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Li D. Role of Spectrin in Endocytosis. Cells 2022; 11:cells11152459. [PMID: 35954302 PMCID: PMC9368487 DOI: 10.3390/cells11152459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/02/2022] [Accepted: 08/06/2022] [Indexed: 11/16/2022] Open
Abstract
Cytoskeletal spectrin is found in (non)erythroid cells. Eukaryotic endocytosis takes place for internalizing cargos from extracellular milieu. The role of spectrin in endocytosis still remains poorly understood. Here, I summarize current knowledge of spectrin function, spectrin-based cytoskeleton and endocytosis of erythrocytes, and highlight how spectrin contributes to endocytosis and working models in different types of cells. From an evolutionary viewpoint, I discuss spectrin and endocytosis in a range of organisms, particularly in plants and yeast where spectrin is absent. Together, the role of spectrin in endocytosis is related to its post-translational modification, movement/rearrangement, elimination (by proteases) and meshwork fencing.
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Affiliation(s)
- Donghai Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
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2
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Bose D, Aggarwal S, Das D, Narayana C, Chakrabarti A. Erythroid spectrin binding modulates peroxidase and catalase activity of heme proteins. IUBMB Life 2022; 74:474-487. [DOI: 10.1002/iub.2607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/27/2022] [Accepted: 02/08/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Dipayan Bose
- Crystallography & Molecular Biology Division Saha Institute of Nuclear Physics Kolkata India
- Homi Bhabha National Institute Mumbai India
| | - Shantanu Aggarwal
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Bengaluru India
| | - Debashree Das
- Crystallography & Molecular Biology Division Saha Institute of Nuclear Physics Kolkata India
| | - Chandrabhas Narayana
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Bengaluru India
| | - Abhijit Chakrabarti
- Crystallography & Molecular Biology Division Saha Institute of Nuclear Physics Kolkata India
- Homi Bhabha National Institute Mumbai India
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3
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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: 2] [Impact Index Per Article: 0.5] [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.
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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.
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4
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Bose D, Chakrabarti A. Localizing the chaperone activity of erythroid spectrin. Cytoskeleton (Hoboken) 2019; 76:383-397. [DOI: 10.1002/cm.21556] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/31/2019] [Accepted: 08/06/2019] [Indexed: 02/05/2023]
Affiliation(s)
- Dipayan Bose
- Crystallography and Molecular Biology DivisionSaha Institute of Nuclear Physics Kolkata India
- Homi Bhabha National Institute Mumbai India
| | - Abhijit Chakrabarti
- Crystallography and Molecular Biology DivisionSaha Institute of Nuclear Physics Kolkata India
- Homi Bhabha National Institute Mumbai India
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5
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Bose D, Chakrabarti A. Substrate specificity in the context of molecular chaperones. IUBMB Life 2017; 69:647-659. [PMID: 28748601 DOI: 10.1002/iub.1656] [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: 05/31/2017] [Accepted: 07/03/2017] [Indexed: 12/23/2022]
Abstract
Molecular chaperones are one of the key players in protein biology and as such their structure and mechanism of action have been extensively studied. However the substrate specificity of molecular chaperones has not been well investigated. This review aims to summarize what is known about the substrate specificity and substrate recognition motifs of chaperones so as to better understand what substrate specificity means in the context of molecular chaperones. Available literature shows that the majority of chaperones have broad substrate range and recognize non-native conformations of proteins depending on recognition of hydrophobic and/or charged patches. Based on these recognition motifs chaperones can select for early, mid or late folding intermediates. Another major contributor to chaperone specificity are the co-chaperones they interact with as well as the sub-cellular location they are expressed in and the inducability of their expression. Some chaperones which have only one or a few known substrates are reported. In their case the mode of recognition seems to be specific structural complementarity between chaperone and substrate. It can be concluded that the vast majority of chaperones do not show a high degree of specificity but recognize elements that signal non-native protein conformation and their substrate range is modulated by the context they function in. However a few chaperones are known that display exquisite specificity of their substrate e.g. mammalian heat shock protein 47 collagen interaction. © 2017 IUBMB Life, 69(9):647-659, 2017.
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Affiliation(s)
- Dipayan Bose
- 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
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6
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Das D, Pramanik U, Patra M, Banerjee M, Chakrabarti A. Differential interactions of imatinib mesylate with the membrane skeletal protein spectrin and hemoglobin. RSC Adv 2016. [DOI: 10.1039/c5ra27276a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The anti-leukaemia drug imatinib has been shown to bind to spectrin, and to hemoglobin in its oxy-form with binding dissociation constants of 48 μM and 63 μM at 25 °C respectively.
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Affiliation(s)
- Debashree Das
- Crystallography & Molecular Biology Division
- Saha Institute of Nuclear Physics
- HBNI
- Kolkata 700064
- India
| | - Ushasi Pramanik
- Biophysics, Molecular Biology and Bioinformatics
- University of Calcutta
- Kolkata 700009
- India
| | - Malay Patra
- Chemistry Department
- University of Calcutta
- Kolkata 700009
- India
| | | | - Abhijit Chakrabarti
- Crystallography & Molecular Biology Division
- Saha Institute of Nuclear Physics
- HBNI
- Kolkata 700064
- India
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7
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Basu A, Chakrabarti A. Hemoglobin interacting proteins and implications of spectrin hemoglobin interaction. J Proteomics 2015; 128:469-75. [DOI: 10.1016/j.jprot.2015.06.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/16/2015] [Accepted: 06/25/2015] [Indexed: 01/09/2023]
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8
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Fluorescence study of the effect of cholesterol on spectrin–aminophospholipid interactions. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 44:635-45. [DOI: 10.1007/s00249-015-1057-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 06/17/2015] [Accepted: 06/25/2015] [Indexed: 11/26/2022]
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9
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Das D, Patra M, Chakrabarti A. Binding of hemin, hematoporphyrin, and protoporphyrin with erythroid spectrin: fluorescence and molecular docking studies. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 44:171-82. [PMID: 25737232 DOI: 10.1007/s00249-015-1012-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/29/2015] [Accepted: 02/03/2015] [Indexed: 11/27/2022]
Abstract
Free heme has toxic effects, for example lipid peroxidation, DNA damage, and protein aggregation. In severe hemolysis, which occurs during pathological states, for example sickle cell disease, ischemia reperfusion, and malaria, levels of free heme increase inside erythrocytes. The purpose of this study was to investigate whether spectrin, the major erythroid cytoskeleton protein, is involved as an acceptor of free heme. We compared the interactions of three heme derivatives, hemin chloride, hematoporphyrin, and protoporphyrin-IX, with dimeric and tetrameric spectrin. The dissociation constants (K d) for binding to spectrin dimer and tetramer were 0.57 and 1.16 µM respectively. Thermodynamic data associated with this binding revealed the binding to be favored by a positive change in entropy. Although molecular docking studies identified the SH3 domain as the unique binding site of these heme derivatives to erythroid spectrin, experimental results indicated a binding stoichiometry of 1 heme attached to both dimeric and tetrameric spectrin, indicating the common self-associating domain to be the unique binding site. We also noticed heme-induced structural changes in the membrane skeletal protein. Erythroid spectrin could thus act as a potential acceptor of heme, particularly relevant under disease conditions.
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Affiliation(s)
- Debashree Das
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, 700064, India
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10
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Patra M, Mukhopadhyay C, Chakrabarti A. Malachite green interacts with the membrane skeletal protein, spectrin. RSC Adv 2015. [DOI: 10.1039/c5ra15488j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Energy minimized complex of MG with the self association domain of spectrin.
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Affiliation(s)
- Malay Patra
- Chemistry Department
- University of Calcutta
- Kolkata 700009
- India
| | | | - Abhijit Chakrabarti
- Crystallography & Molecular Biology Division
- Saha Institute of Nuclear Physics
- Kolkata 700064
- India
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11
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Banerjee M, Maiti S, Kundu I, Chakrabarti A, Basu S. Simultaneous Occurrence of Energy Transfer and Photoinduced Electron Transfer in Interactions of Hen Egg White Lysozyme with 4-Nitroquinoline-1-Oxide. Photochem Photobiol 2010; 86:1237-46. [DOI: 10.1111/j.1751-1097.2010.00811.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Sankhala RS, Swamy MJ. The Major Protein of Bovine Seminal Plasma, PDC-109, Is a Molecular Chaperone. Biochemistry 2010; 49:3908-18. [DOI: 10.1021/bi100051d] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
| | - Musti J. Swamy
- School of Chemistry, University of Hyderabad, Hyderabad-500046, India
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13
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Chakrabarti A, Datta P, Bhattacharya D, Basu S, Saha S. Oxidative crosslinking, spectrin and membrane interactions of hemoglobin mixtures in HbEbeta-thalassemia. ACTA ACUST UNITED AC 2009; 13:361-8. [PMID: 19055866 DOI: 10.1179/102453308x343455] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The authors have studied the interactions of intact hemoglobin mixtures of HbE and HbA, with the major erythroid membrane skeletal protein, spectrin and tailor-made phospholipids membranes containing aminophospholipids to understand the role of spectrin and phospholipids of erythrocytes in the overall pathophysiology of the hemoglobin disorders. Hemoglobin mixtures were isolated and purified from the peripheral blood samples of HbE carriers and different HbEbeta thalassemia patients, taken for diagnosis. Spectrin binding was studied by fluorescence and oxidative crosslinking, by SDS-PAGE. Membrane perturbation experiments were carried out to study the leakage of the self-quenching fluorophore, carboxyfluorescein, entrapped in the phospholipid vesicles. Hemoglobin mixtures with elevated levels of HbE showed stronger interactions with spectrin reflected in the decrease in binding dissociation constant from 17 to 5 muM upon increase in HbE% from about 30 to 90% in the hemolysates. The yield of the spectrin crosslinked complexes of such hemoglobin mixtures also increased with increase in HbE levels. Presence of ATP/Mg and DPG were found to decrease the overall yield of such complexes and the binding affinity of hemoglobins to spectrin. HbE rich hemolysates also induced greater leakage of entrapped carboxyfluorescein (CF) from phospholipid membranes containing aminophospholipids. Results from this study indicate the roles of skeletal proteins and aminophospholipids, particularly under oxidative stress conditions to be important in the premature destruction of erythrocytes in hemoglobin disorders, e.g. HbEbeta-thalassaemia.
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Cotado-Sampayo M, Ramos PO, Perez RO, Ojha M, Barja F. Specificity of commercial anti-spectrin antibody in the study of fungal and Oomycete spectrin: cross-reaction with proteins other than spectrin. Fungal Genet Biol 2008; 45:1008-15. [PMID: 18378170 DOI: 10.1016/j.fgb.2008.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 02/12/2008] [Accepted: 02/13/2008] [Indexed: 10/22/2022]
Abstract
Spectrin was first described in erythrocytes where it forms a filamentous network in the cytoplasmic face of the plasma membrane and participates in the membrane's structural integrity in addition to controlling the lateral mobility of integral membrane proteins. In fungi, spectrin-like proteins have been described in the plasma membrane, concentrated mainly in the region of maximum apical expansion. This localization led to the idea of a spectrin based membrane skeleton in fungi participating in mechanical integrity of the plasma membrane, generating and maintaining cell polarity. The occurrence of spectrin-like proteins in filamentous fungi, yeasts and Oomycetes, however, is questionable since the presence of such proteins has only been demonstrated with immunochemical methods using antibodies whose specificity is unclear. There is no evidence of a gene coding for the high molecular weight alphabeta-spectrin in the genome of these organisms. Mass spectrometric analysis of the anti alphabeta-spectrin immunoreacting peptides from Neurospora crassa and Phytophthora infestans identified them as elongation factor 2 (NCU07700.4) and Hsp70 (PITG_13237.1), respectively. An attempt was made to correlate the reactivity of anti-spectrin antibody to a common feature of these three proteins i.e., spectrin, elongation factor 2 and heat shock protein 70, in that they all have a hydrophobic region implicated in chaperon activity.
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Affiliation(s)
- Marta Cotado-Sampayo
- Laboratory of Bioenergetics and Microbiology, University of Geneva, ch. des Embrouchis 10, CH 1254 Jussy-Geneva, Switzerland
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15
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Datta P, Chakrabarty S, Chakrabarty A, Chakrabarti A. Spectrin interactions with globin chains in the presence of phosphate metabolites and hydrogen peroxide: implications for thalassaemia. J Biosci 2007; 32:1147-51. [PMID: 17954975 DOI: 10.1007/s12038-007-0116-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have shown the differential interactions of the erythroid skeletal protein spectrin with the globin subunits of adult haemoglobin (HbA); these indicate a preference for alpha-globin over that for beta-globin and intact HbA in an adenosine 5'-triphosphate (ATP)-dependent manner. The presence of Mg/ATP led to an appreciable decrease in the binding affinity of the alpha-globin chain to spectrin and the overall yield of globin-spectrin cross-linked complexes formed in the presence of hydrogen peroxide. Similar effects were also seen in the presence of 2-,3-diphosphoglycerate (2,3 DPG), the other important phosphate metabolite of erythrocytes. The binding affinity and yield of cross-linked high molecular weight complexes (HMWCs) formed under oxidative conditions were significantly higher in alpha-globin compared with intact haemoglobin, HbA and the beta-globin chain. The results of this study indicate a possible correlation of the preferential spectrin binding of the alpha-globin chain over that of the beta-globin in the haemoglobin disorder beta-thalassaemia.
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Affiliation(s)
- Poppy Datta
- Biophysics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
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16
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Abstract
Spectrin is the major constituent protein of the erythrocyte cytoskeleton which forms a filamentous network on the cytoplasmic face of the membrane by providing a scaffold for a variety of proteins. In this review, several aspects of spectrin organization are highlighted, particularly with respect to its ability to bind hydrophobic ligands and its interaction with membrane surfaces. The characteristic binding of the fluorescent hydrophobic probes Prodan and pyrene to spectrin, which allows an estimation of the polarity of the hydrophobic probe binding site, is illustrated. In addition, the contribution of uniquely localized and conserved tryptophan residues in the 'spectrin repeats' in these processes is discussed. A functional implication of the presence of hydrophobic binding sites in spectrin is its recently discovered chaperone-like activity. Interestingly, spectrin exhibits residual structural integrity even after denaturation which could be considered as a hallmark of cytoskeletal proteins. Future research could provide useful information about the possible role played by spectrin in cellular physiology in healthy and diseased states.
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Affiliation(s)
- Abhijit Chakrabarti
- Biophysics Division, Saha Institute of Nuclear Physics, Kolkata 700 064, India.
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17
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Ahn M, Kim S, Kang M, Ryu Y, Kim TD. Chaperone-like activities of alpha-synuclein: alpha-synuclein assists enzyme activities of esterases. Biochem Biophys Res Commun 2006; 346:1142-9. [PMID: 16796993 DOI: 10.1016/j.bbrc.2006.05.213] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Accepted: 05/29/2006] [Indexed: 11/16/2022]
Abstract
Alpha-synuclein, a major constituent of Lewy bodies (LBs), has been implicated to play a critical role in the pathogenesis of Parkinson's disease (PD), although the physiological function of alpha-synuclein has not yet been known. Here we have shown that alpha-synuclein, which has no well-defined secondary or tertiary structure, can protect the enzyme activity of microbial esterases against stress conditions such as heat, pH, and organic solvents. In particular, the flexibility of alpha-synuclein and its C-terminal region seems to be important for complex formation, but the structural integrity of the C-terminal region may not be required for stabilization of enzyme activity. In addition, atomic force microscopy (AFM) and in vivo enzyme assays showed highly specific interactions of esterases with alpha-synuclein. Our results indicate that alpha-synuclein not only protects the enzyme activity of microbial esterases in vitro, but also can stabilize the active conformation of microbial esterases in vivo.
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Affiliation(s)
- Misun Ahn
- Division of Biotechnology and Molecular Engineering, College of Engineering, Ajou University, Suwon 443-749, Republic of Korea
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18
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Mok MTS, Edwards MR. Kinetic and physical characterization of the inducible UDP-N-acetylglucosamine pyrophosphorylase from Giardia intestinalis. J Biol Chem 2005; 280:39363-72. [PMID: 16169849 DOI: 10.1074/jbc.m509209200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The UDP-N-acetylglucosamine pyrophosphorylase in Giardia intestinalis (GiUAP) is one of the five inducible enzymes to synthesize UDP-GalNAc, which is an important precursor for cyst wall synthesis. The recombinant UDP-N-acetylglucosamine pyrophosphorylase (rGiUAP) and its mutants G108A and G210A were expressed and identified by SDS-PAGE, size-exclusion chromatography, Western hybridization, and MALDI mass spectrometry. Sequence comparison with other eukaryotic UAPs has identified three specific motifs. Within these motifs alanine substitution for Gly(108) or Gly(210) dramatically reduced the pyrophosphate synthesis, suggesting these amino acids are catalytic residues. Besides, the rGiUAP was found to have relaxed binding to other uridine-based nucleotides, suggesting the substrate binding pocket is specific to uridine rather than phosphate group(s). Moreover, thermal denaturation analysis showed a significant increase in T(m) for the rGiUAP and G108A upon binding of the substrate Mg-UTP. In contrast, G210A showed a decreased T(m) upon binding of Mg-UTP. These results showed that binding of Mg-UTP increases protein stability of the rGiUAP, and the catalytic residue Gly(210) plays a significant role in stabilizing the protein structure. Such stabilization effect induced by substrate binding might be physiologically important as it favors the production of UDP-GlcNAc and hence the downstream GalNAc, which is crucial to survival of Giardia. These results help to define the essential amino acids for catalysis in the GiUAP and reveal the role of Mg-UTP binding in regulation of protein stability.
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Affiliation(s)
- Myth T S Mok
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney 2052, Australia.
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19
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Ray S, Chakrabarti A. Membrane interaction of erythroid spectrin: surface-density-dependent high-affinity binding to phosphatidylethanolamine. Mol Membr Biol 2004; 21:93-100. [PMID: 15204438 DOI: 10.1080/09687680310001625800] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Density-dependent spectrin binding to dimyristoylphosphatidylcholine/dimyristoylphosphatidylethanolamine (DMPC/DMPE) small uni-lamellar vesicles (SUVs) has been directly evaluated in this work from the increase in the extent of quenching of the tryptophan fluorescence of spectrin at two different temperatures, above and below the main phase transition temperatures (Tm). Results from the binding studies of spectrin to phospholipid SUVs indicated that the binding dissociation constant Kd, increased from 45 +/- 7 nM in pure DMPC SUVs to 219 +/- 20 nM in DMPC/DMPE (50:50) SUVs, both in the gel and liquid crystalline phase. However, in pure DMPE SUVs the Kd decreased drastically to 0.7 +/- 0.2 nM in the gel phase at 18 degrees C and to 2.6 +/- 0.7 nM in the fluid phase at 55 degrees C indicating a high affinity binding of spectrin for the bilayer-forming DMPE. The maximum extent of phospholipid-induced quenching and the number of spectrin molecules associated with one SUV particle, evaluated in the present work, led to a model in DMPC/DMPE bilayer membranes indicating the PE-binding site of spectrin to localize at one of the terminal domains of the dimeric spectrin. A direct evidence of the localization of the PE-binding site at one of the terminal ends of the spectrin dimer also came from electron microscopic observation in fluid membranes made of bovine brain PE.
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Affiliation(s)
- Sibnath Ray
- Biophysics Division, Saha Institute of Nuclear Physics, Kolkata, India
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20
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Bhattacharyya M, Ray S, Bhattacharya S, Chakrabarti A. Chaperone activity and prodan binding at the self-associating domain of erythroid spectrin. J Biol Chem 2004; 279:55080-8. [PMID: 15492010 DOI: 10.1074/jbc.m406418200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Spectrin, the major constituent protein of the erythrocyte membrane skeleton, exhibits chaperone activity by preventing the irreversible aggregation of insulin at 25 degrees C and that of alcohol dehydrogenase at 50 degrees C. The dimeric spectrin and the two subunits, alpha-spectrin and beta-spectrin prevent such aggregation appreciably better, 70% in presence of dimeric spectrin at an insulin:spectrin ratio of 1:1, than that in presence of the tetramer of 25%. Our results also show that spectrin binds to denatured enzymes alpha-glucosidase and alkaline phosphatase during refolding and the reactivation yields are increased in the presence of the spectrin derivatives when compared with those refolded in their absence. The unique hydrophobic binding site on spectrin for the fluorescence probe, 6-propionyl-2-(dimethylamino)naphthalene (Prodan) has been established to localize at the self-associating domain with the binding stoichiometry of one Prodan/both dimeric and tetrameric spectrin. The other fluorescence probe, 1-anilinonaphthalene-8-sulfonic acid, does not show such specificity for spectrin, and the binding stoichiometry is between 3 and 5 1-anilinonaphthalene-8-sulfonic acid/dimeric and tetrameric spectrin, respectively. Regions in alpha- and beta-spectrins have been found to have sequence homology with known chaperone proteins. More than 50% similarities in alpha-spectrin near the N terminus with human Hsp90 and in beta-spectrin near the C terminus with human Hsp90 and Escherichia coli DnaJ have been found, indicating a potential chaperone-like sequence to be present near the self-associating domain that is formed by portions of alpha-spectrin near the N terminus and the beta-spectrin near the C terminus. There are other patches of sequences also in both the spectrin polypeptides, at the other termini as well as in the middle of the rod domain having significant homology with well known chaperone proteins.
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Affiliation(s)
- Malyasri Bhattacharyya
- Biophysics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagr, Kolkata 700064, India
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Chattopadhyay A, Rawat SS, Kelkar DA, Ray S, Chakrabarti A. Organization and dynamics of tryptophan residues in erythroid spectrin: novel structural features of denatured spectrin revealed by the wavelength-selective fluorescence approach. Protein Sci 2004; 12:2389-403. [PMID: 14573853 PMCID: PMC2366958 DOI: 10.1110/ps.03302003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We have investigated the organization and dynamics of the functionally important tryptophan residues of erythroid spectrin in native and denatured conditions utilizing the wavelength-selective fluorescence approach. We observed a red edge excitation shift (REES) of 4 nm for the tryptophans in the case of spectrin in its native state. This indicates that tryptophans in spectrin are localized in a microenvironment of restricted mobility, and that the regions surrounding the spectrin tryptophans offer considerable restriction to the reorientational motion of the water dipoles around the excited state tryptophans. Interestingly, spectrin exhibits a REES of 3 nm even when denatured in 8 M urea. This represents the first report of a denatured protein displaying REES. Observation of REES in the denatured state implies that some of the structural and dynamic features of this microenvironment around the spectrin tryptophans are retained even when the protein is denatured. Fluorescence quenching data of denatured spectrin support this conclusion. In addition, we have deduced the organization and dynamics of the hydrophobic binding site of the polarity-sensitive fluorescent probe PRODAN that binds erythroid spectrin with high affinity. When bound to spectrin, PRODAN exhibits a REES of 9 nm. Because PRODAN binds to a hydrophobic site in spectrin, such a result would directly imply that this region of spectrin offers considerable restriction to the reorientational motion of the solvent dipoles around the excited state fluorophore. The results of our study could provide vital insight into the role of tryptophans in the stability and folding of spectrin.
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Datta P, Chakrabarty SB, Chakrabarty A, Chakrabarti A. Interaction of erythroid spectrin with hemoglobin variants: implications in beta-thalassemia. Blood Cells Mol Dis 2003; 30:248-53. [PMID: 12737941 DOI: 10.1016/s1079-9796(03)00019-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Among the few studies, producing contradictory results, done on the interaction of erythroid membrane skeletal spectrin with hemoglobin (Hb), none has been able to provide a quantitative estimate of the association of spectrin with Hb. In this work, studies on the interactions of erythroid spectrin with Hb have been elaborated upon using a novel fluorescence technique. The concentration-dependent change in the fluorescence intensity of fluorescein-conjugated spectrin (F-spectrin) in presence of oxy-Hb indicated binding with a dissociation constant of approximately 20 microM that has been directly evaluated from the increase in the extent of quenching of the fluorescein fluorescence of F-spectrin by reverse titration with the increasing concentrations of different Hb samples isolated from both normal and beta-thalassemic patients. The Hb compositions, with major components of the normal HbA, the fetal HbF, and the variant HbA2, of each individual were estimated using the Variant HPLC device of Bio-Rad. Results of the present study indicated that the dissociation constant, K(d), of spectrin binding to Hb decreased from 19.5 +/- 2 microM in normal individuals to of 6.5 +/- 0.5 microM in the presence of 73% HbA2 along with coeluted variants in the blood samples of patients suffering from beta-thalassemia, indicating differential interactions of the Hb variants with spectrin.
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Affiliation(s)
- Poppy Datta
- Biophysics Division, Saha Institute of Nuclear Physics, 37 Belgachia Road, Kolkata 700037, India
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Mondal M, Chakrabarti A. The tertiary amine local anesthetic dibucaine binds to the membrane skeletal protein spectrin. FEBS Lett 2002; 532:396-400. [PMID: 12482599 DOI: 10.1016/s0014-5793(02)03721-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The quinoline-based tertiary amine dibucaine has been shown to bind the membrane skeletal protein spectrin with a dissociation constant of 3.5x10(-5) M at 25 degrees C. Such binding is detected by monitoring the quenching of the tryptophan fluorescence intensity with increasing concentrations of dibucaine only and not with the benzene-based local anesthetics procaine, tetracaine and lidocaine. Binding of dibucaine also indicated changes in the tertiary structure of spectrin indicated by a circular dichroism spectrum in the near-UV region due to absorption of the aromatic side chains. The thermodynamic parameters associated with the binding indicated the interaction of dibucaine and spectrin to be enthalpy-driven and insensitive to an increase in the ionic strength of the buffer.
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Affiliation(s)
- Mousumi Mondal
- Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, 700064, Calcutta, India
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