1
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Zhao J, Segura E, Marsolais M, Parent L. A CACNA1C variant associated with cardiac arrhythmias provides mechanistic insights in the calmodulation of L-type Ca 2+ channels. J Biol Chem 2022; 298:102632. [PMID: 36273583 PMCID: PMC9691931 DOI: 10.1016/j.jbc.2022.102632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 10/12/2022] [Accepted: 10/15/2022] [Indexed: 11/07/2022] Open
Abstract
We recently reported the identification of a de novo single nucleotide variant in exon 9 of CACNA1C associated with prolonged repolarization interval. Recombinant expression of the glycine to arginine variant at position 419 produced a gain in the function of the L-type CaV1.2 channel with increased peak current density and activation gating but without significant decrease in the inactivation kinetics. We herein reveal that these properties are replicated by overexpressing calmodulin (CaM) with CaV1.2 WT and are reversed by exposure to the CaM antagonist W-13. Phosphomimetic (T79D or S81D), but not phosphoresistant (T79A or S81A), CaM surrogates reproduced the impact of CaM WT on the function of CaV1.2 WT. The increased channel activity of CaV1.2 WT following overexpression of CaM was found to arise in part from enhanced cell surface expression. In contrast, the properties of the variant remained unaffected by any of these treatments. CaV1.2 substituted with the α-helix breaking proline residue were more reluctant to open than CaV1.2 WT but were upregulated by phosphomimetic CaM surrogates. Our results indicate that (1) CaM and its phosphomimetic analogs promote a gain in the function of CaV1.2 and (2) the structural properties of the first intracellular linker of CaV1.2 contribute to its CaM-induced modulation. We conclude that the CACNA1C clinical variant mimics the increased activity associated with the upregulation of CaV1.2 by Ca2+-CaM, thus maintaining a majority of channels in a constitutively active mode that could ultimately promote ventricular arrhythmias.
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Affiliation(s)
- Juan Zhao
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
| | - Emilie Segura
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada
| | - Mireille Marsolais
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada
| | - Lucie Parent
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada,For correspondence: Lucie Parent
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2
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Westerlund AM, Sridhar A, Dahl L, Andersson A, Bodnar AY, Delemotte L. Markov state modelling reveals heterogeneous drug-inhibition mechanism of Calmodulin. PLoS Comput Biol 2022; 18:e1010583. [PMID: 36206305 PMCID: PMC9581412 DOI: 10.1371/journal.pcbi.1010583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 10/19/2022] [Accepted: 09/18/2022] [Indexed: 11/06/2022] Open
Abstract
Calmodulin (CaM) is a calcium sensor which binds and regulates a wide range of target-proteins. This implicitly enables the concentration of calcium to influence many downstream physiological responses, including muscle contraction, learning and depression. The antipsychotic drug trifluoperazine (TFP) is a known CaM inhibitor. By binding to various sites, TFP prevents CaM from associating to target-proteins. However, the molecular and state-dependent mechanisms behind CaM inhibition by drugs such as TFP are largely unknown. Here, we build a Markov state model (MSM) from adaptively sampled molecular dynamics simulations and reveal the structural and dynamical features behind the inhibitory mechanism of TFP-binding to the C-terminal domain of CaM. We specifically identify three major TFP binding-modes from the MSM macrostates, and distinguish their effect on CaM conformation by using a systematic analysis protocol based on biophysical descriptors and tools from machine learning. The results show that depending on the binding orientation, TFP effectively stabilizes features of the calcium-unbound CaM, either affecting the CaM hydrophobic binding pocket, the calcium binding sites or the secondary structure content in the bound domain. The conclusions drawn from this work may in the future serve to formulate a complete model of pharmacological modulation of CaM, which furthers our understanding of how these drugs affect signaling pathways as well as associated diseases. Calmodulin (CaM) is a calcium-sensing protein which makes other proteins dependent on the surrounding calcium concentration by binding to these proteins. Such protein-protein interactions with CaM are vital for calcium to control many physiological pathways within the cell. The antipsychotic drug trifluoperazine (TFP) inhibits CaM’s ability to bind and regulate other proteins. Here, we use molecular dynamics simulations together with Markov state modeling and machine learning to understand the structural and dynamical features by which TFP bound to the one domain of CaM prevents association to other proteins. We find that TFP encourages CaM to adopt a conformation that is like the one stabilized in absence of calcium: depending on the binding orientation of TFP, the drug indeed either affects the CaM hydrophobic binding pocket, the calcium binding sites or the secondary structure content in the domain. Understanding TFP binding is a first step towards designing better drugs targeting CaM.
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Affiliation(s)
- Annie M. Westerlund
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
| | - Akshay Sridhar
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
| | - Leo Dahl
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
| | - Alma Andersson
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
- Division of Gene Technology, Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Anna-Yaroslava Bodnar
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
| | - Lucie Delemotte
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
- * E-mail:
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3
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Zhang T, Ruan HZ, Wang YC, Shao YQ, Zhou W, Weng SJ, Zhong YM. Signaling Mechanism for Modulation by GLP-1 and Exendin-4 of GABA Receptors on Rat Retinal Ganglion Cells. Neurosci Bull 2022; 38:622-636. [PMID: 35278196 PMCID: PMC9206055 DOI: 10.1007/s12264-022-00826-9] [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: 07/02/2021] [Accepted: 11/10/2021] [Indexed: 11/29/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) is expressed in retinal neurons, but its role in the retina is largely unknown. Here, we demonstrated that GLP-1 or the GLP-1 receptor (GLP-1R; a G protein-coupled receptor) agonist exendin-4 suppressed γ-aminobutyric acid receptor (GABAR)-mediated currents through GLP-1Rs in isolated rat retinal ganglion cells (GCs). Pre-incubation with the stimulatory G protein (Gs) inhibitor NF 449 abolished the exendin-4 effect. The exendin-4-induced suppression was mimicked by perfusion with 8-Br-cAMP (a cAMP analog), but was eliminated by the protein kinase A (PKA) inhibitor Rp-cAMP/KT-5720. The exendin-4 effect was accompanied by an increase in [Ca2+]i of GCs through the IP3-sensitive pathway and was blocked in Ca2+-free solution. Furthermore, when the activity of calmodulin (CaM) and CaM-dependent protein kinase II (CaMKII) was inhibited, the exendin-4 effect was eliminated. Consistent with this, exendin-4 suppressed GABAR-mediated light-evoked inhibitory postsynaptic currents in GCs in rat retinal slices. These results suggest that exendin-4-induced suppression may be mediated by a distinct Gs/cAMP-PKA/IP3/Ca2+/CaM/CaMKII signaling pathway, following the activation of GLP-1Rs.
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Affiliation(s)
- Tao Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Hang-Ze Ruan
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Yong-Chen Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Yu-Qi Shao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Wei Zhou
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Shi-Jun Weng
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Yong-Mei Zhong
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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4
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Milanesi L, Trevitt C, Whitehead B, Hounslow A, Tomas S, Hosszu L, Hunter C, Waltho J. High-affinity tamoxifen analogues retain extensive positional disorder when bound to calmodulin. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:629-642. [PMID: 37905217 PMCID: PMC10539762 DOI: 10.5194/mr-2-629-2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/03/2021] [Indexed: 11/02/2023]
Abstract
Using a combination of NMR and fluorescence measurements, we have investigated the structure and dynamics of the complexes formed between calcium-loaded calmodulin (CaM) and the potent breast cancer inhibitor idoxifene, a derivative of tamoxifen. High-affinity binding (K d ∼ 300 nM) saturates with a 2 : 1 idoxifene : CaM complex. The complex is an ensemble where each idoxifene molecule is predominantly in the vicinity of one of the two hydrophobic patches of CaM but, in contrast with the lower-affinity antagonists TFP, J-8, and W-7, does not substantially occupy the hydrophobic pocket. At least four idoxifene orientations per domain of CaM are necessary to satisfy the intermolecular nuclear Overhauser effect (NOE) restraints, and this requires that the idoxifene molecules switch rapidly between positions. The CaM molecule is predominantly in the form where the N and C-terminal domains are in close proximity, allowing for the idoxifene molecules to contact both domains simultaneously. Hence, the 2 : 1 idoxifene : CaM complex illustrates how high-affinity binding occurs without the loss of extensive positional dynamics.
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Affiliation(s)
- Lilia Milanesi
- Department of Molecular Biology and Biotechnology, University of
Sheffield, Sheffield S10 2TN, UK
- Department of Biological Sciences, School of Science, Birkbeck
University of London, London WC1E 7HX, UK
| | - Clare R. Trevitt
- Department of Molecular Biology and Biotechnology, University of
Sheffield, Sheffield S10 2TN, UK
| | - Brian Whitehead
- Department of Molecular Biology and Biotechnology, University of
Sheffield, Sheffield S10 2TN, UK
| | - Andrea M. Hounslow
- Department of Molecular Biology and Biotechnology, University of
Sheffield, Sheffield S10 2TN, UK
| | - Salvador Tomas
- Department of Biological Sciences, School of Science, Birkbeck
University of London, London WC1E 7HX, UK
- Departament de Química, Universitat de les Illes Balears, Cra. de Valldemossa, km 7.5. 07122 Palma de Mallorca, Spain
| | - Laszlo L. P. Hosszu
- Department of Molecular Biology and Biotechnology, University of
Sheffield, Sheffield S10 2TN, UK
- Medical Research Council Prion Unit, University College of London
Institute of Neurology, Queen Square, London WCN1 3BG, UK
| | - Christopher A. Hunter
- Department of Chemistry, University of Cambridge, Lensfield Road,
Cambridge CB2 1EW, UK
| | - Jonathan P. Waltho
- Department of Molecular Biology and Biotechnology, University of
Sheffield, Sheffield S10 2TN, UK
- Manchester Institute of Biotechnology, University of Manchester, 131
Princess Street, Manchester M1 7DN, UK
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5
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Shaik NA, Awan ZA, Verma PK, Elango R, Banaganapalli B. Protein phenotype diagnosis of autosomal dominant calmodulin mutations causing irregular heart rhythms. J Cell Biochem 2018; 119:8233-8248. [PMID: 29932249 DOI: 10.1002/jcb.26834] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 03/09/2018] [Indexed: 12/21/2022]
Abstract
The life-threatening group of irregular cardiac rhythmic disorders also known as Cardiac Arrhythmias (CA) are caused by mutations in highly conserved Calmodulin (CALM/CaM) genes. Herein, we present a multidimensional approach to diagnose changes in phenotypic, stability, and Ca2+ ion binding properties of CA-causing mutations. Mutation pathogenicity was determined by diverse computational machine learning approaches. We further modeled the mutations in 3D protein structure and analyzed residue level phenotype plasticity. We have also examined the influence of torsion angles, number of H-bonds, and free energy dynamics on the stability, near-native simulation dynamic potential of residue fluctuations in protein structures, Ca2+ ion binding potentials, of CaM mutants. Our study recomends to use M-CAP method for measuring the pathogenicity of CA causing CaM variants. Interestingly, most CA-causing variants we analyzed, exists in either third (V/H-96, S/I-98, V-103) or fourth (G/V-130, V/E/H-132, H-134, P-136, G-141, and L-142) EF-hands located in carboxyl domains of the CaM molecule. We observed that the minor structural fluctuations caused by these variants are likely tolerable owing to the highly flexible nature of calmodulin's globular domains. However, our molecular docking results supports that these variants disturb the affinity of CaM toward Ca2+ ions and corroborate previous findings from functional studies. Taken together, these computational findings can explain the molecular reasons for subtle changes in structure, flexibility, and stability aspects of mutant CaM molecule. Our comprehensive molecular scanning approach demonstrates the utility of computational methods in quick preliminary screening of CA- CaM mutations before undertaking time consuming and complicated functional laboratory assays.
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Affiliation(s)
- Noor A Shaik
- Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.,Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders (PACER-HD), King Abdulaziz University, Jeddah, Saudi Arabia
| | - Zuhier A Awan
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Prashant K Verma
- Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ramu Elango
- Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.,Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders (PACER-HD), King Abdulaziz University, Jeddah, Saudi Arabia
| | - Babajan Banaganapalli
- Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.,Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders (PACER-HD), King Abdulaziz University, Jeddah, Saudi Arabia
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6
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Caprara GA, Morabito C, Perni S, Navarra R, Guarnieri S, Mariggiò MA. Evidence for Altered Ca 2+ Handling in Growth Associated Protein 43-Knockout Skeletal Muscle. Front Physiol 2016; 7:493. [PMID: 27833566 PMCID: PMC5080375 DOI: 10.3389/fphys.2016.00493] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/11/2016] [Indexed: 11/13/2022] Open
Abstract
Neuronal growth-associated protein 43 (GAP43) has crucial roles in the nervous system, and during development, regeneration after injury, and learning and memory. GAP43 is expressed in mouse skeletal muscle fibers and satellite cells, with suggested its involvement in intracellular Ca2+ handling. However, the physiological role of GAP43 in muscle remains unknown. Using a GAP43-knockout (GAP43-/-) mouse, we have defined the role of GAP43 in skeletal muscle. GAP43-/- mice showed low survival beyond weaning, reduced adult body weight, decreased muscle strength, and changed myofiber ultrastructure, with no significant differences in the expression of markers of satellite cell and myotube progression through the myogenic program. Thus, GAP43 expression is involved in timing of muscle maturation in-vivo. Intracellular Ca2+ measurements in-vitro in myotubes revealed GAP43 involvement in Ca2+ handling. In the absence of GAP43 expression, the spontaneous Ca2+ variations had greater amplitudes and higher frequency. In GAP43-/- myotubes, also the intracellular Ca2+ variations induced by the activation of dihydropyridine and ryanodine Ca2+ channels, resulted modified. These evidences suggested dysregulation of Ca2+ homeostasis. The emerging hypothesis indicates that GAP43 interacts with calmodulin to indirectly modulate the activities of dihydropyridine and ryanodine Ca2+ channels. This thus influences intracellular Ca2+ dynamics and its related intracellular patterns, from functional excitation-contraction coupling, to cell metabolism, and gene expression.
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Affiliation(s)
- Giusy A Caprara
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Caterina Morabito
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Stefano Perni
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Riccardo Navarra
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Simone Guarnieri
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
| | - Maria A Mariggiò
- Laboratory of Functional Biotechnology, Center of Sciences on Aging and Translational Medicine (CeSI-MeT), Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara Chieti, Italy
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7
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Deng QQ, Sheng WL, Zhang G, Weng SJ, Yang XL, Zhong YM. Signalling mechanism for somatostatin receptor 5-mediated suppression of AMPA responses in rat retinal ganglion cells. Neuropharmacology 2016; 107:215-226. [DOI: 10.1016/j.neuropharm.2016.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 01/25/2016] [Accepted: 03/02/2016] [Indexed: 01/21/2023]
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8
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Identification of a calmodulin-binding domain in Sema4D that regulates its exodomain shedding in platelets. Blood 2013; 121:4221-30. [PMID: 23564909 DOI: 10.1182/blood-2012-11-470609] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Semaphorin 4D (Sema4D) is a transmembrane protein that supports contact-dependent amplification of platelet activation by collagen before being gradually cleaved by the metalloprotease ADAM17, as we have previously shown. Cleavage releases a soluble 120-kDa exodomain fragment for which receptors exist on platelets and endothelial cells. Here we have examined the mechanism that regulates Sema4D exodomain cleavage. The results show that the membrane-proximal cytoplasmic domain of Sema4D contains a binding site for calmodulin within the polybasic region Arg762-Lys779. Coprecipitation studies show that Sema4D and calmodulin are associated in resting platelets, forming a complex that dissociates upon platelet activation by the agonists that trigger Sema4D cleavage. Inhibiting calmodulin with W7 or introducing a membrane-permeable peptide corresponding to the calmodulin-binding site is sufficient to trigger the dissociation of Sema4D from calmodulin and initiate cleavage. Conversely, deletion of the calmodulin-binding site causes constitutive shedding of Sema4D. These results show that (1) Sema4D is a calmodulin-binding protein with a site of interaction in its membrane-proximal cytoplasmic domain, (2) platelet agonists cause dissociation of the calmodulin-Sema4D complex, and (3) dissociation of the complex is sufficient to trigger ADAM17-dependent cleavage of Sema4D, releasing a bioactive fragment.
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9
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Nunomura W, Jinbo Y, Isozumi N, Ohki S, Izumi Y, Matsushima N, Takakuwa Y. Novel Mechanism of Regulation of Protein 4.1G Binding Properties Through Ca2+/Calmodulin-Mediated Structural Changes. Cell Biochem Biophys 2013; 66:545-58. [DOI: 10.1007/s12013-012-9502-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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10
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Sasakura D, Nunomura W, Takakuwa Y. Dynamic secondary structural changes in Ca2+-saturated calmodulin upon interaction with the antagonist, W-7. Biochem Biophys Res Commun 2012; 423:360-5. [DOI: 10.1016/j.bbrc.2012.05.131] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 05/25/2012] [Indexed: 10/28/2022]
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11
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Hayashi N, Titani K. N-myristoylated proteins, key components in intracellular signal transduction systems enabling rapid and flexible cell responses. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2010; 86:494-508. [PMID: 20467215 PMCID: PMC3108300 DOI: 10.2183/pjab.86.494] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 03/23/2010] [Indexed: 05/29/2023]
Abstract
N-myristoylation, one of the co- or post-translational modifications of proteins, has so far been regarded as necessary for anchoring of proteins to membranes. Recently, we have revealed that N(alpha)-myristoylation of several brain proteins unambiguously regulates certain protein-protein interactions that may affect signaling pathways in brain. Comparison of the amino acid sequences of myristoylated proteins including those in other organs suggests that this regulation is involved in signaling pathways not only in brain but also in other organs. Thus, it has been shown that myristoylated proteins in cells regulate the signal transduction between membranes and cytoplasmic fractions. An algorithm we have developed to identify myristoylated proteins in cells predicts the presence of hundreds of myristoylated proteins. Interestingly, a large portion of the myristoylated proteins thought to take part in signal transduction between membranes and cytoplasmic fractions are included in the predicted myristoylated proteins. If the proteins functionally regulated by myristoylation, a posttranslational protein modification, were understood as cross-talk points within the intracellular signal transduction system, known signaling pathways could thus be linked to each other, and a novel map of this intracellular network could be constructed. On the basis of our recent results, this review will highlight the multifunctional aspects of protein N-myristoylation in brain.
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Affiliation(s)
- Nobuhiro Hayashi
- Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama-shi, Kanagawa Pref., 226-8501, Japan.
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12
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Sengupta P, Ruano MJ, Tebar F, Golebiewska U, Zaitseva I, Enrich C, McLaughlin S, Villalobo A. Membrane-permeable calmodulin inhibitors (e.g. W-7/W-13) bind to membranes, changing the electrostatic surface potential: dual effect of W-13 on epidermal growth factor receptor activation. J Biol Chem 2007; 282:8474-86. [PMID: 17227773 DOI: 10.1074/jbc.m607211200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Membrane-permeable calmodulin inhibitors, such as the napthalenesulfonamide derivatives W-7/W-13, trifluoperazine, and calmidazolium, are used widely to investigate the role of calcium/calmodulin (Ca2+/CaM) in living cells. If two chemically different inhibitors (e.g. W-7 and trifluoperazine) produce similar effects, investigators often assume the effects are due to CaM inhibition. Zeta potential measurements, however, show that these amphipathic weak bases bind to phospholipid vesicles at the same concentrations as they inhibit Ca2+/CaM; this suggests that they also bind to the inner leaflet of the plasma membrane, reducing its negative electrostatic surface potential. This change will cause electrostatically bound clusters of basic residues on peripheral (e.g. Src and K-Ras4B) and integral (e.g. epidermal growth factor receptor (EGFR)) proteins to translocate from the membrane to the cytoplasm. We measured inhibitor-mediated translocation of a simple basic peptide corresponding to the calmodulin-binding juxtamembrane region of the EGFR on model membranes; W-7/W-13 causes translocation of this peptide from membrane to solution, suggesting that caution must be exercised when interpreting the results obtained with these inhibitors in living cells. We present evidence that they exert dual effects on autophosphorylation of EGFR; W-13 inhibits epidermal growth factor-dependent EGFR autophosphorylation under different experimental conditions, but in the absence of epidermal growth factor, W-13 stimulates autophosphorylation of the receptor in four different cell types. Our interpretation is that the former effect is due to W-13 inhibition of Ca2+/CaM, but the latter results could be due to binding of W-13 to the plasma membrane.
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Affiliation(s)
- Parijat Sengupta
- Department of Physiology and Biophysics, Health Science Center, State University of New York at Stony Brook, Stony Brook, New York 11794-8661, USA
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13
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Kang S, Kang J, Yoo SH, Park S. Recombinant preparation and characterization of interactions for a calmodulin-binding chromogranin A peptide and calmodulin. J Pept Sci 2007; 13:237-44. [PMID: 17269132 DOI: 10.1002/psc.837] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chromogranin-derived peptides have important and varied biological activities. They affect a wide spectrum of targets such as fungal membranes, blood vessels, myocardial cells, and pancreatic cells. Despite the biological significance and the diverse activities, the molecular mechanisms of the interactions between the peptides and the target proteins have not been well understood. Here, we studied the interaction between a chromogranin A-derived peptide (CGA40-65) and its target protein, calmodulin, with NMR spectroscopy. Calmodulin was easily prepared with standard recombinant technology, but CGA40-65 posed challenges requiring multistep procedures. The recombinantly produced peptide retained the calmodulin-binding property of the full-length CGA, as shown by the HSQC binding experiment. By applying resonance assignments, we identified the residues in calmodulin involved in the CGA40-65 binding. We also found that the peak changes are close to those exhibited by the peptides having the wrap-around binding mechanism. Further analysis revealed that the CGA40-65-induced changes are more similar to those by CaMKIp peptide than those by smMLCKp peptide among the wrap-around binding peptides, suggesting that CGA40-65 can be categorized as a CaMKIp-like peptide. Our report is the first residue-resolution mechanistic study involving chromogranin peptides and their target proteins. Our approaches should be applicable to interaction studies involving other chromogranin-derived peptides and their cellular target proteins.
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Affiliation(s)
- Sunmi Kang
- Department of Biochemistry, Center for Advanced Medical Education by BK21 project, School of Medicine, Inha University, Shinheung-dong, Chung-gu, Incheon, Korea
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14
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Zahn A, Jennings N, Ouwehand WH, Allain JP. Hepatitis C virus interacts with human platelet glycoprotein VI. J Gen Virol 2006; 87:2243-2251. [PMID: 16847120 DOI: 10.1099/vir.0.81826-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Hepatitis C virus (HCV) interacts with human platelets in vivo as a potential transport of infectious virions to the target liver. The binding of native viral particles with the platelet membrane glycoprotein VI (GPVI) was analysed. A consistent interaction between HCV from plasma or after purification by two different methods and the recombinant extracellular immunoglobulin (Ig)-like domains of human GPVI (hD1D2) was observed with two independent experimental approaches: pull-down and ELISA assays. Between 2 and 7 % of HCV particles were specifically bound to hD1D2. The binding was inhibited by an anti-hD1D2 in a dose-dependent manner. Human D1D2 interaction with HCV was significantly higher than the murine D1D2, supporting the specificity of the interaction and to the single human domains (D1 and D2), suggesting that both Ig-like domains of the molecule are required for efficient binding. GPVI may be a platelet surface ligand for HCV playing a role in viral transport and persistence.
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Affiliation(s)
- Astrid Zahn
- National Blood Service, Long Road, Cambridge CB2 2PT, UK
- Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge CB2 2PT, UK
| | - Nicola Jennings
- Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge CB2 2PT, UK
| | - Willem H Ouwehand
- National Blood Service, Long Road, Cambridge CB2 2PT, UK
- Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge CB2 2PT, UK
| | - Jean-Pierre Allain
- Division of Transfusion Medicine, Department of Haematology, University of Cambridge, Cambridge CB2 2PT, UK
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15
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Li MX, Hoffman RMB, Sykes BD. Interaction of cardiac troponin C with calmodulin antagonist [corrected] W7 in the presence of three functional regions of cardiac troponin I. Biochemistry 2006; 45:9833-40. [PMID: 16893183 DOI: 10.1021/bi060779a] [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: 11/28/2022]
Abstract
W7 is a well-known calmodulin (CaM) antagonist and has been implicated as an inhibitor of the troponin C-mediated Ca(2+) activation of cardiac muscle contraction. In this study, we use NMR spectroscopy to study binding of W7 to cardiac troponin C (cTnC) free or in complex with cardiac troponin I (cTnI) peptides. Titration of cTnC.3Ca(2+) with W7 shows that residues throughout the sequence, including the N- and C-domains of cTnC and the central linker, are affected. Analysis of the binding stoichiometry and the trajectories of chemical shift changes indicate that W7 binding occurs at multiple sites. To address the issue of whether multiple-site binding is relevant within the troponin complex, W7 is titrated to a cTnC-cTnI complex (cTnC.3Ca(2+).cTnI(34)(-)(71).cTnI(128)(-)(163)). In the presence of the N-terminal (residues approximately 34-71), inhibitory (residues approximately 128-147), and switch (residues approximately 147-163) regions of cTnI, W7 induces chemical shift changes only in the N-domain and not in the C-domain or the central linker of cTnC. The results indicate that in the presence of cTnI, W7 no longer binds to multiple sites of cTnC but instead binds specifically to the N-domain, and the binding (K(D) = 0.5 +/- 0.1 mM) can occur together with the switch region of cTnI. Hence, W7 may play a role in directly modulating the Ca(2+) sensitivity of the regulatory domain of cTnC and the interaction of the switch region of cTnI and cTnC.
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Affiliation(s)
- Monica X Li
- CIHR Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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16
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Streiff JH, Allen TW, Atanasova E, Juranic N, Macura S, Penheiter AR, Jones KA. Prediction of volatile anesthetic binding sites in proteins. Biophys J 2006; 91:3405-14. [PMID: 16877516 PMCID: PMC1614498 DOI: 10.1529/biophysj.106.082586] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Computational methods designed to predict and visualize ligand protein binding interactions were used to characterize volatile anesthetic (VA) binding sites and unoccupied pockets within the known structures of VAs bound to serum albumin, luciferase, and apoferritin. We found that both the number of protein atoms and methyl hydrogen, which are within approximately 8 A of a potential ligand binding site, are significantly greater in protein pockets where VAs bind. This computational approach was applied to structures of calmodulin (CaM), which have not been determined in complex with a VA. It predicted that VAs bind to [Ca(2+)](4)-CaM, but not to apo-CaM, which we confirmed with isothermal titration calorimetry. The VA binding sites predicted for the structures of [Ca(2+)](4)-CaM are located in hydrophobic pockets that form when the Ca(2+) binding sites in CaM are saturated. The binding of VAs to these hydrophobic pockets is supported by evidence that halothane predominantly makes contact with aliphatic resonances in [Ca(2+)](4)-CaM (nuclear Overhauser effect) and increases the Ca(2+) affinity of CaM (fluorescence spectroscopy). Our computational analysis and experiments indicate that binding of VA to proteins is consistent with the hydrophobic effect and the Meyer-Overton rule.
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Affiliation(s)
- John H Streiff
- Departments of Anesthesiology and Molecular Pharmacology and Experimental Therapeutics and Biochemistry and Molecular Biology, Mayo College of Medicine, Rochester, Minnesota, USA.
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17
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Yu YC, Cao LH, Yang XL. Modulation by brain natriuretic peptide of GABA receptors on rat retinal ON-type bipolar cells. J Neurosci 2006; 26:696-707. [PMID: 16407567 PMCID: PMC6674405 DOI: 10.1523/jneurosci.3653-05.2006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Natriuretic peptides (NPs) may work as neuromodulators through their associated receptors [NP receptors (NPRs)]. By immunocytochemistry, we showed that NPR-A and NPR-B were expressed abundantly on both ON-type and OFF-type bipolar cells (BCs) in rat retina, including the dendrites, somata, and axon terminals. Whole-cell recordings made from isolated ON-type BCs further showed that brain natriuretic peptide (BNP) suppressed GABAA receptor-, but not GABAC receptor-, mediated currents of the BCs, which was blocked by the NPR-A antagonist anantin. The NPR-C agonist c-ANF [des(Gln18, Ser19, Gln20, Leu21, Gly22)ANF(4-23)-NH2] did not suppress GABAA currents. The BNP effect on GABAA currents was abolished with preincubation with the pGC-A/B antagonist HS-142-1 but mimicked by application of 8-bromoguanosine-3',5'-cyclomonophosphate. These results suggest that elevated levels of intracellular cGMP caused by activation of NPR-A may mediate the BNP effect. Internal infusion of the cGMP-dependent protein kinase G (PKG) inhibitor KT5823 essentially blocked the BNP-induced reduction of GABAA currents. Moreover, calcium imaging showed that BNP caused a significant elevation of intracellular calcium that could be caused by increased calcium release from intracellular stores by PKG. The BNP effect was blocked by the ryanodine receptor modulators caffeine, ryanodine, and ruthenium red but not by the IP3 receptor antagonists heparin and xestospongin-C. Furthermore, the BNP effect was abolished after application of the blocker of endoplasmic reticulum Ca2+-ATPase thapsigargin and greatly reduced by the calmodulin inhibitors W-7 and calmidazolium. We therefore conclude that the increased calcium release from ryanodine-sensitive calcium stores by BNP may be responsible for the BNP-caused GABAA response suppression in ON-type BCs through stimulating calmodulin.
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MESH Headings
- Animals
- Atrial Natriuretic Factor/pharmacology
- Caffeine/pharmacology
- Calcium/metabolism
- Calcium Channels
- Calcium Signaling/drug effects
- Calcium-Transporting ATPases/antagonists & inhibitors
- Calmodulin/antagonists & inhibitors
- Calmodulin/physiology
- Carbazoles/pharmacology
- Cyclic GMP/analogs & derivatives
- Cyclic GMP/pharmacology
- Cyclic GMP-Dependent Protein Kinases/physiology
- GABA-A Receptor Antagonists
- Guanylate Cyclase/drug effects
- Guanylate Cyclase/physiology
- Heparin/pharmacology
- Imidazoles/pharmacology
- Indoles/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors
- Macrocyclic Compounds
- Male
- Membrane Potentials/drug effects
- Natriuretic Peptide, Brain/antagonists & inhibitors
- Natriuretic Peptide, Brain/pharmacology
- Natriuretic Peptide, Brain/physiology
- Oxazoles/pharmacology
- Patch-Clamp Techniques
- Peptide Fragments/pharmacology
- Peptides, Cyclic/pharmacology
- Polysaccharides/pharmacology
- Protein Kinase Inhibitors/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Atrial Natriuretic Factor/drug effects
- Receptors, Atrial Natriuretic Factor/physiology
- Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
- Receptors, GABA/physiology
- Receptors, GABA-A/drug effects
- Retinal Bipolar Cells/drug effects
- Retinal Bipolar Cells/physiology
- Ruthenium Red/pharmacology
- Ryanodine/pharmacology
- Ryanodine Receptor Calcium Release Channel/drug effects
- Thapsigargin/pharmacology
- gamma-Aminobutyric Acid/pharmacology
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Affiliation(s)
- Yong-Chun Yu
- Institute of Neurobiology, Fudan University, Shanghai 200433, China
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18
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Milanesi L, Hunter CA, Sedelnikova SE, Waltho JP. Amplification of Bifunctional Ligands for Calmodulin from a Dynamic Combinatorial Library. Chemistry 2006; 12:1081-7. [PMID: 16240315 DOI: 10.1002/chem.200500357] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A well known strategy to prepare high affinity ligands for a biological receptor is to link together low affinity ligands. DCC (dynamic combinatorial chemistry) was used to select bifunctional protein ligands with high affinity relative to the corresponding monofunctional ligands. Thiol to disulfide linkage generated a small dynamic library of bifunctional ligands in the presence of calmodulin, a protein with two independently mobile domains. The binding constant of the bifunctional ligand (disulfide) most amplified by the presence of calmodulin is nearly two orders of magnitude higher than that of the corresponding monofunctional ligand (thiol).
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Affiliation(s)
- Lilia Milanesi
- Centre for Chemical Biology, Krebs Institute for Biomolecular Science, Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
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19
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Hempel A, Camerman N, Mastropaolo D, Camerman A. Calmodulin antagonists: Structure of N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) and comparison with trifluoperazine (TFP) Calmodulin binding. CAN J CHEM 2005. [DOI: 10.1139/v05-133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The crystal structure of the title compound contains one N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride molecule in the asymmetric unit. The molecule adopts an extended conformation with a linear hexyl group. Protonation occurs at the side chain terminal nitrogen atom. Hydrophobic packing and a three-dimensional hydrogen-bond network, involving all the hydrogen atoms capable of making hydrogen-bond contacts, stabilizes the crystal structure. Due to head-to-head and tail-to-tail arrangement of these hydrophobic molecules, an unusually long cell constant (b = 61.27 Å) characterizes the crystal structure. A stereochemical comparison with trifluoperazine suggests similar calmodulin binding mechanisms.Key words: crystal structure, stereochemistry, W-7, calmodulin binding, TFP.
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20
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Turjanski AG, Estrin DA, Rosenstein RE, McCormick JE, Martin SR, Pastore A, Biekofsky RR, Martorana V. NMR and molecular dynamics studies of the interaction of melatonin with calmodulin. Protein Sci 2005; 13:2925-38. [PMID: 15498938 PMCID: PMC2286588 DOI: 10.1110/ps.04611404] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Pineal hormone melatonin (N-acetyl-5-methoxytryptamine) is thought to modulate the calcium/calmodulin signaling pathway either by changing intracellular Ca(2+) concentration via activation of its G-protein-coupled membrane receptors, or through a direct interaction with calmodulin (CaM). The present work studies the direct interaction of melatonin with intact calcium-saturated CaM both experimentally, by fluorescence and nuclear magnetic resonance spectroscopies, and theoretically, by molecular dynamics simulations. The analysis of the experimental data shows that the interaction is calcium-dependent. The affinity, as obtained from monitoring (15)N and (1)H chemical shift changes for a melatonin titration, is weak (in the millimolar range) and comparable for the N- and C-terminal domains. Partial replacement of diamagnetic Ca(2+) by paramagnetic Tb(3+) allowed the measurement of interdomain NMR pseudocontact shifts and residual dipolar couplings, indicating that each domain movement in the complex is not correlated with the other one. Molecular dynamics simulations allow us to follow the dynamics of melatonin in the binding pocket of CaM. Overall, this study provides an example of how a combination of experimental and theoretical approaches can shed light on a weakly interacting system of biological and pharmacological significance.
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Affiliation(s)
- Adrián G Turjanski
- Departamento de Química Inorgánica, Analítica y Química-Física, INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
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21
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Trevitt CR, Craven CJ, Milanesi L, Syson K, Mattinen ML, Perkins J, Annila A, Hunter CA, Waltho JP. Enhanced Ligand Affinity for Receptors in which Components of the Binding Site Are Independently Mobile. ACTA ACUST UNITED AC 2005; 12:89-97. [PMID: 15664518 DOI: 10.1016/j.chembiol.2004.11.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2004] [Revised: 10/30/2004] [Accepted: 11/01/2004] [Indexed: 11/22/2022]
Abstract
Using calmodulin antagonism as a model, it is demonstrated that, under circumstances in which binding sites are motionally independent, it is possible to create bifunctional ligands that bind with significant affinity enhancement over their monofunctional counterparts. Suitable head groups were identified by using a semiquantitative screen of monofunctional tryptophan analogs. Two bifunctional ligands, which contained two copies of the highest-affinity head group tethered by rigid linkers, were synthesized. The bifunctional ligands bound to calmodulin with a stoichiometry of 1:1 and with an affinity enhancement over their monofunctional counterparts; the latter bound with a stoichiometry of 2:1 ligand:protein. A lower limit to the effective concentrations of the domains of calmodulin relative to each other (0.2-2 mM) was determined. A comparable effective concentration was achieved for bifunctional ligands based on higher-affinity naphthalene sulphonamide derivatives.
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Affiliation(s)
- Clare R Trevitt
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
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22
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Chung E, Park JM, Oh SK, Joung YH, Lee S, Choi D. Molecular and biochemical characterization of the Capsicum annuum calcium-dependent protein kinase 3 (CaCDPK3) gene induced by abiotic and biotic stresses. PLANTA 2004; 220:286-295. [PMID: 15449060 DOI: 10.1007/s00425-004-1372-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2004] [Accepted: 07/19/2004] [Indexed: 05/24/2023]
Abstract
The isolated full-length Capsicum annuum calcium-dependent protein kinase 3 (CaCDPK3) cDNA clone was selected from the chili pepper expressed sequence tag database (http://www.pdrc.re.kr/ks200201/pepper.html). Phylogenetic analysis based on the deduced amino acid sequence of CaCDPK3 cDNA revealed significant sequence similarity to the winter squash (Cucurbita maxima) CmCPK2 gene (81% identity). Genomic gel blot analysis disclosed that CaCDPK3 belongs to a multigene family in the pepper genome. CaCDPK3 expression was root tissue-specific, as shown by Northern blot data. The gene was rapidly induced in response to various osmotic stress factors and exogenous abscisic acid application in pepper leaves. Moreover, CaCDPK3 RNA expression was induced by an incompatible pathogen and by plant defense-related chemicals such as ethephon, salicylic acid and jasmonic acid. The biochemical properties of CaCDPK3 were investigated using a CaCDPK3 and glutathione S-transferase (GST) fusion protein. The recombinant proteins retained calcium-binding ability, and displayed autophosphorylation activity in vitro in a calcium-dependent manner. Further transient-expression studies showed that CaCDPK3 fused with soluble modified green fluorescent protein (smGFP) localized to the cytosol in chili pepper protoplasts. We propose that CaCDPK3 is implicated in biotic and abiotic stresses in pepper plants.
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Affiliation(s)
- Eunsook Chung
- Plant Genomics Laboratory, Genome Research Center, KRIBB, P.O. Box 115, Yusung, 305-600 Taejon, Republic of Korea
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23
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Nilsson KPR, Inganäs O. Optical Emission of a Conjugated Polyelectrolyte: Calcium-Induced Conformational Changes in Calmodulin and Calmodulin−Calcineurin Interactions. Macromolecules 2004. [DOI: 10.1021/ma048605t] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- K. Peter R. Nilsson
- The Department of Physics and Measurement technology, Biology and Chemistry, Linköpings University, SE-581 83 Linköping, Sweden
| | - Olle Inganäs
- The Department of Physics and Measurement technology, Biology and Chemistry, Linköpings University, SE-581 83 Linköping, Sweden
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24
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Shepherd CM, Vogel HJ. A molecular dynamics study of Ca(2+)-calmodulin: evidence of interdomain coupling and structural collapse on the nanosecond timescale. Biophys J 2004; 87:780-91. [PMID: 15298887 PMCID: PMC1304488 DOI: 10.1529/biophysj.103.033266] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Accepted: 04/20/2004] [Indexed: 11/18/2022] Open
Abstract
A 20-ns molecular dynamics simulation of Ca(2+)-calmodulin (CaM) in explicit solvent is described. Within 5 ns, the extended crystal structure adopts a compact shape similar in dimension to complexes of CaM and target peptides but with a substantially different orientation between the N- and C-terminal domains. Significant interactions are observed between the terminal domains in this compact state, which are mediated through the same regions of CaM that bind to target peptides derived from protein kinases and most other target proteins. The process of compaction is driven by the loss of helical structure in two separate regions between residues 75-79 and 82-86, the latter being driven by unfavorable electrostatic interactions between acidic residues. In the first 5 ns of the simulation, a substantial number of contacts are observed between the first helix of the N-terminal domain and residues 74-77 of the central linker. These contacts are correlated with the closing of the second EF-hand, indicating a mechanism by which they can lower calcium affinity in the N-terminal domain.
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Affiliation(s)
- Craig M Shepherd
- Structural Biology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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25
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del Río B, García Pedrero JM, Martínez-Campa C, Zuazua P, Lazo PS, Ramos S. Melatonin, an endogenous-specific inhibitor of estrogen receptor alpha via calmodulin. J Biol Chem 2004; 279:38294-302. [PMID: 15229223 DOI: 10.1074/jbc.m403140200] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Melatonin is an indole hormone produced mainly by the pineal gland. We have previously demonstrated that melatonin interferes with estrogen (E(2)) signaling in MCF7 cells by impairing estrogen receptor (ER) pathways. Here we present the characterization of its mechanism of action showing that melatonin is a specific inhibitor of E(2)-induced ERalpha-mediated transcription in both estrogen response element- and AP1-containing promoters, whereas ERbeta-mediated transactivation is not inhibited or even activated at certain promoters. We show that the sensitivity of MCF-7 cells to melatonin depends on the ERalpha/ERbeta ratio, and ectopic expression of ERbeta results in MCF-7 cells becoming insensitive to this hormone. Melatonin acts as a calmodulin antagonist inducing conformational changes in the ERalpha-calmodulin (CaM) complex, thus impairing the binding of E(2).ERalpha.CaM complex to DNA and, therefore, preventing ERalpha-dependent transcription. Moreover the mutant ERalpha (K302G,K303G), unable to bind calmodulin, becomes insensitive to melatonin. The effect of melatonin is specific since other related indoles neither interact with CaM nor inhibit ERalpha-mediated transactivation. Interestingly, melatonin does not affect the binding of coactivators to ERalpha, indicating that melatonin action is different from that of current therapeutic anti-estrogens used in breast cancer therapy. Thus, they target ERalpha at different levels, representing two independent ways to control ERalpha activity. It is, therefore, conceivably a synergistic pharmacological effect of melatonin and current anti-estrogen drugs.
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Affiliation(s)
- Beatriz del Río
- Departamento de Bioquímica y Biología Molecular and Instituto Universitario de Oncología Del Principado de Asturias, Universidad de Oviedo, 33071 Oviedo, Spain
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26
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Hayashi N, Nakagawa C, Ito Y, Takasaki A, Jinbo Y, Yamakawa Y, Titani K, Hashimoto K, Izumi Y, Matsushima N. Myristoylation-regulated Direct Interaction Between Calcium-bound Calmodulin and N-terminal Region of pp60v-src. J Mol Biol 2004; 338:169-80. [PMID: 15050832 DOI: 10.1016/j.jmb.2004.02.041] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2003] [Revised: 02/12/2004] [Accepted: 02/12/2004] [Indexed: 10/26/2022]
Abstract
pp60v-src tyrosine protein kinase was suggested to interact with Ca2+-bound calmodulin (Ca2+/CaM) through the N-terminal region based on its structural similarities to CAP-23/NAP-22, a myristoylated neuron-specific protein, whose myristoyl group is essential for interaction with Ca2+/CaM; (1) the N terminus of pp60v-src is myristoylated like CAP-23/NAP-22; (2) both lysine residues are required for the myristoylation-dependent interaction and serine residues that are thought to regulate the interaction through the phosphorylations located in the N-terminal region of pp60v-src. To verify this possibility, we investigated the direct interaction between pp60v-src and Ca2+/CaM using a myristoylated peptide corresponding to the N-terminal region of pp60v-src. The binding assay indicated that only the myristoylated peptide binds to Ca2+/CaM, and the non-myristoylated peptide is not able to bind to Ca2+/CaM. Analyses of the binding kinetics revealed two independent reactions with the dissociation constants (KD) of 2.07 x 10(-9)M (KD1) and 3.93 x 10(-6)M (KD2), respectively. Two serine residues near the myristoyl moiety of the peptide (Ser2, Ser11) were phosphorylated by protein kinase C in vitro, and the phosphorylation drastically reduced the interaction. NMR experiments indicated that two molecules of the myristoylated peptide were bound around the hydrophobic clefts of a Ca2+/CaM molecule. The small-angle X-ray scattering analyses showed that the size of the peptide-Ca2+/CaM complex is 2-3A smaller than that of the known Ca2+/CaM-target molecule complexes. These results demonstrate clearly the direct interaction between pp60v-src and Ca2+/CaM in a novel manner different from that of known Ca2+/CaM, the target molecules, interactions.
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Affiliation(s)
- Nobuhiro Hayashi
- Division of Biomedical Polymer Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
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27
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Krol E, Dziubińska H, Trebacz K. Low-temperature-induced transmembrane potential changes in mesophyll cells of Arabidopsis thaliana, Helianthus annuus and Vicia faba. PHYSIOLOGIA PLANTARUM 2004; 120:265-270. [PMID: 15032861 DOI: 10.1111/j.0031-9317.2004.0244.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Glass microelectrodes were inserted into mesophyll cells of intact leaves from higher plants: Arabidopsis thaliana, Helianthus annuus and Vicia faba var minor, and transient membrane potential changes were recorded in response to a sudden temperature drop. The cold-induced potential changes were unaffected by an anion channel inhibitor (anthracene-9-carboxylic acid) and potassium channel inhibitor (tetraethyl ammonium ion). Verapamil, a calcium channel inhibitor, caused significant suppression of the cold-induced potential changes. In the presence of calmoduline antagonists (trifluoperazine and N-6-aminohexyl-5-chloro-1-naphtalenesulphonamide), their amplitudes decreased and their durations were prolonged. Neomycin, which suppresses phospholipase C, also caused substantial inhibition of the amplitudes of the cold-induced potential changes. It is concluded that cold-evoked membrane potential changes are due to calcium influxes from both the apoplast and internal stores.
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Affiliation(s)
- Elzbieta Krol
- Department of Biophysics, Institute of Biology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
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28
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Broeke RT, Leusink-Muis T, Hilberdink R, Van Ark I, van den Worm E, Villain M, De Clerck F, Blalock JE, Nijkamp FP, Folkerts G. Specific modulation of calmodulin activity induces a dramatic production of superoxide by alveolar macrophages. J Transl Med 2003. [DOI: 10.1038/labinvest.3700002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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29
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García Pedrero JM, Del Rio B, Martínez-Campa C, Muramatsu M, Lazo PS, Ramos S. Calmodulin is a selective modulator of estrogen receptors. Mol Endocrinol 2002; 16:947-60. [PMID: 11981030 DOI: 10.1210/mend.16.5.0830] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In the search for differences between ERalpha and ERbeta, we analyzed the interaction of both receptors with calmodulin (CaM) and demonstrated that ERalpha but not ERbeta directly interacts with CaM. Using transiently transfected HeLa cells, we examined the effect of the CaM antagonist N-(6-aminohexyl)-5-chloro-naphthalene sulfonilamide hydrochloride (W7) on the transactivation properties of ERalpha and ERbeta in promoters containing either estrogen response elements or activator protein 1 elements. Transactivation by ERalpha was dose-dependently inhibited by W7, whereas that of ERbeta was not inhibited or even activated at low W7 concentrations. In agreement with these results, transactivation of an estrogen response element containing promoter in MCF-7 cells (which express a high ERalpha/ERbeta ratio) was also inhibited by W7. In contrast, transactivation in T47D cells (which express a low ERalpha/ERbeta ratio) was not affected by this CaM antagonist. The sensitivity of MCF-7 cells to W7 was abolished when cells were transfected with increasing amounts of ERbeta, indicating that the sensitivity to CaM antagonists of estrogen-responsive tissues correlates with a high ERalpha/ERbeta ratio. Finally, substitution of lysine residues 302 and 303 of ERalpha for glycine rendered a mutant ERalpha unable to interact with CaM whose transactivation activity became insensitive to W7. Our results indicate that CaM antagonists are selective modulators of ER able to inhibit ERalpha-mediated activity, whereas ERbeta actions were not affected or even potentiated by W7.
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Affiliation(s)
- Juana M García Pedrero
- Departamento de Bioquímica y Biología Molecular and Instituto Universitario de Oncología Principado de Asturias, Universidad de Oviedo, 33007 Oviedo, Spain
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Hayashi N, Matsubara M, Jinbo Y, Titani K, Izumi Y, Matsushima N. Nef of HIV-1 interacts directly with calcium-bound calmodulin. Protein Sci 2002; 11:529-37. [PMID: 11847276 PMCID: PMC2373460 DOI: 10.1110/ps.23702] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
It was recently found that the myristoyl group of CAP-23/NAP-22, a neuron-specific protein kinase C substrate, is essential for the interaction between the protein and Ca(2+)-bound calmodulin (Ca(2+)/CaM). Based on the N-terminal amino acid sequence alignment of CAP-23/NAP-22 and other myristoylated proteins, including the Nef protein from human immunodeficiency virus (HIV), we proposed a new hypothesis that the protein myristoylation plays important roles in protein-calmodulin interactions. To investigate the possibility of direct interaction between Nef and calmodulin, we performed structural studies of Ca(2+)/CaM in the presence of a myristoylated peptide corresponding to the N-terminal region of Nef. The dissociation constant between Ca(2+)/CaM and the myristoylated Nef peptide was determined to be 13.7 nM by fluorescence spectroscopy analyses. The NMR experiments indicated that the chemical shifts of some residues on and around the hydrophobic clefts of Ca(2+)/CaM changed markedly in the Ca(2+)/CaM-Nef peptide complex with the molar ratio of 1:2. Correspondingly, the radius of gyration determined by the small angle X-ray scattering measurements is 2-3 A smaller that of Ca(2+)/CaM alone. These results demonstrate clearly that Nef interacts directly with Ca(2+)/CaM.
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Affiliation(s)
- Nobuhiro Hayashi
- Division of Biomedical Polymer Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
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Olivero J, Ganey PE. Participation of Ca2+/calmodulin during activation of rat neutrophils by polychlorinated biphenyls. Biochem Pharmacol 2001; 62:1125-32. [PMID: 11597581 DOI: 10.1016/s0006-2952(01)00768-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The effects of Ca2+ and Ca2+/calmodulin on the polychlorinated biphenyl (PCB)-induced activation of phospholipase A2 (PLA2) in rat neutrophils were examined. The commercial PCB mixture Aroclor 1242 induced activation of PLA2 and promoted an increase in the intracellular free calcium concentration ([Ca2+]i). Bromoenol lactone (BEL), an inhibitor of the Ca2+-independent PLA2 isoform (iPLA2) activated by PCBs, did not abrogate the increase in [Ca2+]i, suggesting that this change in Ca2+ concentration is not downstream from the activation of iPLA2. TMB-8 [8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate], a blocker of the release of intracellular Ca2+, decreased Aroclor 1242-induced stimulation of PLA2 with a maximal inhibition of 17% at 50 microM. These two results suggest little direct dependence between the PCB-induced activation of iPLA2 and increase in [Ca2+]i. Calmidazolium and W7 [N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide], two chemically distinct calmodulin inhibitors, inhibited Aroclor 1242-induced PLA2 activity, whereas trifluoperazine (TFP), another inhibitor of calmodulin, had no effect at noncytotoxic concentrations. Thus, activation of PLA2 is dependent, in part, on calmodulin. Furthermore, both TFP and Aroclor 1242 inhibited neutrophil degranulation stimulated by the bacterial peptide formyl-methionyl-leucyl-phenylalanine. These results raise the possibility that some of the effects of PCBs on neutrophil function can be explained by effects on Ca2+/calmodulin-dependent processes.
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Affiliation(s)
- J Olivero
- Department of Pharmacology and Toxicology, National Food Safety and Toxicology Center and Institute for Environmental Toxicology, Michigan State University, East Lansing, MI 48824, USA
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32
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Abstract
Trifluoperazine (TFP) has been widely studied in relation to its mode of binding and its inactivation of calmodulin (CaM). Most studies in solution have indicated that CaM has two high-affinity binding sites for TFP. The crystal structure of the 1:4 CaM-TFP complex (CaM-4TFP) shows that three TFP molecules bind to the C-domain of CaM, and that one TFP molecule binds to the N-domain. In contrast, the crystal structure of the 1:1 CaM-TFP complex (CaM-1TFP) shows that one TFP molecule binds to the C-domain. It has been thought that the binding of one TFP molecule to the C-domain is followed by binding to the N-domain. The crystal structure of the 1:2 CaM-TFP complex (CaM-2TFP), moreover, has recently been determined, showing that two TFP molecules bind to the C-domain. In order to determine the structure of the CaM-TFP complex and to clarify the interaction between CaM and TFP in solution, we performed a molecular dynamics simulation of the CaM-TFP complex in aqueous solution starting from the CaM-4TFP crystal structure. The obtained solution structure is very similar to the CaM-2TFP crystal structure. The computer simulation showed that the binding ability of the secondary binding site of the C-domain is higher than that of the primary binding site of the N-domain.
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Affiliation(s)
- N Yamaotsu
- Laboratory of Physical Chemistry for Drug Design, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641 Japan
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Hayashi N, Izumi Y, Titani K, Matsushima N. The binding of myristoylated N-terminal nonapeptide from neuro-specific protein CAP-23/NAP-22 to calmodulin does not induce the globular structure observed for the calmodulin-nonmyristylated peptide complex. Protein Sci 2000; 9:1905-13. [PMID: 11106163 PMCID: PMC2144459 DOI: 10.1110/ps.9.10.1905] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
CAP-23/NAP-22, a neuron-specific protein kinase C substrate, is Nalpha-myristoylated and interacts with calmodulin (CaM) in the presence of Ca2+ ions. Takasaki et al. (1999, J Biol Chem 274:11848-11853) have recently found that the myristoylated N-terminal nonapeptide of CAP-23/NAP-22 (mC/N9) binds to Ca2+ -bound CaM (Ca2+/CaM). In the present study, small-angle X-ray scattering was used to investigate structural changes of Ca2+/CaM induced by its binding to mC/N9 in solution. The binding of one mC/N9 molecule induced an insignificant structural change in Ca2+/CaM. The 1:1 complex appeared to retain the extended conformation much like that of Ca2+/CaM in isolation. However, it could be seen that the binding of two mC/N9 molecules induced a drastic structural change in Ca2+/CaM, followed by a slight structural change by the binding of more than two but less than four mC/N9 molecules. Under the saturated condition (the molar ratio of 1:4), the radius of gyration (Rg) for the Ca2+/CaM-mC/N9 complex was 19.8 +/- 0.3 A. This value was significantly smaller than that of Ca2+/CaM (21.9 +/- 0.3 A), which adopted a dumbbell structure and was conversely 2-3 A larger than those of the complexes of Ca2+/CaM with the nonmyristoylated target peptides of myosin light chain kinase or CaM kinase II, which adopted a compact globular structure. The pair distance distribution function had no shoulder peak at around 40 A, which was mainly due to the dumbbell structure. These results suggest that Ca2+/CaM interacts with Nalpha-myristoylated CAP-23/NAP-22 differently than it does with other nonmyristoylated target proteins. The N-terminal amino acid sequence alignment of CAP-23/NAP-22 and other myristoylated proteins suggests that the protein myristoylation plays important roles not only in the binding of CAP-23/NAP-22 to Ca2+/CaM, but also in the protein-protein interactions related to other myristoylated proteins.
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Affiliation(s)
- N Hayashi
- Division of Biomedical Polymer Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan.
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Wilson MA, Brunger AT. The 1.0 A crystal structure of Ca(2+)-bound calmodulin: an analysis of disorder and implications for functionally relevant plasticity. J Mol Biol 2000; 301:1237-56. [PMID: 10966818 DOI: 10.1006/jmbi.2000.4029] [Citation(s) in RCA: 250] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Calmodulin (CaM) is a highly conserved 17 kDa eukaryotic protein that can bind specifically to over 100 protein targets in response to a Ca(2+) signal. Ca(2+)-CaM requires a considerable degree of structural plasticity to accomplish this physiological role; however, the nature and extent of this plasticity remain poorly characterized. Here, we present the 1.0 A crystal structure of Paramecium tetraurelia Ca(2+)-CaM, including 36 discretely disordered residues and a fifth Ca(2+) that mediates a crystal contact. The 36 discretely disordered residues are located primarily in the central helix and the two hydrophobic binding pockets, and reveal correlated side-chain disorder that may assist target-specific deformation of the binding pockets. Evidence of domain displacements and discrete backbone disorder is provided by translation-libration-screw (TLS) analysis and multiconformer models of protein disorder, respectively. In total, the evidence for disorder at every accessible length-scale in Ca(2+)-CaM suggests that the protein occupies a large number of hierarchically arranged conformational substates in the crystalline environment and may sample a quasi-continuous spectrum of conformations in solution. Therefore, we propose that the functionally distinct forms of CaM are less structurally distinct than previously believed, and that the different activities of CaM in response to Ca(2+) may result primarily from Ca(2+)-mediated alterations in the dynamics of the protein.
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Affiliation(s)
- M A Wilson
- Departments of Molecular and Cellular Physiology, Neurology and Neurological Sciences and Stanford Synchrotron Radiation Laboratory, The Howard Hughes Medical Institute and, Stanford, CA, 94305, USA
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Biekofsky RR, Muskett FW, Schmidt JM, Martin SR, Browne JP, Bayley PM, Feeney J. NMR approaches for monitoring domain orientations in calcium-binding proteins in solution using partial replacement of Ca2+ by Tb3+. FEBS Lett 1999; 460:519-26. [PMID: 10556528 DOI: 10.1016/s0014-5793(99)01410-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This work shows that the partial replacement of diamagnetic Ca2+ by paramagnetic Tb3+ in Ca2+/calmodulin systems in solution allows the measurement of interdomain NMR pseudocontact shifts and leads to magnetic alignment of the molecule such that significant residual dipolar couplings can be measured. Both these parameters can be used to provide structural information. Species in which Tb3+ ions are bound to only one domain of calmodulin (the N-domain) and Ca2+ ions to the other (the C-domain) provide convenient systems for measuring these parameters. The nuclei in the C-domain experience the local magnetic field induced by the paramagnetic Tb3+ ions bound to the other domain at distances of over 40 A from the Tb3+ ion, shifting the resonances for these nuclei. In addition, the Tb3+ ions bound to the N-domain of calmodulin greatly enhance the magnetic susceptibility anisotropy of the molecule so that a certain degree of alignment is produced due to interaction with the external magnetic field. In this way, dipolar couplings between nuclear spins are not averaged to zero due to solution molecular tumbling and yield dipolar coupling contributions to, for example, the one-bond 15N-1H splittings of up to 17 Hz in magnitude. The degree of alignment of the C-domain will also depend on the degree of orientational freedom of this domain with respect to the N-domain containing the Tb3+ ions. Pseudocontact shifts for NH groups and 1H-15N residual dipolar couplings for the directly bonded atoms have been measured for calmodulin itself, where the domains have orientational freedom, and for the complex of calmodulin with a target peptide from skeletal muscle myosin light chain kinase, where the domains have fixed orientations with respect to each other. The simultaneous measurements of these parameters for systems with domains in fixed orientations show great potential for the determination of the relative orientation of the domains.
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Affiliation(s)
- R R Biekofsky
- Molecular Structure Division, National Institute for Medical Research, The Ridgeway, Mill Hill, London, UK
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