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Oncomodulin (OCM) uniquely regulates calcium signaling in neonatal cochlear outer hair cells. Cell Calcium 2022; 105:102613. [PMID: 35797824 PMCID: PMC9297295 DOI: 10.1016/j.ceca.2022.102613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/06/2022] [Accepted: 06/09/2022] [Indexed: 11/23/2022]
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2
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What Is Parvalbumin for? Biomolecules 2022; 12:biom12050656. [PMID: 35625584 PMCID: PMC9138604 DOI: 10.3390/biom12050656] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/25/2022] [Accepted: 04/28/2022] [Indexed: 12/28/2022] Open
Abstract
Parvalbumin (PA) is a small, acidic, mostly cytosolic Ca2+-binding protein of the EF-hand superfamily. Structural and physical properties of PA are well studied but recently two highly conserved structural motifs consisting of three amino acids each (clusters I and II), which contribute to the hydrophobic core of the EF-hand domains, have been revealed. Despite several decades of studies, physiological functions of PA are still poorly known. Since no target proteins have been revealed for PA so far, it is believed that PA acts as a slow calcium buffer. Numerous experiments on various muscle systems have shown that PA accelerates the relaxation of fast skeletal muscles. It has been found that oxidation of PA by reactive oxygen species (ROS) is conformation-dependent and one more physiological function of PA in fast muscles could be a protection of these cells from ROS. PA is thought to regulate calcium-dependent metabolic and electric processes within the population of gamma-aminobutyric acid (GABA) neurons. Genetic elimination of PA results in changes in GABAergic synaptic transmission. Mammalian oncomodulin (OM), the β isoform of PA, is expressed mostly in cochlear outer hair cells and in vestibular hair cells. OM knockout mice lose their hearing after 3–4 months. It was suggested that, in sensory cells, OM maintains auditory function, most likely affecting outer hair cells’ motility mechanisms.
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3
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The Highly Conservative Cysteine of Oncomodulin as a Feasible Redox Sensor. Biomolecules 2021; 11:biom11010066. [PMID: 33419032 PMCID: PMC7825312 DOI: 10.3390/biom11010066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/01/2021] [Accepted: 01/03/2021] [Indexed: 11/17/2022] Open
Abstract
Oncomodulin (Ocm), or parvalbumin β, is an 11-12 kDa Ca2+-binding protein found inside and outside of vertebrate cells, which regulates numerous processes via poorly understood mechanisms. Ocm consists of two active Ca2+-specific domains of the EF-hand type ("helix-loop-helix" motif), covered by an EF-hand domain with inactive EF-hand loop, which contains a highly conservative cysteine with unknown function. In this study, we have explored peculiarities of the microenvironment of the conservative Cys18 of recombinant rat Ocm (rWT Ocm), redox properties of this residue, and structural/functional sensitivity of rWT Ocm to the homologous C18S substitution. We have found that pKa
of the Cys18 thiol lays beyond the physiological pH range. The measurement of redox dependence of rWT Ocm thiol-disulfide equilibrium (glutathione redox pair) showed that redox potential of Cys18 for the metal-free and Ca2+-loaded protein is of -168 mV and -176 mV, respectively. Therefore, the conservative thiol of rWT Ocm is prone to disulfide dimerization under physiological redox conditions. The C18S substitution drastically reduces α-helices content of the metal-free and Mg2+-bound Ocm, increases solvent accessibility of its hydrophobic residues, eliminates the cooperative thermal transition in the apo-protein, suppresses Ca2+/Mg2+ affinity of the EF site, and accelerates Ca2+ dissociation from Ocm. The distinct structural and functional consequences of the minor structural modification of Cys18 indicate its possible redox sensory function. Since some other EF-hand proteins also contain a conservative redox-sensitive cysteine located in an inactive EF-hand loop, it is reasonable to suggest that in the course of evolution, some of the EF-hands attained redox sensitivity at the expense of the loss of their Ca2+ affinity.
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4
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Amyloid formation of fish β-parvalbumin involves primary nucleation triggered by disulfide-bridged protein dimers. Proc Natl Acad Sci U S A 2020; 117:27997-28004. [PMID: 33093204 PMCID: PMC7668186 DOI: 10.1073/pnas.2015503117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Amyloid fibrils are generally related to neurodegenerative diseases, but they can also be part of normal protein function. Amyloid formation involves numerous steps and intermediate species. In this study, we investigated a fish protein, beta-parvalbumin, which readily forms amyloid on ligand removal. Using biophysical experiments, we provide evidence that the underlying mechanism of amyloid formation includes primary nucleation and elongation processes; we also reveal a key role for a disulfide-bridged dimer in the nucleation step. Little is known about intermolecular disulfides in amyloid formation, but covalent dimers and dimer-induced aggregation may be of clinical relevance, because oxidative stress, which can trigger covalent bond formation, is often a hallmark of human neurodegenerative diseases. Amyloid formation involves the conversion of soluble protein species to an aggregated state. Amyloid fibrils of β-parvalbumin, a protein abundant in fish, act as an allergen but also inhibit the in vitro assembly of the Parkinson protein α-synuclein. However, the intrinsic aggregation mechanism of β-parvalbumin has not yet been elucidated. We performed biophysical experiments in combination with mathematical modeling of aggregation kinetics and discovered that the aggregation of β-parvalbumin is initiated by the formation of dimers stabilized by disulfide bonds and then proceeds via primary nucleation and fibril elongation processes. Dimer formation is accelerated by H2O2 and hindered by reducing agents, resulting in faster and slower aggregation rates, respectively. Purified β-parvalbumin dimers readily assemble into amyloid fibrils with similar morphology as those formed when starting from monomer solutions. Furthermore, addition of preformed dimers accelerates the aggregation reaction of monomers. Aggregation of purified β-parvalbumin dimers follows the same kinetic mechanism as that of monomers, implying that the rate-limiting primary nucleus is larger than a dimer and/or involves structural conversion. Our findings demonstrate a folded protein system in which spontaneously formed intermolecular disulfide bonds initiate amyloid fibril formation by recruitment of monomers. This dimer-induced aggregation mechanism may be of relevance for human amyloid diseases in which oxidative stress is often an associated hallmark.
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5
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Schwaller B. Cytosolic Ca 2+ Buffers Are Inherently Ca 2+ Signal Modulators. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035543. [PMID: 31308146 DOI: 10.1101/cshperspect.a035543] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
For precisely regulating intracellular Ca2+ signals in a time- and space-dependent manner, cells make use of various components of the "Ca2+ signaling toolkit," including Ca2+ entry and Ca2+ extrusion systems. A class of cytosolic Ca2+-binding proteins termed Ca2+ buffers serves as modulators of such, mostly short-lived Ca2+ signals. Prototypical Ca2+ buffers include parvalbumins (α and β isoforms), calbindin-D9k, calbindin-D28k, and calretinin. Although initially considered to function as pure Ca2+ buffers, that is, as intracellular Ca2+ signal modulators controlling the shape (amplitude, decay, spread) of Ca2+ signals, evidence has accumulated that calbindin-D28k and calretinin have additional Ca2+ sensor functions. These other functions are brought about by direct interactions with target proteins, thereby modulating their targets' function/activity. Dysregulation of Ca2+ buffer expression is associated with several neurologic/neurodevelopmental disorders including autism spectrum disorder (ASD) and schizophrenia. In some cases, the presence of these proteins is presumed to confer a neuroprotective effect, as evidenced in animal models of Parkinson's or Alzheimer's disease.
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Affiliation(s)
- Beat Schwaller
- Department of Anatomy, Section of Medicine, University of Fribourg, CH-1700 Fribourg, Switzerland
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6
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Climer LK, Cox AM, Reynolds TJ, Simmons DD. Oncomodulin: The Enigmatic Parvalbumin Protein. Front Mol Neurosci 2019; 12:235. [PMID: 31649505 PMCID: PMC6794386 DOI: 10.3389/fnmol.2019.00235] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 09/13/2019] [Indexed: 01/21/2023] Open
Abstract
EF-hand Ca2+-binding protein family members, α- and β-parvalbumins have been studied for decades. Yet, considerable information is lacking distinguishing functional differences between mammalian α-parvalbumin (PVALB) and oncomodulin (OCM), a branded β-parvalbumin. Herein, we provide an overview detailing the current body of work centered around OCM as an EF-Hand Ca2+-binding protein and describe potential mechanisms of OCM function within the inner ear and immune cells. Additionally, we posit that OCM is evolutionarily distinct from PVALB and most other β-parvalbumins. This review summarizes recent studies pertaining to the function of OCM and emphasizes OCM as a parvalbumin possessing a unique cell and tissue distribution, Ca2+ buffering capacity and phylogenetic origin.
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Affiliation(s)
- Leslie K Climer
- Department of Biology, Baylor University, Waco, TX, United States.,Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
| | - Andrew M Cox
- Department of Biology, Baylor University, Waco, TX, United States.,Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States
| | | | - Dwayne D Simmons
- Department of Biology, Baylor University, Waco, TX, United States.,Department of Psychology and Neuroscience, Baylor University, Waco, TX, United States.,Biomedical Sciences Program, Baylor University, Waco, TX, United States
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7
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Deryusheva EI, Denesyuk AI, Denessiouk K, Uversky VN, Permyakov SE, Permyakov EA. On the relationship between the conserved ‘black’ and ‘gray’ structural clusters and intrinsic disorder in parvalbumins. Int J Biol Macromol 2018; 120:1055-1062. [DOI: 10.1016/j.ijbiomac.2018.08.183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 08/28/2018] [Accepted: 08/30/2018] [Indexed: 12/20/2022]
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8
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Seafood allergy: A comprehensive review of fish and shellfish allergens. Mol Immunol 2018; 100:28-57. [PMID: 29858102 DOI: 10.1016/j.molimm.2018.04.008] [Citation(s) in RCA: 188] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 04/11/2018] [Accepted: 04/16/2018] [Indexed: 11/23/2022]
Abstract
Seafood refers to several distinct groups of edible aquatic animals including fish, crustacean, and mollusc. The two invertebrate groups of crustacean and mollusc are, for culinary reasons, often combined as shellfish but belong to two very different phyla. The evolutionary and taxonomic diversity of the various consumed seafood species poses a challenge in the identification and characterisation of the major and minor allergens critical for reliable diagnostics and therapeutic treatments. Many allergenic proteins are very different between these groups; however, some pan-allergens, including parvalbumin, tropomyosin and arginine kinase, seem to induce immunological and clinical cross-reactivity. This extensive review details the advances in the bio-molecular characterisation of 20 allergenic proteins within the three distinct seafood groups; fish, crustacean and molluscs. Furthermore, the structural and biochemical properties of the major allergens are described to highlight the immunological and subsequent clinical cross-reactivities. A comprehensive list of purified and recombinant allergens is provided, and the applications of component-resolved diagnostics and current therapeutic developments are discussed.
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9
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Kucharski AN, Scott CE, Davis JP, Kekenes-Huskey PM. Understanding Ion Binding Affinity and Selectivity in β-Parvalbumin Using Molecular Dynamics and Mean Spherical Approximation Theory. J Phys Chem B 2016; 120:8617-30. [PMID: 27267153 DOI: 10.1021/acs.jpcb.6b02666] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Parvalbumin (PV) is a globular calcium (Ca(2+))-selective protein expressed in a variety of biological tissues. Our computational studies of the rat β-parvalbumin (β-PV) isoform seek to elucidate the molecular thermodynamics of Ca(2+) versus magnesium (Mg(2+)) binding at the protein's two EF-hand motifs. Specifically, we have utilized molecular dynamics (MD) simulations and a mean-field electrolyte model (mean spherical approximation (MSA) theory) to delineate how the EF-hand scaffold controls the "local" thermodynamics of Ca(2+) binding selectivity over Mg(2+). Our MD simulations provide the probability density of metal-chelating oxygens within the EF-hand scaffolds for both Ca(2+) and Mg(2+), as well the conformational strain induced by Mg(2+) relative to Ca(2+) binding. MSA theory utilizes the binding domain oxygen and charge distributions to predict the chemical potential of ion binding, as well as their corresponding concentrations within the binding domain. We find that the electrostatic and steric contributions toward ion binding were similar for Mg(2+) and Ca(2+), yet the latter was 5.5 kcal/mol lower in enthalpy when internal strain within the EF hand was considered. We therefore speculate that beyond differences in dehydration energies for the Ca(2+) versus Mg(2+), strain induced in the β-PV EF hand by cation binding significantly contributes to the nearly 10,000-fold difference in binding affinity reported in the literature. We further complemented our analyses of local factors governing cation binding selectivity with whole-protein (global) contributions, such as interhelical residue-residue contacts and solvent exposure of hydrophobic surface. These contributions were found to be comparable for both Ca(2+)- and Mg(2+)-bound β-PV, which may implicate local factors, EF-hand strain, and dehydration, in providing the primary means of selectivity. We anticipate these methods could be used to estimate metal binding thermodynamics across a broad range of PV sequence homologues and EF-hand-containing, Ca(2+) binding proteins.
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Affiliation(s)
- Amir N Kucharski
- Department of Chemistry, University of Kentucky , Lexington, Kentucky 40506, United States
| | - Caitlin E Scott
- Department of Chemistry, University of Kentucky , Lexington, Kentucky 40506, United States
| | - Jonathan P Davis
- Department of Physiology and Cell Biology, Ohio State University , Columbus, Ohio 43210, United States
| | - Peter M Kekenes-Huskey
- Department of Chemistry, University of Kentucky , Lexington, Kentucky 40506, United States
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10
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Kazakov AS, Sokolov AS, Vologzhannikova AA, Permyakova ME, Khorn PA, Ismailov RG, Denessiouk KA, Denesyuk AI, Rastrygina VA, Baksheeva VE, Zernii EY, Zinchenko DV, Glazatov VV, Uversky VN, Mirzabekov TA, Permyakov EA, Permyakov SE. Interleukin-11 binds specific EF-hand proteins via their conserved structural motifs. J Biomol Struct Dyn 2016; 35:78-91. [PMID: 26726132 DOI: 10.1080/07391102.2015.1132392] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Interleukin-11 (IL-11) is a hematopoietic cytokine engaged in numerous biological processes and validated as a target for treatment of various cancers. IL-11 contains intrinsically disordered regions that might recognize multiple targets. Recently we found that aside from IL-11RA and gp130 receptors, IL-11 interacts with calcium sensor protein S100P. Strict calcium dependence of this interaction suggests a possibility of IL-11 interaction with other calcium sensor proteins. Here we probed specificity of IL-11 to calcium-binding proteins of various types: calcium sensors of the EF-hand family (calmodulin, S100B and neuronal calcium sensors: recoverin, NCS-1, GCAP-1, GCAP-2), calcium buffers of the EF-hand family (S100G, oncomodulin), and a non-EF-hand calcium buffer (α-lactalbumin). A specific subset of the calcium sensor proteins (calmodulin, S100B, NCS-1, GCAP-1/2) exhibits metal-dependent binding of IL-11 with dissociation constants of 1-19 μM. These proteins share several amino acid residues belonging to conservative structural motifs of the EF-hand proteins, 'black' and 'gray' clusters. Replacements of the respective S100P residues by alanine drastically decrease its affinity to IL-11, suggesting their involvement into the association process. Secondary structure and accessibility of the hinge region of the EF-hand proteins studied are predicted to control specificity and selectivity of their binding to IL-11. The IL-11 interaction with the EF-hand proteins is expected to occur under numerous pathological conditions, accompanied by disintegration of plasma membrane and efflux of cellular components into the extracellular milieu.
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Affiliation(s)
- Alexei S Kazakov
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Andrei S Sokolov
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Alisa A Vologzhannikova
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Maria E Permyakova
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Polina A Khorn
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Ramis G Ismailov
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Konstantin A Denessiouk
- b Faculty of Science and Engineering , Åbo Akademi University , Biskopsgatan 8, Åbo 20500 , Finland
| | - Alexander I Denesyuk
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia.,b Faculty of Science and Engineering , Åbo Akademi University , Biskopsgatan 8, Åbo 20500 , Finland
| | - Victoria A Rastrygina
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Viktoriia E Baksheeva
- c Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University , Leninskye Gory, House 1, Building 40, Moscow 119992 , Russia
| | - Evgeni Yu Zernii
- c Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University , Leninskye Gory, House 1, Building 40, Moscow 119992 , Russia
| | - Dmitry V Zinchenko
- d Branch of Shemyakin and Ovchinnikov , Institute of Bioorganic Chemistry of the Russian Academy of Sciences , Institutskaya str. 6, Pushchino, Moscow Region 142290 , Russia
| | | | - Vladimir N Uversky
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia.,f Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine , University of South Florida , Tampa , FL 33612 , USA
| | - Tajib A Mirzabekov
- g Antherix , Institutskaya str. 7, Pushchino, Moscow Region 142290 , Russia.,h Biomirex Inc. , 304 Pleasant Street, Watertown , MA 02472 , USA
| | - Eugene A Permyakov
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
| | - Sergei E Permyakov
- a Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya str., 7, Pushchino, Moscow Region 142290 , Russia
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11
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Site-directed mutagenesis of rat α-parvalbumin: replacement of canonical CD-site residues with their non-consensus counterparts from rat β-parvalbumin. Biophys Chem 2014; 197:25-39. [PMID: 25553513 DOI: 10.1016/j.bpc.2014.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 11/24/2022]
Abstract
Rat β-parvalbumin (β-PV) displays low divalent-ion affinity. Its CD site is distinguished by six non-consensus residues--the "CD-loop residues"--at positions 49, 50, 57-60. Additionally, leucine occupies position 85, rather than phenylalanine, the β-lineage-consensus residue. Replacement of the CD-loop residues in rat β with the canonical residues was previously found to have little effect on divalent-ion affinity, unless L85 is replaced by phenylalanine. Herein, we replace the canonical CD-loop residues in rat α-PV with their rat β-PV counterparts. Although the mutations have a generally modest impact on affinity, E59D confers Ca(2+)-specificity on the CD site, in the presence or absence of the other mutations. Despite their minimal impact on ΔG, several CD-loop mutations markedly alter ΔH, evidently by perturbing the apo-protein conformation. The L85F mutation was also examined. In wild-type rat α, L85F increases EF-site Ca(2+) affinity. In the CD-loop variants, the mutation leaves the ΔG for Ca(2+)-binding largely unaffected. However, several variants display highly exothermic binding enthalpies, indicative of ligation-linked protein-folding. Consistent with that idea, scanning-calorimetry data confirm that L85F has significantly destabilized those proteins.
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Wafer LN, Tzul FO, Pandharipande PP, Makhatadze GI. Novel interactions of the TRTK12 peptide with S100 protein family members: specificity and thermodynamic characterization. Biochemistry 2013; 52:5844-56. [PMID: 23899389 DOI: 10.1021/bi400788s] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The S100 protein family consists of small, dimeric proteins that exert their biological functions in response to changing calcium concentrations. S100B is the best-studied member and has been shown to interact with more than 20 binding partners in a calcium-dependent manner. The TRTK12 peptide, derived from the consensus binding sequence for S100B, has previously been found to interact with S100A1 and has been proposed to be a general binding partner of the S100 family. To test this hypothesis and gain a better understanding of the specificity of binding for the S100 proteins, 16 members of the human S100 family were screened against this peptide and its alanine variants. Novel interactions were found with only two family members, S100P and S100A2, indicating that TRTK12 selectively interacts with a small subset of the S100 proteins. Substantial promiscuity was observed in the binding site of S100B thereby accommodating variations in the peptide sequence, while S100A1, S100A2, and S100P exhibited larger differences in the binding constants for the TRTK12 alanine variants. This suggests that single-point substitutions can be used to selectively modulate the affinity of TRTK12 peptides for individual S100 proteins. This study has important implications for the rational drug design of inhibitors for the S100 proteins, which are involved in a variety of cancers and neurodegenerative diseases.
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Affiliation(s)
- Lucas N Wafer
- Department of Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
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Novak Kujundžić R, Steffens WL, Brewer JM, Henzl MT, Ragland WL. Characterization of avian thymic hormone and chicken parvalbumin 3 target cells. Int Immunopharmacol 2013; 15:282-8. [PMID: 23333630 DOI: 10.1016/j.intimp.2012.12.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 12/05/2012] [Accepted: 12/18/2012] [Indexed: 10/27/2022]
Abstract
Avian thymic hormone (ATH) is a β-parvalbumin produced by epithelial cells in the thymic cortex and in the eyes of chickens. Chicken parvalbumin 3 (CPV3) is a homologous protein produced in the thymus and in hair cells of the chicken ear. ATH circulates in the blood on a five-day cycle and stimulates cell-mediated immunity when administered to young chickens. We report the identification of target cells for ATH and CPV3 and the immunophenotype of target cells for ATH. Newly hatched chicks were injected intracoelomically with ATH and killed 5, 10, 15 or 20 min later. Naïve chickens also were killed at 1, 7 and 14 days of age. Various tissues were examined by EM for the presence of either ATH or CPV3 using colloidal gold labeling. Gold particles were initially present on plasma membranes of lymphocytes in T cell areas of spleen and cecal tonsils from the chicks injected with ATH, internalized within 10 min, and accumulated in nuclei by 20 min. Immunofluorescence staining also identified the presence of ATH in T cell areas of spleen and cecal tonsils. Target cells labeled for ATH were immunophenotyped by double labeling. They were positive for CD3, CD8 and the lymphocyte receptor TCR-1, a phenotype characteristic of cytotoxic γδ T cells. Some of the target cells in the spleen were TCR-3 positive. Targeting of lymphocytes by CPV3 indicated that it may also be an immunomodulating hormone.
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15
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Whittington AC, Moerland TS. Resurrecting prehistoric parvalbumins to explore the evolution of thermal compensation in extant Antarctic fish parvalbumins. J Exp Biol 2012; 215:3281-92. [PMID: 22693024 DOI: 10.1242/jeb.070615] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Parvalbumins (PVs) from Antarctic notothenioid fishes display a pattern of thermal adaptation that likely reflects evolutionary changes in protein conformational flexibility. We have used ancestral sequence reconstruction and homology modeling to identify two amino acid changes that could potentially account for the present thermal sensitivity pattern of Antarctic fish PVs compared with a PV from a theoretical warm-adapted ancestral fish. To test this hypothesis, ancient PVs were resurrected in the lab using PV from the notothenioid Gobionotothen gibberifrons as a platform for introducing mutations comparable to the reconstructed ancestral PV sequences. The wild-type PV (WT) as well as three mutant expression constructs were engineered: lysine 8 to asparagine (K8N), lysine 26 to asparagine (K26N) and a double mutant (DM). Calcium equilibrium dissociation constants (K(d)) versus temperature curves for all mutants were right-shifted, as predicted, relative to that of WT PV. The K(d) values for the K8N and K26N single mutants were virtually identical at all temperatures and showed an intermediate level of thermal sensitivity. The DM construct displayed a full conversion of thermal sensitivity pattern to that of a PV from a warm/temperate-adapted fish. Additionally, the K(d) versus temperature curve for the WT construct revealed greater thermal sensitivity compared with the mutant constructs. Measurements of the rates of Ca(2+) dissociation (k(off)) showed that all mutants generally had slower k(off) values than WT at all temperatures. Calculated rates of Ca(2+) binding (k(on)) for the K8N and K26N mutants were similar to values for the WT PV at all temperatures. In contrast, the calculated k(on) values for the DM PV were faster, providing mechanistic insights into the nature of potentially adaptive changes in Ca(2+) binding in this PV. The overall results suggest that the current thermal phenotype of Antarctic PVs can be recapitulated by just two amino acid substitutions.
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Affiliation(s)
- A Carl Whittington
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA.
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16
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Wafer LN, Streicher WW, McCallum SA, Makhatadze GI. Thermodynamic and kinetic analysis of peptides derived from CapZ, NDR, p53, HDM2, and HDM4 binding to human S100B. Biochemistry 2012; 51:7189-201. [PMID: 22913742 PMCID: PMC3448795 DOI: 10.1021/bi300865g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
S100B is a member of the S100 subfamily of EF-hand proteins that has been implicated in malignant melanoma and neurodegenerative conditions such as Alzheimer's disease and Parkinson's disease. Calcium-induced conformational changes expose a hydrophobic binding cleft, facilitating interactions with a wide variety of nuclear, cytoplasmic, and extracellular target proteins. Previously, peptides derived from CapZ, p53, NDR, HDM2, and HDM4 have been shown to interact with S100B in a calcium-dependent manner. However, the thermodynamic and kinetic basis of these interactions remains largely unknown. To gain further insight, we screened these peptides against the S100B protein using isothermal titration calorimetry and nuclear magnetic resonance. All peptides were found to have binding affinities in the low micromolar to nanomolar range. Binding-induced changes in the line shapes of S100B backbone (1)H and (15)N resonances were monitored to obtain the dissociation constants and the kinetic binding parameters. The large microscopic K(on) rate constants observed in this study (≥1 × 10(7) M(-1) s(-1)) suggest that S100B utilizes a "fly casting mechanism" in the recognition of these peptide targets.
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Affiliation(s)
- Lucas N. Wafer
- Center for Biotechnology and Interdisciplinary Studies and Department of Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | | | - Scott A. McCallum
- Center for Biotechnology and Interdisciplinary Studies and Department of Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - George I. Makhatadze
- Center for Biotechnology and Interdisciplinary Studies and Department of Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
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17
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Bakunts AG. Metal-specific structural changes in parvalbumin. Biochem Biophys Res Commun 2012; 424:730-5. [PMID: 22809511 DOI: 10.1016/j.bbrc.2012.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 07/08/2012] [Indexed: 10/28/2022]
Abstract
Parvalbumin is a small protein of EF-hand family whose main role is considered to be metal buffering. Recent evidences indicate that parvalbumin also fulfills more complicated functions, which may be determined by the diversity in structural changes in response to the binding of different metal cations. In the present work the conformations of α and β isoforms of pike parvalbumin in the Ca(2+)- and Mg(2+)-loaded state were studied by intrinsic fluorescence, circular dichroism and bis-ANS extrinsic fluorescence. We have determined the structural region causing different spectral response on the binding of Mg(2+)- and Ca(2+) ions in pike β-parvalbumin. Our data reveal similarity of the metal-bound forms of α-parvalbumin. In contrast, those of β isoform differ significantly in the tyrosine spectral range. We also discuss the possible physiological consequences of the structural rearrangements accompanied Mg(2+)/Ca(2+) exchange in pike β-parvalbumin.
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Affiliation(s)
- Anush G Bakunts
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Institutskaya Str. 7, Pushchino, Moscow Region 142290, Russia.
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18
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Raghuram V, Sharma Y, Kreutz MR. Ca(2+) sensor proteins in dendritic spines: a race for Ca(2+). Front Mol Neurosci 2012; 5:61. [PMID: 22586368 PMCID: PMC3347464 DOI: 10.3389/fnmol.2012.00061] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Accepted: 04/18/2012] [Indexed: 12/21/2022] Open
Abstract
Dendritic spines are believed to be micro-compartments of Ca2+ regulation. In a recent study, it was suggested that the ubiquitous and evolutionarily conserved Ca2+ sensor, calmodulin (CaM), is the first to intercept Ca2+ entering the spine and might be responsible for the fast decay of Ca2+ transients in spines. Neuronal calcium sensor (NCS) and neuronal calcium-binding protein (nCaBP) families consist of Ca2+ sensors with largely unknown synaptic functions despite an increasing number of interaction partners. Particularly how these sensors operate in spines in the presence of CaM has not been discussed in detail before. The limited Ca2+ resources and the existence of common targets create a highly competitive environment where Ca2+ sensors compete with each other for Ca2+ and target binding. In this review, we take a simple numerical approach to put forth possible scenarios and their impact on signaling via Ca2+ sensors of the NCS and nCaBP families. We also discuss the ways in which spine geometry and properties of ion channels, their kinetics and distribution, alter the spatio-temporal aspects of Ca2+ transients in dendritic spines, whose interplay with Ca2+ sensors in turn influences the race for Ca2+.
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Affiliation(s)
- Vijeta Raghuram
- Centre for Cellular and Molecular Biology, CSIR Hyderabad, India
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19
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Henzl MT, Tanner JJ, Tan A. Solution structures of chicken parvalbumin 3 in the Ca2+-free and Ca2+-bound states. Proteins 2010; 79:752-64. [DOI: 10.1002/prot.22915] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 09/29/2010] [Accepted: 10/07/2010] [Indexed: 11/09/2022]
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20
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Simmons DD, Tong B, Schrader AD, Hornak AJ. Oncomodulin identifies different hair cell types in the mammalian inner ear. J Comp Neurol 2010; 518:3785-802. [PMID: 20653034 DOI: 10.1002/cne.22424] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The tight regulation of Ca(2+) is essential for inner ear function, and yet the role of Ca(2+) binding proteins (CaBPs) remains elusive. By using immunofluorescence and reverse transcriptase-polymerase chain reaction (RT-PCR), we investigated the expression of oncomodulin (Ocm), a member of the parvalbumin family, relative to other EF-hand CaBPs in cochlear and vestibular organs in the mouse. In the mouse cochlea, Ocm is found only in outer hair cells and is localized preferentially to the basolateral outer hair cell membrane and to the base of the hair bundle. Developmentally, Ocm immunoreactivity begins as early as postnatal day (P) 2 and shows preferential localization to the basolateral membrane and hair bundle after P8. Unlike the cochlea, Ocm expression is substantially reduced in vestibular tissues at older adult ages. In vestibular organs, Ocm is found in type I striolar or central hair cells, and has a more diffuse subcellular localization throughout the hair cell body. Additionally, Ocm immunoreactivity in vestibular hair cells is present as early as E18 and is not obviously affected by mutations that cause a disruption of hair bundle polarity. We also find Ocm expression in striolar hair cells across mammalian species. These data suggest that Ocm may have distinct functional roles in cochlear and vestibular hair cells.
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Affiliation(s)
- Dwayne D Simmons
- Department of Integrative Biology and Physiology and the Brain Research Institute, University of California Los Angeles, Los Angeles, California 90095, USA.
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21
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Tan A, Markus LA, Henzl MT. Disparate Impact of the S33V Mutation on Conformational Stability in Rat β-Parvalbumin (Oncomodulin) and Chicken Parvalbumin 3. J Phys Chem B 2010; 114:16171-83. [DOI: 10.1021/jp1063325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anmin Tan
- Department of Biochemistry, 117 Schweitzer Hall, University of Missouri, Columbia, Missouri 65211, United States
| | - Lindsey A. Markus
- Department of Biochemistry, 117 Schweitzer Hall, University of Missouri, Columbia, Missouri 65211, United States
| | - Michael T. Henzl
- Department of Biochemistry, 117 Schweitzer Hall, University of Missouri, Columbia, Missouri 65211, United States
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22
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Abstract
"Ca(2+) buffers," a class of cytosolic Ca(2+)-binding proteins, act as modulators of short-lived intracellular Ca(2+) signals; they affect both the temporal and spatial aspects of these transient increases in [Ca(2+)](i). Examples of Ca(2+) buffers include parvalbumins (α and β isoforms), calbindin-D9k, calbindin-D28k, and calretinin. Besides their proven Ca(2+) buffer function, some might additionally have Ca(2+) sensor functions. Ca(2+) buffers have to be viewed as one of the components implicated in the precise regulation of Ca(2+) signaling and Ca(2+) homeostasis. Each cell is equipped with proteins, including Ca(2+) channels, transporters, and pumps that, together with the Ca(2+) buffers, shape the intracellular Ca(2+) signals. All of these molecules are not only functionally coupled, but their expression is likely to be regulated in a Ca(2+)-dependent manner to maintain normal Ca(2+) signaling, even in the absence or malfunctioning of one of the components.
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23
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Structure of avian thymic hormone, a high-affinity avian beta-parvalbumin, in the Ca2+-free and Ca2+-bound states. J Mol Biol 2010; 397:991-1002. [PMID: 20156445 DOI: 10.1016/j.jmb.2010.02.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 01/28/2010] [Accepted: 02/09/2010] [Indexed: 11/23/2022]
Abstract
Originally isolated on the basis of its capacity to stimulate T-cell maturation and proliferation, avian thymic hormone (ATH) is nevertheless a parvalbumin, one of two beta-lineage isoforms expressed in birds. We recently learned that addition of Ca(2+)-free ATH to a solution of 8-anilinonaphthalene-1-sulfonate (ANS) markedly increases ANS emission. This behavior, not observed in the presence of Ca(2+), suggests that apolar surface area buried in the Ca(2+)-bound state becomes solvent accessible upon Ca(2+) removal. In order to elucidate the conformational alterations that accompany Ca(2+) binding, we have obtained the solution structure of the Ca(2+)-free protein using NMR spectroscopy and compared it to the Ca(2+)-loaded protein, solved by X-ray crystallography. Although the metal-ion-binding (CD-EF) domains are largely coincident in the superimposed structures, a major difference is observed in the AB domains. The tight association of helix B with the E and F helices in the Ca(2+)-bound state is lost upon removal of Ca(2+), producing a deep hydrophobic cavity. The B helix also undergoes substantial rotation, exposing the side chains of F24, Y26, F29, and F30 to solvent. Presumably, the increase in ANS emission observed in the presence of unliganded ATH reflects the interaction of these hydrophobic residues with the fluorescent probe. The increased solvent exposure of apolar surface area in the Ca(2+)-free protein is consistent with previously collected scanning calorimetry data, which indicated an unusually low change in heat capacity upon thermal denaturation. The Ca(2+)-free structure also provides added insight into the magnitude of ligation-linked conformational alteration compatible with a high-affinity metal-ion-binding signature. The exposure of substantial apolar surface area suggests the intriguing possibility that ATH could function as a reverse Ca(2+) sensor.
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24
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Is high concentration of parvalbumin a requirement for superfast relaxation? J Muscle Res Cell Motil 2009; 30:57-65. [PMID: 19387850 DOI: 10.1007/s10974-009-9175-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Accepted: 03/21/2009] [Indexed: 10/20/2022]
Abstract
It is generally thought that the rapid relaxation of fast muscles is facilitated by the Ca(2+) binding protein parvalbumin (Parv). Indeed superfast swimbladder (SWB) muscle of toadfish contains the largest concentration of this protein ever observed (up to 1.5 mM). At 15 degrees C toadfish perform a 100 Hz call, 400 ms in duration, followed by a long (5-15 s) intercall interval. It has been proposed that Parv helps sequester the Ca(2+) during the call, and then Ca(2+) unbinds and is pumped back into the sarcoplasmic reticulum during the long intercall interval. Midshipman (Porichthys notatus) is another fish which calls at a high frequency; 80-100 Hz at a temperature of 12-15 degrees C. However, unlike toadfish, midshipman call with a 100% duty cycle. Without an intercall interval, Parv would seem of little use as it would become saturated early in calling. Here we show that the midshipman SWB has only about 1/8th of the Parv in toadfish. Moreover, total Parv content in calling male midshipman SWB was not different from that in the non-calling female and the much slower locomotory muscles. These data suggest that Parv does not play a large role in the calling of midshipman, which is accomplished without a high concentration of this protein. Native gel-electrophoresis also revealed presence of three major (PA-I, PA-II and PA-III) and two minor (PA-Ia and PA-IIIa, <5% of total content) Parv isoforms in adult toadfish SWB. Midshipman SWB contained about equal amounts of PA-I and PA-II and also a small (approximately 10%) amount of PA-III. By amino acid composition, toadfish PA-Ia and PA-I isoforms were different from PA-II and PA-III isoforms (by 24 and 14 residues, respectively).
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25
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Tan A, Henzl MT. Evidence for a Ca2+-Specific Conformational Change in Avian Thymic Hormone, a High-Affinity β-Parvalbumin. Biochemistry 2009; 48:3936-45. [DOI: 10.1021/bi900029j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Anmin Tan
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211
| | - Michael T. Henzl
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211
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Henzl MT, Davis ME, Tan A. Leucine 85 is an important determinant of divalent ion affinity in rat beta-parvalbumin (Oncomodulin). Biochemistry 2009; 47:13635-46. [PMID: 19075559 DOI: 10.1021/bi8014899] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Despite 69% sequence identity with chicken parvalbumin 3 (CPV3), rat beta-parvalbumin (beta-PV) exhibits a substantially lower Ca(2+) affinity (DeltaDeltaG degrees ' = 2.0 kcal/mol). This difference largely reflects the disparate behavior of the respective CD sites. Replacement of the rat beta-PV codon with the CPV3 codon at positions 49, 50, and 57-60 produces virtual sequence identity with the CPV3 CD site. However, the resulting protein exhibits a modest (0.5 kcal/mol) improvement in Ca(2+) affinity, implying that sequence differences beyond the binding site modulate divalent ion binding behavior. The solution structure of Ca(2+)-free rat beta-PV suggested that Leu-85, phenylalanine in CPV3, might be an important determinant. Therefore, the impact of the L85F mutation on divalent ion affinity was examined in rat beta-PV, in the variant harboring all six of the aforementioned CD site mutations, and in the intermediate CD site variants. We find that the identity of residue 85, located within the E helix, strongly influences divalent ion affinity in the mammalian beta-PV isoform and that its impact is mediated by interactions with residues in the CD site. In the wild-type protein, L85F primarily affects the EF site. By contrast, in the presence of the six CD site mutations, L85F also improves the CD site performance, yielding a protein with Ca(2+) affinity rivaling that of CPV3 and markedly enhanced Mg(2+) affinity as well. The impact of L85F on CD site Ca(2+) affinity is particularly sensitive to the identities of residues 59 and 60. Interestingly, however, significant improvement in CD site Mg(2+) affinity also requires mutation of additional CD site residues.
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Affiliation(s)
- Michael T Henzl
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA.
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27
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Abstract
Mammals express two parvalbumins-an alpha isoform and a beta isoform. In rat, the alpha-parvalbumin (alpha-PV) exhibits superior divalent ion affinity. For example, the standard free energies for Ca2+ binding differ by 5.5 kcal/mol in 0.15 M KCl (pH 7.4). High-resolution structures of the Ca2+-bound proteins provide little insight into this disparity, prompting a structural analysis of the apo-proteins. A recent analysis of rat beta-PV suggested that Ca2+ removal provokes substantial conformational changes-reorientation of the C, D, and E helices; reorganization of the hydrophobic core; reduced interdomain contact; and remodeling of the AB domain. The energetic penalty attendant to reversing these changes, it was suggested, could contribute to the attenuated divalent ion-binding signature of that protein. That hypothesis is supported by data presented herein, describing the solution structure and peptide backbone dynamics of Ca2+-free rat alpha-PV. In marked contrast to rat beta-PV, the apo- and Ca2+-loaded forms of the rat alpha isoform are quite similar. Significant structural differences appear to be confined to the loop regions of the molecule. This finding implies that the alpha-PV isoform enjoys elevated divalent ion affinity because the metal ion-binding events do not require major structural rearrangement and the concomitant sacrifice of binding energy.
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Affiliation(s)
- Michael T Henzl
- Department of Biochemistry, University of Missouri-Columbia, Columbia, Missouri 65211, USA.
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