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Lock C, Bentlage B, Raymundo LJ. Calcium homeostasis disruption initiates rapid growth after micro-fragmentation in the scleractinian coral Porites lobata. Ecol Evol 2022; 12:e9345. [PMID: 36188520 PMCID: PMC9502066 DOI: 10.1002/ece3.9345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
Coral reefs are ecosystems under increasing threat from global climate change. Coral restoration is a tool for preserving the biological and ecological function of coral reefs by mitigating coral loss and maintaining the structural integrity and complexity of reefs. To generate the necessary stock for coral restoration, larger coral colonies are usually fragmented to generate smaller specimens for outplanting, taking advantage of the high regenerative ability of corals. In this study, we utilized RNA-seq technology to understand the physiological responses of Porites lobata colonies to physical fragmentation and outplanting, which have thus far not been characterized. Our results demonstrate that P. lobata fragments undergoing physical injury recover through two distinct phases: rapid wound regeneration of the cut margins, followed by a slower growth phase that cements the colony to the substrate. Our study found rapid physiological responses to acute physical injury and outplanting in the coral host that involved significantly increased energy production, calcium homeostasis disruption, and endoplasmic reticulum (ER) stress leading to increased antioxidant expression and rates of protein turnover. Our results suggest that phosphoinositide-mediated acute calcium homeostasis disruption stimulates wound recovery processes in response to physical injury. Symbiont gene expression revealed extremely low gene differences in response to fragmentation, growth, and outplanting. These results provide insight into the physiological mechanisms that allow for rapid wound healing and stabilization in response to physical injury in corals.
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Affiliation(s)
- Colin Lock
- Marine LaboratoryUniversity of GuamMangilaoGuamUSA
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2
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Hernández-Elizárraga VH, Olguín-López N, Hernández-Matehuala R, Ocharán-Mercado A, Cruz-Hernández A, Guevara-González RG, Caballero-Pérez J, Ibarra-Alvarado C, Sánchez-Rodríguez J, Rojas-Molina A. Comparative Analysis of the Soluble Proteome and the Cytolytic Activity of Unbleached and Bleached Millepora complanata ("Fire Coral") from the Mexican Caribbean. Mar Drugs 2019; 17:md17070393. [PMID: 31277227 PMCID: PMC6669453 DOI: 10.3390/md17070393] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 01/24/2023] Open
Abstract
Coral bleaching caused by global warming has resulted in massive damage to coral reefs worldwide. Studies addressing the consequences of elevated temperature have focused on organisms of the class Anthozoa, and up to now, there is little information regarding the mechanisms by which reef forming Hydrozoans face thermal stress. In this study, we carried out a comparative analysis of the soluble proteome and the cytolytic activity of unbleached and bleached Millepora complanata ("fire coral") that inhabited reef colonies exposed to the 2015-2016 El Niño-Southern Oscillation in the Mexican Caribbean. A differential proteomic response involving proteins implicated in key cellular processes, such as glycolysis, DNA repair, stress response, calcium homeostasis, exocytosis, and cytoskeleton organization was found in bleached hydrocorals. Four of the proteins, whose levels increased in bleached specimens, displayed sequence similarity to a phospholipase A2, an astacin-like metalloprotease, and two pore forming toxins. However, a protein, which displayed sequence similarity to a calcium-independent phospholipase A2, showed lower levels in bleached cnidarians. Accordingly, the hemolytic effect of the soluble proteome of bleached hydrocorals was significantly higher, whereas the phospholipase A2 activity was significantly reduced. Our results suggest that bleached M. complanata is capable of increasing its toxins production in order to balance the lack of nutrients supplied by its symbionts.
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Affiliation(s)
- Víctor Hugo Hernández-Elizárraga
- Posgrado en Ciencias Químico Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, C.P. 76010 Querétaro, Querétaro, México
| | - Norma Olguín-López
- Posgrado en Ciencias Químico Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, C.P. 76010 Querétaro, Querétaro, México
| | - Rosalina Hernández-Matehuala
- Posgrado en Ciencias Químico Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, C.P. 76010 Querétaro, Querétaro, México
| | - Andrea Ocharán-Mercado
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, C.P. 76010 Querétaro, Querétaro, México
| | - Andrés Cruz-Hernández
- Laboratorio de Biología Molecular. Escuela de Agronomía, Universidad de La Salle Bajío, Av. Universidad 15 602, Colonia Lomas del Campestre, C.P. 37150 León, Guanajuato, México
| | - Ramón Gerardo Guevara-González
- C.A Ingeniería de Biosistemas, Facultad de Ingeniería-Campus Amazcala, Universidad Autónoma de Querétaro, Carr. Chichimequillas-Amazcala Km. 1, S/N, C.P. 76265 Amazcala, El Marqués, Querétaro, México
| | - Juan Caballero-Pérez
- Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, C.P. 76010 Querétaro, Querétaro, México
| | - César Ibarra-Alvarado
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, C.P. 76010 Querétaro, Querétaro, México
| | - Judith Sánchez-Rodríguez
- Unidad Académica de Sistemas Arrecifales Puerto Morelos, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Prolongación Niños Héroes S/N, Puerto Morelos, C.P. 77580 Quintana Roo, México
| | - Alejandra Rojas-Molina
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, C.P. 76010 Querétaro, Querétaro, México.
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Olguín-López N, Hérnandez-Elizárraga VH, Hernández-Matehuala R, Cruz-Hernández A, Guevara-González R, Caballero-Pérez J, Ibarra-Alvarado C, Rojas-Molina A. Impact of El Niño-Southern Oscillation 2015-2016 on the soluble proteomic profile and cytolytic activity of Millepora alcicornis ("fire coral") from the Mexican Caribbean. PeerJ 2019; 7:e6593. [PMID: 30918755 PMCID: PMC6428038 DOI: 10.7717/peerj.6593] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/09/2019] [Indexed: 12/24/2022] Open
Abstract
Reef-forming cnidarians are extremely susceptible to the “bleaching” phenomenon caused by global warming. The effect of elevated seawater temperature has been extensively studied on Anthozoans; however, to date the impact of thermal stress on the expression of genes and proteins in Hydrozoan species has not been investigated. The present study aimed to determine the differential proteomic profile of Millepora alcicornis, which inhabits the Mexican Caribbean, in response to the El Niño-Southern Oscillation 2015–2016. Additionally, the cytolytic activity of the soluble proteomes obtained from normal and bleached M. alcicornis was assessed. Bleached specimens showed decreased symbiont’s density and chlorophyll a and c2 levels. After bleaching, we observed a differential expression of 17 key proteins, tentatively identified as related to exocytosis, calcium homeostasis, cytoskeletal organization, and potential toxins, including a metalloprotease, a phospholipase A2 (PLA2), and an actitoxin. Although, some of the differentially expressed proteins included potential toxins, the hemolytic, PLA2, and proteolytic activities elicited by the soluble proteomes from bleached and normal specimens were not significantly different. The present study provides heretofore-unknown evidence that thermal stress produces a differential expression of proteins involved in essential cellular processes of Hydrozoan species. Even though our results showed an over-expression of some potential toxin-related proteins, the cytolytic effect (as assessed by hemolytic, PLA2, and caseinolytic activities) was not increased in bleached M. alcicornis, which suggests that the cytolysis is mainly produced by toxins whose expression was not affected by temperature stress. These findings allow hypothesizing that this hydrocoral is able to prey heterotrophically when suffering from moderate bleaching, giving it a better chance to withstand the effects of high temperature.
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Affiliation(s)
- Norma Olguín-López
- Posgrado en Ciencias Químico Biológicas-Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, Mexico.,Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, Mexico
| | - Víctor Hugo Hérnandez-Elizárraga
- Posgrado en Ciencias Químico Biológicas-Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, Mexico.,Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, Mexico
| | - Rosalina Hernández-Matehuala
- Posgrado en Ciencias Químico Biológicas-Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, Mexico.,Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, Mexico
| | - Andrés Cruz-Hernández
- Laboratorio de Biología Molecular-Escuela de Agronomía, Universidad De la Salle Bajío, León, Guanajuato, México
| | - Ramón Guevara-González
- C.A Ingeniería de Biosistemas-Facultad de Ingeniería-Campus Amazcala, Universidad Autónoma de Querétaro, Querétaro, Querétaro, Mexico
| | - Juan Caballero-Pérez
- Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, Mexico
| | - César Ibarra-Alvarado
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, Mexico
| | - Alejandra Rojas-Molina
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, Querétaro, Mexico
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4
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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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Gong Y, Zhu Y, Zou Y, Ma B, Nussinov R, Zhang Q. Human Neuronal Calcium Sensor-1 Protein Avoids Histidine Residues To Decrease pH Sensitivity. J Phys Chem B 2017; 121:508-517. [PMID: 28030949 PMCID: PMC6413881 DOI: 10.1021/acs.jpcb.6b11094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
pH is highly regulated in mammalian central nervous systems. Neuronal calcium sensor-1 (NCS-1) can interact with numerous target proteins. Compared to that in the NCS-1 protein of Caenorhabditis elegans, evolution has avoided the placement of histidine residues at positions 102 and 83 in the NCS-1 protein of humans and Xenopus laevis, possibly to decrease the conformational sensitivity to pH gradients in synaptic processes. We used all-atom molecular dynamics simulations to investigate the effects of amino acid substitutions between species on human NCS-1 by substituting Arg102 and Ser83 for histidine at neutral (R102H and S83H) and acidic pHs (R102Hp and S83Hp). Our cumulative 5 μs simulations revealed that the R102H mutation slightly increases the structural flexibility of loop L2 and the R102Hp mutation decreases protein stability. Community network analysis illustrates that the R102H and S83H mutations weaken the interdomain and strengthen the intradomain communications. Secondary structure contents in the S83H and S83Hp mutants are similar to those in the wild type, whereas the global structural stabilities and salt-bridge probabilities decrease. This study highlights the conformational dynamics effects of the R102H and S83H mutations on the local structural flexibility and global stability of NCS-1, whereas protonated histidine decreases the stability of NCS-1. Thus, histidines at positions 102 and 83 may not be compatible with the function of NCS-1 whether in the neutral or protonated state.
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Affiliation(s)
- Yehong Gong
- College of Physical Education and Training, Shanghai University of Sport, 399 Chang Hai Road, Shanghai, 200438, China
| | - Yuzhen Zhu
- Shanghai Normal University Physical Education College, 100 Gui Lin Road, Shanghai, 200234, 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
- Department of Human Genetics and Molecular Medicine, Sackler Inst. of 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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6
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Ricaurte M, Schizas NV, Ciborowski P, Boukli NM. Proteomic analysis of bleached and unbleached Acropora palmata, a threatened coral species of the Caribbean. MARINE POLLUTION BULLETIN 2016; 107:224-232. [PMID: 27105725 PMCID: PMC6540970 DOI: 10.1016/j.marpolbul.2016.03.068] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 03/29/2016] [Accepted: 03/31/2016] [Indexed: 05/02/2023]
Abstract
There has been an increase in the scale and frequency of coral bleaching around the world due mainly to changes in sea temperature. This may occur at large scales, often resulting in significant decline in coral coverage. In order to understand the molecular and cellular basis of the ever-increasing incidence of coral bleaching, we have undertaken a comparative proteomic approach with the endangered Caribbean coral Acropora palmata. Using a proteomic tandem mass spectrometry approach, we identified 285 and 321 expressed protein signatures in bleached and unbleached A. palmata colonies, respectively, in southwestern Puerto Rico. Overall the expression level of 38 key proteins was significantly different between bleached and unbleached corals. A wide range of proteins was detected and categorized, including transcription factors involved mainly in heat stress/UV responses, immunity, apoptosis, biomineralization, the cytoskeleton, and endo-exophagocytosis. The results suggest that for bleached A. palmata, there was an induced differential protein expression response compared with those colonies that did not bleach under the same environmental conditions.
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Affiliation(s)
- Martha Ricaurte
- Department of Marine Sciences, University of Puerto Rico, Mayagüez, Call Box 9000, Mayagüez, 00681, Puerto Rico
| | - Nikolaos V Schizas
- Department of Marine Sciences, University of Puerto Rico, Mayagüez, Call Box 9000, Mayagüez, 00681, Puerto Rico
| | - Pawel Ciborowski
- Mass Spectrometry and Proteomics Core Facility, Durham Research Center, Room 3048, 985800, University of Nebraska Medical Center (UNMC), Omaha, NE 68198-5800, USA
| | - Nawal M Boukli
- Biomedical Proteomics Facility, Microbiology and Immunology Department, Universidad Central del Caribe, Bayamón, 00960, Puerto Rico.
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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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Reyes-Bermudez A, Villar-Briones A, Ramirez-Portilla C, Hidaka M, Mikheyev AS. Developmental Progression in the Coral Acropora digitifera Is Controlled by Differential Expression of Distinct Regulatory Gene Networks. Genome Biol Evol 2016; 8:851-70. [PMID: 26941230 PMCID: PMC4824149 DOI: 10.1093/gbe/evw042] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2016] [Indexed: 12/20/2022] Open
Abstract
Corals belong to the most basal class of the Phylum Cnidaria, which is considered the sister group of bilaterian animals, and thus have become an emerging model to study the evolution of developmental mechanisms. Although cell renewal, differentiation, and maintenance of pluripotency are cellular events shared by multicellular animals, the cellular basis of these fundamental biological processes are still poorly understood. To understand how changes in gene expression regulate morphogenetic transitions at the base of the eumetazoa, we performed quantitative RNA-seq analysis duringAcropora digitifera's development. We collected embryonic, larval, and adult samples to characterize stage-specific transcription profiles, as well as broad expression patterns. Transcription profiles reconstructed development revealing two main expression clusters. The first cluster grouped blastula and gastrula and the second grouped subsequent developmental time points. Consistently, we observed clear differences in gene expression between early and late developmental transitions, with higher numbers of differentially expressed genes and fold changes around gastrulation. Furthermore, we identified three coexpression clusters that represented discrete gene expression patterns. During early transitions, transcriptional networks seemed to regulate cellular fate and morphogenesis of the larval body. In late transitions, these networks seemed to play important roles preparing planulae for switch in lifestyle and regulation of adult processes. Although developmental progression inA. digitiferais regulated to some extent by differential coexpression of well-defined gene networks, stage-specific transcription profiles appear to be independent entities. While negative regulation of transcription is predominant in early development, cell differentiation was upregulated in larval and adult stages.
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Affiliation(s)
- Alejandro Reyes-Bermudez
- Okinawa Institute of Science and Technology, Okinawa, Japan School of Natural Sciences, Ryukyus University, Okinawa, Japan
| | | | | | - Michio Hidaka
- School of Natural Sciences, Ryukyus University, Okinawa, Japan
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Direct single-molecule observation of calcium-dependent misfolding in human neuronal calcium sensor-1. Proc Natl Acad Sci U S A 2014; 111:13069-74. [PMID: 25157171 DOI: 10.1073/pnas.1401065111] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Neurodegenerative disorders are strongly linked to protein misfolding, and crucial to their explication is a detailed understanding of the underlying structural rearrangements and pathways that govern the formation of misfolded states. Here we use single-molecule optical tweezers to monitor misfolding reactions of the human neuronal calcium sensor-1, a multispecific EF-hand protein involved in neurotransmitter release and linked to severe neurological diseases. We directly observed two misfolding trajectories leading to distinct kinetically trapped misfolded conformations. Both trajectories originate from an on-pathway intermediate state and compete with native folding in a calcium-dependent manner. The relative probability of the different trajectories could be affected by modulating the relaxation rate of applied force, demonstrating an unprecedented real-time control over the free-energy landscape of a protein. Constant-force experiments in combination with hidden Markov analysis revealed the free-energy landscape of the misfolding transitions under both physiological and pathological calcium concentrations. Remarkably for a calcium sensor, we found that higher calcium concentrations increased the lifetimes of the misfolded conformations, slowing productive folding to the native state. We propose a rugged, multidimensional energy landscape for neuronal calcium sensor-1 and speculate on a direct link between protein misfolding and calcium dysregulation that could play a role in neurodegeneration.
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Heidarsson P, Otazo M, Bellucci L, Mossa A, Imparato A, Paci E, Corni S, Di Felice R, Kragelund B, Cecconi C. Single-Molecule Folding Mechanism of an EF-Hand Neuronal Calcium Sensor. Structure 2013; 21:1812-21. [DOI: 10.1016/j.str.2013.07.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 07/13/2013] [Accepted: 07/28/2013] [Indexed: 11/28/2022]
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