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Lim D, Tapella L, Dematteis G, Talmon M, Genazzani AA. Calcineurin Signalling in Astrocytes: From Pathology to Physiology and Control of Neuronal Functions. Neurochem Res 2023; 48:1077-1090. [PMID: 36083398 PMCID: PMC10030417 DOI: 10.1007/s11064-022-03744-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 07/31/2022] [Accepted: 08/29/2022] [Indexed: 10/14/2022]
Abstract
Calcineurin (CaN), a Ca2+/calmodulin-activated serine/threonine phosphatase, acts as a Ca2+-sensitive switch regulating cellular functions through protein dephosphorylation and activation of gene transcription. In astrocytes, the principal homeostatic cells in the CNS, over-activation of CaN is known to drive pathological transcriptional remodelling, associated with neuroinflammation in diseases such as Alzheimer's disease, epilepsy and brain trauma. Recent reports suggest that, in physiological conditions, the activity of CaN in astrocytes is transcription-independent and is required for maintenance of basal protein synthesis rate and activation of astrocytic Na+/K+ pump thereby contributing to neuronal functions such as neuronal excitability and memory formation. In this contribution we overview the role of Ca2+ and CaN signalling in astroglial pathophysiology focusing on the emerging physiological role of CaN in astrocytes. We propose a model for the context-dependent switch of CaN activity from the post-transcriptional regulation of cell proteostasis in healthy astrocytes to the CaN-dependent transcriptional activation in neuroinflammation-associated diseases.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy.
| | - Laura Tapella
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy
| | - Giulia Dematteis
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy
| | - Maria Talmon
- Department of Health Sciences, School of Medicine, Università del Piemonte Orientale "Amedeo Avogadro", Via Solaroli 17, 28100, Novara, Italy
| | - Armando A Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Via Bovio 6, 28100, Novara, Italy.
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2
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Zhang J, Zhou F, Liang X, Yang G. SCAMPER: Accurate Type-Specific Prediction of Calcium-Binding Residues Using Sequence-Derived Features. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2023; 20:1406-1416. [PMID: 35536812 DOI: 10.1109/tcbb.2022.3173437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Understanding molecular mechanisms involved in calcium-protein interactions and modeling corresponding docking rely on the accurate identification of calcium-binding residues (CaBRs). The defects of experimentally annotating protein functions enhances the development of computational approaches that correctly identify calcium-binding interactions. Studies have reported that current methods severely cross-predict residues that interact with other types of molecules (e.g., nucleic acids, proteins, and small ligands) as CaBRs. In this study, a novel predictor named SCAMPER (Selective CAlciuM-binding PrEdictoR) is proposed for the accurate and specific prediction of CaBRs. SCAMPER is designed using newly compiled dataset with complete UniProt sequences and annotations, which include calcium-binding, nucleic acid-binding, protein-binding, and small ligand-binding residues. We use a novel designed two-layer scheme to perform predictions as well as penalize cross-predictions. Empirical tests on an independent test dataset reveals that the proposed method significantly outperforms state-of-the-art predictors. SCAMPER is proved to be capable of distinguishing CaBRs from different types of metal-ion binding residues. We further perform CaBRs predictions on the whole human proteome, and use the results to hypothesize calcium-binding proteins (CaBPs). The latest experimental verified CaBPs and GO analysis prove the accuracy of our predictions. We implement the proposed method and share the data at http://www.inforstation.com/webservers/SCAMPER/.
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3
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Sidoli M, Reed CB, Scapin C, Paez P, Cavener DR, Kaufman RJ, D'Antonio M, Feltri ML, Wrabetz L. Calcineurin Activity Is Increased in Charcot-Marie-Tooth 1B Demyelinating Neuropathy. J Neurosci 2021; 41:4536-4548. [PMID: 33879538 PMCID: PMC8152608 DOI: 10.1523/jneurosci.2384-20.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 03/08/2021] [Accepted: 03/17/2021] [Indexed: 11/21/2022] Open
Abstract
Schwann cells produce a considerable amount of lipids and proteins to form myelin in the PNS. For this reason, the quality control of myelin proteins is crucial to ensure proper myelin synthesis. Deletion of serine 63 from P0 (P0S63del) protein in myelin forming Schwann cells causes Charcot-Marie-Tooth type 1B neuropathy in humans and mice. Misfolded P0S63del accumulates in the ER of Schwann cells where it elicits the unfolded protein response (UPR). PERK is the UPR transducer that attenuates global translation and reduces ER stress by phosphorylating the translation initiation factor eIF2alpha. Paradoxically, Perk ablation in P0S63del Schwann cells (S63del/PerkSCKO ) reduced the level of P-eIF2alpha, leaving UPR markers upregulated, yet unexpectedly improved S63del myelin defects in vivo We therefore investigated the hypothesis that PERK may interfere with signals outside of the UPR and specifically with calcineurin/NFATc4 pro-myelinating pathway. Using mouse genetics including females and males in our experimental setting, we show that PERK and calcineurin interact in P0S63del nerves and that calcineurin activity and NFATc4 nuclear localization are increased in S63del Schwann cells, without altering EGR2/KROX20 expression. Moreover, genetic manipulation of the calcineurin subunits appears to be either protective or toxic in S63del in a context-dependent manner, suggesting that Schwann cells are highly sensitive to alterations of calcineurin activity.SIGNIFICANCE STATEMENT Our work shows a novel activity and function for calcineurin in Schwann cells in the context of ER stress. Schwann cells expressing the S63del mutation in P0 protein induce the unfolded protein response and upregulate calcineurin activity. Calcineurin interacts with the ER stress transducer PERK, but the relationship between the UPR and calcineurin in Schwann cells is unclear. Here we propose a protective role for calcineurin in S63del neuropathy, although Schwann cells appear to be very sensitive to its regulation. The paper uncovers a new important role for calcineurin in a demyelinating diseases.
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Affiliation(s)
- Mariapaola Sidoli
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
- Department of Developmental Biology, School of Medicine, Stanford University, Stanford, California 94305
| | - Chelsey B Reed
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
| | - Cristina Scapin
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, DIBIT, Milan 20132, Italy
| | - Pablo Paez
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
| | - Douglas R Cavener
- Department of Biology, Center for Cellular Dynamics, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037
| | - Maurizio D'Antonio
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, DIBIT, Milan 20132, Italy
| | - M Laura Feltri
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
| | - Lawrence Wrabetz
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14203
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4
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Dudilot A, Trillaud-Doppia E, Boehm J. RCAN1 Regulates Bidirectional Synaptic Plasticity. Curr Biol 2020; 30:1167-1176.e2. [DOI: 10.1016/j.cub.2020.01.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/14/2019] [Accepted: 01/13/2020] [Indexed: 01/26/2023]
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5
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Roy J, Cyert MS. Identifying New Substrates and Functions for an Old Enzyme: Calcineurin. Cold Spring Harb Perspect Biol 2020; 12:a035436. [PMID: 31308145 PMCID: PMC7050593 DOI: 10.1101/cshperspect.a035436] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Biological processes are dynamically regulated by signaling networks composed of protein kinases and phosphatases. Calcineurin, or PP3, is a conserved phosphoserine/phosphothreonine-specific protein phosphatase and member of the PPP family of phosphatases. Calcineurin is unique, however, in its activation by Ca2+ and calmodulin. This ubiquitously expressed phosphatase controls Ca2+-dependent processes in all human tissues, but is best known for driving the adaptive immune response by dephosphorylating the nuclear factor of the activated T-cells (NFAT) family of transcription factors. Therefore, calcineurin inhibitors, FK506 (tacrolimus), and cyclosporin A serve as immunosuppressants. We describe some of the adverse effects associated with calcineurin inhibitors that result from inhibition of calcineurin in nonimmune tissues, illustrating the many functions of this enzyme that have yet to be elucidated. In fact, calcineurin has essential roles beyond the immune system, from yeast to humans, but since its discovery more than 30 years ago, only a small number of direct calcineurin substrates have been shown (∼75 proteins). This is because of limitations in current methods for identification of phosphatase substrates. Here we discuss recent insights into mechanisms of calcineurin activation and substrate recognition that have been critical in the development of novel approaches for identifying its targets systematically. Rather than comprehensively reviewing known functions of calcineurin, we highlight new approaches to substrate identification for this critical regulator that may reveal molecular mechanisms underlying toxicities caused by calcineurin inhibitor-based immunosuppression.
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Affiliation(s)
- Jagoree Roy
- Department of Biology, Stanford University, Stanford, California 94305-5020
| | - Martha S Cyert
- Department of Biology, Stanford University, Stanford, California 94305-5020
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6
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Rich MT, Huang YH, Torregrossa MM. Calcineurin Promotes Neuroplastic Changes in the Amygdala Associated with Weakened Cocaine-Cue Memories. J Neurosci 2020; 40:1344-1354. [PMID: 31862855 PMCID: PMC7002139 DOI: 10.1523/jneurosci.0453-19.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 11/23/2019] [Accepted: 12/10/2019] [Indexed: 01/03/2023] Open
Abstract
Interfering with memory reconsolidation or inducing memory extinction are two approaches for weakening maladaptive memories in disorders such as addiction and post-traumatic stress disorder. Both extinction and reconsolidation are regulated by intracellular protein kinases and phosphatases, and interfering with these signaling molecules can alter memory strength. The calcium-dependent protein phosphatase, calcineurin (CaN), has been implicated in both the consolidation and extinction of fear memories. However, the role of CaN in regulating drug-cue associative memories has not been investigated. Prior studies have demonstrated that plasticity at thalamo-lateral amygdala (T-LA) synapses is critically involved in the regulation of cocaine-cue memories. Therefore, in the present study, we tested the effects of LA administration of an activator of CaN, chlorogenic acid (CGA), on behavioral and electrophysiological indices of cocaine cue memory reconsolidation and extinction. Male, Sprague-Dawley rats were trained to self-administer cocaine paired with an audiovisual cue. The cue memory was then either briefly reactivated, extinguished, or not manipulated, followed immediately by LA infusion of CGA. Rats were tested 24 h later for cue-induced reinstatement, or LA slices were prepared for electrophysiological recordings. We found that intra-LA infusions of CGA following cue extinction or reconsolidation reduced cue-induced reinstatement, which was blocked by co-infusion of the CaN inhibitor, FK-506. Similarly, CGA infusions following cue re-exposure significantly attenuated EPSC amplitude at T-LA synapses, suggesting that CaN affects cocaine-cue memory reconsolidation and extinction by altering T-LA synaptic strength. Therefore, CaN signaling in the LA may represent a novel target for disrupting cocaine-associated memories to reduce relapse.SIGNIFICANCE STATEMENT Repetitive drug use induces synaptic plasticity that underlies the formation of long-lasting associative memories for environmental cues paired with the drug. We previously identified thalamo-amygdala synapses (T-LA) that project via the interal capsule, as an important locus for the regulation of cocaine-cue memories. These synapses are strengthened by repeated cocaine-cue pairings, but this is reversed by extinction training or by optogenetic induction of in vivo long-term depression (LTD). Here, we demonstrate that activating calcineurin, a calcium-dependent phosphatase, following the reactivation or extinction of a cocaine-cue memory, induces LTD-like changes at T-LA synapses, and a corresponding decrease in cue-induced reinstatement, suggesting that calcineurin may be a potential therapeutic target for relapse prevention.
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Affiliation(s)
- Matthew T Rich
- Department of Psychiatry
- Center for Neuroscience, and
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, Pennsylvania 15219
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7
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Sun B, Vaughan D, Tikunova S, Creamer TP, Davis JP, Kekenes-Huskey PM. Calmodulin-Calcineurin Interaction beyond the Calmodulin-Binding Region Contributes to Calcineurin Activation. Biochemistry 2019; 58:4070-4085. [PMID: 31483613 DOI: 10.1021/acs.biochem.9b00626] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Calcineurin (CaN) is a calcium-dependent phosphatase involved in numerous signaling pathways. Its activation is in part driven by the binding of calmodulin (CaM) to a CaM recognition region (CaMBR) within CaN's regulatory domain (RD). However, secondary interactions between CaM and the CaN RD may be necessary to fully activate CaN. Specifically, it is established that the CaN RD folds upon CaM binding and a region C-terminal to CaMBR, the "distal helix", assumes an α-helix fold and contributes to activation [Dunlap, T. B., et al. (2013) Biochemistry 52, 8643-8651]. We hypothesized in that previous study that this distal helix can bind CaM in a region distinct from the canonical CaMBR. To test this hypothesis, we utilized molecular simulations, including replica-exchange molecular dynamics, protein-protein docking, and computational mutagenesis, to determine potential distal helix-binding sites on CaM's surface. We isolated a potential binding site on CaM (site D) that facilitates moderate-affinity interprotein interactions and predicted that mutation of site D residues K30 and G40 on CaM would weaken CaN distal helix binding. We experimentally confirmed that two variants (K30E and G40D) indicate weaker binding of a phosphate substrate p-nitrophenyl phosphate to the CaN catalytic site by a phosphatase assay. This weakened substrate affinity is consistent with competitive binding of the CaN autoinhibition domain to the catalytic site, which we suggest is due to the weakened distal helix-CaM interactions. This study therefore suggests a novel mechanism for CaM regulation of CaN that may extend to other CaM targets.
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Affiliation(s)
- Bin Sun
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - Darin Vaughan
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - Svetlana Tikunova
- Department of Physiology and Cell Biology , The Ohio State University , Columbus , Ohio 43210 , United States
| | - Trevor P Creamer
- Center for Structural Biology and Department of Molecular & Cellular Biochemistry , University of Kentucky , Lexington , Kentucky 40536 , United States
| | - Jonathan P Davis
- Department of Physiology and Cell Biology , The Ohio State University , Columbus , Ohio 43210 , United States
| | - P M Kekenes-Huskey
- Department of Chemical and Materials Engineering , University of Kentucky , Lexington , Kentucky 40506 , United States.,Department of Cell and Molecular Physiology , Loyola University Chicago , Maywood , Illinois 60153 , United States
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Fajardo VA, Watson CJF, Bott KN, Moradi F, Maddalena LA, Bellissimo CA, Turner KD, Peters SJ, LeBlanc PJ, MacNeil AJ, Stuart JA, Tupling AR. Neurogranin is expressed in mammalian skeletal muscle and inhibits calcineurin signaling and myoblast fusion. Am J Physiol Cell Physiol 2019; 317:C1025-C1033. [PMID: 31433693 DOI: 10.1152/ajpcell.00345.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Calcineurin is a Ca2+/calmodulin (CaM)-dependent phosphatase that plays a critical role in promoting the slow fiber phenotype and myoblast fusion in skeletal muscle, thereby making calcineurin an attractive cellular target for enhancing fatigue resistance, muscle metabolism, and muscle repair. Neurogranin (Ng) is a CaM-binding protein thought to be expressed solely in brain and neurons, where it inhibits calcineurin signaling by sequestering CaM, thus lowering its cellular availability. Here, we demonstrate for the first time the expression of Ng protein and mRNA in mammalian skeletal muscle. Both protein and mRNA levels are greater in slow-oxidative compared with fast-glycolytic muscles. Coimmunoprecipitation of CaM with Ng in homogenates of C2C12 myotubes, mouse soleus, and human vastus lateralis suggests that these proteins physically interact. To determine whether Ng inhibits calcineurin signaling in muscle, we used Ng siRNA with C2C12 myotubes to reduce Ng protein levels by 60%. As a result of reduced Ng expression, C2C12 myotubes had enhanced CaM-calcineurin binding and calcineurin signaling as indicated by reduced phosphorylation of nuclear factor of activated T cells and increased utrophin mRNA. In addition, calcineurin signaling affects the expression of myogenin and stabilin-2, which are involved in myogenic differentiation and myoblast fusion, respectively. Here, we found that both myogenin and stabilin-2 were significantly elevated by Ng siRNA in C2C12 cells, concomitantly with an increased fusion index. Taken together, these results demonstrate the expression of Ng in mammalian skeletal muscle where it appears to be a novel regulator of calcineurin signaling.
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Affiliation(s)
- Val A Fajardo
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Colton J F Watson
- Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Kirsten N Bott
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
| | - Fereshteh Moradi
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Lucas A Maddalena
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada
| | | | - Kelli D Turner
- Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Sandra J Peters
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Paul J LeBlanc
- Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Adam J MacNeil
- Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Jeffrey A Stuart
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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9
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Yang H, Wang M, Zhang Y, Li F, Yu S, Zhu L, Guo Y, Yang L, Yang S. Conformational-transited protein corona regulated cell-membrane penetration and induced cytotoxicity of ultrasmall Au nanoparticles. RSC Adv 2019; 9:4435-4444. [PMID: 35520163 PMCID: PMC9060578 DOI: 10.1039/c8ra10049g] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 01/23/2019] [Indexed: 12/17/2022] Open
Abstract
Nanoparticles (NP) in biological fluids almost invariably become coated with proteins to form protein coronas. It is the NP-protein corona rather than the bare nanoparticle that determines the nanoparticle's bio-behavior. Here, ultrasmall gold nanoparticles (AuNPs) coated by a human serum albumin (HSA) corona were studied by Fourier transform infrared spectroscopy, denature experiments, fluorescence quenching. Moreover, the intracellular fate of AuNPs and the AuNP-HSA corona has also been investigated. The results show that HSA corona undergo a conformational transition (partial β-sheet changed to α-helicity) when they adsorb on AuNPs, which lead to an enhanced thermal stability. Importantly, we observed that the conformation-transited protein corona-AuNP complex could induce cell apoptosis. Meanwhile, for the first time, the conformation-transited HSA on the AuNPs surface are shown to disrupt living cell membranes. The results obtained here not only provide the detailed conformational behavior of HSA molecules on nanoparticles, but also reveal the structure-function relationship of protein corona, which is of utmost importance in the safe application of nanoscale objects in living organisms.
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Affiliation(s)
- Huayan Yang
- Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Ministry of Education, Henan Normal University Xinxiang People's Republic of China
| | - Meng Wang
- Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Ministry of Education, Henan Normal University Xinxiang People's Republic of China
| | - Yanmin Zhang
- Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Ministry of Education, Henan Normal University Xinxiang People's Republic of China
| | - Feng Li
- University of Shanghai for Science and Technology Shanghai People's Republic of China
| | - Shaoning Yu
- Fudan University Shanghai People's Republic of China
| | - Lin Zhu
- Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Ministry of Education, Henan Normal University Xinxiang People's Republic of China
| | - Yuming Guo
- Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Ministry of Education, Henan Normal University Xinxiang People's Republic of China
| | - Lin Yang
- Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Ministry of Education, Henan Normal University Xinxiang People's Republic of China
| | - Shouning Yang
- Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Ministry of Education, Henan Normal University Xinxiang People's Republic of China
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10
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Sun B, Cook EC, Creamer TP, Kekenes-Huskey PM. Electrostatic control of calcineurin's intrinsically-disordered regulatory domain binding to calmodulin. Biochim Biophys Acta Gen Subj 2018; 1862:2651-2659. [PMID: 30071273 PMCID: PMC6317854 DOI: 10.1016/j.bbagen.2018.07.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 07/13/2018] [Accepted: 07/24/2018] [Indexed: 12/26/2022]
Abstract
Calcineurin (CaN) is a serine/threonine phosphatase that regulates a variety of physiological and pathophysiological processes in mammalian tissue. The calcineurin (CaN) regulatory domain (RD) is responsible for regulating the enzyme's phosphatase activity, and is believed to be highly-disordered when inhibiting CaN, but undergoes a disorder-to-order transition upon diffusion-limited binding with the regulatory protein calmodulin (CaM). The prevalence of polar and charged amino acids in the regulatory domain (RD) suggests electrostatic interactions are involved in mediating calmodulin (CaM) binding, yet the lack of atomistic-resolution data for the bound complex has stymied efforts to probe how the RD sequence controls its conformational ensemble and long-range attractions contribute to target protein binding. In the present study, we investigated via computational modeling the extent to which electrostatics and structural disorder facilitate CaM/CaN association kinetics. Specifically, we examined several RD constructs that contain the CaM binding region (CAMBR) to characterize the roles of electrostatics versus conformational diversity in controlling diffusion-limited association rates, via microsecond-scale molecular dynamics (MD) and Brownian dynamic (BD) simulations. Our results indicate that the RD amino acid composition and sequence length influence both the dynamic availability of conformations amenable to CaM binding, as well as long-range electrostatic interactions to steer association. These findings provide intriguing insight into the interplay between conformational diversity and electrostatically-driven protein-protein association involving CaN, which are likely to extend to wide-ranging diffusion-limited processes regulated by intrinsically-disordered proteins.
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Affiliation(s)
- Bin Sun
- Department of Chemistry, University of Kentucky, 505 Rose St., Chemistry-Physics Building, Lexington, KY, USA 40506
| | - Erik C Cook
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 South Limestone, St. Lexington, KY, USA 40536
| | - Trevor P Creamer
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 South Limestone, St. Lexington, KY, USA 40536
| | - Peter M Kekenes-Huskey
- Department of Chemistry, University of Kentucky, 505 Rose St., Chemistry-Physics Building, Lexington, KY, USA 40506.
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11
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Saraf J, Bhattacharya P, Kalia K, Borah A, Sarmah D, Kaur H, Dave KR, Yavagal DR. A Friend or Foe: Calcineurin across the Gamut of Neurological Disorders. ACS CENTRAL SCIENCE 2018; 4:805-819. [PMID: 30062109 PMCID: PMC6062828 DOI: 10.1021/acscentsci.8b00230] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Indexed: 05/24/2023]
Abstract
The serine/threonine phosphatase calcineurin (CaN) is a unique but confounding calcium/calmodulin-mediated enzyme. CaN has shown to play essential roles from regulating calcium homeostasis to being an intricate part of learning and memory formation. Neurological disorders, despite differing in their etiology, share similar pathological outcomes, such as mitochondrial dysfunction and apoptotic signaling brought about by excitotoxic elements. CaN, being deeply integrated in vital neuronal functions, may be implicated in various neurological disorders. Understanding the enzyme and its physiological niche in the nervous system is vital in uncovering its roles in the spectrum of brain disorders. By reviewing the crosstalk in different neurological pathologies, a possible grasp of CaN's complex signaling may lead to forming better neurotherapy. This Outlook attempts to explore the various neuronal functions of CaN and investigate its pervasive role through the gamut of neurological disorders.
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Affiliation(s)
- Jackson Saraf
- Department
of Pharmacology and Toxicology, National
Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Pallab Bhattacharya
- Department
of Pharmacology and Toxicology, National
Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Kiran Kalia
- Department
of Pharmacology and Toxicology, National
Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Anupom Borah
- Cellular
and Molecular Neurobiology Laboratory, Department of Life Science
and Bioinformatics, Assam University, Silchar, Assam 788011, India
| | - Deepaneeta Sarmah
- Department
of Pharmacology and Toxicology, National
Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Harpreet Kaur
- Department
of Pharmacology and Toxicology, National
Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Kunjan R Dave
- Department
of Neurology, University of Miami Miller
School of Medicine, Miami, Florida 33136, United States
| | - Dileep R Yavagal
- Department
of Neurology, University of Miami Miller
School of Medicine, Miami, Florida 33136, United States
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12
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Malenczyk K, Szodorai E, Schnell R, Lubec G, Szabó G, Hökfelt T, Harkany T. Secretagogin protects Pdx1 from proteasomal degradation to control a transcriptional program required for β cell specification. Mol Metab 2018; 14:108-120. [PMID: 29910119 PMCID: PMC6034064 DOI: 10.1016/j.molmet.2018.05.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE Specification of endocrine cell lineages in the developing pancreas relies on extrinsic signals from non-pancreatic tissues, which initiate a cell-autonomous sequence of transcription factor activation and repression switches. The steps in this pathway share reliance on activity-dependent Ca2+ signals. However, the mechanisms by which phasic Ca2+ surges become converted into a dynamic, cell-state-specific and physiologically meaningful code made up by transcription factors constellations remain essentially unknown. METHODS We used high-resolution histochemistry to explore the coincident expression of secretagogin and transcription factors driving β cell differentiation. Secretagogin promoter activity was tested in response to genetically manipulating Pax6 and Pax4 expression. Secretagogin null mice were produced with their pancreatic islets morphologically and functionally characterized during fetal development. A proteomic approach was utilized to identify the Ca2+-dependent interaction of secretagogin with subunits of the 26S proteasome and verified in vitro by focusing on Pdx1 retention. RESULTS Here, we show that secretagogin, a Ca2+ sensor protein that controls α and β cell turnover in adult, is in fact expressed in endocrine pancreas from the inception of lineage segregation in a Pax4-and Pax6-dependent fashion. By genetically and pharmacologically manipulating secretagogin expression and interactome engagement in vitro, we find secretagogin to gate excitation-driven Ca2+ signals for β cell differentiation and insulin production. Accordingly, secretagogin-/- fetuses retain a non-committed pool of endocrine progenitors that co-express both insulin and glucagon. We identify the Ca2+-dependent interaction of secretagogin with subunits of the 26S proteasome complex to prevent Pdx1 degradation through proteasome inactivation. This coincides with retained Nkx6.1, Pax4 and insulin transcription in prospective β cells. CONCLUSIONS In sum, secretagogin scales the temporal availability of a Ca2+-dependent transcription factor network to define β cell identity.
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Affiliation(s)
- Katarzyna Malenczyk
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090, Vienna, Austria; Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-17177, Stockholm, Sweden
| | - Edit Szodorai
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090, Vienna, Austria; Paracelsus Medical University, Strubergasse 21, A-5020, Salzburg, Austria
| | - Robert Schnell
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles väg 2, SE-17177, Stockholm, Sweden
| | - Gert Lubec
- Paracelsus Medical University, Strubergasse 21, A-5020, Salzburg, Austria
| | - Gábor Szabó
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony utca 43, H-1083, Budapest, Hungary
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-17177, Stockholm, Sweden
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090, Vienna, Austria; Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-17177, Stockholm, Sweden.
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13
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Wild AR, Dell'Acqua ML. Potential for therapeutic targeting of AKAP signaling complexes in nervous system disorders. Pharmacol Ther 2017; 185:99-121. [PMID: 29262295 DOI: 10.1016/j.pharmthera.2017.12.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A common feature of neurological and neuropsychiatric disorders is a breakdown in the integrity of intracellular signal transduction pathways. Dysregulation of ion channels and receptors in the cell membrane and the enzymatic mediators that link them to intracellular effectors can lead to synaptic dysfunction and neuronal death. However, therapeutic targeting of these ubiquitous signaling elements can lead to off-target side effects due to their widespread expression in multiple systems of the body. A-kinase anchoring proteins (AKAPs) are multivalent scaffolding proteins that compartmentalize a diverse range of receptor and effector proteins to streamline signaling within nanodomain signalosomes. A number of essential neurological processes are known to critically depend on AKAP-directed signaling and an understanding of the role AKAPs play in nervous system disorders has emerged in recent years. Selective targeting of AKAP protein-protein interactions may be a means to uncouple pathologically active signaling pathways in neurological disorders with a greater degree of specificity. In this review we will discuss the role of AKAPs in both regulating normal nervous system function and dysfunction associated with disease, and the potential for therapeutic targeting of AKAP signaling complexes.
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Affiliation(s)
- Angela R Wild
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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14
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Yadav DK, Tata SR, Hunt J, Cook EC, Creamer TP, Fitzkee NC. 1H, 15N, and 13C chemical shift assignments of the regulatory domain of human calcineurin. BIOMOLECULAR NMR ASSIGNMENTS 2017; 11:215-219. [PMID: 28803387 PMCID: PMC5693698 DOI: 10.1007/s12104-017-9751-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 08/05/2017] [Indexed: 06/01/2023]
Abstract
Calcineurin (CaN) plays an important role in T-cell activation, cardiac system development and nervous system function. Previous studies have demonstrated that the regulatory domain (RD) of CaN binds calmodulin (CaM) towards the N-terminal end. Calcium-loaded CaM activates the serine/threonine phosphatase activity of CaN by binding to the RD, although the mechanistic details of this interaction remain unclear. It is thought that CaM binding at the RD displaces the auto-inhibitory domain (AID) from the active site of CaN, activating phosphatase activity. In the absence of calcium-loaded CaM, the RD is disordered, and binding of CaM induces folding in the RD. In order to provide mechanistic detail about the CaM-CaN interaction, we have undertaken an NMR study of the RD of CaN. Complete 13C, 15N and 1H assignments of the RD of CaN were obtained using solution NMR spectroscopy. The backbone of RD has been assigned using a combination of 13C-detected CON-IPAP experiments as well as traditional HNCO, HNCA, HNCOCA and HNCACB-based 3D NMR spectroscopy. A 15N-resolved TOCSY experiment has been used to assign Hα and Hβ chemical shifts.
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Affiliation(s)
- Dinesh K Yadav
- Department of Chemistry, Mississippi State University, Hand Lab 1115, 310 Presidents Circle, Mississippi State, MS, 39762, USA
| | - Sri Ramya Tata
- Department of Chemistry, Mississippi State University, Hand Lab 1115, 310 Presidents Circle, Mississippi State, MS, 39762, USA
| | - John Hunt
- Department of Chemistry, Mississippi State University, Hand Lab 1115, 310 Presidents Circle, Mississippi State, MS, 39762, USA
| | - Erik C Cook
- Department of Molecular and Cellular Biochemistry, Center for Structural Biology, University of Kentucky, Lexington, USA
| | - Trevor P Creamer
- Department of Molecular and Cellular Biochemistry, Center for Structural Biology, University of Kentucky, Lexington, USA
| | - Nicholas C Fitzkee
- Department of Chemistry, Mississippi State University, Hand Lab 1115, 310 Presidents Circle, Mississippi State, MS, 39762, USA.
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15
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Malenczyk K, Girach F, Szodorai E, Storm P, Segerstolpe Å, Tortoriello G, Schnell R, Mulder J, Romanov RA, Borók E, Piscitelli F, Di Marzo V, Szabó G, Sandberg R, Kubicek S, Lubec G, Hökfelt T, Wagner L, Groop L, Harkany T. A TRPV1-to-secretagogin regulatory axis controls pancreatic β-cell survival by modulating protein turnover. EMBO J 2017; 36:2107-2125. [PMID: 28637794 PMCID: PMC5510001 DOI: 10.15252/embj.201695347] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 04/27/2017] [Accepted: 05/09/2017] [Indexed: 12/20/2022] Open
Abstract
Ca2+-sensor proteins are generally implicated in insulin release through SNARE interactions. Here, secretagogin, whose expression in human pancreatic islets correlates with their insulin content and the incidence of type 2 diabetes, is shown to orchestrate an unexpectedly distinct mechanism. Single-cell RNA-seq reveals retained expression of the TRP family members in β-cells from diabetic donors. Amongst these, pharmacological probing identifies Ca2+-permeable transient receptor potential vanilloid type 1 channels (TRPV1) as potent inducers of secretagogin expression through recruitment of Sp1 transcription factors. Accordingly, agonist stimulation of TRPV1s fails to rescue insulin release from pancreatic islets of glucose intolerant secretagogin knock-out(-/-) mice. However, instead of merely impinging on the SNARE machinery, reduced insulin availability in secretagogin-/- mice is due to β-cell loss, which is underpinned by the collapse of protein folding and deregulation of secretagogin-dependent USP9X deubiquitinase activity. Therefore, and considering the desensitization of TRPV1s in diabetic pancreata, a TRPV1-to-secretagogin regulatory axis seems critical to maintain the structural integrity and signal competence of β-cells.
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Affiliation(s)
- Katarzyna Malenczyk
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Fatima Girach
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Edit Szodorai
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Petter Storm
- Department of Clinical Sciences, Diabetes and Endocrinology CRC, Skåne University Hospital Malmö, Malmö, Sweden
| | - Åsa Segerstolpe
- Integrated Cardio Metabolic Centre, Karolinska Institutet, Huddinge, Sweden
| | | | - Robert Schnell
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Jan Mulder
- Science for Life Laboratory, Karolinska Institutet, Solna, Sweden
| | - Roman A Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Erzsébet Borók
- Department of Cognitive Neurobiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Fabiana Piscitelli
- Endocannabinoid Research Group, Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, Pozzuoli Naples, Italy
| | - Vincenzo Di Marzo
- Endocannabinoid Research Group, Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, Pozzuoli Naples, Italy
| | - Gábor Szabó
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Rickard Sandberg
- Integrated Cardio Metabolic Centre, Karolinska Institutet, Huddinge, Sweden
| | - Stefan Kubicek
- CeMM Research Centre for Molecular Medicine, Vienna, Austria
| | - Gert Lubec
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ludwig Wagner
- University Clinic for Internal Medicine III, General Hospital Vienna, Vienna, Austria
| | - Leif Groop
- Department of Clinical Sciences, Diabetes and Endocrinology CRC, Skåne University Hospital Malmö, Malmö, Sweden
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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16
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Stochastic Induction of Long-Term Potentiation and Long-Term Depression. Sci Rep 2016; 6:30899. [PMID: 27485552 PMCID: PMC4971485 DOI: 10.1038/srep30899] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/10/2016] [Indexed: 01/23/2023] Open
Abstract
Long-term depression (LTD) and long-term potentiation (LTP) of granule-Purkinje cell synapses are persistent synaptic alterations induced by high and low rises of the intracellular calcium ion concentration ([Ca2+]), respectively. The occurrence of LTD involves the activation of a positive feedback loop formed by protein kinase C, phospholipase A2, and the extracellular signal-regulated protein kinase pathway, and its expression comprises the reduction of the population of synaptic AMPA receptors. Recently, a stochastic computational model of these signalling processes demonstrated that, in single synapses, LTD is probabilistic and bistable. Here, we expanded this model to simulate LTP, which requires protein phosphatases and the increase in the population of synaptic AMPA receptors. Our results indicated that, in single synapses, while LTD is bistable, LTP is gradual. Ca2+ induced both processes stochastically. The magnitudes of the Ca2+ signals and the states of the signalling network regulated the likelihood of LTP and LTD and defined dynamic macroscopic Ca2+ thresholds for the synaptic modifications in populations of synapses according to an inverse Bienenstock, Cooper and Munro (BCM) rule or a sigmoidal function. In conclusion, our model presents a unifying mechanism that explains the macroscopic properties of LTP and LTD from their dynamics in single synapses.
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17
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Modelling intracellular competition for calcium: kinetic and thermodynamic control of different molecular modes of signal decoding. Sci Rep 2016; 6:23730. [PMID: 27033299 PMCID: PMC4817061 DOI: 10.1038/srep23730] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 03/14/2016] [Indexed: 02/06/2023] Open
Abstract
Frequently, a common chemical entity triggers opposite cellular processes, which implies that the components of signalling networks must detect signals not only through their chemical natures, but also through their dynamic properties. To gain insights on the mechanisms of discrimination of the dynamic properties of cellular signals, we developed a computational stochastic model and investigated how three calcium ion (Ca2+)-dependent enzymes (adenylyl cyclase (AC), phosphodiesterase 1 (PDE1), and calcineurin (CaN)) differentially detect Ca2+ transients in a hippocampal dendritic spine. The balance among AC, PDE1 and CaN might determine the occurrence of opposite Ca2+-induced forms of synaptic plasticity, long-term potentiation (LTP) and long-term depression (LTD). CaN is essential for LTD. AC and PDE1 regulate, indirectly, protein kinase A, which counteracts CaN during LTP. Stimulations of AC, PDE1 and CaN with artificial and physiological Ca2+ signals demonstrated that AC and CaN have Ca2+ requirements modulated dynamically by different properties of the signals used to stimulate them, because their interactions with Ca2+ often occur under kinetic control. Contrarily, PDE1 responds to the immediate amplitude of different Ca2+ transients and usually with the same Ca2+ requirements observed under steady state. Therefore, AC, PDE1 and CaN decode different dynamic properties of Ca2+ signals.
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18
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Cooperative autoinhibition and multi-level activation mechanisms of calcineurin. Cell Res 2016; 26:336-49. [PMID: 26794871 DOI: 10.1038/cr.2016.14] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/12/2015] [Accepted: 11/27/2015] [Indexed: 11/08/2022] Open
Abstract
The Ca(2+)/calmodulin-dependent protein phosphatase calcineurin (CN), a heterodimer composed of a catalytic subunit A and an essential regulatory subunit B, plays critical functions in various cellular processes such as cardiac hypertrophy and T cell activation. It is the target of the most widely used immunosuppressants for transplantation, tacrolimus (FK506) and cyclosporin A. However, the structure of a large part of the CNA regulatory region remains to be determined, and there has been considerable debate concerning the regulation of CN activity. Here, we report the crystal structure of full-length CN (β isoform), which revealed a novel autoinhibitory segment (AIS) in addition to the well-known autoinhibitory domain (AID). The AIS nestles in a hydrophobic intersubunit groove, which overlaps the recognition site for substrates and immunosuppressant-immunophilin complexes. Indeed, disruption of this AIS interaction results in partial stimulation of CN activity. More importantly, our biochemical studies demonstrate that calmodulin does not remove AID from the active site, but only regulates the orientation of AID with respect to the catalytic core, causing incomplete activation of CN. Our findings challenge the current model for CN activation, and provide a better understanding of molecular mechanisms of CN activity regulation.
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19
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Baldassarre M, Li C, Eremina N, Goormaghtigh E, Barth A. Simultaneous Fitting of Absorption Spectra and Their Second Derivatives for an Improved Analysis of Protein Infrared Spectra. Molecules 2015; 20:12599-622. [PMID: 26184143 PMCID: PMC6331840 DOI: 10.3390/molecules200712599] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 02/06/2023] Open
Abstract
Infrared spectroscopy is a powerful tool in protein science due to its sensitivity to changes in secondary structure or conformation. In order to take advantage of the full power of infrared spectroscopy in structural studies of proteins, complex band contours, such as the amide I band, have to be decomposed into their main component bands, a process referred to as curve fitting. In this paper, we report on an improved curve fitting approach in which absorption spectra and second derivative spectra are fitted simultaneously. Our approach, which we name co-fitting, leads to a more reliable modelling of the experimental data because it uses more spectral information than the standard approach of fitting only the absorption spectrum. It also avoids that the fitting routine becomes trapped in local minima. We have tested the proposed approach using infrared absorption spectra of three mixed α/β proteins with different degrees of spectral overlap in the amide I region: ribonuclease A, pyruvate kinase, and aconitase.
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Affiliation(s)
- Maurizio Baldassarre
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.
| | - Chenge Li
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.
| | - Nadejda Eremina
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.
| | - Erik Goormaghtigh
- Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, 1050 Brussels, Belgium.
| | - Andreas Barth
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.
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20
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Fu C, Zhang J, Zheng Y, Xu H, Yu S. Binding of calmodulin changes the calcineurin regulatory region to a less dynamic conformation. Int J Biol Macromol 2015; 79:235-9. [PMID: 25956027 DOI: 10.1016/j.ijbiomac.2015.04.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 12/24/2022]
Abstract
Calcineurin (CN) is a Ca(2+)/calmodulin (CaM) activated serine/threonine phosphatase, and its regulatory region (CNRR) plays a critical role in the coupling of Ca(2+) signals to cellular responses. Ca(2+)/CaM binds to the CNRR, resulting in a conformational change that removes an autoinhibitory domain (CN467-486) from the active site of the phosphatase and activates the enzyme. However, almost the entire regulatory region (CN374-521) is not visible in the electron density maps of reported structures. In this study, we produced separate CN fragments corresponding to the CNRR (CNRR381-521, CN residues 381-521) and determined the binding affinity of CNRR381-521 for Ca(2+)/CaM using isothermal titration calorimetry (ITC). The structural change in CNRR381-521 induced by Ca(2+)/CaM binding was also investigated by Fourier transform infrared spectroscopy (FT-IR). The results indicate that Ca(2+)/CaM binding to CNRR381-521 is an exothermic reaction with a dissociation constant of 2.0×10(-6) M. Binding of calmodulin changes the calcineurin regulatory region to a less dynamic conformation.
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Affiliation(s)
- Cuiping Fu
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Junting Zhang
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Ye Zheng
- Shanghai Pinghe Bilingual School, China
| | - Hongbing Xu
- Department of Clinical Pharmacy, Shanghai First People's Hospital, Shanghai Jiaotong University, Shanghai 200080, China.
| | - Shaoning Yu
- Department of Chemistry, Fudan University, Shanghai 200433, China.
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21
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Yang H, Yang S, Kong J, Dong A, Yu S. Obtaining information about protein secondary structures in aqueous solution using Fourier transform IR spectroscopy. Nat Protoc 2015; 10:382-96. [PMID: 25654756 DOI: 10.1038/nprot.2015.024] [Citation(s) in RCA: 667] [Impact Index Per Article: 74.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Fourier transform IR (FTIR) spectroscopy is a nondestructive technique for structural characterization of proteins and polypeptides. The IR spectral data of polymers are usually interpreted in terms of the vibrations of a structural repeat. The repeat units in proteins give rise to nine characteristic IR absorption bands (amides A, B and I-VII). Amide I bands (1,700-1,600 cm(-1)) are the most prominent and sensitive vibrational bands of the protein backbone, and they relate to protein secondary structural components. In this protocol, we have detailed the principles that underlie the determination of protein secondary structure by FTIR spectroscopy, as well as the basic steps involved in protein sample preparation, instrument operation, FTIR spectra collection and spectra analysis in order to estimate protein secondary-structural components in aqueous (both H2O and deuterium oxide (D2O)) solution using algorithms, such as second-derivative, deconvolution and curve fitting. Small amounts of high-purity (>95%) proteins at high concentrations (>3 mg ml(-1)) are needed in this protocol; typically, the procedure can be completed in 1-2 d.
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Affiliation(s)
- Huayan Yang
- Department of Chemistry, Fudan University, Shanghai, China
| | - Shouning Yang
- Department of Chemistry, Fudan University, Shanghai, China
| | - Jilie Kong
- Department of Chemistry, Fudan University, Shanghai, China
| | - Aichun Dong
- Department of Chemistry and Biochemistry, University of Northern Colorado, Greeley, Colorado, USA
| | - Shaoning Yu
- Department of Chemistry, Fudan University, Shanghai, China
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22
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Zhou X, Mester C, Stemmer PM, Reid GE. Oxidation-induced conformational changes in calcineurin determined by covalent labeling and tandem mass spectrometry. Biochemistry 2014; 53:6754-65. [PMID: 25286016 PMCID: PMC4222536 DOI: 10.1021/bi5009744] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The Ca2+/calmodulin activated
phosphatase, calcineurin,
is inactivated by H2O2 or superoxide-induced
oxidation, both in vivo and in vitro. However, the potential for global and/or local conformation changes
occurring within calcineurin as a function of oxidative modification,
that may play a role in the inactivation process, has not been examined.
Here, the susceptibility of calcineurin methionine residues toward
H2O2-induced oxidation were determined using
a multienzyme digestion strategy coupled with capillary HPLC–electrospray
ionization mass spectrometry and tandem mass spectrometry analysis.
Then, regions within the protein complex that underwent significant
conformational perturbation upon oxidative modification were identified
by monitoring changes in the modification rates of accessible lysine
residues between native and oxidized forms of calcineurin, using an
amine-specific covalent labeling reagent, S,S′-dimethylthiobutanoylhydroxysuccinimide ester (DMBNHS),
and tandem mass spectrometry. Importantly, methionine residues found
to be highly susceptible toward oxidation, and the lysine residues
exhibiting large increases in accessibility upon oxidation, were all
located in calcineurin functional domains involved in Ca2+/CaM binding regulated calcineurin stimulation. These findings therefore
provide initial support for the novel mechanistic hypothesis that
oxidation-induced global and/or local conformational changes within
calcineurin contribute to inactivation via (i) impairing the interaction
between calcineurin A and calcineurin B, (ii) altering the low-affinity
Ca2+ binding site in calcineurin B, (iii) inhibiting calmodulin
binding to calcineurin A, and/or (iv) by altering the affinity between
the calcineurin A autoinhibitory domain and the catalytic center.
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Affiliation(s)
- Xiao Zhou
- Department of Chemistry, and §Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
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Zhao Y, Yang H, Meng K, Yu S. Probing the Ca2+/CaM-induced secondary structural and conformational changes in calcineurin. Int J Biol Macromol 2014; 64:453-7. [DOI: 10.1016/j.ijbiomac.2013.12.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 12/24/2013] [Accepted: 12/27/2013] [Indexed: 10/25/2022]
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Ye Q, Feng Y, Yin Y, Faucher F, Currie MA, Rahman MN, Jin J, Li S, Wei Q, Jia Z. Structural basis of calcineurin activation by calmodulin. Cell Signal 2013; 25:2661-7. [PMID: 24018048 DOI: 10.1016/j.cellsig.2013.08.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 08/30/2013] [Indexed: 01/26/2023]
Abstract
Calcineurin is the only known calmodulin (CaM) activated protein phosphatase, which is involved in the regulation of numerous cellular and developmental processes and in calcium-dependent signal transduction. Although commonly assumed that CaM displaces the autoinhibitory domain (AID) blocking substrate access to its active site, the structural basis underlying activation remains elusive. We have created a fused ternary complex (CBA) by covalently linking three polypeptides: CaM, calcineurin regulatory B subunit (CnB) and calcineurin catalytic A subunit (CnA). CBA catalytic activity is comparable to that of fully activated native calcineurin in the presence of CaM. The crystal structure showed virtually no structural change in the active site and no evidence of CaM despite being covalently linked. The asymmetric unit contains four molecules; two parallel CBA pairs are packed in an antiparallel mode and the large cavities in crystal packing near the calcineurin active site would easily accommodate multiple positions of AID-bound CaM. Intriguingly, the conformation of the ordered segment of AID is not altered by CaM; thus, it is the disordered part of AID, which resumes a regular α-helical conformation upon binding to CaM, which is displaced by CaM for activation. We propose that the structural basis of calcineurin activation by CaM is through displacement of the disordered fragment of AID which otherwise impedes active site access.
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Affiliation(s)
- Qilu Ye
- College of Chemistry, Beijing Normal University, Beijing 100875, People's Republic of China; Department of Biomedical and Molecular Sciences, Queen's University, 18 Stuart Street, Kingston, Ontario K7L 3N6, Canada
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25
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Vanitha S, Thiagarajan VRK, Muthuraman A, Krishnan S, Aruna A, Tharabai R. Pharmacological evaluation of methanolic leaf extract of Swietenia mahagoni on acrylamide-induced neuropathic pain in rats. Toxicol Ind Health 2013; 31:1185-94. [PMID: 23719848 DOI: 10.1177/0748233713491808] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The present study was designed to investigate the antinociceptive effects of methanolic leaf extract of Swietenia mahagoni (MESM) on acrylamide-induced painful neuropathy in rats. The intraperitoneal administration of acrylamide (30 mg/kg; for 24 consecutive days) has been employed for the induction of painful neuropathy. Acrylamide induced nociceptive pain sensitive changes, which have been assessed by hot plate, Von Frey Hair, and tail immersion tests at different time intervals, that is, 0, 6, 12, 18, and 24th day. Furthermore, the biochemical changes, that is, thiobarbituric acid-reactive substances, reduced glutathione, and total calcium levels have been estimated in sciatic nerve tissue on 24th day and histopathological changes have been observed in sciatic nerve tissue sample. MESM and pregabalin have been administered for 14 consecutive days before 1 h of the each acrylamide injection. Administration of acrylamide resulted in significant changes in behavioral and biochemical parameters. Pretreatment of MESM ameliorated acrylamide-induced behavioral, biochemical, and histopathological changes in a dose-dependent manner, which is similar to that of pregabalin-pretreated group. These findings suggested that the neuroprotective effect of S. mahagoni may be due to its potential of antioxidative, calcium channel modulatory, and neuroprotective action.
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Affiliation(s)
- Subburaj Vanitha
- Department of Pharmacognosy, College of Pharmacy, Madurai Medical College, Madurai, Tamil Nadu, India
| | | | - Arunachalam Muthuraman
- Pharmacology Division, Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, India
| | | | - Ajithadas Aruna
- Department of Pharmacognosy, College of Pharmacy, Madurai Medical College, Madurai, Tamil Nadu, India
| | - R Tharabai
- Department of Pharmacognosy, College of Pharmacy, Madurai Medical College, Madurai, Tamil Nadu, India
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Calcium-dependent conformational transition of calmodulin determined by Fourier transform infrared spectroscopy. Int J Biol Macromol 2013; 56:57-61. [PMID: 23403030 DOI: 10.1016/j.ijbiomac.2013.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 02/01/2013] [Accepted: 02/01/2013] [Indexed: 11/21/2022]
Abstract
The Ca(2+)-induced conformational changes in calmodulin (CaM) were monitored by Fourier transform infrared spectroscopy (FT-IR) at different molar ratios of Ca(2+) to CaM. The results show that these changes occur in two distinctive transitions. The first transition involves significant changes in the overall secondary structure with a small gain in solvent accessibility, and is completed after the second Ca(2+) binds to both EF-hands of its C-terminal domain. The second transition is accompanied by CaM folding into a tighter, less hydrogen-exchangeable structure, and is completed by the addition of the fourth Ca(2+) to have four Ca(2+) per molecule. Particularly, α-helices in CaM-nCa(2+)(n=0, 1, 2) are less stable than those in CaM-nCa(2+)(n=3, 4).
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Melamed P, Savulescu D, Lim S, Wijeweera A, Luo Z, Luo M, Pnueli L. Gonadotrophin-releasing hormone signalling downstream of calmodulin. J Neuroendocrinol 2012; 24:1463-75. [PMID: 22775470 DOI: 10.1111/j.1365-2826.2012.02359.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/24/2012] [Accepted: 07/03/2012] [Indexed: 01/26/2023]
Abstract
Gonadotrophin-releasing hormone (GnRH) regulates reproduction via binding a G-protein coupled receptor on the surface of the gonadotroph, through which it transmits signals, mostly via the mitogen-activated protein (MAPK) cascade, to increase synthesis of the gonadotrophin hormones: luteinising hormone (LH) and follicle-stimulating hormone (FSH). Activation of the MAPK cascade requires an elevation in cytosolic Ca(2+) levels, which is a result of both calcium influx and mobilisation from intracellular stores. However, Ca(2+) also transmits signals via an MAPK-independent pathway, through binding calmodulin (CaM), which is then able to bind a number of proteins to impart diverse downstream effects. Although the ability of GnRH to activate CaM was recognised over 20 years ago, only recently have some of the downstream effects been elucidated. GnRH was shown to activate the CaM-dependent phosphatase, calcineurin, which targets gonadotrophin gene expression both directly and indirectly via transcription factors such as nuclear factor of activated T-cells and Nur77, the Transducer of Regulated CREB (TORC) co-activators and also the prolyl isomerase, Pin1. Gonadotrophin gene expression is also regulated by GnRH-induced CaM-dependent kinases (CaMKs); CaMKI is able to derepress the histone deacetylase-inhibition of β-subunit gene expression, whereas CaMKII appears to be essential for the GnRH-activation of all three subunit genes. Asides from activating gonadotrophin gene expression, GnRH also exerts additional effects on gonadotroph function, some of which clearly occur via CaM, including the proliferation of immature gonadotrophs, which is dependent on calcineurin. In this review, we summarise these pathways, and discuss the additional functions that have been proposed for CaM with respect to modifying GnRH-induced signalling pathways via the regulation of the small GTP-binding protein, Gem, and/or the regulator of G-protein signalling protein 2.
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Affiliation(s)
- P Melamed
- Technion-Israel Institute of Technology, Haifa, Israel.
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28
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Baumgärtel K, Mansuy IM. Neural functions of calcineurin in synaptic plasticity and memory. Learn Mem 2012; 19:375-84. [PMID: 22904368 DOI: 10.1101/lm.027201.112] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Major brain functions depend on neuronal processes that favor the plasticity of neuronal circuits while at the same time maintaining their stability. The mechanisms that regulate brain plasticity are complex and engage multiple cascades of molecular components that modulate synaptic efficacy. Protein kinases (PKs) and phosphatases (PPs) are among the most important of these components that act as positive and negative regulators of neuronal signaling and plasticity, respectively. In these cascades, the PP protein phosphatase 2B or calcineurin (CaN) is of particular interest because it is the only Ca(2+)-activated PP in the brain and a major regulator of key proteins essential for synaptic transmission and neuronal excitability. This review describes the primary properties of CaN and illustrates its functions and modes of action by focusing on several representative targets, in particular glutamate receptors, striatal enriched protein phosphatase (STEP), and neuromodulin (GAP43), and their functional significance for synaptic plasticity and memory.
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Affiliation(s)
- Karsten Baumgärtel
- Dorris Neuroscience Center, Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037-1000, USA
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29
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Rumi-Masante J, Rusinga FI, Lester TE, Dunlap TB, Williams TD, Dunker AK, Weis DD, Creamer TP. Structural basis for activation of calcineurin by calmodulin. J Mol Biol 2011; 415:307-17. [PMID: 22100452 DOI: 10.1016/j.jmb.2011.11.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 11/02/2011] [Accepted: 11/04/2011] [Indexed: 11/29/2022]
Abstract
The highly conserved phosphatase calcineurin (CaN) plays vital roles in numerous processes including T-cell activation, development and function of the central nervous system, and cardiac growth. It is activated by the calcium sensor calmodulin (CaM). CaM binds to a regulatory domain (RD) within CaN, causing a conformational change that displaces an autoinhibitory domain (AID) from the active site, resulting in activation of the phosphatase. This is the same general mechanism by which CaM activates CaM-dependent protein kinases. Previously published data have hinted that the RD of CaN is intrinsically disordered. In this work, we demonstrate that the RD is unstructured and that it folds upon binding CaM, ousting the AID from the catalytic site. The RD is 95 residues long, with the AID attached to its C-terminal end and the 24-residue CaM binding region toward the N-terminal end. This is unlike the CaM-dependent protein kinases that have CaM binding sites and AIDs immediately adjacent in sequence. Our data demonstrate that not only does the CaM binding region folds but also an ∼25- to 30-residue region between it and the AID folds, resulting in over half of the RD adopting α-helical structure. This appears to be the first observation of CaM inducing folding of this scale outside of its binding site on a target protein.
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Affiliation(s)
- Julie Rumi-Masante
- Center for Structural Biology, Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 South Limestone Street, Lexington, KY 40536-0509, USA
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Li H, Rao A, Hogan PG. Interaction of calcineurin with substrates and targeting proteins. Trends Cell Biol 2011; 21:91-103. [PMID: 21115349 PMCID: PMC3244350 DOI: 10.1016/j.tcb.2010.09.011] [Citation(s) in RCA: 277] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 09/15/2010] [Accepted: 09/27/2010] [Indexed: 12/18/2022]
Abstract
Calcineurin is a calcium activated protein phosphatase with a major role in calcium signaling in diverse cells and organs and clinical importance as the target of the immunosuppressive drugs cyclosporin A and tacrolimus (FK506). Cell biology studies have focused mainly on the role of calcineurin in transcriptional signaling. Calcium entry in response to extracellular stimuli results in calcineurin activation, and signal transmission from the cytosol into the nucleus through dephosphorylation and nuclear translocation of the transcription factor nuclear factor of activated T cells (NFAT). This initiates a cascade of transcriptional events involved in physiological and developmental processes. Molecular analyses of the calcineurin-NFAT interaction have been extended recently to encompass the interaction of calcineurin with other substrates, targeting proteins and regulators of calcineurin activity. These studies have increased our understanding of how this essential calcium activated enzyme orchestrates intracellular events in cooperation with other signaling pathways, and have suggested a link between altered calcineurin signaling and the developmental anomalies of Down syndrome.
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Affiliation(s)
- Huiming Li
- Immune Disease Institute and Program in Cellular and Molecular Medicine, Children's Hospital, Boston, MA 02115, USA
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O'Donnell SE, Yu L, Fowler CA, Shea MA. Recognition of β-calcineurin by the domains of calmodulin: thermodynamic and structural evidence for distinct roles. Proteins 2010; 79:765-86. [PMID: 21287611 DOI: 10.1002/prot.22917] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 10/04/2010] [Accepted: 10/07/2010] [Indexed: 11/08/2022]
Abstract
Calcineurin (CaN, PP2B, PPP3), a heterodimeric Ca(2+)-calmodulin-dependent Ser/Thr phosphatase, regulates swimming in Paramecia, stress responses in yeast, and T-cell activation and cardiac hypertrophy in humans. Calcium binding to CaN(B) (the regulatory subunit) triggers conformational change in CaN(A) (the catalytic subunit). Two isoforms of CaN(A) (α, β) are both abundant in brain and heart and activated by calcium-saturated calmodulin (CaM). The individual contribution of each domain of CaM to regulation of calcineurin is not known. Hydrodynamic analyses of (Ca(2+))₄-CaM(1-148) bound to βCaNp, a peptide representing its CaM-binding domain, indicated a 1:1 stoichiometry. βCaNp binding to CaM increased the affinity of calcium for the N- and C-domains equally, thus preserving intrinsic domain differences, and the preference of calcium for sites III and IV. The equilibrium constants for individual calcium-saturated CaM domains dissociating from βCaNp were ∼1 μM. A limiting K(d) ≤ 1 nM was measured directly for full-length CaM, while thermodynamic linkage analysis indicated that it was approximately 1 pM. βCaNp binding to ¹⁵N-(Ca(2+))₄-CaM(1-148) monitored by ¹⁵N/¹HN HSQC NMR showed that association perturbed the N-domain of CaM more than its C-domain. NMR resonance assignments of CaM and βCaNp, and interpretation of intermolecular NOEs observed in the ¹³C-edited and ¹²C-¹⁴N-filtered 3D NOESY spectrum indicated anti-parallel binding. The sole aromatic residue (Phe) located near the βCaNp C-terminus was in close contact with several residues of the N-domain of CaM outside the hydrophobic cleft. These structural and thermodynamic properties would permit the domains of CaM to have distinct physiological roles in regulating activation of βCaN.
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Affiliation(s)
- Susan E O'Donnell
- Department of Biochemistry, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa 52242-1109, USA
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32
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Ren Y, Wang ZX, Wei Q. Mechanism of activation of Saccharomyces cerevisiae calcineurin by Mn2+. Biol Chem 2009; 390:1155-62. [PMID: 19558332 DOI: 10.1515/bc.2009.108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Saccharomyces cerevisiae calcineurin (CN) consists of a catalytic subunit CNA1 or CNA2 and a regulatory subunit CNB1. The kinetics of activation of yeast CN holoenzymes and their catalytic domains by Mn2+ were investigated. We report that the in vitro phosphatase reaction activated by Mn2+ typically has a pronounced initial lag phase caused by slow conformational rearrangement of the holoenzyme-Mn2+. A similar lag phase was detected using just the catalytic domain of yeast CN, indicating that the slowness of Mn2+-induced conformational change of CN results from a rearrangement within the catalytic domain. The Mn2+-activation of CN was reversible. The dissociation constant of the CN heterodimer containing the CNA2 subunit in the presence of Mn2+ was 3-fold higher than that of CN containing the CNA1 subunit and that of the catalytic domains of CNA1 and CNA2, pointing to differences between the residues surrounding the Mn2+-binding sites of CNA1 and CNA2.
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Affiliation(s)
- Yan Ren
- Department of Biochemistry and Molecular Biology, Beijing Normal University, Beijing Key Laboratory, Beijing 100875, P.R. China
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Turner JD, Thomas AP, Reeves JP, Hantash BM. Calcineurin activation by slow calcium release from intracellular stores suppresses protein kinase C regulation of L-type calcium channels in L6 cells. Cell Calcium 2009; 46:242-7. [DOI: 10.1016/j.ceca.2009.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2009] [Revised: 06/13/2009] [Accepted: 07/16/2009] [Indexed: 10/20/2022]
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