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Willet AH, Turner LA, Park JS, Ren L, Snider CE, Gould KL. Characterization of Pik1 function in fission yeast reveals its conserved role in lipid synthesis and not cytokinesis. J Cell Sci 2023; 136:jcs261415. [PMID: 37815455 PMCID: PMC10629694 DOI: 10.1242/jcs.261415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023] Open
Abstract
Phosphatidylinositol (PI)-4-phosphate (PI4P) is a lipid found at the plasma membrane (PM) and Golgi in cells from yeast to humans. PI4P is generated from PI by PI4-kinases and can be converted into PI-4,5-bisphosphate [PI(4,5)P2]. Schizosaccharomyces pombe have two essential PI4-kinases - Stt4 and Pik1. Stt4 localizes to the PM, and its loss from the PM results in a decrease of PM PI4P and PI(4,5)P2. As a result, cells divide non-medially due to disrupted cytokinetic ring-PM anchoring. However, the localization and function of S. pombe Pik1 has not been thoroughly examined. Here, we found that Pik1 localizes exclusively to the trans-Golgi and is required for Golgi PI4P production. We determined that Ncs1 regulates Pik1, but unlike in other organisms, it is not required for Pik1 Golgi localization. When Pik1 function was disrupted, PM PI4P but not PI(4,5)P2 levels were reduced, a major difference compared with Stt4. We conclude that Stt4 is the chief enzyme responsible for producing the PI4P that generates PI(4,5)P2. Also, that cells with disrupted Pik1 do not divide asymmetrically highlights the specific importance of PM PI(4,5)P2 for cytokinetic ring-PM anchoring.
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Affiliation(s)
- Alaina H. Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Lesley A. Turner
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Joshua S. Park
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Liping Ren
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Chloe E. Snider
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kathleen L. Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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2
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Willet AH, Turner LA, Park JS, Ren L, Snider CE, Gould KL. Characterization of Pik1 function in fission yeast reveals its conserved role in lipid synthesis and not cytokinesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.550375. [PMID: 37546978 PMCID: PMC10402101 DOI: 10.1101/2023.07.24.550375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Phosphatidylinositol (PI)-4-phosphate (PI4P) is a lipid found at the plasma membrane (PM) and Golgi in cells from yeast to humans. PI4P is generated from PI by PI4-kinases and can be converted to PI-4,5-bisphosphate [PI(4,5)P 2 ]. Schizosaccharomyces pombe have 2 essential PI4-kinases: Stt4 and Pik1. Stt4 localizes to the PM and its loss from the PM results in a decrease of PM PI4P and PI(4,5)P 2 . As a result, cells divide non-medially due to disrupted cytokinetic ring-PM anchoring. However, the localization and function of S. pombe Pik1 has not been thoroughly examined. Here, we found that Pik1 localizes exclusively to the trans-Golgi and is required for Golgi PI4P production. We determined that Ncs1 regulates Pik1, but unlike in other organisms, it is not required for Pik1 Golgi localization. When Pik1 function was disrupted, PM PI4P but not PI(4,5)P 2 levels were reduced, a major difference with Stt4. We conclude that Stt4 is the chief enzyme responsible for producing the PI4P that generates PI(4,5)P 2 . Also, that cells with disrupted Pik1 do not divide asymmetrically highlights the specific importance of PM PI(4,5)P 2 for cytokinetic ring-PM anchoring. Summary statement Fission yeast Pik1 localizes exclusively to the trans-Golgi independently of Ncs1, where it contributes to PI4P but not PI(4,5)P 2 synthesis. Pik1 does not affect cytokinesis.
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3
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Kanie T, Ng R, Abbott KL, Pongs O, Jackson PK. Myristoylated Neuronal Calcium Sensor-1 captures the ciliary vesicle at distal appendages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.06.523037. [PMID: 36712037 PMCID: PMC9881967 DOI: 10.1101/2023.01.06.523037] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The primary cilium is a microtubule-based organelle that cycles through assembly and disassembly. In many cell types, formation of the cilium is initiated by recruitment of ciliary vesicles to the distal appendage of the mother centriole. However, the distal appendage mechanism that directly captures ciliary vesicles is yet to be identified. In an accompanying paper, we show that the distal appendage protein, CEP89, is important for thef ciliary vesicle recruitment, but not for other steps of cilium formation (Tomoharu Kanie, Love, Fisher, Gustavsson, & Jackson, 2023). The lack of a membrane binding motif in CEP89 suggests that it may indirectly recruit ciliary vesicles via another binding partner. Here, we identify Neuronal Calcium Sensor-1 (NCS1) as a stoichiometric interactor of CEP89. NCS1 localizes to the position between CEP89 and a ciliary vesicle marker, RAB34, at the distal appendage. This localization was completely abolished in CEP89 knockouts, suggesting that CEP89 recruits NCS1 to the distal appendage. Similarly to CEP89 knockouts, ciliary vesicle recruitment as well as subsequent cilium formation was perturbed in NCS1 knockout cells. The ability of NCS1 to recruit the ciliary vesicle is dependent on its myristoylation motif and NCS1 knockout cells expressing myristoylation defective mutant failed to rescue the vesicle recruitment defect despite localizing proper localization to the centriole. In sum, our analysis reveals the first known mechanism for how the distal appendage recruits the ciliary vesicles.
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Affiliation(s)
- Tomoharu Kanie
- Baxter Laboratory, Department of Microbiology & Immunology and Department of Pathology, Stanford University, Stanford, CA, 94305
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma, OK, 73112
| | - Roy Ng
- Baxter Laboratory, Department of Microbiology & Immunology and Department of Pathology, Stanford University, Stanford, CA, 94305
| | - Keene L. Abbott
- Baxter Laboratory, Department of Microbiology & Immunology and Department of Pathology, Stanford University, Stanford, CA, 94305
| | - Olaf Pongs
- Institute for Physiology, Center for Integrative Physiology and Molecular Medicine (CIPPM), Saarland University, Homburg, Germany
| | - Peter K. Jackson
- Baxter Laboratory, Department of Microbiology & Immunology and Department of Pathology, Stanford University, Stanford, CA, 94305
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Takahashi D, Yonezawa K, Okizaki Y, Caaveiro JMM, Ueda T, Shimada A, Sakane F, Shimizu N. Ca 2+ -induced structural changes and intramolecular interactions in N-terminal region of diacylglycerol kinase alpha. Protein Sci 2022; 31:e4365. [PMID: 35762720 DOI: 10.1002/pro.4365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 05/09/2022] [Accepted: 05/27/2022] [Indexed: 11/05/2022]
Abstract
Diacylglycerol kinases (DGKs) are multi-domain lipid kinases that modulate the levels of lipid messengers, diacylglycerol, and phosphatidic acid. Recently, increasing attention has been paid to its α isozyme (DGKα) as a potential target for cancer immunotherapy. However, little progress has been made on the structural biology of DGKs, and a detailed understanding of the Ca2+ -triggered activation of DGKα, for which the N-terminal domains likely play a critical role, remains unclear. We have recently shown that Ca2+ binding to DGKα-EF induces conformational changes from a protease-susceptible "open" conformation in the apo state to a well-folded one in its holo state. Here, we further studied the structural properties of DGKα N-terminal (RVH and EF) domains using a series of biophysical techniques. We first revealed that the N-terminal RVH domain is a novel Ca2+ -binding domain, but the Ca2+ -induced conformational changes mainly occur in the EF domain. This was corroborated by NMR experiments showing that the EF domain adopts a molten-globule like structure in the apo state. Further analyses using SEC-SAXS and NMR indicate that the partially unfolded EF domain interacts with RVH domain, likely via hydrophobic interactions in the absence of Ca2+ , and this interaction is modified in the presence of Ca2+ . Taken together, these results present novel insights into the structural rearrangement of DGKα N-terminal domains upon binding to Ca2+ , which is essential for the activation of the enzyme.
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Affiliation(s)
- Daisuke Takahashi
- Department of Protein Structure, Function, and Design, Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, Japan
| | - Kento Yonezawa
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Japan.,Center for Digital Green-Innovation (CDG), Nara Institute of Science and Technology (NAIST), Ikoma, Japan
| | - Yuki Okizaki
- Department of Protein Structure, Function, and Design, Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, Japan
| | - Jose M M Caaveiro
- Department of Global Healthcare, Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, Japan
| | - Tadashi Ueda
- Department of Protein Structure, Function, and Design, Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, Japan
| | - Atsushi Shimada
- Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Nobutaka Shimizu
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Japan
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5
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Alam MS, Azam S, Pham K, Leyva D, Fouque KJD, Fernandez-Lima F, Miksovska J. Nanomolar affinity of EF-hands in neuronal calcium sensor 1 for bivalent cations Pb2+, Mn2+ and Hg2. Metallomics 2022; 14:6601456. [PMID: 35657675 DOI: 10.1093/mtomcs/mfac039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 05/31/2022] [Indexed: 11/12/2022]
Abstract
Abiogenic metals Pb and Hg are highly toxic since chronic and/or acute exposure often leads to severe neuropathologies. Mn2+ is an essential metal ion but in excess can impair neuronal function. In this study, we address in vitro the interactions between neuronal calcium sensor 1 (NCS1) and divalent cations. Results showed that non-physiological ions (Pb2+, Mn2+ and Hg2+) bind to EF-hands in NCS1 with nanomolar affinity and lower equilibrium dissociation constant than the physiological Ca2+ ion. (Kd,Pb2+ = 7.0±1.0 nM; Kd,Mn2+ = 34.0±6.0 nM; Kd, Hg2+ = 0.5±0.1 nM and 27.0±13.0 nM and Kd,Ca2+ = 96.0±48.0 nM). Native ultra-high resolution mass spectrometry (FT-ICR MS) and trapped ion mobility spectrometry - mass spectrometry (nESI-TIMS-MS) studies provided the NCS1-metal complex compositions - up to four Ca2+ or Mn2+ ions and three Pb2+ ions (M⋅Pb1-3Ca1-3, M⋅Mn1-4Ca1-2, and M⋅Ca1-4) were observed in complex - and similarity across the mobility profiles suggests that the overall native structure is preserved regardless of the number and type of cations. However, the non-physiological metal ions (Pb2+, Mn2+, and Hg2+) binding to NCS1 leads to more efficient quenching of Trp emission and a decrease in W30 and W103 solvent exposure compared to the apo and Ca2+ bound form, although the secondary structural rearrangement and exposure of hydrophobic sites are analogous to those for Ca2+ bound protein. Only Pb2+ and Hg2+ binding to EF-hands leads to the NCS1 dimerization whereas Mn2+ bound NCS1 remains in the monomeric form, suggesting that other factors in addition to metal ion coordination, are required for protein dimerization.
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Affiliation(s)
- Md Shofiul Alam
- Department of Chemistry and Biochemistry, Florida International University, Miami FL 33199USA
| | - Samiol Azam
- Department of Chemistry and Biochemistry, Florida International University, Miami FL 33199USA
| | - Khoa Pham
- Department of Chemistry and Biochemistry, Florida International University, Miami FL 33199USA
| | - Dennys Leyva
- Department of Chemistry and Biochemistry, Florida International University, Miami FL 33199USA
| | - Kevin Jeanne Dit Fouque
- Department of Chemistry and Biochemistry, Florida International University, Miami FL 33199USA.,Biomolecular Sciences Institute, Florida International University, Miami, 33199USA
| | - Francisco Fernandez-Lima
- Department of Chemistry and Biochemistry, Florida International University, Miami FL 33199USA.,Biomolecular Sciences Institute, Florida International University, Miami, 33199USA
| | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry, Florida International University, Miami FL 33199USA.,Biomolecular Sciences Institute, Florida International University, Miami, 33199USA
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Squizani ED, Reuwsaat JC, Motta H, Tavanti A, Kmetzsch L. Calcium: a central player in Cryptococcus biology. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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7
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Highland CM, Fromme JC. Arf1 directly recruits the Pik1-Frq1 PI4K complex to regulate the final stages of Golgi maturation. Mol Biol Cell 2021; 32:1064-1080. [PMID: 33788598 PMCID: PMC8101487 DOI: 10.1091/mbc.e21-02-0069] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 12/21/2022] Open
Abstract
Proper Golgi complex function depends on the activity of Arf1, a GTPase whose effectors assemble and transport outgoing vesicles. Phosphatidylinositol 4-phosphate (PI4P) generated at the Golgi by the conserved PI 4-kinase Pik1 (PI4KIIIβ) is also essential for Golgi function, although its precise roles in vesicle formation are less clear. Arf1 has been reported to regulate PI4P production, but whether Pik1 is a direct Arf1 effector is not established. Using a combination of live-cell time-lapse imaging analyses, acute PI4P depletion experiments, and in vitro protein-protein interaction assays on Golgi-mimetic membranes, we present evidence for a model in which Arf1 initiates the final stages of Golgi maturation by tightly controlling PI4P production through direct recruitment of the Pik1-Frq1 PI4-kinase complex. This PI4P serves as a critical signal for AP-1 and secretory vesicle formation, the final events at maturing Golgi compartments. This work therefore establishes the regulatory and temporal context surrounding Golgi PI4P production and its precise roles in Golgi maturation.
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Affiliation(s)
- Carolyn M. Highland
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - J. Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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8
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Squizani ED, Reuwsaat JCV, Lev S, Motta H, Sperotto J, Kaufman-Francis K, Desmarini D, Vainstein MH, Staats CC, Djordjevic JT, Kmetzsch L. Calcium Binding Protein Ncs1 Is Calcineurin Regulated in Cryptococcus neoformans and Essential for Cell Division and Virulence. mSphere 2020; 5:e00761-20. [PMID: 32907953 PMCID: PMC7485688 DOI: 10.1128/msphere.00761-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/28/2020] [Indexed: 12/24/2022] Open
Abstract
Intracellular calcium (Ca2+) is crucial for signal transduction in Cryptococcus neoformans, the major cause of fatal fungal meningitis. The calcineurin pathway is the only Ca2+-requiring signaling cascade implicated in cryptococcal stress adaptation and virulence, with Ca2+ binding mediated by the EF-hand domains of the Ca2+ sensor protein calmodulin. In this study, we identified the cryptococcal ortholog of neuronal calcium sensor 1 (Ncs1) as a member of the EF-hand superfamily. We demonstrated that Ncs1 has a role in Ca2+ homeostasis under stress and nonstress conditions, as the ncs1Δ mutant is sensitive to a high Ca2+ concentration and has an elevated basal Ca2+ level. Furthermore, NCS1 expression is induced by Ca2+, with the Ncs1 protein adopting a punctate subcellular distribution. We also demonstrate that, in contrast to the case with Saccharomyces cerevisiae, NCS1 expression in C. neoformans is regulated by the calcineurin pathway via the transcription factor Crz1, as NCS1 expression is reduced by FK506 treatment and CRZ1 deletion. Moreover, the ncs1Δ mutant shares a high temperature and high Ca2+ sensitivity phenotype with the calcineurin and calmodulin mutants (cna1Δ and cam1Δ), and the NCS1 promoter contains two calcineurin/Crz1-dependent response elements (CDRE1). Ncs1 deficiency coincided with reduced growth, characterized by delayed bud emergence and aberrant cell division, and hypovirulence in a mouse infection model. In summary, our data show that Ncs1 has a significant role as a Ca2+ sensor in C. neoformans, working with calcineurin to regulate Ca2+ homeostasis and, consequently, promote fungal growth and virulence.IMPORTANCECryptococcus neoformans is the major cause of fungal meningitis in HIV-infected patients. Several studies have highlighted the important contributions of Ca2+ signaling and homeostasis to the virulence of C. neoformans Here, we identify the cryptococcal ortholog of neuronal calcium sensor 1 (Ncs1) and demonstrate its role in Ca2+ homeostasis, bud emergence, cell cycle progression, and virulence. We also show that Ncs1 function is regulated by the calcineurin/Crz1 signaling cascade. Our work provides evidence of a link between Ca2+ homeostasis and cell cycle progression in C. neoformans.
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Affiliation(s)
- Eamim Daidrê Squizani
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | | | - Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Heryk Motta
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Julia Sperotto
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Keren Kaufman-Francis
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Marilene Henning Vainstein
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Charley Christian Staats
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia
- Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Lívia Kmetzsch
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
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9
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Coordination of a Single Calcium Ion in the EF-hand Maintains the Off State of the Stromal Interaction Molecule Luminal Domain. J Mol Biol 2020; 432:367-383. [DOI: 10.1016/j.jmb.2019.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 09/17/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022]
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10
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Choudhary D, Kragelund BB, Heidarsson PO, Cecconi C. The Complex Conformational Dynamics of Neuronal Calcium Sensor-1: A Single Molecule Perspective. Front Mol Neurosci 2018; 11:468. [PMID: 30618617 PMCID: PMC6304440 DOI: 10.3389/fnmol.2018.00468] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 12/03/2018] [Indexed: 01/16/2023] Open
Abstract
The human neuronal calcium sensor-1 (NCS-1) is a multispecific two-domain EF-hand protein expressed predominantly in neurons and is a member of the NCS protein family. Structure-function relationships of NCS-1 have been extensively studied showing that conformational dynamics linked to diverse ion-binding is important to its function. NCS-1 transduces Ca2+ changes in neurons and is linked to a wide range of neuronal functions such as regulation of neurotransmitter release, voltage-gated Ca2+ channels and neuronal outgrowth. Defective NCS-1 can be deleterious to cells and has been linked to serious neuronal disorders like autism. Here, we review recent studies describing at the single molecule level the structural and mechanistic details of the folding and misfolding processes of the non-myristoylated NCS-1. By manipulating one molecule at a time with optical tweezers, the conformational equilibria of the Ca2+-bound, Mg2+-bound and apo states of NCS-1 were investigated revealing a complex folding mechanism underlain by a rugged and multidimensional energy landscape. The molecular rearrangements that NCS-1 undergoes to transit from one conformation to another and the energetics of these reactions are tightly regulated by the binding of divalent ions (Ca2+ and Mg2+) to its EF-hands. At pathologically high Ca2+ concentrations the protein sometimes follows non-productive misfolding pathways leading to kinetically trapped and potentially harmful misfolded conformations. We discuss the significance of these misfolding events as well as the role of inter-domain interactions in shaping the energy landscape and ultimately the biological function of NCS-1. The conformational equilibria of NCS-1 are also compared to those of calmodulin (CaM) and differences and similarities in the behavior of these proteins are rationalized in terms of structural properties.
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Affiliation(s)
- Dhawal Choudhary
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Modena, Italy.,Center S3, CNR Institute Nanoscience, Modena, Italy
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Ciro Cecconi
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Modena, Italy.,Center S3, CNR Institute Nanoscience, Modena, Italy
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11
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Grabon A, Bankaitis VA, McDermott MI. The interface between phosphatidylinositol transfer protein function and phosphoinositide signaling in higher eukaryotes. J Lipid Res 2018; 60:242-268. [PMID: 30504233 DOI: 10.1194/jlr.r089730] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/12/2018] [Indexed: 12/22/2022] Open
Abstract
Phosphoinositides are key regulators of a large number of diverse cellular processes that include membrane trafficking, plasma membrane receptor signaling, cell proliferation, and transcription. How a small number of chemically distinct phosphoinositide signals are functionally amplified to exert specific control over such a diverse set of biological outcomes remains incompletely understood. To this end, a novel mechanism is now taking shape, and it involves phosphatidylinositol (PtdIns) transfer proteins (PITPs). The concept that PITPs exert instructive regulation of PtdIns 4-OH kinase activities and thereby channel phosphoinositide production to specific biological outcomes, identifies PITPs as central factors in the diversification of phosphoinositide signaling. There are two evolutionarily distinct families of PITPs: the Sec14-like and the StAR-related lipid transfer domain (START)-like families. Of these two families, the START-like PITPs are the least understood. Herein, we review recent insights into the biochemical, cellular, and physiological function of both PITP families with greater emphasis on the START-like PITPs, and we discuss the underlying mechanisms through which these proteins regulate phosphoinositide signaling and how these actions translate to human health and disease.
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Affiliation(s)
- Aby Grabon
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Vytas A Bankaitis
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Mark I McDermott
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
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12
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Boeckel GR, Ehrlich BE. NCS-1 is a regulator of calcium signaling in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1660-1667. [PMID: 29746899 DOI: 10.1016/j.bbamcr.2018.05.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 05/02/2018] [Accepted: 05/04/2018] [Indexed: 02/07/2023]
Abstract
Neuronal Calcium Sensor-1 (NCS-1) is a highly conserved calcium binding protein which contributes to the maintenance of intracellular calcium homeostasis and regulation of calcium-dependent signaling pathways. It is involved in a variety of physiological cell functions, including exocytosis, regulation of calcium permeable channels, neuroplasticity and response to neuronal damage. Over the past 30 years, continuing investigation of cellular functions of NCS-1 and associated disease states have highlighted its function in the pathophysiology of several disorders and as a therapeutic target. Among the diseases that were found to be associated with NCS-1 are neurological disorders such as bipolar disease and non-neurological conditions such as breast cancer. Furthermore, alteration of NCS-1 expression is associated with substance abuse disorders and severe side effects of chemotherapeutic agents. The objective of this article is to summarize the current body of evidence describing NCS-1 and its interactions on a molecular and cellular scale, as well as describing macroscopic implications in physiology and medicine. Particular attention is paid to the role of NCS-1 in development and prevention of chemotherapy induced peripheral neuropathy (CIPN).
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Affiliation(s)
- Göran R Boeckel
- Department of Pharmacology, Yale University, New Haven, CT, United States; Institut für Physiologie, Universität zu Lübeck, Ratzeburger Allee 160, D-23562 Lübeck, Germany
| | - Barbara E Ehrlich
- Department of Pharmacology, Yale University, New Haven, CT, United States; Institut für Physiologie, Universität zu Lübeck, Ratzeburger Allee 160, D-23562 Lübeck, Germany.
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13
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Astegno A, Bonza MC, Vallone R, La Verde V, D'Onofrio M, Luoni L, Molesini B, Dominici P. Arabidopsis calmodulin-like protein CML36 is a calcium (Ca 2+) sensor that interacts with the plasma membrane Ca 2+-ATPase isoform ACA8 and stimulates its activity. J Biol Chem 2017; 292:15049-15061. [PMID: 28726644 PMCID: PMC5592680 DOI: 10.1074/jbc.m117.787796] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 07/07/2017] [Indexed: 11/06/2022] Open
Abstract
Calmodulin-like (CML) proteins are major EF-hand-containing, calcium (Ca2+)-binding proteins with crucial roles in plant development and in coordinating plant stress tolerance. Given their abundance in plants, the properties of Ca2+ sensors and identification of novel target proteins of CMLs deserve special attention. To this end, we recombinantly produced and biochemically characterized CML36 from Arabidopsis thaliana We analyzed Ca2+ and Mg2+ binding to the individual EF-hands, observed metal-induced conformational changes, and identified a physiologically relevant target. CML36 possesses two high-affinity Ca2+/Mg2+ mixed binding sites and two low-affinity Ca2+-specific sites. Binding of Ca2+ induced an increase in the α-helical content and a conformational change that lead to the exposure of hydrophobic regions responsible for target protein recognition. Cation binding, either Ca2+ or Mg2+, stabilized the secondary and tertiary structures of CML36, guiding a large structural transition from a molten globule apo-state to a compact holoconformation. Importantly, through in vitro binding and activity assays, we showed that CML36 interacts directly with the regulative N terminus of the Arabidopsis plasma membrane Ca2+-ATPase isoform 8 (ACA8) and that this interaction stimulates ACA8 activity. Gene expression analysis revealed that CML36 and ACA8 are co-expressed mainly in inflorescences. Collectively, our results support a role for CML36 as a Ca2+ sensor that binds to and modulates ACA8, uncovering a possible involvement of the CML protein family in the modulation of plant-autoinhibited Ca2+ pumps.
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Affiliation(s)
- Alessandra Astegno
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
| | - Maria Cristina Bonza
- the Department of Biosciences, University of Milano, Via Celoria 26, 20133 Milano, Italy
| | - Rosario Vallone
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
| | - Valentina La Verde
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
| | - Mariapina D'Onofrio
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
| | - Laura Luoni
- the Department of Biosciences, University of Milano, Via Celoria 26, 20133 Milano, Italy
| | - Barbara Molesini
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
| | - Paola Dominici
- From the Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy and
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14
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Mansilla A, Chaves-Sanjuan A, Campillo NE, Semelidou O, Martínez-González L, Infantes L, González-Rubio JM, Gil C, Conde S, Skoulakis EMC, Ferrús A, Martínez A, Sánchez-Barrena MJ. Interference of the complex between NCS-1 and Ric8a with phenothiazines regulates synaptic function and is an approach for fragile X syndrome. Proc Natl Acad Sci U S A 2017; 114:E999-E1008. [PMID: 28119500 PMCID: PMC5307446 DOI: 10.1073/pnas.1611089114] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The protein complex formed by the Ca2+ sensor neuronal calcium sensor 1 (NCS-1) and the guanine exchange factor protein Ric8a coregulates synapse number and probability of neurotransmitter release, emerging as a potential therapeutic target for diseases affecting synapses, such as fragile X syndrome (FXS), the most common heritable autism disorder. Using crystallographic data and the virtual screening of a chemical library, we identified a set of heterocyclic small molecules as potential inhibitors of the NCS-1/Ric8a interaction. The aminophenothiazine FD44 interferes with NCS-1/Ric8a binding, and it restores normal synapse number and associative learning in a Drosophila FXS model. The synaptic effects elicited by FD44 feeding are consistent with the genetic manipulation of NCS-1. The crystal structure of NCS-1 bound to FD44 and the structure-function studies performed with structurally close analogs explain the FD44 specificity and the mechanism of inhibition, in which the small molecule stabilizes a mobile C-terminal helix inside a hydrophobic crevice of NCS-1 to impede Ric8a interaction. Our study shows the drugability of the NCS-1/Ric8a interface and uncovers a suitable region in NCS-1 for development of additional drugs of potential use on FXS and related synaptic disorders.
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Affiliation(s)
- Alicia Mansilla
- Departamento de Neurobiología del Desarrollo, Instituto Cajal, Spanish National Research Council, 28002 Madrid, Spain
| | - Antonio Chaves-Sanjuan
- Departamento de Cristalografía y Biología Estructural, Instituto de Química Física Rocasolano, Spanish National Research Council, 28006 Madrid, Spain
| | - Nuria E Campillo
- Centro de Investigaciones Biológicas, Spanish National Research Council, 28040 Madrid, Spain
| | - Ourania Semelidou
- Division of Neuroscience, Biomedical Sciences Research Centre Alexander Fleming, 16672 Vari, Greece
| | | | - Lourdes Infantes
- Departamento de Cristalografía y Biología Estructural, Instituto de Química Física Rocasolano, Spanish National Research Council, 28006 Madrid, Spain
| | - Juana María González-Rubio
- Departamento de Cristalografía y Biología Estructural, Instituto de Química Física Rocasolano, Spanish National Research Council, 28006 Madrid, Spain
| | - Carmen Gil
- Centro de Investigaciones Biológicas, Spanish National Research Council, 28040 Madrid, Spain
| | - Santiago Conde
- Instituto de Química Médica, Spanish National Research Council, 28006 Madrid, Spain
| | - Efthimios M C Skoulakis
- Division of Neuroscience, Biomedical Sciences Research Centre Alexander Fleming, 16672 Vari, Greece
| | - Alberto Ferrús
- Departamento de Neurobiología del Desarrollo, Instituto Cajal, Spanish National Research Council, 28002 Madrid, Spain
| | - Ana Martínez
- Centro de Investigaciones Biológicas, Spanish National Research Council, 28040 Madrid, Spain
| | - María José Sánchez-Barrena
- Departamento de Cristalografía y Biología Estructural, Instituto de Química Física Rocasolano, Spanish National Research Council, 28006 Madrid, Spain;
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15
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Zhu Y, Ma B, Nussinov R, Zhang Q. Temperature-Dependent Conformational Properties of Human Neuronal Calcium Sensor-1 Protein Revealed by All-Atom Simulations. J Phys Chem B 2016; 120:3551-9. [PMID: 27007011 PMCID: PMC6415918 DOI: 10.1021/acs.jpcb.5b12299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neuronal calcium sensor-1 (NCS-1) protein has orthologues from Saccharomyces cerevisiae to human with highly conserved amino acid sequences. NCS-1 is an important factor controlling the animal's response to temperature change. This leads us to investigate the temperature effects on the conformational dynamics of human NCS-1 at 310 and 316 K by all-atom molecular dynamics (MD) simulations and dynamic community network analysis. Four independent 500 ns MD simulations show that secondary structure content at 316 K is similar to that at 310 K, whereas the global protein structure is expanded. Loop 3 (L3) adopts an extended state occuping the hydrophobic crevice, and the number of suboptimal communication paths between residue D176 and V190 is reduced at 316 K. The dynamic community network analysis suggests that the interdomain correlation is weakened, and the intradomain coupling is strengthened at 316 K. The elevated temperature reduces the number of the salt bridges, especially in C-domain. This study suggests that the elevated temperature affects the conformational dynamics of human NCS-1 protein. Comparison of the structural dynamics of R102Q mutant and Δ176-190 truncated NCS-1 suggests that the structural and dynamical response of NCS-1 protein to elevated temperature may be one of its intrinsic functional properties.
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Affiliation(s)
- Yuzhen Zhu
- College of Physical Education and Training, Shanghai University of Sport, 399 Chang Hai Road, Shanghai, 200438, China
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- Sackler Inst. of Molecular Medicine Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Qingwen Zhang
- College of Physical Education and Training, Shanghai University of Sport, 399 Chang Hai Road, Shanghai, 200438, China
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16
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Lemire S, Jeromin A, Boisselier É. Membrane binding of Neuronal Calcium Sensor-1 (NCS1). Colloids Surf B Biointerfaces 2015; 139:138-47. [PMID: 26705828 DOI: 10.1016/j.colsurfb.2015.11.065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 10/29/2015] [Accepted: 11/22/2015] [Indexed: 01/10/2023]
Abstract
Neuronal Calcium Sensor-1 (NCS1) belongs to the family of Neuronal Calcium Sensor (NCS) proteins. NCS1 is composed of four EF-hand motifs and an N-terminal myristoylation. However, the presence of a calcium-myristoyl switch in NCS1 and its role in the membrane binding are controversial. The model of Langmuir lipid monolayers is thus used to mimic the cell membrane in order to characterize the membrane interactions of NCS1. Two binding parameters are calculated from monolayer measurements: the maximum insertion pressure, up to which protein binding is energetically favorable, and the synergy, reporting attractive or repulsive interactions with the lipid monolayers. Binding membrane measurements performed in the presence of myristoylated NCS1 reveal better binding interactions for phospholipids composed of phosphoethanolamine polar head groups and unsaturated fatty acyl chains. In the absence of calcium, the membrane binding measurements are drastically modified and suggest that the protein is more strongly bound to the membrane. Indeed, the binding of calcium by three EF-hand motifs of NCS1 leads to a conformation change. NCS1 arrangement at the membrane could thus be reshuffled for better interactions with its substrates. The N-terminal peptide of NCS1 is composed of two amphiphilic helices involved in the membrane interactions of NCS1. Moreover, the presence of the myristoyl group has a weak influence on the membrane binding of NCS1 suggesting the absence of a calcium-myristoyl switch mechanism in this protein. The myristoylation could thus have a structural role required in the folding/unfolding of NCS1 which is essential to its multiple biological functions.
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Affiliation(s)
- Samuel Lemire
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec, Canada
| | | | - Élodie Boisselier
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec, Canada.
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17
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Zhu Y, Yang S, Qi R, Zou Y, Ma B, Nussinov R, Zhang Q. Effects of the C-Terminal Tail on the Conformational Dynamics of Human Neuronal Calcium Sensor-1 Protein. J Phys Chem B 2015; 119:14236-44. [PMID: 26447771 PMCID: PMC6456052 DOI: 10.1021/acs.jpcb.5b07962] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Neuronal calcium sensor-1 (NCS-1) protein has been implicated in multiple neuronal functions by binding partners mostly through a largely exposed hydrophobic crevice (HC). In the absence of a ligand, the C-terminal tail (loop L3, residues D176 to V190) binds directly to the HC pocket as a ligand mimetic, occupying the HC and regulating its conformational stability. A recent experimental study reported that L3 deletion resulted in global structure destabilization. However, the influence of C-terminal tail on the conformations of NCS-1 protein is unclear at the atomic level. In this study, we investigated the structural properties and the conformational dynamics of wild type NCS-1 and L3 truncation variant by extensive all-atom molecular dynamics (MD) simulations. Our cumulative 2 μs MD simulations demonstrated that L3 deletion increased the structural flexibility of the C-domain and the distant N-domain. The community network analysis illustrated that C-terminal tail truncation weakened the interdomain correlation. Moreover, our data showed that the variant significantly disrupted the salt bridges network and expanded simultaneously the global structure and HC. These conformational changes caused by C-terminal tail truncation may affect the regulation of target interactions. Our study provides atomic details of the conformational dynamics effects of the C-terminal tail on human wild type NCS-1.
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Affiliation(s)
- Yuzhen Zhu
- College of Physical Education and Training, Shanghai University of Sport, 399 Chang Hai Road, Shanghai 200438, China
| | - Shuang Yang
- College of Physical Education and Training, Shanghai University of Sport, 399 Chang Hai Road, Shanghai 200438, China
| | - Ruxi Qi
- Department of Physics, Fudan University, 220 Handan Road, Shanghai 200433, China
| | - Yu Zou
- College of Physical Education and Training, Shanghai University of Sport, 399 Chang Hai Road, Shanghai 200438, China
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- Sackler Inst. of Molecular Medicine Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Qingwen Zhang
- College of Physical Education and Training, Shanghai University of Sport, 399 Chang Hai Road, Shanghai 200438, China
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18
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Pandalaneni S, Karuppiah V, Saleem M, Haynes LP, Burgoyne RD, Mayans O, Derrick JP, Lian LY. Neuronal Calcium Sensor-1 Binds the D2 Dopamine Receptor and G-protein-coupled Receptor Kinase 1 (GRK1) Peptides Using Different Modes of Interactions. J Biol Chem 2015; 290:18744-56. [PMID: 25979333 PMCID: PMC4513130 DOI: 10.1074/jbc.m114.627059] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Indexed: 11/25/2022] Open
Abstract
Neuronal calcium sensor-1 (NCS-1) is the primordial member of the neuronal calcium sensor family of EF-hand Ca2+-binding proteins. It interacts with both the G-protein-coupled receptor (GPCR) dopamine D2 receptor (D2R), regulating its internalization and surface expression, and the cognate kinases GRK1 and GRK2. Determination of the crystal structures of Ca2+/NCS-1 alone and in complex with peptides derived from D2R and GRK1 reveals that the differential recognition is facilitated by the conformational flexibility of the C-lobe-binding site. We find that two copies of the D2R peptide bind within the hydrophobic crevice on Ca2+/NCS-1, but only one copy of the GRK1 peptide binds. The different binding modes are made possible by the C-lobe-binding site of NCS-1, which adopts alternative conformations in each complex. C-terminal residues Ser-178–Val-190 act in concert with the flexible EF3/EF4 loop region to effectively form different peptide-binding sites. In the Ca2+/NCS-1·D2R peptide complex, the C-terminal region adopts a 310 helix-turn-310 helix, whereas in the GRK1 peptide complex it forms an α-helix. Removal of Ser-178–Val-190 generated a C-terminal truncation mutant that formed a dimer, indicating that the NCS-1 C-terminal region prevents NCS-1 oligomerization. We propose that the flexible nature of the C-terminal region is essential to allow it to modulate its protein-binding sites and adapt its conformation to accommodate both ligands. This appears to be driven by the variability of the conformation of the C-lobe-binding site, which has ramifications for the target specificity and diversity of NCS-1.
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Affiliation(s)
- Sravan Pandalaneni
- From the NMR Centre for Structural Biology, Institute of Integrative Biology, and
| | - Vijaykumar Karuppiah
- From the NMR Centre for Structural Biology, Institute of Integrative Biology, and the Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, and
| | - Muhammad Saleem
- the Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, and
| | - Lee P Haynes
- the Physiological Laboratory, Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L37 4BY, United Kingdom
| | - Robert D Burgoyne
- the Physiological Laboratory, Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L37 4BY, United Kingdom
| | - Olga Mayans
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB
| | - Jeremy P Derrick
- the Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, and
| | - Lu-Yun Lian
- From the NMR Centre for Structural Biology, Institute of Integrative Biology, and
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19
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Lee HL, Dhenadhayalan N, Lin KC. Metal ion induced fluorescence resonance energy transfer between crown ether functionalized quantum dots and rhodamine B: selectivity of K+ ion. RSC Adv 2015. [DOI: 10.1039/c4ra10925b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A ratiometric fluorescent metal ion sensor based on the mechanism of fluorescence resonance energy transfer between 15-crown-5-ether capped CdSe/ZnS quantum dots and 15-crown-5-ether attached rhodamine B.
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Affiliation(s)
- Hsin-Lung Lee
- Department of Chemistry
- National Taiwan University
- Institute of Atomic and Molecular Sciences
- Academia Sinica
- Taipei 106
| | - Namasivayam Dhenadhayalan
- Department of Chemistry
- National Taiwan University
- Institute of Atomic and Molecular Sciences
- Academia Sinica
- Taipei 106
| | - King-Chuen Lin
- Department of Chemistry
- National Taiwan University
- Institute of Atomic and Molecular Sciences
- Academia Sinica
- Taipei 106
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20
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Romero-Pozuelo J, Dason JS, Mansilla A, Baños-Mateos S, Sardina JL, Chaves-Sanjuán A, Jurado-Gómez J, Santana E, Atwood HL, Hernández-Hernández Á, Sánchez-Barrena MJ, Ferrús A. The guanine-exchange factor Ric8a binds to the Ca²⁺ sensor NCS-1 to regulate synapse number and neurotransmitter release. J Cell Sci 2014; 127:4246-59. [PMID: 25074811 DOI: 10.1242/jcs.152603] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The conserved Ca(2+)-binding protein Frequenin (homolog of the mammalian NCS-1, neural calcium sensor) is involved in pathologies that result from abnormal synapse number and probability of neurotransmitter release per synapse. Both synaptic features are likely to be co-regulated but the intervening mechanisms remain poorly understood. We show here that Drosophila Ric8a (a homolog of mammalian synembryn, which is also known as Ric8a), a receptor-independent activator of G protein complexes, binds to Frq2 but not to the virtually identical homolog Frq1. Based on crystallographic data on Frq2 and site-directed mutagenesis on Frq1, the differential amino acids R94 and T138 account for this specificity. Human NCS-1 and Ric8a reproduce the binding and maintain the structural requirements at these key positions. Drosophila Ric8a and Gαs regulate synapse number and neurotransmitter release, and both are functionally linked to Frq2. Frq2 negatively regulates Ric8a to control synapse number. However, the regulation of neurotransmitter release by Ric8a is independent of Frq2 binding. Thus, the antagonistic regulation of these two synaptic properties shares a common pathway, Frq2-Ric8a-Gαs, which diverges downstream. These mechanisms expose the Frq2-Ric8a interacting surface as a potential pharmacological target for NCS-1-related diseases and provide key data towards the corresponding drug design.
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Affiliation(s)
- Jesús Romero-Pozuelo
- Department of Molecular, Cellular and Developmental Neurobiology, Institute Cajal, CSIC, Avenida Dr. Arce 37, Madrid 28002, Spain
| | - Jeffrey S Dason
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Alicia Mansilla
- Department of Molecular, Cellular and Developmental Neurobiology, Institute Cajal, CSIC, Avenida Dr. Arce 37, Madrid 28002, Spain
| | - Soledad Baños-Mateos
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry 'Rocasolano', CSIC, Serrano 119, Madrid 28006, Spain
| | - José L Sardina
- Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca 37007, Spain
| | - Antonio Chaves-Sanjuán
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry 'Rocasolano', CSIC, Serrano 119, Madrid 28006, Spain
| | - Jaime Jurado-Gómez
- Department of Molecular, Cellular and Developmental Neurobiology, Institute Cajal, CSIC, Avenida Dr. Arce 37, Madrid 28002, Spain
| | - Elena Santana
- Department of Molecular, Cellular and Developmental Neurobiology, Institute Cajal, CSIC, Avenida Dr. Arce 37, Madrid 28002, Spain
| | - Harold L Atwood
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ángel Hernández-Hernández
- Department of Molecular, Cellular and Developmental Neurobiology, Institute Cajal, CSIC, Avenida Dr. Arce 37, Madrid 28002, Spain Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca 37007, Spain Institute for Biomedical Research (IBSAL), Salamanca 37007, Spain
| | - María-José Sánchez-Barrena
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry 'Rocasolano', CSIC, Serrano 119, Madrid 28006, Spain
| | - Alberto Ferrús
- Department of Molecular, Cellular and Developmental Neurobiology, Institute Cajal, CSIC, Avenida Dr. Arce 37, Madrid 28002, Spain
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21
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Lim S, Dizhoor AM, Ames JB. Structural diversity of neuronal calcium sensor proteins and insights for activation of retinal guanylyl cyclase by GCAP1. Front Mol Neurosci 2014; 7:19. [PMID: 24672427 PMCID: PMC3956117 DOI: 10.3389/fnmol.2014.00019] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 02/27/2014] [Indexed: 01/08/2023] Open
Abstract
Neuronal calcium sensor (NCS) proteins, a sub-branch of the calmodulin superfamily, are expressed in the brain and retina where they transduce calcium signals and are genetically linked to degenerative diseases. The amino acid sequences of NCS proteins are highly conserved but their physiological functions are quite different. Retinal recoverin controls Ca2+-dependent inactivation of light-excited rhodopsin during phototransduction, guanylyl cyclase activating proteins 1 and 2 (GCAP1 and GCAP2) promote Ca2+-dependent activation of retinal guanylyl cyclases, and neuronal frequenin (NCS-1) modulates synaptic activity and neuronal secretion. Here we review the molecular structures of myristoylated forms of NCS-1, recoverin, and GCAP1 that all look very different, suggesting that the attached myristoyl group helps to refold these highly homologous proteins into different three-dimensional folds. Ca2+-binding to both recoverin and NCS-1 cause large protein conformational changes that ejects the covalently attached myristoyl group into the solvent exterior and promotes membrane targeting (Ca2+-myristoyl switch). The GCAP proteins undergo much smaller Ca2+-induced conformational changes and do not possess a Ca2+-myristoyl switch. Recent structures of GCAP1 in both its activator and Ca2+-bound inhibitory states will be discussed to understand structural determinants that control their Ca2+-dependent activation of retinal guanylyl cyclases.
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Affiliation(s)
- Sunghyuk Lim
- Department of Chemistry, University of California at Davis Davis, CA, USA
| | - Alexander M Dizhoor
- Basic Sciences, Pennsylvania College of Optometry, Salus University Elkins Park, PA, USA
| | - James B Ames
- Department of Chemistry, University of California at Davis Davis, CA, USA
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22
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Tan J, Brill JA. Cinderella story: PI4P goes from precursor to key signaling molecule. Crit Rev Biochem Mol Biol 2013; 49:33-58. [PMID: 24219382 DOI: 10.3109/10409238.2013.853024] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Phosphatidylinositol lipids are signaling molecules involved in nearly all aspects of cellular regulation. Production of phosphatidylinositol 4-phosphate (PI4P) has long been recognized as one of the first steps in generating poly-phosphatidylinositol phosphates involved in actin organization, cell migration, and signal transduction. In addition, progress over the last decade has brought to light independent roles for PI4P in membrane trafficking and lipid homeostasis. Here, we describe recent advances that reveal the breadth of processes regulated by PI4P, the spectrum of PI4P effectors, and the mechanisms of spatiotemporal control that coordinate crosstalk between PI4P and cellular signaling pathways.
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Affiliation(s)
- Julie Tan
- Department of Molecular Genetics, University of Toronto , Toronto, Ontario , Canada and
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23
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Bellucci L, Corni S, Di Felice R, Paci E. The structure of neuronal calcium sensor-1 in solution revealed by molecular dynamics simulations. PLoS One 2013; 8:e74383. [PMID: 24098643 PMCID: PMC3787052 DOI: 10.1371/journal.pone.0074383] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 07/31/2013] [Indexed: 02/07/2023] Open
Abstract
Neuronal calcium sensor-1 (NCS-1) is a protein able to trigger signal transduction processes by binding a large number of substrates and re-shaping its structure depending on the environmental conditions. The X-ray crystal structure of the unmyristoilated NCS-1 shows a large solvent-exposed hydrophobic crevice (HC); this HC is partially occupied by the C-terminal tail and thus elusive to the surrounding solvent. We studied the native state of NCS-1 by performing room temperature molecular dynamics (MD) simulations starting from the crystal and the solution structures. We observe relaxation to a state independent of the initial structure, in which the C-terminal tail occupies the HC. We suggest that the C-terminal tail shields the HC binding pocket and modulates the affinity of NCS-1 for its natural targets. By analyzing the topology and nature of the inter-residue potential energy, we provide a compelling description of the interaction network that determines the three-dimensional organization of NCS-1.
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Affiliation(s)
- Luca Bellucci
- Center S3, CNR Institute Nanoscience, Modena, Italy
- * E-mail:
| | | | | | - Emanuele Paci
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
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24
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Structural Biology of a Major Signaling Network that Regulates Plant Abiotic Stress: The CBL-CIPK Mediated Pathway. Int J Mol Sci 2013; 14:5734-49. [PMID: 23481636 PMCID: PMC3634423 DOI: 10.3390/ijms14035734] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 02/27/2013] [Accepted: 02/28/2013] [Indexed: 01/17/2023] Open
Abstract
The Arabidopsis SOS2 family of twenty-six protein kinases (CIPKs), their interacting activators, the SOS3 family of ten calcium-binding proteins (CBLs) and protein phosphatases type 2C (PP2C), function together in decoding calcium signals elicited by different environmental stimuli. Biochemical data suggest that stable CBL-CIPK or CIPK-PP2C complexes may be regulating the activity of various substrates controlling ion homeostasis. The available structural information provides a general regulatory mechanism in which calcium perception by CBLs and kinase activation is coupled. The structural basis of this molecular mechanism and the specificity of the network is reviewed and discussed in detail.
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25
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26
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Ames JB, Lim S. Molecular structure and target recognition of neuronal calcium sensor proteins. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1820:1205-13. [PMID: 22020049 PMCID: PMC3266469 DOI: 10.1016/j.bbagen.2011.10.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/06/2011] [Accepted: 10/07/2011] [Indexed: 02/06/2023]
Abstract
BACKGROUND Neuronal calcium sensor (NCS) proteins, a sub-branch of the calmodulin superfamily, are expressed in the brain and retina where they transduce calcium signals and are genetically linked to degenerative diseases. The amino acid sequences of NCS proteins are highly conserved but their physiological functions are quite distinct. Retinal recoverin and guanylate cyclase activating proteins (GCAPs) both serve as calcium sensors in retinal rod cells, neuronal frequenin (NCS1) modulate synaptic activity and neuronal secretion, K+ channel interacting proteins (KChIPs) regulate ion channels to control neuronal excitability, and DREAM (KChIP3) is a transcriptional repressor that regulates neuronal gene expression. SCOPE OF REVIEW Here we review the molecular structures of myristoylated forms of NCS1, recoverin, and GCAP1 that all look very different, suggesting that the sequestered myristoyl group helps to refold these highly homologous proteins into very different structures. The molecular structure of NCS target complexes have been solved for recoverin bound to rhodopsin kinase, NCS-1 bound to phosphatidylinositol 4-kinase, and KChIP1 bound to A-type K+ channels. MAJOR CONCLUSIONS We propose the idea that N-terminal myristoylation is critical for shaping each NCS family member into a unique structure, which upon Ca2+-induced extrusion of the myristoyl group exposes a unique set of previously masked residues, thereby exposing a distinctive ensemble of hydrophobic residues to associate specifically with a particular physiological target. This article is part of a Special Issue entitled Biochemical, biophysical and genetic approaches to intracellular calcium signaling.
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Affiliation(s)
- James B Ames
- University of California, Davis Department of Chemistry, Davis, CA 95616, USa.
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Ames JB, Lim S, Ikura M. Molecular structure and target recognition of neuronal calcium sensor proteins. Front Mol Neurosci 2012; 5:10. [PMID: 22363261 PMCID: PMC3275791 DOI: 10.3389/fnmol.2012.00010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 01/26/2012] [Indexed: 01/19/2023] Open
Abstract
Neuronal calcium sensor (NCS) proteins, a sub-branch of the EF-hand superfamily, are expressed in the brain and retina where they transduce calcium signals and are genetically linked to degenerative diseases. The amino acid sequences of NCS proteins are highly conserved but their physiological functions are quite distinct. Retinal recoverin and guanylate cyclase activating proteins (GCAPs) both serve as calcium sensors in retinal rod cells, neuronal frequenin (NCS1) modulates synaptic activity and neuronal secretion, K+ channel interacting proteins (KChIPs) regulate ion channels to control neuronal excitability, and DREAM (KChIP3) is a transcriptional repressor that regulates neuronal gene expression. Here we review the molecular structures of myristoylated forms of NCS1, recoverin, and GCAP1 that all look very different, suggesting that the sequestered myristoyl group helps to refold these highly homologous proteins into very different structures. The molecular structure of NCS target complexes have been solved for recoverin bound to rhodopsin kinase (RK), NCS-1 bound to phosphatidylinositol 4-kinase, and KChIP1 bound to A-type K+ channels. We propose that N-terminal myristoylation is critical for shaping each NCS family member into a different structure, which upon Ca2+-induced extrusion of the myristoyl group exposes a unique set of previously masked residues that interact with a particular physiological target.
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Affiliation(s)
- James B Ames
- Department of Chemistry, University of California, Davis CA, USA
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28
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Identification of the critical structural determinants of the EF-hand domain arrangements in calcium binding proteins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:608-19. [PMID: 22285364 DOI: 10.1016/j.bbapap.2012.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 12/02/2011] [Accepted: 01/04/2012] [Indexed: 11/22/2022]
Abstract
EF-hand calcium binding proteins (CaBPs) share strong sequence homology, but exhibit great diversity in structure and function. Thus although calmodulin (CaM) and calcineurin B (CNB) both consist of four EF hands, their domain arrangements are quite distinct. CaM and the CaM-like proteins are characterized by an extended architecture, whereas CNB and the CNB-like proteins have a more compact form. In this study, we performed structural alignments and molecular dynamics (MD) simulations on 3 CaM-like proteins and 6 CNB-like proteins, and quantified their distinct structural and dynamical features in an effort to establish how their sequences specify their structures and dynamics. Alignments of the EF2-EF3 region of these proteins revealed that several residues (not restricted to the linker between the EF2 and EF3 motifs) differed between the two groups of proteins. A customized inverse folding approach followed by structural assessments and MD simulations established the critical role of these residues in determining the structure of the proteins. Identification of the critical determinants of the two different EF-hand domain arrangements and the distinct dynamical features relevant to their respective functions provides insight into the relationships between sequence, structure, dynamics and function among these EF-hand CaBPs.
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29
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Heidarsson PO, Bjerrum-Bohr IJ, Jensen GA, Pongs O, Finn BE, Poulsen FM, Kragelund BB. The C-terminal tail of human neuronal calcium sensor 1 regulates the conformational stability of the Ca²⁺₋ activated state. J Mol Biol 2011; 417:51-64. [PMID: 22227393 DOI: 10.1016/j.jmb.2011.12.049] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 12/19/2011] [Accepted: 12/23/2011] [Indexed: 01/20/2023]
Abstract
Neuronal calcium sensor 1 (NCS-1) and orthologs are expressed in all organisms from yeast to humans. In the latter, NCS-1 plays an important role in neurotransmitter release and interacts with a plethora of binding partners mostly through a large solvent-exposed hydrophobic crevice. The structural basis behind the multispecific binding profile is not understood. To begin to address this, we applied NMR spectroscopy to determine the solution structure of calcium-bound human NCS-1. The structure in solution demonstrates interdomain flexibility and, in the absence of a binding partner, the C-terminal tail residues occupy the hydrophobic crevice as a ligand mimic. A variant with a C-terminal tail deletion shows lack of a defined structure but maintained cooperative unfolding and dramatically reduced global stability. The results suggest that the C-terminal tail is important for regulating the conformational stability of the Ca(2+)-activated state. Furthermore, a single amino acid mutation that was recently diagnosed in a patient with autistic spectrum disorder was seen to affect the C-terminal tail and binding crevice in NCS-1.
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Affiliation(s)
- Pétur O Heidarsson
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
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30
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Lian LY, Pandalaneni SR, Patel P, McCue HV, Haynes LP, Burgoyne RD. Characterisation of the interaction of the C-terminus of the dopamine D2 receptor with neuronal calcium sensor-1. PLoS One 2011; 6:e27779. [PMID: 22114693 PMCID: PMC3218054 DOI: 10.1371/journal.pone.0027779] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 10/25/2011] [Indexed: 11/19/2022] Open
Abstract
NCS-1 is a member of the neuronal calcium sensor (NCS) family of EF-hand Ca(2+) binding proteins which has been implicated in several physiological functions including regulation of neurotransmitter release, membrane traffic, voltage gated Ca(2+) channels, neuronal development, synaptic plasticity, and learning. NCS-1 binds to the dopamine D2 receptor, potentially affecting its internalisation and controlling dopamine D2 receptor surface expression. The D2 receptor binds NCS-1 via a short 16-residue cytoplasmic C-terminal tail. We have used NMR and fluorescence spectroscopy to characterise the interactions between the NCS-1/Ca(2+) and D2 peptide. The data show that NCS-1 binds D2 peptide with a K(d) of ∼14.3 µM and stoichiometry of peptide binding to NCS-1 of 2:1. NMR chemical shift mapping confirms that D2 peptide binds to the large, solvent-exposed hydrophobic groove, on one face of the NCS-1 molecule, with residues affected by the presence of the peptide spanning both the N and C-terminal portions of the protein. The NMR and mutagenesis data further show that movement of the C-terminal helix 11 of NCS-1 to fully expose the hydrophobic groove is important for D2 peptide binding. Molecular docking using restraints derived from the NMR chemical shift data, together with the experimentally-derived stoichiometry, produced a model of the complex between NCS-1 and the dopamine receptor, in which two molecules of the receptor are able to simultaneously bind to the NCS-1 monomer.
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Affiliation(s)
- Lu-Yun Lian
- NMR Centre for Structural Biology, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- * E-mail: (LYL); (RDB)
| | - Sravan R. Pandalaneni
- NMR Centre for Structural Biology, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Pryank Patel
- NMR Centre for Structural Biology, Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Hannah V. McCue
- The Physiological Laboratory, Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Lee P. Haynes
- The Physiological Laboratory, Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Robert D. Burgoyne
- The Physiological Laboratory, Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
- * E-mail: (LYL); (RDB)
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31
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Deka R, Kumar R, Tamuli R. Neurospora crassa homologue of Neuronal Calcium Sensor-1 has a role in growth, calcium stress tolerance, and ultraviolet survival. Genetica 2011; 139:885-94. [DOI: 10.1007/s10709-011-9592-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 06/22/2011] [Indexed: 10/18/2022]
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32
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Xu X, Ishima R, Ames JB. Conformational dynamics of recoverin's Ca2+-myristoyl switch probed by 15N NMR relaxation dispersion and chemical shift analysis. Proteins 2011; 79:1910-22. [PMID: 21465563 DOI: 10.1002/prot.23014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 01/26/2011] [Accepted: 01/28/2011] [Indexed: 11/05/2022]
Abstract
Recoverin, a member of the neuronal calcium sensor (NCS) branch of the calmodulin superfamily, serves as a calcium sensor in retinal rod cells. Ca(2+) -induced conformational changes in recoverin promote extrusion of its covalently attached myristate, known as the Ca(2+)-myristoyl switch. Here, we present nuclear magnetic resonance (NMR) relaxation dispersion and chemical shift analysis on (15) N-labeled recoverin to probe main chain conformational dynamics. (15) N NMR relaxation data suggest that Ca(2+)-free recoverin undergoes millisecond conformational dynamics at particular amide sites throughout the protein. The addition of trace Ca(2+) levels (0.05 equivalents) increases the number of residues that show detectable relaxation dispersion. The Ca(2+)-dependent chemical shifts and relaxation dispersion suggest that recoverin has an intermediate conformational state (I) between the sequestered apo state (T) and Ca(2+) saturated extruded state (R): T ↔ I ↔ R. The first step is a fast conformational equilibrium ([T]/[I] < 100) on the millisecond time scale (τ(ex) δω < 1). The final step (I ↔ R) is much slower (τ(ex) δω > 1). The main chain structure of I is similar in part to the structure of half-saturated E85Q recoverin with a sequestered myristoyl group. We propose that millisecond dynamics during T ↔ I may transiently increase the exposure of Ca(2+)-binding sites to initiate Ca(2+) binding that drives extrusion of the myristoyl group during I ↔ R.
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Affiliation(s)
- Xianzhong Xu
- Department of Chemistry, University of California, Davis, California 95616, USA
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33
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Lim S, Strahl T, Thorner J, Ames JB. Structure of a Ca2+-myristoyl switch protein that controls activation of a phosphatidylinositol 4-kinase in fission yeast. J Biol Chem 2011; 286:12565-77. [PMID: 21288895 DOI: 10.1074/jbc.m110.208868] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuronal calcium sensor (NCS) proteins transduce Ca2+ signals and are highly conserved from yeast to humans. We determined NMR structures of the NCS-1 homolog from fission yeast (Ncs1), which activates a phosphatidylinositol 4-kinase. Ncs1 contains an α-NH2-linked myristoyl group on a long N-terminal arm and four EF-hand motifs, three of which bind Ca2+, assembled into a compact structure. In Ca2+-free Ncs1, the N-terminal arm positions the fatty acyl chain inside a cavity near the C terminus. The C14 end of the myristate is surrounded by residues in the protein core, whereas its amide-linked (C1) end is flanked by residues at the protein surface. In Ca2+-bound Ncs1, the myristoyl group is extruded (Ca2+-myristoyl switch), exposing a prominent patch of hydrophobic residues that specifically contact phosphatidylinositol 4-kinase. The location of the buried myristate and structure of Ca2+-free Ncs1 are quite different from those in other NCS proteins. Thus, a unique remodeling of each NCS protein by its myristoyl group, and Ca2+-dependent unmasking of different residues, may explain how each family member recognizes distinct target proteins.
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Affiliation(s)
- Sunghyuk Lim
- Department of Chemistry, University of California, Davis, California 95616, USA
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34
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Li C, Pan W, Braunewell KH, Ames JB. Structural analysis of Mg2+ and Ca2+ binding, myristoylation, and dimerization of the neuronal calcium sensor and visinin-like protein 1 (VILIP-1). J Biol Chem 2010; 286:6354-66. [PMID: 21169352 DOI: 10.1074/jbc.m110.173724] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Visinin-like protein 1 (VILIP-1) belongs to the neuronal calcium sensor family of Ca(2+)-myristoyl switch proteins that regulate signal transduction in the brain and retina. Here we analyze Ca(2+) and Mg(2+) binding, characterize metal-induced conformational changes, and determine structural effects of myristoylation and dimerization. Mg(2+) binds functionally to VILIP-1 at EF3 (ΔH = +1.8 kcal/mol and K(D) = 20 μM). Unmyristoylated VILIP-1 binds two Ca(2+) sequentially at EF2 and EF3 (K(EF3) = 0.1 μM and K(EF2) = 1-4 μM), whereas myristoylated VILIP-1 binds two Ca(2+) with lower affinity (K(D) = 1.2 μM) and positive cooperativity (Hill slope = 1.5). NMR assignments and structural analysis indicate that Ca(2+)-free VILIP-1 contains a sequestered myristoyl group like that of recoverin. NMR resonances of the attached myristate exhibit Ca(2+)-dependent chemical shifts and NOE patterns consistent with Ca(2+)-induced extrusion of the myristate. VILIP-1 forms a dimer in solution independent of Ca(2+) and myristoylation. The dimerization site is composed of residues in EF4 and the loop region between EF3 and EF4, confirmed by mutagenesis. We present the structure of the VILIP-1 dimer and a Ca(2+)-myristoyl switch to provide structural insights into Ca(2+)-induced trafficking of nicotinic acetylcholine receptors.
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Affiliation(s)
- Congmin Li
- Department of Chemistry, University of California, Davis, California 95616, USA
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35
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Tamuli R, Kumar R, Deka R. Cellular roles of neuronal calcium sensor-1 and calcium/calmodulin-dependent kinases in fungi. J Basic Microbiol 2010; 51:120-8. [PMID: 21077122 DOI: 10.1002/jobm.201000184] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 08/03/2010] [Indexed: 11/07/2022]
Abstract
The neuronal calcium sensor-1 (NCS-1) possesses a consensus signal for N-terminal myristoylation and four EF-hand Ca(2+)-binding sites, and mediates the effects of cytosolic Ca(2+). Minute changes in free intracellular Ca(2+) are quickly transformed into changes in the activity of several kinases including calcium/calmodulin-dependent protein kinases (Ca(2+)/CaMKs) that are involved in regulating many eukaryotic cell functions. However, our current knowledge of NCS-1 and Ca(2+)/CaMKs comes mostly from studies of the mammalian enzymes. Thus far very few fungal homologues of NCS-1 and Ca(2+)/CaMKs have been characterized and little is known about their cellular roles. In this minireview, we describe the known sequences, interactions with target proteins and cellular roles of NCS-1 and Ca(2+)/CaMKs in fungi.
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Affiliation(s)
- Ranjan Tamuli
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, India.
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36
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Giladi M, Boyman L, Mikhasenko H, Hiller R, Khananshvili D. Essential role of the CBD1-CBD2 linker in slow dissociation of Ca2+ from the regulatory two-domain tandem of NCX1. J Biol Chem 2010; 285:28117-25. [PMID: 20587421 PMCID: PMC2934676 DOI: 10.1074/jbc.m110.127001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 06/28/2010] [Indexed: 11/06/2022] Open
Abstract
In NCX proteins CBD1 and CBD2 domains are connected through a short linker (3 or 4 amino acids) forming a regulatory tandem (CBD12). Only three of the six CBD12 Ca(2+)-binding sites contribute to NCX regulation. Two of them are located on CBD1 (K(d) = approximately 0.2 microM), and one is on CBD2 (K(d) = approximately 5 microM). Here we analyze how the intrinsic properties of individual regulatory sites are affected by linker-dependent interactions in CBD12 (AD splice variant). The three sites of CBD12 and CBD1 + CBD2 have comparable K(d) values but differ dramatically in their Ca(2+) dissociation kinetics. CBD12 exhibits multiphasic kinetics for the dissociation of three Ca(2+) ions (k(r) = 280 s(-1), k(f) = 7 s(-1), and k(s) = 0.4 s(-1)), whereas the dissociation of two Ca(2+) ions from CBD1 (k(f) = 16 s(-1)) and one Ca(2+) ion from CBD2 (k(r) = 125 s(-1)) is monophasic. Insertion of seven alanines into the linker (CBD12-7Ala) abolishes slow dissociation of Ca(2+), whereas the kinetic and equilibrium properties of three Ca(2+) sites of CBD12-7Ala and CBD1 + CBD2 are similar. Therefore, the linker-dependent interactions in CBD12 decelerate the Ca(2+) on/off kinetics at a specific CBD1 site by 50-80-fold, thereby representing Ca(2+) "occlusion" at CBD12. Notably, the kinetic and equilibrium properties of the remaining two sites of CBD12 are "linker-independent," so their intrinsic properties are preserved in CBD12. In conclusion, the dynamic properties of three sites are specifically modified, conserved, diversified, and integrated by the linker in CBD12, thereby generating a wide range dynamic sensor.
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Affiliation(s)
- Moshe Giladi
- From the Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv 69978, Israel
| | - Liron Boyman
- From the Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv 69978, Israel
| | - Helen Mikhasenko
- From the Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv 69978, Israel
| | - Reuben Hiller
- From the Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv 69978, Israel
| | - Daniel Khananshvili
- From the Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv 69978, Israel
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37
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Wang X, Zhao K, Kirberger M, Wong H, Chen G, Yang JJ. Analysis and prediction of calcium-binding pockets from apo-protein structures exhibiting calcium-induced localized conformational changes. Protein Sci 2010; 19:1180-90. [PMID: 20512971 DOI: 10.1002/pro.394] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Calcium binding in proteins exhibits a wide range of polygonal geometries that relate directly to an equally diverse set of biological functions. The binding process stabilizes protein structures and typically results in local conformational change and/or global restructuring of the backbone. Previously, we established the MUG program, which utilized multiple geometries in the Ca(2+)-binding pockets of holoproteins to identify such pockets, ignoring possible Ca(2+)-induced conformational change. In this article, we first report our progress in the analysis of Ca(2+)-induced conformational changes followed by improved prediction of Ca(2+)-binding sites in the large group of Ca(2+)-binding proteins that exhibit only localized conformational changes. The MUG(SR) algorithm was devised to incorporate side chain torsional rotation as a predictor. The output from MUG(SR) presents groups of residues where each group, typically containing two to five residues, is a potential binding pocket. MUG(SR) was applied to both X-ray apo structures and NMR holo structures, which did not use calcium distance constraints in structure calculations. Predicted pockets were validated by comparison with homologous holo structures. Defining a "correct hit" as a group of residues containing at least two true ligand residues, the sensitivity was at least 90%; whereas for a "correct hit" defined as a group of residues containing at least three true ligand residues, the sensitivity was at least 78%. These data suggest that Ca(2+)-binding pockets are at least partially prepositioned to chelate the ion in the apo form of the protein.
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Affiliation(s)
- Xue Wang
- Department of Computer Science, Georgia State University, Atlanta, Georgia 30303, USA
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38
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Hawkins BJ, Irrinki KM, Mallilankaraman K, Lien YC, Wang Y, Bhanumathy CD, Subbiah R, Ritchie MF, Soboloff J, Baba Y, Kurosaki T, Joseph SK, Gill DL, Madesh M. S-glutathionylation activates STIM1 and alters mitochondrial homeostasis. ACTA ACUST UNITED AC 2010; 190:391-405. [PMID: 20679432 PMCID: PMC2922639 DOI: 10.1083/jcb.201004152] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Oxidant stress induces constitutive calcium entry by tacking glutathiones onto the Orai CRAC channel activator STIM1. Oxidant stress influences many cellular processes, including cell growth, differentiation, and cell death. A well-recognized link between these processes and oxidant stress is via alterations in Ca2+ signaling. However, precisely how oxidants influence Ca2+ signaling remains unclear. Oxidant stress led to a phenotypic shift in Ca2+ mobilization from an oscillatory to a sustained elevated pattern via calcium release–activated calcium (CRAC)–mediated capacitive Ca2+ entry, and stromal interaction molecule 1 (STIM1)– and Orai1-deficient cells are resistant to oxidant stress. Functionally, oxidant-induced Ca2+ entry alters mitochondrial Ca2+ handling and bioenergetics and triggers cell death. STIM1 is S-glutathionylated at cysteine 56 in response to oxidant stress and evokes constitutive Ca2+ entry independent of intracellular Ca2+ stores. These experiments reveal that cysteine 56 is a sensor for oxidant-dependent activation of STIM1 and demonstrate a molecular link between oxidant stress and Ca2+ signaling via the CRAC channel.
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Affiliation(s)
- Brian J Hawkins
- Department of Biochemistry, Temple University, Philadelphia, PA 19140, USA
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39
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Burgoyne RD, Haynes LP. Neuronal calcium sensor proteins: emerging roles in membrane traffic and synaptic plasticity. F1000 BIOLOGY REPORTS 2010; 2. [PMID: 20948784 PMCID: PMC2948346 DOI: 10.3410/b2-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca2+ plays a crucial role in the regulation of neuronal function. Recent work has revealed important functions for two families of neuronally expressed Ca2+ sensor proteins. These include roles in membrane traffic and in alterations in synaptic plasticity underlying changes in behaviour.
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Affiliation(s)
- Robert D Burgoyne
- The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool Crown Street, Liverpool, L69 3BX UK
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40
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Hamasaki-Katagiri N, Ames JB. Neuronal calcium sensor-1 (Ncs1p) is up-regulated by calcineurin to promote Ca2+ tolerance in fission yeast. J Biol Chem 2009; 285:4405-14. [PMID: 20018864 DOI: 10.1074/jbc.m109.058594] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuronal calcium sensor (NCS) proteins regulate signal transduction and are highly conserved from yeast to humans. NCS homolog in fission yeast (Ncs1p) is essential for cell growth under extreme Ca(2+) conditions. Ncs1p expression increases approximately 100-fold when fission yeast grows in high extracellular Ca(2+) (>0.1 M). Here, we show that Ca(2+)-induced expression of Ncs1p is controlled at the level of transcription. Transcriptional reporter assays show that ncs1 promoter activity increased 30-fold when extracellular Ca(2+) was raised to 0.1 M and was highly Ca(2+)-specific. Ca(2+)-dependent transcription of ncs1 is abolished by the calcineurin inhibitor (FK506) and by knocking out the calcineurin target, prz1. Thus, Ca(2+)-induced expression of Ncs1p is linked to the calcineurin/prz1 stress response. The Ca(2+)-responsive ncs1 promoter region consists of 130 nucleotides directly upstream from the start codon and contains tandem repeats of the sequence, 5'-caact-3', that binds to Prz1p. The Ca(2+)-sensitive ncs1Delta phenotype is rescued by a yam8 null mutation, suggesting a possible interaction between Ncs1p and the Ca(2+) channel, Yam8p. Ca(2+) uptake and Ncs1p binding to yeast membranes are both decreased in yam8Delta, suggesting Ca(2+)-induced binding of Ncs1p to Yam8p results in channel closure. We propose that Ncs1p promotes Ca(2+) tolerance in fission yeast, in part by cytosolic Ca(2+) buffering and perhaps by negatively regulating the Yam8p Ca(2+) channel.
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Affiliation(s)
- Nobuko Hamasaki-Katagiri
- Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, Maryland 20850, USA
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41
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Lim S, Ames JB. (1)H, (15)N, and (13)C chemical shift assignments of neuronal calcium sensor-1 homolog from fission yeast. BIOMOLECULAR NMR ASSIGNMENTS 2009; 3:269-271. [PMID: 19851889 PMCID: PMC2772964 DOI: 10.1007/s12104-009-9191-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 10/08/2009] [Indexed: 05/28/2023]
Abstract
The neuronal calcium sensor (NCS) proteins regulate signal transduction processes and are highly conserved from yeast to humans. We report complete NMR chemical shift assignments of the NCS homolog from fission yeast (Schizosaccharomyces pombe), referred to in this study as Ncs1p. (BMRB no. 16446).
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Affiliation(s)
- Sunghyuk Lim
- Department of Chemistry, University of California, Davis, CA 95616 USA
| | - James B. Ames
- Department of Chemistry, University of California, Davis, CA 95616 USA
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42
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Liao YS, Chen KC, Chang LS. Functional role of EF-hands 3 and 4 in membrane-binding of KChIP1. J Biosci 2009; 34:203-11. [PMID: 19550036 DOI: 10.1007/s12038-009-0024-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The aim of the present study is to explore whether membrane targeting of K+ channel-interacting protein 1 (KChIP1) is associated with its EF-hand motifs and varies with specific phospholipids. Truncated KChIP1, in which the EFhands 3 and 4 were deleted, retained the alpha-helix structure, indicating that the N-terminal half of KChIP1 could fold appropriately. Compared with wild-type KChIP1, truncated KChIP1 exhibited lower lipid-binding capability. Compared with wild-type KChIP1, increasing membrane permeability by the use of digitonin caused a marked loss of truncated KChIP1, suggesting that intact EF-hands 3 and 4 were crucial for the anchorage of KChIP1 on membrane. KChIP1 showed a higher binding capability with phosphatidylserine (PS) than truncated KChIP1. Unlike that of truncated KChIP1, the binding of wild-type KChIP1 with membrane was enhanced by increasing the PS content. Moreover, the binding of KChIP1 with phospholipid vesicles induced a change in the structure of KChIP1 in the presence of PS. Taken together, our data suggest that EF-hands 3 and 4 of KChIP1 are functionally involved in a specific association with PS on the membrane.
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Affiliation(s)
- Yan-Shun Liao
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
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43
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Kim J, Morozumi T, Nakamura H. Fluorescence Chemosensor with Specific Response for Mg2+. CHEM LETT 2009. [DOI: 10.1246/cl.2009.994] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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44
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Li J, Jia Z, Zhou W, Wei Q. Calcineurin regulatory subunit B is a unique calcium sensor that regulates calcineurin in both calcium-dependent and calcium-independent manner. Proteins 2009; 77:612-23. [DOI: 10.1002/prot.22474] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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45
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Boyman L, Mikhasenko H, Hiller R, Khananshvili D. Kinetic and Equilibrium Properties of Regulatory Calcium Sensors of NCX1 Protein. J Biol Chem 2009; 284:6185-93. [DOI: 10.1074/jbc.m809012200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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46
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Lim S, Peshenko I, Dizhoor A, Ames JB. Effects of Ca2+, Mg2+, and myristoylation on guanylyl cyclase activating protein 1 structure and stability. Biochemistry 2009; 48:850-62. [PMID: 19143494 PMCID: PMC2637916 DOI: 10.1021/bi801897p] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Guanylyl cyclase activating protein 1 (GCAP1), a member of the neuronal calcium sensor (NCS) subclass of the calmodulin superfamily, confers Ca(2+)-dependent activation of retinal guanylyl cylcase (RetGC) during phototransduction in vision. Here we analyze the energetics of Ca(2+) and Mg(2+) binding to the individual EF-hands, characterize metal-induced conformational changes, and evaluate structural effects of myristoylation as studied by isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). GCAP1 binds cooperatively to Ca(2+) at EF3 and EF4 (DeltaH(EF3) = -3.5 kcal/mol, and DeltaH(EF4) = -0.9 kcal/mol) with nanomolar affinity (K(EF3) = 80 nM, and K(EF4) = 200 nM), and a third Ca(2+) binds entropically at EF2 (DeltaH(EF2) = 3.1 kcal/mol, and K(EF2) = 0.9 microM). GCAP1 binds functionally to Mg(2+) at EF2 (DeltaH(EF2) = 4.3 kcal/mol, and K(EF2) = 0.7 mM) required for RetGC activation. Ca(2+) and/or Mg(2+) binding to GCAP1 dramatically alters DSC and NMR spectra, indicating metal-induced protein conformational changes in EF2, EF3, and EF4. Myristoylation of GCAP1 does not significantly alter its metal binding energetics or NMR spectra, suggesting that myristoylation does not influence the structure of the metal-binding EF-hands. Myristoylation also has almost no effect on protein folding stability measured by DSC. NMR resonances of myristate attached to GCAP1 are exchange-broadened, upfield-shifted, and insensitive to Ca(2+), consistent with the myristoyl group being sequestered inside the protein as seen in the crystal structure. We conclude that the protein environment near the myristate is not influenced by Mg(2+) or Ca(2+) binding but instead is constitutively dynamic and may play a role in promoting interactions of GCAP1 with the cyclase.
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Affiliation(s)
- Sunghyuk Lim
- Department of Chemistry, University of California, Davis, CA 95616
| | - Igor Peshenko
- Basic Sciences, Pennsylvania College of Optometry, Salus University, Elkins Park, PA 19027
| | - Alexander Dizhoor
- Basic Sciences, Pennsylvania College of Optometry, Salus University, Elkins Park, PA 19027
| | - James B. Ames
- Department of Chemistry, University of California, Davis, CA 95616
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47
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Optimized expression and purification of myristoylated human neuronal calcium sensor 1 in E. coli. Protein Expr Purif 2008; 61:103-12. [PMID: 18634883 DOI: 10.1016/j.pep.2008.06.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 06/05/2008] [Accepted: 06/10/2008] [Indexed: 11/22/2022]
Abstract
We have developed a protocol to produce large quantities of high purity myristoylated and non-myristoylated neuronal calcium sensor 1 (NCS-1) protein. NCS-1 is a member of the neuronal calcium sensor (NCS) family and plays an important role in modulating G-protein signaling and exocytosis pathways in cells. Many of these functions are calcium-dependent and require NCS-1 to be modified with an N-terminal myristoyl moiety. In our system, a C-terminally 6x His-tagged variant of NCS-1 was co-expressed with yeast N-myristoyltransferase (NMT) in ZYP-5052 auto-induction media supplemented with sodium myristate (100-200 microM). With optimized growth conditions and a high capacity metal affinity purification scheme, >50mg of homogenous myristoylated NCS-1 is obtained from 1L of culture in a single step. The properties of the C-terminally tagged NCS-1 variants are indistinguishable from those reported for untagged NCS-1. Using this system, we have also isolated and characterized mutant NCS-1 proteins that have attenuated (NCS-1 E120Q) and abrogated (NCS-1 DeltaEF) ability to bind calcium. The large quantities of NCS-1 proteins isolated from small culture volumes of auto-inducible media will provide the necessary reagents for further biochemical and structural characterization. The affinity tag at the C-terminus of the protein provides a suitable reagent for easily identifying binding partners of the various NCS-1 constructs. Additionally, this method could be used to produce other recombinant proteins of the NCS family, and may be extended to express and isolate myristoylated variants of other proteins.
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Schwenk J, Zolles G, Kandias NG, Neubauer I, Kalbacher H, Covarrubias M, Fakler B, Bentrop D. NMR analysis of KChIP4a reveals structural basis for control of surface expression of Kv4 channel complexes. J Biol Chem 2008; 283:18937-46. [PMID: 18458082 DOI: 10.1074/jbc.m800976200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Potassium channel-interacting proteins (KChIPs) are EF-hand calcium-binding proteins of the recoverin/neuronal calcium sensor 1 family that co-assemble with the pore-forming Kv4 alpha-subunits and thus control surface trafficking of the voltage-gated potassium channels mediating the neuronal I(A) and cardiac I(to) currents. Different from the other KChIPs, KChIP4a largely reduces surface expression of the Kv4 channel complexes. Using solution NMR we show that the unique N terminus of KChIP4a forms a 6-turn alpha-helix that is connected to the highly conserved core of the KChIP protein via a solvent-exposed linker. As identified by chemical shift changes, N-terminal alpha-helix and core domain of KChIP4a interact with each other through the same hydrophobic surface pocket that is involved in intermolecular interaction between the N-terminal helix of Kv4alpha and KChIP in Kv4-KChIP complexes. Electrophysiological recordings and biochemical interaction assays of complexes formed by wild-type and mutant Kv4alpha and KChIP4a proteins suggest that competition of these two helical domains for the surface groove is responsible for the reduced trafficking of Kv4-KChIP4a complexes to the plasma membrane. Surface expression of Kv4 complexes may thus be controlled by an auto-inhibitory domain in the KChIP subunit.
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Affiliation(s)
- Jochen Schwenk
- Institute of Physiology II, University of Freiburg, D-79104 Freiburg, Germany
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Stephen R, Filipek S, Palczewski K, Sousa MC. Ca2+ -dependent regulation of phototransduction. Photochem Photobiol 2008; 84:903-10. [PMID: 18346093 DOI: 10.1111/j.1751-1097.2008.00323.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Photon absorption by rhodopsin triggers the phototransduction signaling pathway that culminates in degradation of cGMP, closure of cGMP-gated ion channels and hyperpolarization of the photoreceptor membrane. This process is accompanied by a decrease in free Ca(2+) concentration in the photoreceptor cytosol sensed by Ca(2+)-binding proteins that modulate phototransduction and activate the recovery phase to reestablish the photoreceptor dark potential. Guanylate cyclase-activating proteins (GCAPs) belong to the neuronal calcium sensor (NCS) family and are responsible for activating retinal guanylate cyclases (retGCs) at low Ca(2+) concentrations triggering synthesis of cGMP and recovery of the dark potential. Here we review recent structural insight into the role of the N-terminal myristoylation in GCAPs and compare it to other NCS family members. We discuss previous studies identifying regions of GCAPs important for retGC1 regulation in the context of the new structural data available for myristoylated GCAP1. In addition, we present a hypothetical model for the Ca(2+)-triggered conformational change in GCAPs and retGC1 regulation. Finally, we briefly discuss the involvement of mutant GCAP1 proteins in the etiology of retinal degeneration as well as the importance of other Ca(2+) sensors in the modulation of phototransduction.
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Affiliation(s)
- Ricardo Stephen
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO, USA
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Stephen R, Bereta G, Golczak M, Palczewski K, Sousa MC. Stabilizing function for myristoyl group revealed by the crystal structure of a neuronal calcium sensor, guanylate cyclase-activating protein 1. Structure 2008; 15:1392-402. [PMID: 17997965 DOI: 10.1016/j.str.2007.09.013] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 08/27/2007] [Accepted: 09/07/2007] [Indexed: 11/26/2022]
Abstract
Guanylate cyclase-activating proteins (GCAPs) are Ca(2+)-binding proteins myristoylated at the N terminus that regulate guanylate cyclases in photoreceptor cells and belong to the family of neuronal calcium sensors (NCS). Many NCS proteins display a recoverin-like "calcium-myristoyl switch" whereby the myristoyl group, buried inside the protein in the Ca(2+)-free state, becomes fully exposed upon Ca(2+) binding. Here we present a 2.0 A resolution crystal structure of myristoylated GCAP1 with Ca(2+) bound. The acyl group is buried inside Ca(2+)-bound GCAP1. This is in sharp contrast to Ca(2+)-bound recoverin, where the myristoyl group is solvent exposed. Furthermore, we provide direct evidence that the acyl group in GCAP1 remains buried in the Ca(2+)-free state and does not undergo switching. A pronounced kink in the C-terminal helix and the presence of the myristoyl group allow clustering of sequence elements crucial for GCAP1 activity.
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Affiliation(s)
- Ricardo Stephen
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309, USA
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