Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois60637, United States
| | - Binhua Lin
- NSF's ChemMatCARS, Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois60637, United States
| |
Collapse
|
4
|
Silva AM, Chan FY, Norman MJ, Sobral AF, Zanin E, Gassmann R, Belmonte JM, Carvalho AX. β-heavy-spectrin stabilizes the constricting contractile ring during cytokinesis. J Cell Biol 2022; 222:213538. [PMID: 36219157 PMCID: PMC9559602 DOI: 10.1083/jcb.202202024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 08/17/2022] [Accepted: 09/20/2022] [Indexed: 11/22/2022] Open
Abstract
Cytokinesis requires the constriction of an actomyosin-based contractile ring and involves multiple F-actin crosslinkers. We show that partial depletion of the C. elegans cytokinetic formin generates contractile rings with low F-actin levels that constrict but are structurally fragile, and we use this background to investigate the roles of the crosslinkers plastin/PLST-1 and β-heavy-spectrin/SMA-1 during ring constriction. We show that the removal of PLST-1 or SMA-1 has opposite effects on the structural integrity of fragile rings. PLST-1 loss reduces cortical tension that resists ring constriction and makes fragile rings less prone to ruptures and regressions, whereas SMA-1 loss exacerbates structural defects, leading to frequent ruptures and cytokinesis failure. Fragile rings without SMA-1 or containing a shorter SMA-1, repeatedly rupture at the same site, and SMA-1::GFP accumulates at repair sites in fragile rings and in rings cut by laser microsurgery. These results establish that β-heavy-spectrin stabilizes the constricting ring and reveals the importance of β-heavy-spectrin size for network connectivity at low F-actin density.
Collapse
Affiliation(s)
- Ana Marta Silva
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Fung-Yi Chan
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Michael J. Norman
- Department of Physics, North Carolina State University, Raleigh, NC,Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC
| | - Ana Filipa Sobral
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Esther Zanin
- Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Reto Gassmann
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Julio Monti Belmonte
- Department of Physics, North Carolina State University, Raleigh, NC,Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC
| | - Ana Xavier Carvalho
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal,Correspondence to Ana Xavier Carvalho:
| |
Collapse
|
5
|
Leterrier C, Pullarkat PA. Mechanical role of the submembrane spectrin scaffold in red blood cells and neurons. J Cell Sci 2022; 135:276327. [PMID: 35972759 DOI: 10.1242/jcs.259356] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Spectrins are large, evolutionarily well-conserved proteins that form highly organized scaffolds on the inner surface of eukaryotic cells. Their organization in different cell types or cellular compartments helps cells withstand mechanical challenges with unique strategies depending on the cell type. This Review discusses our understanding of the mechanical properties of spectrins, their very distinct organization in red blood cells and neurons as two examples, and the contribution of the scaffolds they form to the mechanical properties of these cells.
Collapse
Affiliation(s)
- Christophe Leterrier
- Aix Marseille Université, CNRS, INP UMR 7051, NeuroCyto, Marseille 13005, France
| | | |
Collapse
|
6
|
Dong Y, Yang Y, Lin C, Liu D. Frame-Guided Assembly of Amphiphiles. Acc Chem Res 2022; 55:1938-1948. [PMID: 35786832 DOI: 10.1021/acs.accounts.2c00234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ConspectusAmphiphiles tend to self-assemble into various structures and morphologies in aqueous environments (e.g., micelles, tubes, fibers, vesicles, and lamellae). These assemblies and their properties have made significant impact in traditional chemical industries, e.g., increasing solubility, decreasing surface tension, facilitating foaming, etc. It is well-known that the molecular structure and its environment play a critical role in the assembly process, and many theories, including critical packing factor, thermodynamic models, etc., have been proposed to explain and predict the assembly morphology. It has been recognized that the morphology of the amphiphilic assembly plays important roles in determining the functions, such as curvature-dependent biophysical (e.g., liposome fusion and fission) and biochemical (e.g., lipid metabolism and membrane protein trafficking) processes, size-related EPR (enhanced permeability and retention) effects, etc. Meanwhile, various nanomaterials have promised great potential in directing the arrangement of molecules, thus generating unique functions. Therefore, control over the amphiphilic morphology is of great interest to scientists, especially in nanoscale with the assistance of functional nanomaterials. However, how to precisely manipulate the sizes and shapes of the assemblies is challenged by the entropic nature of the hydrophobic interaction. Inspired by the "cytoskeleton-membrane protein-lipid bilayer" principle of the cell membrane, a strategy termed "frame-guided assembly (FGA)" has been proposed and developed to direct the arrangement of amphiphiles. The FGA strategy welcomes various nanomaterials with precisely controlled properties to serve as scaffolds. By introducing scattered hydrophobic molecules, which are defined as either leading hydrophobic groups (LHGs) or nucleation seeds onto a selected scaffold, a discontinuous hydrophobic trace along the scaffold can be outlined, which will further guide the amphiphiles in the system to grow and form customized two- or three-dimensional (2D/3D) membrane geometries.Topologically, the supporting frame can be classified as three types including inner-frame, outer-frame, and planar-frame. Each type of FGA assembly possesses particular advantages: (1) The inner-frame, similar to endoskeletons of many cellular structures, steadily supports the membrane from the inside and exposes the full surface area outside. (2) The outer-frame, on the other hand, molds and constrains the membrane-wrapped vesicles to regulate their size and shape. It also allows postengineering of the frame to precisely decorate and dynamically manipulate the membrane. (3) The planar-frame mediates the growth of the 2D membrane that profits from the scanning-probe microscopic characterization and benefits the investigation of membrane proteins.In this Account, we introduce the recent progress of frame-guided assembly strategy in the preparation of customized amphiphile assemblies, evaluate their achievements and limitations, and discuss prospective developments and applications. The basic principle of FGA is discussed, and the morphology controllability is summarized in the inner-, outer-, and planar-frame categories. As a versatile strategy, FGA is able to guide different types of amphiphiles by designing specific LHGs for given molecular structures. The mechanism of FGA is then discussed systematically, including the driving force of the assembly, density and distribution of the LHGs, amphiphile concentration, and the kinetic process. Furthermore, the applications of FGA have been developed for liposome engineering, membrane protein incorporation, and drug delivery, which suggest the huge potential of FGA in fabricating novel and functional complexes.
Collapse
Affiliation(s)
- Yuanchen Dong
- Institute of Chemistry, CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yang Yang
- Institute of Molecular Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200025, China
| | - Chenxiang Lin
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, United States.,Nanobiology Institute, Yale University, West Haven, Connecticut 06516, United States.,Department of Biomedical Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Dongsheng Liu
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| |
Collapse
|
7
|
Lordén G, Newton A. Conventional protein kinase C in the brain: repurposing cancer drugs for neurodegenerative treatment? Neuronal Signal 2021; 5:NS20210036. [PMID: 34737895 PMCID: PMC8536831 DOI: 10.1042/ns20210036] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 12/23/2022] Open
Abstract
Protein Kinase C (PKC) isozymes are tightly regulated kinases that transduce a myriad of signals from receptor-mediated hydrolysis of membrane phospholipids. They play an important role in brain physiology, and dysregulation of PKC activity is associated with neurodegeneration. Gain-of-function mutations in PKCα are associated with Alzheimer's disease (AD) and mutations in PKCγ cause spinocerebellar ataxia (SCA) type 14 (SCA14). This article presents an overview of the role of the conventional PKCα and PKCγ in neurodegeneration and proposes repurposing PKC inhibitors, which failed in clinical trials for cancer, for the treatment of neurodegenerative diseases.
Collapse
Affiliation(s)
- Gema Lordén
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, U.S.A
| | - Alexandra C. Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92037, U.S.A
| |
Collapse
|
8
|
Costa AR, Sousa MM. The role of the membrane-associated periodic skeleton in axons. Cell Mol Life Sci 2021; 78:5371-5379. [PMID: 34085116 PMCID: PMC11071922 DOI: 10.1007/s00018-021-03867-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 05/14/2021] [Accepted: 05/27/2021] [Indexed: 11/24/2022]
Abstract
The identification of the membrane periodic skeleton (MPS), composed of a periodic lattice of actin rings interconnected by spectrin tetramers, was enabled by the development of super-resolution microscopy, and brought a new exciting perspective to our view of neuronal biology. This exquisite cytoskeleton arrangement plays an important role on mechanisms regulating neuronal (dys)function. The MPS was initially thought to provide mainly for axonal mechanical stability. Since its discovery, the importance of the MPS in multiple aspects of neuronal biology has, however, emerged. These comprise its capacity to act as a signaling platform, regulate axon diameter-with important consequences on the efficiency of axonal transport and electrophysiological properties- participate in the assembly and function of the axon initial segment, and control axon microtubule stability. Recently, MPS disassembly has also surfaced as an early player in the course of axon degeneration. Here, we will discuss the current knowledge on the role of the MPS in axonal physiology and disease.
Collapse
Affiliation(s)
- Ana Rita Costa
- Nerve Regeneration Group, IBMC- Instituto de Biologia Molecular e Celular and i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
| | - Monica Mendes Sousa
- Nerve Regeneration Group, IBMC- Instituto de Biologia Molecular e Celular and i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal.
| |
Collapse
|
9
|
Solé L, Tamkun MM. Trafficking mechanisms underlying Na v channel subcellular localization in neurons. Channels (Austin) 2020; 14:1-17. [PMID: 31841065 PMCID: PMC7039628 DOI: 10.1080/19336950.2019.1700082] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 11/13/2019] [Indexed: 01/06/2023] Open
Abstract
Voltage gated sodium channels (Nav) play a crucial role in action potential initiation and propagation. Although the discovery of Nav channels dates back more than 65 years, and great advances in understanding their localization, biophysical properties, and links to disease have been made, there are still many questions to be answered regarding the cellular and molecular mechanisms involved in Nav channel trafficking, localization and regulation. This review summarizes the different trafficking mechanisms underlying the polarized Nav channel localization in neurons, with an emphasis on the axon initial segment (AIS), as well as discussing the latest advances regarding how neurons regulate their excitability by modifying AIS length and location. The importance of Nav channel localization is emphasized by the relationship between mutations, impaired trafficking and disease. While this review focuses on Nav1.6, other Nav isoforms are also discussed.
Collapse
Affiliation(s)
- Laura Solé
- Molecular, Cellular and Integrative Neurosciences Graduate Program, Colorado State University, Fort Collins, CO, USA
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Michael M. Tamkun
- Molecular, Cellular and Integrative Neurosciences Graduate Program, Colorado State University, Fort Collins, CO, USA
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| |
Collapse
|
10
|
Zhou H, Huang B, Qu K, Liu J, Zhang J, Lei C. The distribution of four missense mutations in SPTBN5 gene across native Chinese breeds. Anim Biotechnol 2020; 33:796-800. [PMID: 33063596 DOI: 10.1080/10495398.2020.1831521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Modern cattle belong to two subspecies, Bos taurus and Bos indicus. Since divergence, cattle types have accumulated different genetic variations, which have contributed to highly differentiated phenotypes. The mammalian inner ear possesses functional and morphological innovations that contribute to its unique hearing capacities. The spectrin beta, non-erythrocytic 5 (SPTBN5) gene has been shown to play an important function in the inner ear. Four missense mutations: rs522333459 (c.7232G > C:p.Cys2411Ser), rs718838405 (c.6568A > C:p.Met2190Leu), rs516536785 (c.6283C > T:p.Leu2095Phe) and rs480278206 (c.4201T > C:p.Cys1401Arg) were identified in the bovine SPTBN5 gene by whole genome resequencing (http://animal.nwsuaf.edu.cn/code/index.php/BosVar), which might be candidate mutations related with hearing of both taurine and indicine cattle. In our study, PCR and DNA sequencing were used to explore the allele frequencies of four mutations of 971 individuals belonging to 38 native Chinese cattle breeds. We find that four mutant alleles showing strong geographic distribution, consisting with the ancestry distribution of taurine and indicine in China. In addition, we identified four mutations of SPTBN5 were diverged in taurine and indicine cattle showing signatures of adaptive evolution in two subspecies, which might participate in bovine inner ear development.
Collapse
Affiliation(s)
- Hongchao Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Bizhi Huang
- Yunnan Academy of Grassland Animal Science, Kunming, China
| | - Kaixing Qu
- Yunnan Academy of Grassland Animal Science, Kunming, China
| | - Jianyong Liu
- Yunnan Academy of Grassland Animal Science, Kunming, China
| | - Jicai Zhang
- Yunnan Academy of Grassland Animal Science, Kunming, China
| | - Chuzhao Lei
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| |
Collapse
|
11
|
Bose D, Chakrabarti A. Multiple Functions of Spectrin: Convergent Effects. J Membr Biol 2020; 253:499-508. [PMID: 32990795 DOI: 10.1007/s00232-020-00142-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/19/2020] [Indexed: 10/23/2022]
Abstract
Spectrin is a multifunctional, multi-domain protein most well known in the membrane skeleton of mature human erythrocytes. Here we review the literature on the crosstalk of the chaperone activity of spectrin with its other functionalities. We hypothesize that the chaperone activity is derived from the surface exposed hydrophobic patches present in individual "spectrin-repeat" domains and show a competition between the membrane phospholipid binding functionality and chaperone activity of spectrin. Moreover, we show that post-translational modifications such as glycation which shield these surface exposed hydrophobic patches, reduce the chaperone function. On the other hand, oligomerization which is linked to increase of hydrophobicity is seen to increase it. We note that spectrin seems to prefer haemoglobin as its chaperone client, binding with it preferentially over other denatured proteins. Spectrin is also known to interact with unstable haemoglobin variants with a higher affinity than in the case of normal haemoglobin. We propose that chaperone activity of spectrin could be important in the cellular biochemistry of haemoglobin, particularly in the context of diseases.
Collapse
Affiliation(s)
- Dipayan Bose
- Crystallography & Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India.,Homi Bhabha National Institute, Mumbai, 400094, India
| | - Abhijit Chakrabarti
- Crystallography & Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India. .,Homi Bhabha National Institute, Mumbai, 400094, India.
| |
Collapse
|
12
|
LaBella ML, Hujber EJ, Moore KA, Rawson RL, Merrill SA, Allaire PD, Ailion M, Hollien J, Bastiani MJ, Jorgensen EM. Casein Kinase 1δ Stabilizes Mature Axons by Inhibiting Transcription Termination of Ankyrin. Dev Cell 2020; 52:88-103.e18. [PMID: 31910362 DOI: 10.1016/j.devcel.2019.12.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/09/2019] [Accepted: 12/10/2019] [Indexed: 01/19/2023]
Abstract
After axon outgrowth and synapse formation, the nervous system transitions to a stable architecture. In C. elegans, this transition is marked by the appearance of casein kinase 1δ (CK1δ) in the nucleus. In CK1δ mutants, neurons continue to sprout growth cones into adulthood, leading to a highly ramified nervous system. Nervous system architecture in these mutants is completely restored by suppressor mutations in ten genes involved in transcription termination. CK1δ prevents termination by phosphorylating and inhibiting SSUP-72. SSUP-72 would normally remodel the C-terminal domain of RNA polymerase in anticipation of termination. The antitermination activity of CK1δ establishes the mature state of a neuron by promoting the expression of the long isoform of a single gene, the cytoskeleton protein Ankyrin.
Collapse
Affiliation(s)
- Matthew L LaBella
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA
| | - Edward J Hujber
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA
| | - Kristin A Moore
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | - Randi L Rawson
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA
| | - Sean A Merrill
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA
| | - Patrick D Allaire
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA
| | - Michael Ailion
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Julie Hollien
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | | | - Erik M Jorgensen
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA.
| |
Collapse
|
13
|
Vassilopoulos S, Gibaud S, Jimenez A, Caillol G, Leterrier C. Ultrastructure of the axonal periodic scaffold reveals a braid-like organization of actin rings. Nat Commun 2019; 10:5803. [PMID: 31862971 PMCID: PMC6925202 DOI: 10.1038/s41467-019-13835-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 11/27/2019] [Indexed: 12/31/2022] Open
Abstract
Recent super-resolution microscopy studies have unveiled a periodic scaffold of actin rings regularly spaced by spectrins under the plasma membrane of axons. However, ultrastructural details are unknown, limiting a molecular and mechanistic understanding of these enigmatic structures. Here, we combine platinum-replica electron and optical super-resolution microscopy to investigate the cortical cytoskeleton of axons at the ultrastructural level. Immunogold labeling and correlative super-resolution/electron microscopy allow us to unambiguously resolve actin rings as braids made of two long, intertwined actin filaments connected by a dense mesh of aligned spectrins. This molecular arrangement contrasts with the currently assumed model of actin rings made of short, capped actin filaments. Along the proximal axon, we resolved the presence of phospho-myosin light chain and the scaffold connection with microtubules via ankyrin G. We propose that braided rings explain the observed stability of the actin-spectrin scaffold and ultimately participate in preserving the axon integrity.
Collapse
Affiliation(s)
- Stéphane Vassilopoulos
- Sorbonne Université, INSERM, Institute of Myology, Centre of Research in Myology, UMRS 974, Paris, France.
| | - Solène Gibaud
- Aix Marseille Université, CNRS, INP UMR7051, NeuroCyto, Marseille, France
| | - Angélique Jimenez
- Aix Marseille Université, CNRS, INP UMR7051, NeuroCyto, Marseille, France
| | - Ghislaine Caillol
- Aix Marseille Université, CNRS, INP UMR7051, NeuroCyto, Marseille, France
| | | |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
|
16
|
Liu CH, Rasband MN. Axonal Spectrins: Nanoscale Organization, Functional Domains and Spectrinopathies. Front Cell Neurosci 2019; 13:234. [PMID: 31191255 PMCID: PMC6546920 DOI: 10.3389/fncel.2019.00234] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/09/2019] [Indexed: 11/13/2022] Open
Abstract
Spectrin cytoskeletons are found in all metazoan cells, and their physical interactions between actin and ankyrins establish a meshwork that provides cellular structural integrity. With advanced super-resolution microscopy, the intricate spatial organization and associated functional properties of these cytoskeletons can now be analyzed with unprecedented clarity. Long neuronal processes like peripheral sensory and motor axons may be subject to intense mechanical forces including bending, stretching, and torsion. The spectrin-based cytoskeleton is essential to protect axons against these mechanical stresses. Additionally, spectrins are critical for the assembly and maintenance of axonal excitable domains including the axon initial segment and the nodes of Ranvier (NoR). These sites facilitate rapid and efficient action potential initiation and propagation in the nervous system. Recent studies revealed that pathogenic spectrin variants and diseases that protealyze and breakdown spectrins are associated with congenital neurological disorders and nervous system injury. Here, we review recent studies of spectrins in the nervous system and focus on their functions in axonal health and disease.
Collapse
Affiliation(s)
- Cheng-Hsin Liu
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States
| | - Matthew Neil Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
| |
Collapse
|
17
|
Liu Y, Qi J, Chen X, Tang M, Chu C, Zhu W, Li H, Tian C, Yang G, Zhong C, Zhang Y, Ni G, He S, Chai R, Zhong G. Critical role of spectrin in hearing development and deafness. SCIENCE ADVANCES 2019; 5:eaav7803. [PMID: 31001589 PMCID: PMC6469942 DOI: 10.1126/sciadv.aav7803] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 03/01/2019] [Indexed: 06/09/2023]
Abstract
Inner ear hair cells (HCs) detect sound through the deflection of mechanosensory stereocilia. Stereocilia are inserted into the cuticular plate of HCs by parallel actin rootlets, where they convert sound-induced mechanical vibrations into electrical signals. The molecules that support these rootlets and enable them to withstand constant mechanical stresses underpin our ability to hear. However, the structures of these molecules have remained unknown. We hypothesized that αII- and βII-spectrin subunits fulfill this role, and investigated their structural organization in rodent HCs. Using super-resolution fluorescence imaging, we found that spectrin formed ring-like structures around the base of stereocilia rootlets. These spectrin rings were associated with the hearing ability of mice. Further, HC-specific, βII-spectrin knockout mice displayed profound deafness. Overall, our work has identified and characterized structures of spectrin that play a crucial role in mammalian hearing development.
Collapse
Affiliation(s)
- Yan Liu
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Jieyu Qi
- iHuman Institute, ShanghaiTech University, Shanghai, China
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
- Co-innovation Center of Neuroregeneration, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
| | - Xin Chen
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Mingliang Tang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
- Co-innovation Center of Neuroregeneration, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
| | - Cenfeng Chu
- iHuman Institute, ShanghaiTech University, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Weijie Zhu
- iHuman Institute, ShanghaiTech University, Shanghai, China
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
- Co-innovation Center of Neuroregeneration, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
| | - Hui Li
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Cuiping Tian
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Guang Yang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Chao Zhong
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ying Zhang
- Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, 5850 College Street, Halifax, Canada
| | - Guangjian Ni
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Laboratory of Neural Engineering and Rehabilitation, Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China
| | - Shuijin He
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
- Co-innovation Center of Neuroregeneration, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Research Institute of Otolaryngology, No.321 Zhongshan Road, Nanjing, China
- Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, 100069, China
| | - Guisheng Zhong
- iHuman Institute, ShanghaiTech University, Shanghai, China
- Co-innovation Center of Neuroregeneration, Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| |
Collapse
|
18
|
Papandréou MJ, Leterrier C. The functional architecture of axonal actin. Mol Cell Neurosci 2018; 91:151-159. [PMID: 29758267 DOI: 10.1016/j.mcn.2018.05.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 05/10/2018] [Accepted: 05/11/2018] [Indexed: 11/17/2022] Open
Abstract
The cytoskeleton builds and supports the complex architecture of neurons. It orchestrates the specification, growth, and compartmentation of the axon: axon initial segment, axonal shaft, presynapses. The cytoskeleton must then maintain this intricate architecture for the whole life of its host, but also drive its adaptation to new network demands and changing physiological conditions. Microtubules are readily visible inside axon shafts by electron microscopy, whereas axonal actin study has long been focused on dynamic structures of the axon such as growth cones. Super-resolution microscopy and live-cell imaging have recently revealed new actin-based structures in mature axons: rings, hotspots and trails. This has caused renewed interest for axonal actin, with efforts underway to understand the precise organization and cellular functions of these assemblies. Actin is also present in presynapses, where its arrangement is still poorly defined, and its functions vigorously debated. Here we review the organization of axonal actin, focusing on recent advances and current questions in this rejuvenated field.
Collapse
|
19
|
The Axon Initial Segment: An Updated Viewpoint. J Neurosci 2018; 38:2135-2145. [PMID: 29378864 DOI: 10.1523/jneurosci.1922-17.2018] [Citation(s) in RCA: 168] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 01/20/2018] [Accepted: 01/25/2018] [Indexed: 12/20/2022] Open
Abstract
At the base of axons sits a unique compartment called the axon initial segment (AIS). The AIS generates and shapes the action potential before it is propagated along the axon. Neuronal excitability thus depends crucially on the AIS composition and position, and these adapt to developmental and physiological conditions. The AIS also demarcates the boundary between the somatodendritic and axonal compartments. Recent studies have brought insights into the molecular architecture of the AIS and how it regulates protein trafficking. This Viewpoints article summarizes current knowledge about the AIS and highlights future challenges in understanding this key actor of neuronal physiology.
Collapse
|
20
|
Pan L, Yan R, Li W, Xu K. Super-Resolution Microscopy Reveals the Native Ultrastructure of the Erythrocyte Cytoskeleton. Cell Rep 2018; 22:1151-1158. [DOI: 10.1016/j.celrep.2017.12.107] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 11/23/2017] [Accepted: 12/29/2017] [Indexed: 11/30/2022] Open
|
21
|
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.
Collapse
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
| |
Collapse
|
22
|
|
23
|
Structural organization of the actin-spectrin-based membrane skeleton in dendrites and soma of neurons. Proc Natl Acad Sci U S A 2017; 114:E6678-E6685. [PMID: 28739933 DOI: 10.1073/pnas.1705043114] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Actin, spectrin, and associated molecules form a membrane-associated periodic skeleton (MPS) in neurons. In the MPS, short actin filaments, capped by actin-capping proteins, form ring-like structures that wrap around the circumference of neurites, and these rings are periodically spaced along the neurite by spectrin tetramers, forming a quasi-1D lattice structure. This 1D MPS structure was initially observed in axons and exists extensively in axons, spanning nearly the entire axonal shaft of mature neurons. Such 1D MPS was also observed in dendrites, but the extent to which it exists and how it develops in dendrites remain unclear. It is also unclear whether other structural forms of the membrane skeleton are present in neurons. Here, we investigated the spatial organizations of spectrin, actin, and adducin, an actin-capping protein, in the dendrites and soma of cultured hippocampal neurons at different developmental stages, and compared results with those obtained in axons, using superresolution imaging. We observed that the 1D MPS exists in a substantial fraction of dendritic regions in relatively mature neurons, but this structure develops slower and forms with a lower propensity in dendrites than in axons. In addition, we observed that spectrin, actin, and adducin also form a 2D polygonal lattice structure, resembling the expanded erythrocyte membrane skeleton structure, in the somatodendritic compartment. This 2D lattice structure also develops substantially more slowly in the soma and dendrites than the development of the 1D MPS in axons. These results suggest membrane skeleton structures are differentially regulated across different subcompartments of neurons.
Collapse
|
24
|
Williams NE. AN APPARENT DISJUNCTION BETWEEN THE EVOLUTION OF FORM AND SUBSTANCE IN THE GENUS
TETRAHYMENA. Evolution 2017; 38:25-33. [DOI: 10.1111/j.1558-5646.1984.tb00256.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/1982] [Revised: 02/22/1983] [Indexed: 11/30/2022]
|
25
|
Bose D, Patra M, Chakrabarti A. Effect of pH on stability, conformation, and chaperone activity of erythroid & non-erythroid spectrin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:694-702. [PMID: 28373029 DOI: 10.1016/j.bbapap.2017.03.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/28/2017] [Accepted: 03/30/2017] [Indexed: 11/29/2022]
Abstract
Spectrin, a major component of the eukaryotic membrane skeleton, has been shown to have chaperone like activity. Here we investigate the pH induced changes in the structure and stability of erythroid and brain spectrin by spectroscopic methods. We also correlate these changes with modulations of chaperone potential at different pH. We have followed the pH induced structural changes by circular dichroism spectroscopy and intrinsic tryptophan fluorescence. It is seen that lowering the pH from 9 has little effect on structure of the proteins till about pH6. At pH4, there is significant change of the secondary structure of the proteins, along with a 5nm hypsochromic shift of the emission maxima. Below pH4 the proteins undergo acid denaturation. Probing exposed hydrophobic patches on the proteins using protein-bound 8-anilinonaphthalene-1-sulfonate fluorescence demonstrates that there is higher solvent accessibility of hydrophobic surfaces in both forms of spectrin at around pH4. Dynamic light scattering and 90° light scattering studies show that the both forms of spectrin forms oligomers at pH~4. Chemical unfolding data shows that these oligomers are less stable than the tetrameric form. Aggregation studies with BSA show that at pH4, both spectrins exhibit better chaperone activity. This enhancement of chaperone like activity appears to result from an increase in regions of solvent-exposed hydrophobicity and oligomeric state of the spectrins which in turn are induced by moderately acid pH. This may have in-vivo implications in cells facing stress conditions where cytoplasmic pH is lowered.
Collapse
Affiliation(s)
- Dipayan Bose
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, HBNI, Kolkata, India
| | - Malay Patra
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, HBNI, Kolkata, India
| | - Abhijit Chakrabarti
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, HBNI, Kolkata, India.
| |
Collapse
|
26
|
D'Este E, Kamin D, Velte C, Göttfert F, Simons M, Hell SW. Subcortical cytoskeleton periodicity throughout the nervous system. Sci Rep 2016; 6:22741. [PMID: 26947559 PMCID: PMC4779989 DOI: 10.1038/srep22741] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/18/2016] [Indexed: 01/22/2023] Open
Abstract
Superresolution fluorescence microscopy recently revealed a ~190 nm periodic cytoskeleton lattice consisting of actin, spectrin, and other proteins underneath the membrane of cultured hippocampal neurons. Whether the periodic cytoskeleton lattice is a structural feature of all neurons and how it is modified when axons are ensheathed by myelin forming glial cells is not known. Here, STED nanoscopy is used to demonstrate that this structure is a commonplace of virtually all neuron types in vitro. To check how the subcortical meshwork is modified during myelination, we studied sciatic nerve fibers from adult mice. Periodicity of both actin and spectrin was uncovered at the internodes, indicating no substantial differences between unmyelinated and myelinated axons. Remarkably, the actin/spectrin pattern was also detected in glial cells such as cultured oligodendrocyte precursor cells. Altogether our work shows that the periodic subcortical cytoskeletal meshwork is a fundamental characteristic of cells in the nervous system and is not a distinctive feature of neurons, as previously thought.
Collapse
Affiliation(s)
- Elisa D'Este
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Dirk Kamin
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Caroline Velte
- Department of Cellular Neuroscience, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075 Göttingen, Germany
| | - Fabian Göttfert
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Mikael Simons
- Department of Cellular Neuroscience, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075 Göttingen, Germany
| | - Stefan W Hell
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| |
Collapse
|
27
|
|
28
|
Leterrier C, Potier J, Caillol G, Debarnot C, Rueda Boroni F, Dargent B. Nanoscale Architecture of the Axon Initial Segment Reveals an Organized and Robust Scaffold. Cell Rep 2015; 13:2781-93. [DOI: 10.1016/j.celrep.2015.11.051] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/14/2015] [Accepted: 11/13/2015] [Indexed: 12/17/2022] Open
|
29
|
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.
Collapse
|
30
|
Neupane B, Jin T, Mellor LF, Loboa EG, Ligler FS, Wang G. Continuous-Wave Stimulated Emission Depletion Microscope for Imaging Actin Cytoskeleton in Fixed and Live Cells. SENSORS 2015; 15:24178-90. [PMID: 26393614 PMCID: PMC4610488 DOI: 10.3390/s150924178] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 09/12/2015] [Accepted: 09/16/2015] [Indexed: 11/16/2022]
Abstract
Stimulated emission depletion (STED) microscopy provides a new opportunity to study fine sub-cellular structures and highly dynamic cellular processes, which are challenging to observe using conventional optical microscopy. Using actin as an example, we explored the feasibility of using a continuous wave (CW)-STED microscope to study the fine structure and dynamics in fixed and live cells. Actin plays an important role in cellular processes, whose functioning involves dynamic formation and reorganization of fine structures of actin filaments. Frequently used confocal fluorescence and STED microscopy dyes were employed to image fixed PC-12 cells (dyed with phalloidin- fluorescein isothiocyante) and live rat chondrosarcoma cells (RCS) transfected with actin-green fluorescent protein (GFP). Compared to conventional confocal fluorescence microscopy, CW-STED microscopy shows improved spatial resolution in both fixed and live cells. We were able to monitor cell morphology changes continuously; however, the number of repetitive analyses were limited primarily by the dyes used in these experiments and could be improved with the use of dyes less susceptible to photobleaching. In conclusion, CW-STED may disclose new information for biological systems with a proper characteristic length scale. The challenges of using CW-STED microscopy to study cell structures are discussed.
Collapse
Affiliation(s)
- Bhanu Neupane
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC 27695, USA.
| | - Tao Jin
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
| | - Liliana F Mellor
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC 27695, USA.
| | - Elizabeth G Loboa
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC 27695, USA.
| | - Frances S Ligler
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC 27695, USA.
| | - Gufeng Wang
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
| |
Collapse
|
31
|
|
32
|
Abstract
In this minireview, we cover the discovery of the human erythrocyte α spectrin E2/E3 ubiquitin conjugating/ligating enzymatic activity and the specific cysteines involved. We then discuss the consequences when this activity is partially inhibited in sickle cell disease and the possibility that the same attenuation is occurring in multiple organ dysfunction syndrome. We finish by discussing the reasons for believing that nonerythroid α spectrin isoforms (I and II) also have this activity and the importance of testing this hypothesis. If correct, this would suggest that the nonerythroid spectrin isoforms play a major role in protein ubiquitination in all cell types. This would open new fields in experimental biology focused on uncovering the impact that this enzymatic activity has upon protein-protein interactions, protein turnover, cellular signaling, and many other functions impacted by spectrin, including DNA repair.
Collapse
Affiliation(s)
- Steven R Goodman
- Department of Biochemistry and Molecular Biology, Department of Pediatrics, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Rachel Petrofes Chapa
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, College Station, TX 77843, USA
| | - Warren E Zimmer
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, College Station, TX 77843, USA
| |
Collapse
|
33
|
Dong Y, Yang Z, Liu D. Using Small Molecules to Prepare Vesicles with Designable Shapes and Sizes via Frame-Guided Assembly Strategy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:3768-3771. [PMID: 25939398 DOI: 10.1002/smll.201500240] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 03/16/2015] [Indexed: 06/04/2023]
Abstract
Following the principle of frame-guided assembly (FGA), a small amphiphilic molecule, sodium dodecyl sulfate, is shown to form vesicles with cholesterol as the leading hydrophobic group. These findings not only demonstrate the generality of the FGA but also provide a clue to understand the formation mechanism of the cell membrane, and even the origin of life.
Collapse
Affiliation(s)
- Yuanchen Dong
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Zhongqiang Yang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Dongsheng Liu
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| |
Collapse
|
34
|
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.
Collapse
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:
| |
Collapse
|
35
|
Chakrabarti A, Patra M. Differential interactions of two local anesthetics with phospholipid membrane and nonerythroid spectrin: Localization in presence of cholesterol and ganglioside, GM1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:821-32. [DOI: 10.1016/j.bbamem.2014.11.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 11/18/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
|
36
|
Patra M, Mukhopadhyay C, Chakrabarti A. Probing conformational stability and dynamics of erythroid and nonerythroid spectrin: effects of urea and guanidine hydrochloride. PLoS One 2015; 10:e0116991. [PMID: 25617632 PMCID: PMC4305312 DOI: 10.1371/journal.pone.0116991] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 12/18/2014] [Indexed: 11/19/2022] Open
Abstract
We have studied the conformational stability of the two homologous membrane skeletal proteins, the erythroid and non-erythroid spectrins, in their dimeric and tetrameric forms respectively during unfolding in the presence of urea and guanidine hydrochloride (GuHCl). Fluorescence and circular dichroism (CD) spectroscopy have been used to study the changes of intrinsic tryptophan fluorescence, anisotropy, far UV-CD and extrinsic fluorescence of bound 1-anilinonapthalene-8-sulfonic acid (ANS). Chemical unfolding of both proteins were reversible and could be described as a two state transition. The folded erythroid spectrin and non-erythroid spectrin were directly converted to unfolded monomer without formation of any intermediate. Fluorescence quenching, anisotropy, ANS binding and dynamic light scattering data suggest that in presence of low concentrations of the denaturants (up-to 1M) hydrogen bonding network and van der Waals interaction play a role inducing changes in quaternary as well as tertiary structures without complete dissociation of the subunits. This is the first report of two large worm like, multi-domain proteins obeying twofold rule which is commonly found in small globular proteins. The free energy of stabilization (ΔGuH20) for the dimeric spectrin has been 20 kcal/mol lesser than the tetrameric from.
Collapse
Affiliation(s)
- Malay Patra
- Chemistry Department, University of Calcutta, Kolkata, West Bengal, India
| | | | - Abhijit Chakrabarti
- Crystallography & Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal, India
| |
Collapse
|
37
|
Wong KKL, Li W, An Y, Duan Y, Li Z, Kang Y, Yan Y. β-Spectrin regulates the hippo signaling pathway and modulates the basal actin network. J Biol Chem 2015; 290:6397-407. [PMID: 25589787 DOI: 10.1074/jbc.m114.629493] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Emerging evidence suggests functional regulation of the Hippo pathway by the actin cytoskeleton, although the detailed molecular mechanism remains incomplete. In a genetic screen, we identified a requirement for β-Spectrin in the posterior follicle cells for the oocyte repolarization process during Drosophila mid-oogenesis. β-spectrin mutations lead to loss of Hippo signaling activity in the follicle cells. A similar reduction of Hippo signaling activity was observed after β-Spectrin knockdown in mammalian cells. We further demonstrated that β-spectrin mutations disrupt the basal actin network in follicle cells. The abnormal stress fiber-like actin structure on the basal side of follicle cells provides a likely link between the β-spectrin mutations and the loss of the Hippo signaling activity phenotype.
Collapse
Affiliation(s)
- Kenneth Kin Lam Wong
- From the Division of Life Science and Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China and
| | - Wenyang Li
- the Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544
| | - Yanru An
- From the Division of Life Science and Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China and
| | | | | | - Yibin Kang
- the Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544
| | - Yan Yan
- From the Division of Life Science and Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China and
| |
Collapse
|
38
|
Defects in Erythrocyte Membrane Skeletal Architecture. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 842:41-59. [DOI: 10.1007/978-3-319-11280-0_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
39
|
Zhao Z, Chen C, Dong Y, Yang Z, Fan QH, Liu D. Thermally Triggered Frame-Guided Assembly. Angew Chem Int Ed Engl 2014; 53:13468-70. [DOI: 10.1002/anie.201408231] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Indexed: 11/06/2022]
|
40
|
Zhao Z, Chen C, Dong Y, Yang Z, Fan QH, Liu D. Thermally Triggered Frame-Guided Assembly. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201408231] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
41
|
Blunk AD, Akbergenova Y, Cho RW, Lee J, Walldorf U, Xu K, Zhong G, Zhuang X, Littleton JT. Postsynaptic actin regulates active zone spacing and glutamate receptor apposition at the Drosophila neuromuscular junction. Mol Cell Neurosci 2014; 61:241-54. [PMID: 25066865 PMCID: PMC4134997 DOI: 10.1016/j.mcn.2014.07.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/14/2014] [Accepted: 07/23/2014] [Indexed: 12/26/2022] Open
Abstract
Synaptic communication requires precise alignment of presynaptic active zones with postsynaptic receptors to enable rapid and efficient neurotransmitter release. How transsynaptic signaling between connected partners organizes this synaptic apparatus is poorly understood. To further define the mechanisms that mediate synapse assembly, we carried out a chemical mutagenesis screen in Drosophila to identify mutants defective in the alignment of active zones with postsynaptic glutamate receptor fields at the larval neuromuscular junction. From this screen we identified a mutation in Actin 57B that disrupted synaptic morphology and presynaptic active zone organization. Actin 57B, one of six actin genes in Drosophila, is expressed within the postsynaptic bodywall musculature. The isolated allele, act(E84K), harbors a point mutation in a highly conserved glutamate residue in subdomain 1 that binds members of the Calponin Homology protein family, including spectrin. Homozygous act(E84K) mutants show impaired alignment and spacing of presynaptic active zones, as well as defects in apposition of active zones to postsynaptic glutamate receptor fields. act(E84K) mutants have disrupted postsynaptic actin networks surrounding presynaptic boutons, with the formation of aberrant actin swirls previously observed following disruption of postsynaptic spectrin. Consistent with a disruption of the postsynaptic actin cytoskeleton, spectrin, adducin and the PSD-95 homolog Discs-Large are all mislocalized in act(E84K) mutants. Genetic interactions between act(E84K) and neurexin mutants suggest that the postsynaptic actin cytoskeleton may function together with the Neurexin-Neuroligin transsynaptic signaling complex to mediate normal synapse development and presynaptic active zone organization.
Collapse
Affiliation(s)
- Aline D Blunk
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Yulia Akbergenova
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Richard W Cho
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Jihye Lee
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; The Department of Oral Pathology, School of Dentistry, Pusan National University, Republic of Korea
| | - Uwe Walldorf
- Department of Developmental Biology, University of Saarland, Homburg, Saar, Germany
| | - Ke Xu
- Howard Hughes Medical Institute (HHMI), Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Guisheng Zhong
- Howard Hughes Medical Institute (HHMI), Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Xiaowei Zhuang
- Howard Hughes Medical Institute (HHMI), Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States; Department of Physics, Harvard University, Cambridge, MA 02138, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
| |
Collapse
|
42
|
Dong Y, Sun Y, Wang L, Wang D, Zhou T, Yang Z, Chen Z, Wang Q, Fan Q, Liu D. Frame-Guided Assembly of Vesicles with Programmed Geometry and Dimensions. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201310715] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
43
|
Dong Y, Sun Y, Wang L, Wang D, Zhou T, Yang Z, Chen Z, Wang Q, Fan Q, Liu D. Frame-Guided Assembly of Vesicles with Programmed Geometry and Dimensions. Angew Chem Int Ed Engl 2014; 53:2607-10. [DOI: 10.1002/anie.201310715] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Indexed: 11/08/2022]
|
44
|
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.
Collapse
Affiliation(s)
- Meng He
- Department of Pharmacology and Cancer Biology, Duke University, Medical Center, Durham, North Carolina 27710, USA
| | | | | |
Collapse
|
45
|
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]
|
46
|
Fowler VM. The human erythrocyte plasma membrane: a Rosetta Stone for decoding membrane-cytoskeleton structure. CURRENT TOPICS IN MEMBRANES 2013; 72:39-88. [PMID: 24210427 DOI: 10.1016/b978-0-12-417027-8.00002-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The mammalian erythrocyte, or red blood cell (RBC), is a unique experiment of nature: a cell with no intracellular organelles, nucleus or transcellular cytoskeleton, and a plasma membrane with uniform structure across its entire surface. By virtue of these specialized properties, the RBC membrane has provided a template for discovery of the fundamental actin filament network machine of the membrane skeleton, now known to confer mechanical resilience, anchor membrane proteins, and organize membrane domains in all cells. This chapter provides a historical perspective and critical analysis of the biochemistry, structure, and physiological functions of this actin filament network in RBCs. The core units of this network are nodes of ~35-37 nm-long actin filaments, interconnected by long strands of (α1β1)₂-spectrin tetramers, forming a 2D isotropic lattice with quasi-hexagonal symmetry. Actin filament length and stability is critical for network formation, relying upon filament capping at both ends: tropomodulin-1 at pointed ends and αβ-adducin at barbed ends. Tropomodulin-1 capping is essential for precise filament lengths, and is enhanced by tropomyosin, which binds along the short actin filaments. αβ-adducin capping recruits spectrins to sites near barbed ends, promoting network formation. Accessory proteins, 4.1R and dematin, also promote spectrin binding to actin and, with αβ-adducin, link to membrane proteins, targeting actin nodes to the membrane. Dissection of the molecular organization within the RBC membrane skeleton is one of the paramount achievements of cell biological research in the past century. Future studies will reveal the structure and dynamics of actin filament capping, mechanisms of precise length regulation, and spectrin-actin lattice symmetry.
Collapse
Affiliation(s)
- Velia M Fowler
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA.
| |
Collapse
|
47
|
He J, Liu Y, Wang Q, Ji J. Purification and proteomic analysis of liver membrane skeletons. Methods Mol Biol 2012; 909:97-111. [PMID: 22903711 DOI: 10.1007/978-1-61779-959-4_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
The detergent-resistant membrane skeletons play a critical role in cell shaping and signaling. The focus of the methods described in this chapter is first on the preparation of membrane skeletons from liver by multistep sucrose density gradient centrifugation, and then on the analysis of the protein components of membrane skeletons using proteomics techniques. Two proteomic analysis strategies are described. In the first strategy, membrane skeleton proteins are separated by two-dimensional gel electrophoresis and identified by matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry. In the other strategy, proteins are separated by SDS-PAGE and identified by liquid chromatography-electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The methods facilitate the understanding of the structure of membrane skeletons.
Collapse
Affiliation(s)
- Jintang He
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, People's Republic of China
| | | | | | | |
Collapse
|
48
|
Xu K, Zhong G, Zhuang X. Actin, spectrin, and associated proteins form a periodic cytoskeletal structure in axons. Science 2012; 339:452-6. [PMID: 23239625 DOI: 10.1126/science.1232251] [Citation(s) in RCA: 845] [Impact Index Per Article: 70.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Actin and spectrin play important roles in neurons, but their organization in axons and dendrites remains unclear. We used stochastic optical reconstruction microscopy to study the organization of actin, spectrin, and associated proteins in neurons. Actin formed ringlike structures that wrapped around the circumference of axons and were evenly spaced along axonal shafts with a periodicity of ~180 to 190 nanometers. This periodic structure was not observed in dendrites, which instead contained long actin filaments running along dendritic shafts. Adducin, an actin-capping protein, colocalized with the actin rings. Spectrin exhibited periodic structures alternating with those of actin and adducin, and the distance between adjacent actin-adducin rings was comparable to the length of a spectrin tetramer. Sodium channels in axons were distributed in a periodic pattern coordinated with the underlying actin-spectrin-based cytoskeleton.
Collapse
Affiliation(s)
- Ke Xu
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | | | | |
Collapse
|
49
|
Spectrin Breakdown Products (SBDPs) as Potential Biomarkers for Neurodegenerative Diseases. ACTA ACUST UNITED AC 2012; 1:85-93. [PMID: 23710421 DOI: 10.1007/s13670-012-0009-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The world's human population ages rapidly thanks to the great advance in modern medicine. While more and more body system diseases become treatable and curable, age-related neurodegenerative diseases remain poorly understood mechanistically, and are desperately in need of preventive and therapeutic interventions. Biomarker development consists of a key part of concerted effort in combating neurodegenerative diseases. In many chronic neurodegenerative conditions, neuronal damage/death occurs long before the onset of disease symptoms, and abnormal proteolysis may either play an active role or be a companying event of neuronal injury. Increased spectrin cleavage yielding elevated spectrin breakdown products (SBDPs) by calcium-sensitive proteases such as calpain and caspases has been established in conditions associated with acute neuronal damage such as traumatic brain injury (TBI). Here we review literature regarding spectrin expression and metabolism in the brain, and propose a potential use of SBDPs as biomarkers for neurodegenerative diseases such as Alzheimer's diseases.
Collapse
|
50
|
Inter-subunit interactions in erythroid and non-erythroid spectrins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:420-7. [DOI: 10.1016/j.bbapap.2010.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 12/09/2010] [Accepted: 12/22/2010] [Indexed: 11/19/2022]
|