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Su J, Xiao Y, Wei L, Lei H, Sun F, Wang W, Yin J, Xiong R, Li S, Zhang P, Zhou Y, Wang X, Zheng J, Wang JZ. Generation of tau dephosphorylation-targeting chimeras for the treatment of Alzheimer's disease and related tauopathies. Sci Bull (Beijing) 2024; 69:1137-1152. [PMID: 38341350 DOI: 10.1016/j.scib.2024.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/06/2023] [Accepted: 01/08/2024] [Indexed: 02/12/2024]
Abstract
Abnormal hyperphosphorylation and accumulation of tau protein play a pivotal role in neurodegeneration in Alzheimer's disease (AD) and many other tauopathies. Selective elimination of hyperphosphorylated tau is promising for the therapy of these diseases. We have conceptualized a strategy, named dephosphorylation-targeting chimeras (DEPTACs), for specifically hijacking phosphatases to tau to debilitate its hyperphosphorylation. Here, we conducted the step-by-step optimization of each constituent motif to generate DEPTACs with reasonable effectiveness in facilitating the dephosphorylation and subsequent clearance of pathological tau. Specifically, for one of the selected chimeras, D16, we demonstrated its significant efficiency in rescuing the neurodegeneration caused by neurotoxic K18-tau seeds in vitro. Moreover, intravenous administration of D16 also alleviated tau pathologies in the brain and improved memory deficits in AD mice. These results suggested DEPTACs as targeted modulators of tau phosphorylation, which hold therapeutic potential for AD and other tauopathies.
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Affiliation(s)
- Jingfen Su
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yue Xiao
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; School of Artificial Intelligence and Automation, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Linyu Wei
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang 453003, China
| | - Huiyang Lei
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Fei Sun
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Weixia Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jun Yin
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430030, China
| | - Rui Xiong
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shihong Li
- Department of Anesthesiology, The First Affiliated Hospital of Gannan Medical University, Ganzhou 341000, China
| | - Pei Zhang
- The Core Facility and Technical Support, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430030, China
| | - Ying Zhou
- Research Center for Medicine and Structural Biology, Wuhan University, Wuhan 430030, China
| | - Xiaochuan Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; School of Artificial Intelligence and Automation, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Jie Zheng
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Beijing 100083, China.
| | - Jian-Zhi Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226000, China.
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Peters CH, Singh RK, Langley AA, Nichols WG, Ferris HR, Jeffrey DA, Proenza C, Bankston JR. LRMP inhibits cAMP potentiation of HCN4 channels by disrupting intramolecular signal transduction. eLife 2024; 12:RP92411. [PMID: 38652113 PMCID: PMC11037915 DOI: 10.7554/elife.92411] [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] [Indexed: 04/25/2024] Open
Abstract
Lymphoid restricted membrane protein (LRMP) is a specific regulator of the hyperpolarization-activated cyclic nucleotide-sensitive isoform 4 (HCN4) channel. LRMP prevents cAMP-dependent potentiation of HCN4, but the interaction domains, mechanisms of action, and basis for isoform-specificity remain unknown. Here, we identify the domains of LRMP essential for this regulation, show that LRMP acts by disrupting the intramolecular signal transduction between cyclic nucleotide binding and gating, and demonstrate that multiple unique regions in HCN4 are required for LRMP isoform-specificity. Using patch clamp electrophysiology and Förster resonance energy transfer (FRET), we identified the initial 227 residues of LRMP and the N-terminus of HCN4 as necessary for LRMP to associate with HCN4. We found that the HCN4 N-terminus and HCN4-specific residues in the C-linker are necessary for regulation of HCN4 by LRMP. Finally, we demonstrated that LRMP-regulation can be conferred to HCN2 by addition of the HCN4 N-terminus along with mutation of five residues in the S5 region and C-linker to the cognate HCN4 residues. Taken together, these results suggest that LRMP inhibits HCN4 through an isoform-specific interaction involving the N-terminals of both proteins that prevents the transduction of cAMP binding into a change in channel gating, most likely via an HCN4-specific orientation of the N-terminus, C-linker, and S4-S5 linker.
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Affiliation(s)
- Colin H Peters
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Rohit K Singh
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical CampusAuroraUnited States
- Skaggs School of Pharmacy, Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Avery A Langley
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - William G Nichols
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Hannah R Ferris
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Danielle A Jeffrey
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Catherine Proenza
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical CampusAuroraUnited States
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - John R Bankston
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical CampusAuroraUnited States
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3
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Rode S, Kaur H, Sharma M, Shah V, Singh SS, Gubyad M, Ghosh DK, Sircar D, Kumar P, Roy P, Sharma AK. Characterization of Type1 Lipid Transfer Protein from Citrus sinensis: Unraveling its potential as an antimicrobial and insecticidal agent. Int J Biol Macromol 2024; 265:130811. [PMID: 38490399 DOI: 10.1016/j.ijbiomac.2024.130811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 12/27/2023] [Accepted: 03/10/2024] [Indexed: 03/17/2024]
Abstract
Lipid Transfer Protein1 (LTP1) is a cationic, multifaceted protein belonging to the pathogenesis-related protein (PR14) family. Despite being involved in diverse physiological processes and defense mechanisms, the precise in-vivo role of LTP1 remains undiscovered. This work presents the characterization of recombinant Citrus sinensis LTP1 (CsLTP1) along with lipid binding studies through in-silico and in-vitro approaches. CsLTP1 demonstrated great thermal and pH stability with a huge biotechnological potential. It showed in-vitro binding capacity with jasmonic acid and lipids involved in regulating plant immune responses. Gene expression profiling indicated a significant upregulation of CsLTP1 in Candidatus-infected Citrus plants. CsLTP1 disrupted the cell membrane integrity of various pathogens, making it a potent antimicrobial agent. Further, in-vivo antimicrobial and insecticidal properties of CsLTP1 have been explored. The impact of exogenous CsLTP1 treatment on rice crop metabolism for managing blight disease has been studied using GC-MS. CsLTP1 triggered crucial metabolic pathways in rice plants while controlling the blight disease. CsLTP1 effectively inhibited Helicoverpa armigera larvae by impeding mid-gut α-amylase activity and obstructing its developmental stages. This study highlights the pivotal role of CsLTP1 in plant defense by offering insights for developing multi-target therapeutic agent or disease-resistant varieties to comprehensively tackle the challenges towards crop protection.
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Affiliation(s)
- Surabhi Rode
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Harry Kaur
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Monica Sharma
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Vivek Shah
- Division of Crop Protection, ICAR Central Institute for Cotton Research, Nagpur, India
| | - Shiv Shakti Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Mrugendra Gubyad
- Plant Virology Laboratory, Central Citrus Research Institute, Nagpur, India
| | - Dilip Kumar Ghosh
- Plant Virology Laboratory, Central Citrus Research Institute, Nagpur, India
| | - Debabrata Sircar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Pravindra Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Partha Roy
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Ashwani Kumar Sharma
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India.
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4
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Peters CH, Singh RK, Langley AA, Nichols WG, Ferris HR, Jeffrey DA, Proenza C, Bankston JR. LRMP inhibits cAMP potentiation of HCN4 channels by disrupting intramolecular signal transduction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.29.555242. [PMID: 37693562 PMCID: PMC10491135 DOI: 10.1101/2023.08.29.555242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Lymphoid restricted membrane protein (LRMP) is a specific regulator of the hyperpolarization-activated cyclic nucleotide-sensitive isoform 4 (HCN4) channel. LRMP prevents cAMP-dependent potentiation of HCN4 but the interaction domains, mechanisms of action, and basis for isoform-specificity remain unknown. Here we identify the domains of LRMP essential for regulation. We show that LRMP acts by disrupting the intramolecular signal transduction between cyclic nucleotide binding and gating. And we demonstrate that multiple unique regions in HCN4 are required for LRMP isoform-specificity. Using patch clamp electrophysiology and Förster resonance energy transfer (FRET), we showed that the initial 227 residues of LRMP and the N-terminus of HCN4 are necessary for LRMP to interact with HCN4. We found that the HCN4 N-terminus and HCN4-specific residues in the C-linker are necessary for regulation of HCN4 by LRMP. And we demonstrate that LRMP-regulation can be conferred to HCN2 by addition of the HCN4 N-terminus along with mutation of 5 residues in the S5 region and C-linker to the cognate HCN4 residues. Taken together, these results suggest that LRMP inhibits HCN4 through an isoform-specific interaction involving the N-terminals of both proteins that prevents the transduction of cAMP binding into a change in channel gating via an HCN4-specific orientation of the N-terminus, C-linker, and S4-S5 linker.
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Affiliation(s)
- Colin H Peters
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, 12800 E. 19 Avenue, Aurora, CO 80045
| | - Rohit K Singh
- Skaggs School of Pharmacy, Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 E. Montview Boulevard, Aurora, CO 80045
| | - Avery A Langley
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, 12800 E. 19 Avenue, Aurora, CO 80045
| | - William G Nichols
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, 12800 E. 19 Avenue, Aurora, CO 80045
| | - Hannah R Ferris
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, 12800 E. 19 Avenue, Aurora, CO 80045
| | - Danielle A Jeffrey
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, 12800 E. 19 Avenue, Aurora, CO 80045
| | - Catherine Proenza
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, 12800 E. 19 Avenue, Aurora, CO 80045
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, 12631 E. 17 Avenue, Aurora, CO 80045
| | - John R Bankston
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, 12800 E. 19 Avenue, Aurora, CO 80045
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5
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Sendo S, Kiosses WB, Yang S, Wu DJ, Lee DWK, Liu L, Aschner Y, Vela AJ, Downey GP, Santelli E, Bottini N. Clustering of phosphatase RPTPα promotes Src signaling and the arthritogenic action of synovial fibroblasts. Sci Signal 2023; 16:eabn8668. [PMID: 37402225 PMCID: PMC10544828 DOI: 10.1126/scisignal.abn8668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 06/15/2023] [Indexed: 07/06/2023]
Abstract
Receptor-type protein phosphatase α (RPTPα) promotes fibroblast-dependent arthritis and fibrosis, in part, by enhancing the activation of the kinase SRC. Synovial fibroblasts lining joint tissue mediate inflammation and tissue damage, and their infiltration into adjacent tissues promotes disease progression. RPTPα includes an ectodomain and two intracellular catalytic domains (D1 and D2) and, in cancer cells, undergoes inhibitory homodimerization, which is dependent on a D1 wedge motif. Through single-molecule localization and labeled molecule interaction microscopy of migrating synovial fibroblasts, we investigated the role of RPTPα dimerization in the activation of SRC, the migration of synovial fibroblasts, and joint damage in a mouse model of arthritis. RPTPα clustered with other RPTPα and with SRC molecules in the context of actin-rich structures. A known dimerization-impairing mutation in the wedge motif (P210L/P211L) and the deletion of the D2 domain reduced RPTPα-RPTPα clustering; however, it also unexpectedly reduced RPTPα-SRC association. The same mutations also reduced recruitment of RPTPα to actin-rich structures and inhibited SRC activation and cellular migration. An antibody against the RPTPα ectodomain that prevented the clustering of RPTPα also inhibited RPTPα-SRC association and SRC activation and attenuated fibroblast migration and joint damage in arthritic mice. A catalytically inactivating RPTPα-C469S mutation protected mice from arthritis and reduced SRC activation in synovial fibroblasts. We conclude that RPTPα clustering retains it to actin-rich structures to promote SRC-mediated fibroblast migration and can be modulated through the extracellular domain.
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Affiliation(s)
- Sho Sendo
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - William B. Kiosses
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
- La Jolla Institute for Immunology, La Jolla, CA 92037
| | - Shen Yang
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Dennis J. Wu
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Daniel W. K. Lee
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Lin Liu
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Yael Aschner
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
| | - Allison J. Vela
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Gregory P. Downey
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
- Department of Biomedical Research, National Jewish Health, Denver, Colorado
- Department of Immunology and Microbiology, University of Colorado, Aurora, Colorado
- Department of Pediatrics, National Jewish Health, Denver, Colorado
| | - Eugenio Santelli
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Nunzio Bottini
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
- Department of Medicine, Kao Autoimmunity Institute, Cedars Sinai Medical Center, Los Angeles, CA, USA
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6
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Layana C, Vilardo ES, Corujo G, Hernández G, Rivera-Pomar R. Drosophila Me31B is a Dual eIF4E-Interacting Protein. J Mol Biol 2023; 435:167949. [PMID: 36638908 DOI: 10.1016/j.jmb.2023.167949] [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: 11/12/2021] [Revised: 12/14/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023]
Abstract
Eukaryotic translation initiation factor 4E (eIF4E) is a key factor involved in different aspects of mRNA metabolism. Drosophila melanogaster genome encodes eight eIF4E isoforms, and the canonical isoform eIF4E-1 is a ubiquitous protein that plays a key role in mRNA translation. eIF4E-3 is specifically expressed in testis and controls translation during spermatogenesis. In eukaryotic cells, translational control and mRNA decay is highly regulated in different cytoplasmic ribonucleoprotein foci, which include the processing bodies (PBs). In this study, we show that Drosophila eIF4E-1 and eIF4E-3 occur in PBs along the DEAD-box RNA helicase Me31B. We show that Me31B interacts with eIF4E-1 and eIF4E-3 by means of yeast two-hybrid system, FRET in D. melanogaster S2 cells and coimmunoprecipitation in testis. Truncation and point mutations of Me31B proteins show two eIF4E-binding sites located in different protein domains. Residues Y401-L407 (at the carboxy-terminus) are essential for interaction with eIF4E-1, whereas residues F63-L70 (at the amino-terminus) are critical for interaction with eIF4E-3. The residue W117 in eIF4E-1 and the homolog position F103 in eIF4E-3 are necessary for Me31B-eIF4E interaction suggesting that the change of tryptophan to phenylalanine provides specificity. Me31B represents a novel type of eIF4E-interacting protein with dual and specific interaction domains that might be recognized by different eIF4E isoforms in different tissues, adding complexity to the control of gene expression in eukaryotes.
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Affiliation(s)
- Carla Layana
- Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Boulevard 120 N° 1459, 1900 La Plata, Argentina.
| | - Emiliano Salvador Vilardo
- Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Boulevard 120 N° 1459, 1900 La Plata, Argentina
| | - Gonzalo Corujo
- Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Boulevard 120 N° 1459, 1900 La Plata, Argentina
| | - Greco Hernández
- Translation and Cancer Laboratory, Unit of Biomedical Research on Cancer, National Institute of Cancer (Instituto Nacional de Cancerología, INCan), 22 San Fernando Ave., Tlalpan, 14080 Mexico City, Mexico
| | - Rolando Rivera-Pomar
- Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Boulevard 120 N° 1459, 1900 La Plata, Argentina; Centro de Investigación y Transferencia del Noroeste de Buenos Aires (CITNOBA) - Centro de Bioinvestigaciones, Universidad Nacional del Noroeste de Buenos Aires, Av. Presidente Frondizi Km 4, 2700 Pergamino, Argentina; Molecular Developmental Biology Emeritus Group, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
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7
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Strotmann VI, Stahl Y. Visualization of in vivo protein-protein interactions in plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3866-3880. [PMID: 35394544 PMCID: PMC9232200 DOI: 10.1093/jxb/erac139] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 04/01/2022] [Indexed: 06/14/2023]
Abstract
Molecular processes depend on the concerted and dynamic interactions of proteins, either by one-on-one interactions of the same or different proteins or by the assembly of larger protein complexes consisting of many different proteins. Here, not only the protein-protein interaction (PPI) itself, but also the localization and activity of the protein of interest (POI) within the cell is essential. Therefore, in all cell biological experiments, preserving the spatio-temporal state of one POI relative to another is key to understanding the underlying complex and dynamic regulatory mechanisms in vivo. In this review, we examine some of the applicable techniques to measure PPIs in planta as well as recent combinatorial advances of PPI methods to measure the formation of higher order complexes with an emphasis on in vivo imaging techniques. We compare the different methods and discuss their benefits and potential pitfalls to facilitate the selection of appropriate techniques by providing a comprehensive overview of how to measure in vivo PPIs in plants.
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Affiliation(s)
- Vivien I Strotmann
- Institute for Developmental Genetics, Heinrich-Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Yvonne Stahl
- Institute for Developmental Genetics, Heinrich-Heine University, Universitätsstr. 1, D-40225 Düsseldorf, Germany
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8
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Bourgeois B, Gui T, Hoogeboom D, Hocking HG, Richter G, Spreitzer E, Viertler M, Richter K, Madl T, Burgering BMT. Multiple regulatory intrinsically disordered motifs control FOXO4 transcription factor binding and function. Cell Rep 2021; 36:109446. [PMID: 34320339 DOI: 10.1016/j.celrep.2021.109446] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 04/15/2021] [Accepted: 07/02/2021] [Indexed: 12/11/2022] Open
Abstract
Transcription factors harbor defined regulatory intrinsically disordered regions (IDRs), which raises the question of how they mediate binding to structured co-regulators and modulate their activity. Here, we present a detailed molecular regulatory mechanism of Forkhead box O4 (FOXO4) by the structured transcriptional co-regulator β-catenin. We find that the disordered FOXO4 C-terminal region, which contains its transactivation domain, binds β-catenin through two defined interaction sites, and this is regulated by combined PKB/AKT- and CK1-mediated phosphorylation. Binding of β-catenin competes with the autoinhibitory interaction of the FOXO4 disordered region with its DNA-binding Forkhead domain, and thereby enhances FOXO4 transcriptional activity. Furthermore, we show that binding of the β-catenin inhibitor protein ICAT is compatible with FOXO4 binding to β-catenin, suggesting that ICAT acts as a molecular switch between anti-proliferative FOXO and pro-proliferative Wnt/TCF/LEF signaling. These data illustrate how the interplay of IDRs, post-translational modifications, and co-factor binding contribute to transcription factor function.
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Affiliation(s)
- Benjamin Bourgeois
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Tianshu Gui
- Oncode Institute and Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Diana Hoogeboom
- Oncode Institute and Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Henry G Hocking
- Department Chemie, Technische Universität München, 85747 Garching, Germany
| | - Gesa Richter
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Emil Spreitzer
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| | - Martin Viertler
- Department Chemie, Technische Universität München, 85747 Garching, Germany
| | - Klaus Richter
- Department Chemie, Technische Universität München, 85747 Garching, Germany
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria.
| | - Boudewijn M T Burgering
- Oncode Institute and Department of Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands.
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9
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Armacki M, Polaschek S, Waldenmaier M, Morawe M, Ruhland C, Schmid R, Lechel A, Tharehalli U, Steup C, Bektas Y, Li H, Kraus JM, Kestler HA, Kruger S, Ormanns S, Walther P, Eiseler T, Seufferlein T. Protein Kinase D1, Reduced in Human Pancreatic Tumors, Increases Secretion of Small Extracellular Vesicles From Cancer Cells That Promote Metastasis to Lung in Mice. Gastroenterology 2020; 159:1019-1035.e22. [PMID: 32446697 DOI: 10.1053/j.gastro.2020.05.052] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 04/21/2020] [Accepted: 05/13/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS Pancreatic tumor cells release small extracellular vesicles (sEVs, exosomes) that contain lipids and proteins, RNA, and DNA molecules that might promote formation of metastases. It is not clear what cargo these vesicles contain and how they are released. Protein kinase D1 (PRKD1) inhibits cell motility and is believed to be dysregulated in pancreatic ductal adenocarcinomas. We investigated whether it regulates production of sEVs in pancreatic cancer cells and their ability to form premetastatic niches for pancreatic cancer cells in mice. METHODS We analyzed data from UALCAN and human pancreatic tissue microarrays to compare levels of PRKD1 between tumor and nontumor tissues. We studied mice with pancreas-specific disruption of Prkd1 (PRKD1KO mice), mice that express oncogenic KRAS (KC mice), and KC mice with disruption of Prkd1 (PRKD1KO-KC mice). Subcutaneous xenograft tumors were grown in NSG mice from Panc1 cells; some mice were then given injections of sEVs. Pancreata and lung tissues from mice were analyzed by histology, immunohistochemistry, and/or quantitative polymerase chain reaction; we performed nanoparticle tracking analysis of plasma sEVs. The Prkd1 gene was disrupted in Panc1 cells using CRISPR-Cas9 or knocked down with small hairpin RNAs, or PRKD1 activity was inhibited with the selective inhibitor CRT0066101. Pancreatic cancer cell lines were analyzed by gene-expression microarray, quantitative polymerase chain reaction, immunoblot, and immunofluorescence analyses. sEVs secreted by Panc1 cell lines were analyzed by flow cytometry, transmission electron microscopy, and mass spectrometry. RESULTS Levels of PRKD1 were reduced in human pancreatic ductal adenocarcinoma tissues compared with nontumor tissues. PRKD1KO-KC mice developed more pancreatic intraepithelial neoplasia, at a faster rate, than KC mice, and had more lung metastases and significantly shorter average survival time. Serum from PRKD1KO-KC mice had increased levels of sEVs compared with KC mice. Pancreatic cancer cells with loss or inhibition of PRKD1 increased secretion of sEVs; loss of PRKD1 reduced phosphorylation of its substrate, cortactin, resulting in increased F-actin levels at the plasma membrane. sEVs from cells with loss or reduced expression of PRKD1 had altered content, and injection of these sEVs into mice increased metastasis of xenograft tumors to lung, compared with sEVs from pancreatic cells that expressed PRKD1. PRKD1-deficient pancreatic cancer cells showed increased loading of integrin α6β4 into sEVs-a process that required CD82. CONCLUSIONS Human pancreatic ductal adenocarcinoma has reduced levels of PRKD1 compared with nontumor pancreatic tissues. Loss of PRKD1 results in reduced phosphorylation of cortactin in pancreatic cancer cell lines, resulting in increased in F-actin at the plasma membrane and increased release of sEVs, with altered content. These sEVs promote metastasis of xenograft and pancreatic tumors to lung in mice.
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Affiliation(s)
- Milena Armacki
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany
| | - Sandra Polaschek
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany
| | | | - Mareen Morawe
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany
| | - Claudia Ruhland
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany
| | - Rebecca Schmid
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany
| | - André Lechel
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany
| | - Umesh Tharehalli
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany
| | - Christoph Steup
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany
| | - Yasin Bektas
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany
| | - Hongxia Li
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany
| | - Johann M Kraus
- Institute of Medical Systems Biology, Ulm University, Ulm, Germany
| | - Hans A Kestler
- Institute of Medical Systems Biology, Ulm University, Ulm, Germany
| | - Stephan Kruger
- Department of Medicine III, University Hospital, Ludwig Maximilian University of Munich, Munich, Germany
| | - Steffen Ormanns
- Institute of Pathology, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany
| | - Paul Walther
- Central Facility for Electron Microscopy, University of Ulm, Ulm, Germany
| | - Tim Eiseler
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany.
| | - Thomas Seufferlein
- Department of Internal Medicine I, University Hospital Ulm, Ulm, Germany.
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10
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Huang X, Jiang C, Yu L, Yang A. Current and Emerging Approaches for Studying Inter-Organelle Membrane Contact Sites. Front Cell Dev Biol 2020; 8:195. [PMID: 32292782 PMCID: PMC7118198 DOI: 10.3389/fcell.2020.00195] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/09/2020] [Indexed: 12/24/2022] Open
Abstract
Inter-organelle membrane contact sites (MCSs) are classically defined as areas of close proximity between heterologous membranes and established by specific proteins (termed tethers). The interest on MCSs has rapidly increased in the last years, since MCSs play a crucial role in the transfer of cellular components between different organelles and have been involved in important cellular functions such as apoptosis, organelle division and biogenesis, and cell growth. Recently, an unprecedented depth and breadth in insights into the details of MCSs have been uncovered. On one hand, extensive MCSs (organelles interactome) are revealed by comprehensive analysis of organelle network with high temporal-spatial resolution at the system level. On the other hand, more and more tethers involving in MCSs are identified and further works are focusing on addressing the role of these tethers in regulating the function of MCSs at the molecular level. These enormous progresses largely depend on the powerful approaches, including several different types of microscopies and various biochemical techniques. These approaches have greatly accelerated recent advances in MCSs at the system and molecular level. In this review, we summarize the current and emerging approaches for studying MCSs, such as various microscopies, proximity-driven fluorescent signal generation and proximity-dependent biotinylation. In addition, we highlight the advantages and disadvantages of the techniques to provide a general guidance for the study of MCSs.
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Affiliation(s)
- Xue Huang
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Chen Jiang
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Lihua Yu
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Aimin Yang
- School of Life Sciences, Chongqing University, Chongqing, China
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11
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Weeber F, Becher A, Seibold T, Seufferlein T, Eiseler T. Concerted regulation of actin polymerization during constitutive secretion by cortactin and PKD2. J Cell Sci 2019; 132:jcs.232355. [PMID: 31727638 DOI: 10.1242/jcs.232355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 11/07/2019] [Indexed: 12/27/2022] Open
Abstract
Constitutive secretion from the trans-Golgi-network (TGN) is facilitated by a concerted regulation of vesicle biogenesis and fission processes. The protein kinase D family (PKD) has been previously described to enhance vesicle fission by modifying the lipid environment. PKD also phosphorylates the actin regulatory protein cortactin at S298 to impair synergistic actin polymerization. We here report additional functions for PKD2 (also known as PRKD2) and cortactin in the regulation of actin polymerization during the fission of transport carriers from the TGN. Phosphorylation of cortactin at S298 impairs the interaction between WIP (also known as WIPF1) and cortactin. WIP stabilizes the autoinhibited conformation of N-WASP (also known as WASL). This leads to an inhibition of synergistic Arp2/3-complex-dependent actin polymerization at the TGN. PKD2 activity at the TGN is controlled by active CDC42-GTP which directly activates N-WASP, inhibits PKD2 and shifts the balance to non-S298-phosphorylated cortactin, which can in turn sequester WIP from N-WASP. Consequently, synergistic actin polymerization at the TGN and constitutive secretion are enhanced.
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Affiliation(s)
- Florian Weeber
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
| | - Alexander Becher
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
| | - Tanja Seibold
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
| | - Thomas Seufferlein
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
| | - Tim Eiseler
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
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12
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Photobleaching and Sensitized Emission-Based Methods for the Detection of Förster Resonance Energy Transfer. Methods Mol Biol 2019. [PMID: 31432483 DOI: 10.1007/978-1-4939-9686-5_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Förster resonance energy transfer (FRET) is a non-radiative interaction between two molecules that happens at distances in the range of a few nanometers. Using FRET interactions between suitably selected fluorophores allows to study molecular interactions or conformational changes of single molecules on fluorescence microscopes even though the optical resolution of the microscope is limited to distances that are almost two orders of magnitude higher.In this chapter several variants of FRET detection methods are described that are based either on the targeted photobleaching of one of the participating molecule species or on the direct detection of the fluorescence signal that is created as a result of the FRET interactions.
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13
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MicroRNA-15a Regulates the Differentiation of Intramuscular Preadipocytes by Targeting ACAA1, ACOX1 and SCP2 in Chickens. Int J Mol Sci 2019; 20:ijms20164063. [PMID: 31434294 PMCID: PMC6720712 DOI: 10.3390/ijms20164063] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 08/09/2019] [Accepted: 08/19/2019] [Indexed: 12/16/2022] Open
Abstract
Our previous studies showed that microRNA-15a (miR-15a) was closely related to intramuscular fat (IMF) deposition in chickens; however, its regulatory mechanism remains unclear. Here, we evaluated the expression characteristics of miR-15a and its relationship with the expression of acetyl-CoA acyltransferase 1 (ACAA1), acyl-CoA oxidase 1 (ACOX1) and sterol carrier protein 2 (SCP2) by qPCR analysis in Gushi chicken breast muscle at 6, 14, 22, and 30 weeks old, where we performed transfection tests of miR-15a mimics in intramuscular preadipocytes and verified the target gene of miR-15a in chicken fibroblasts (DF1). The miR-15a expression level at 30 weeks increased 13.5, 4.5, and 2.7-fold compared with the expression levels at 6, 14, and 22 weeks, respectively. After 6 days of induction, miR-15a over-expression significantly promoted intramuscular adipogenic differentiation and increased cholesterol and triglyceride accumulation in adipocytes. Meanwhile, 48 h after transfection with miR-15a mimics, the expression levels of ACAA1, ACOX1 and SCP2 genes decreased by 56.52%, 31.18% and 37.14% at the mRNA level in intramuscular preadipocytes. In addition, the co-transfection of miR-15a mimics and ACAA1, ACOX1 and SCP2 3′UTR (untranslated region) dual-luciferase vector significantly inhibited dual-luciferase activity in DF1 cells. Taken together, our data demonstrate that miR-15a can reduce fatty acid oxidation by targeting ACAA1, ACOX1, and SCP2, which subsequently indirectly promotes the differentiation of chicken intramuscular preadipocytes.
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14
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Okumoto K, Miyata N, Fujiki Y. Identification of Peroxisomal Protein Complexes with PTS Receptors, Pex5 and Pex7, in Mammalian Cells. Subcell Biochem 2019; 89:287-298. [PMID: 30378028 DOI: 10.1007/978-981-13-2233-4_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Pex5 and Pex7 are cytosolic receptors for peroxisome targeting signal type-1 (PTS1) and type-2 (PTS2), respectively, and play a pivotal role in import of peroxisomal matrix proteins. Recent advance in mass spectrometry analysis has facilitated comprehensive analysis of protein-protein interaction network by a combination with immunoprecipitation or biochemical purification. In this chapter, we introduce several findings obtained by these methods applied to mammalian cells. Exploring Pex5-binding partners in mammalian cells revealed core components comprising the import machinery complex of matrix proteins and a number of PTS1-type cargo proteins. Biochemical purification of the Pex5-export stimulating factor from rat liver cytosol fraction identified Awp1, providing further insight into molecular mechanisms of the export step of mono-ubiquitinated Pex5. Identification of DDB1 (damage-specific DNA-binding protein 1), a component of CRL4 (Cullin4A-RING ubiquitin ligase) E3 complex, as a Pex7-interacting protein revealed that quality control of Pex7 by CRL4A is important for PTS2 protein import by preventing the accumulation of dysfunctional Pex7. Furthermore, analysis of binding partners of an intraperoxisomal processing enzyme, trypsin-domain containing 1 (Tysnd1), showed a protein network regulating peroxisomal fatty acid β-oxidation.
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Affiliation(s)
- Kanji Okumoto
- Department of Biology, Faculty of Sciences, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan.,Graduate School of Systems Life Sciences, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Non Miyata
- Department of Biology, Faculty of Sciences, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan.,Department of Chemistry, Faculty of Sciences, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Yukio Fujiki
- Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Fukuoka, 812-8582, Japan.
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15
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Lebowitz JJ, Pino JA, Mackie PM, Lin M, Hurst C, Divita K, Collins AT, Koutzoumis DN, Torres GE, Khoshbouei H. Clustered Kv2.1 decreases dopamine transporter activity and internalization. J Biol Chem 2019; 294:6957-6971. [PMID: 30824538 DOI: 10.1074/jbc.ra119.007441] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/26/2019] [Indexed: 01/16/2023] Open
Abstract
The dopamine transporter (DAT) regulates dopamine neurotransmission via reuptake of dopamine released into the extracellular space. Interactions with partner proteins alter DAT function and thereby dynamically shape dopaminergic tone important for normal brain function. However, the extent and nature of these interactions are incompletely understood. Here, we describe a novel physical and functional interaction between DAT and the voltage-gated K+ channel Kv2.1 (potassium voltage-gated channel subfamily B member 1 or KCNB1). To examine the functional consequences of this interaction, we employed a combination of immunohistochemistry, immunofluorescence live-cell microscopy, co-immunoprecipitation, and electrophysiological approaches. Consistent with previous reports, we found Kv2.1 is trafficked to membrane-bound clusters observed both in vivo and in vitro in rodent dopamine neurons. Our data provide evidence that clustered Kv2.1 channels decrease DAT's lateral mobility and inhibit its internalization, while also decreasing canonical transporter activity by altering DAT's conformational equilibrium. These results suggest that Kv2.1 clusters exert a spatially discrete homeostatic braking mechanism on DAT by inducing a relative increase in inward-facing transporters. Given recent reports of Kv2.1 dysregulation in neurological disorders, it is possible that alterations in the functional interaction between DAT and Kv2.1 affect dopamine neuron activity.
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Affiliation(s)
- Joseph J Lebowitz
- From the Departments of Neuroscience and.,T32 in Movement Disorders and Neurorestoration, Fixel Center for Neurological Diseases, UF Health, Gainesville, Florida 32610
| | - Jose A Pino
- Pharmacology and Experimental Therapeutics, College of Medicine, University of Florida, Gainesville, Florida 32610 and
| | | | - Min Lin
- From the Departments of Neuroscience and
| | | | | | | | - Dimitri N Koutzoumis
- Pharmacology and Experimental Therapeutics, College of Medicine, University of Florida, Gainesville, Florida 32610 and
| | - Gonzalo E Torres
- Pharmacology and Experimental Therapeutics, College of Medicine, University of Florida, Gainesville, Florida 32610 and
| | - Habibeh Khoshbouei
- From the Departments of Neuroscience and .,T32 in Movement Disorders and Neurorestoration, Fixel Center for Neurological Diseases, UF Health, Gainesville, Florida 32610
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16
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Abstract
FRET is a powerful approach to study the interactions of fluorescent molecules, and numerous methods have been developed to measure FRET in cells. Here, we present a method based on a donor molecule's photoswitching properties, which are slower in the presence vs. the absence of an acceptor. The technique, photoswitching FRET (psFRET), is similar to an established but underutilized method called photobleaching FRET (pbFRET), with the major difference being that the molecules are switched "off" rather than photobleached. The psFRET technique has some of the FRET imaging advantages normally attributed to fluorescence lifetime imaging microscopy (FLIM), such as monitoring only donor fluorescence. However, it can be performed on a conventional widefield microscope, requires less illumination light to photoswitch off than photobleaching, and can be photoswitched "on" again to repeat the experiment. We present data testing the validity of the psFRET approach to quantify FRET in cells and demonstrate its use in imaging protein-protein interactions and fluorescent protein-based biosensors.
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Affiliation(s)
- Kristin H Rainey
- Section on Biophotonics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | - George H Patterson
- Section on Biophotonics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
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17
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Lund I, El Kertaoui N, Izquierdo MS, Dominguez D, Hansen BW, Kestemont P. The importance of phospholipids combined with long-chain PUFA in formulated diets for pikeperch (Sander lucioperca) larvae. Br J Nutr 2018; 120:628-644. [PMID: 30058990 DOI: 10.1017/s0007114518001794] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Dietary phosphoglycerides and n-3 long-chain PUFA (LC-PUFA) play important functions in the development of pikeperch (Sander lucioperca) larvae. This study aimed to determine optimal dietary levels of soyabean lecithin (SBL)-derived phospholipids (PL) in starter feeds for pikeperch larvae 10-30 d post-hatch (DPH) and examine performance and ontogeny by additional supplementation of n-3 LC-PUFA in the form of Algatrium DHA 70 (glyceride product; 660-700 mg/g DHA; EPA 60-75 mg/g). In total, six isoproteic and isoenergetic extruded diets were formulated with increasing levels of PL (3·7, 8·3 or 14·5 % wet weight (w.w.), respectively); however, three of the diets were supplemented with three levels of Algatrium DHA 70 (0·6, 2·0 or 3·4 %, respectively). Liver proteomic analyses of larvae at 30 DPH were included for effects of PL and primarily DHA on performance, physiological expression and interactions in larval proteins. In addition, bone anomalies, digestive enzymatic activity, candidate gene expression and skeleton morphogenesis were examined. Results confirmed the importance of dietary PL levels of at least 8·2 % w.w., and an additional beneficiary effect of supplementation with DHA plus EPA. Thus, combined supplementation of SBL (up to 14·51 % w.w. PL) and n-3 LC-PUFA (1·004 % DM DHA and 0·169 % DM EPA) in the form of TAG resulted in highest growth and lowest incidence of anomalies, improved digestive enzyme activity and had differential effect on liver proteomics. The results denote that essential fatty acids can be supplemented as TAG to have beneficial effects in pikeperch larvae development.
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Affiliation(s)
- Ivar Lund
- 1Technical University of Denmark,DTU Aqua,Section for Aquaculture,The North Sea Research Centre,PO Box 101,DK-9850 Hirtshals,Denmark
| | - Najlae El Kertaoui
- 2Research Unit in Environmental and Evolutionary Biology,University of Namur,Rue de Bruxelles,61-5000 Namur,Belgium
| | - Marisol S Izquierdo
- 3Grupo de Investigación en Acuicultura (GIA),Instituto Universitario Ecoaqua, Universidad de Las Palmas de Gran Canaria,Crta. Taliarte s/n,35214 Telde,Spain
| | - David Dominguez
- 3Grupo de Investigación en Acuicultura (GIA),Instituto Universitario Ecoaqua, Universidad de Las Palmas de Gran Canaria,Crta. Taliarte s/n,35214 Telde,Spain
| | - Benni W Hansen
- 4Department for Science and Environment,Roskilde University,4000 Roskilde,Denmark
| | - Patrick Kestemont
- 2Research Unit in Environmental and Evolutionary Biology,University of Namur,Rue de Bruxelles,61-5000 Namur,Belgium
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18
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Octeau JC, Chai H, Jiang R, Bonanno SL, Martin KC, Khakh BS. An Optical Neuron-Astrocyte Proximity Assay at Synaptic Distance Scales. Neuron 2018; 98:49-66.e9. [PMID: 29621490 PMCID: PMC5916847 DOI: 10.1016/j.neuron.2018.03.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 01/21/2018] [Accepted: 03/02/2018] [Indexed: 02/06/2023]
Abstract
Astrocytes are complex bushy cells that serve important functions through close contacts between their processes and synapses. However, the spatial interactions and dynamics of astrocyte processes relative to synapses have proven problematic to study in adult living brain tissue. Here, we report a genetically targeted neuron-astrocyte proximity assay (NAPA) to measure astrocyte-synapse spatial interactions within intact brain preparations and at synaptic distance scales. The method exploits resonance energy transfer between extracellularly displayed fluorescent proteins targeted to synapses and astrocyte processes. We validated the method in the striatal microcircuitry following in vivo expression. We determined the proximity of striatal astrocyte processes to distinct neuronal input pathways, to D1 and D2 medium spiny neuron synapses, and we evaluated how astrocyte-to-excitatory synapse proximity changed following cortical afferent stimulation, during ischemia and in a model of Huntington's disease. NAPA provides a simple approach to measure astrocyte-synapse spatial interactions in a variety of experimental scenarios. VIDEO ABSTRACT.
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Affiliation(s)
- J Christopher Octeau
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Hua Chai
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Ruotian Jiang
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Shivan L Bonanno
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Kelsey C Martin
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA; Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA.
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McIntosh AL, Storey SM, Huang H, Kier AB, Schroeder F. Sex-dependent impact of Scp-2/Scp-x gene ablation on hepatic phytol metabolism. Arch Biochem Biophys 2017; 635:17-26. [PMID: 29051070 DOI: 10.1016/j.abb.2017.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/10/2017] [Accepted: 10/14/2017] [Indexed: 12/19/2022]
Abstract
While prior studies focusing on male mice suggest a role for sterol carrier protein-2/sterol carrier protein-x (SCP-2/SCP-x; DKO) on hepatic phytol metabolism, its role in females is unresolved. This issue was addressed using female and male wild-type (WT) and DKO mice fed a phytoestrogen-free diet without or with 0.5% phytol. GC/MS showed that hepatic: i) phytol was absent and its branched-chain fatty acid (BCFA) metabolites were barely detectable in WT control-fed mice; ii) accumulation of phytol as well as its peroxisomal metabolite BCFAs (phytanic acid » pristanic and 2,3-pristenic acids) was increased by dietary phytol in WT females, but only slightly in WT males; iii) accumulation of phytol and BCFA was further increased by DKO in phytol-fed females, but much more markedly in males. Livers of phytol-fed WT female mice as well as phytol-fed DKO female and male mice also accumulated increased proportion of saturated straight-chain fatty acids (LCFA) at the expense of unsaturated LCFA. Liver phytol accumulation was not due to increased SCP-2 binding/transport of phytol since SCP-2 bound phytanic acid, but not its precursor phytol. Thus, the loss of Scp-2/Scp-x contributed to a sex-dependent hepatic accumulation of dietary phytol and BCFA.
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Affiliation(s)
- Avery L McIntosh
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States
| | - Stephen M Storey
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States
| | - Huan Huang
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University, TVMC, College Station, TX 77843-4467, United States
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, United States.
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20
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Prost-Fingerle K, Hoffmann MD, Schützhold V, Cantore M, Fandrey J. Optical analysis of cellular oxygen sensing. Exp Cell Res 2017; 356:122-127. [DOI: 10.1016/j.yexcr.2017.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 03/07/2017] [Indexed: 12/22/2022]
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21
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Landrock D, Milligan S, Martin GG, McIntosh AL, Landrock KK, Schroeder F, Kier AB. Effect of Fabp1/Scp-2/Scp-x Ablation on Whole Body and Hepatic Phenotype of Phytol-Fed Male Mice. Lipids 2017; 52:385-397. [PMID: 28382456 PMCID: PMC5500168 DOI: 10.1007/s11745-017-4249-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/28/2017] [Indexed: 11/29/2022]
Abstract
Liver fatty acid binding protein (Fabp1) and sterol carrier protein-2/sterol carrier protein-x (SCP-2/SCP-x) genes encode proteins that enhance hepatic uptake, cytosolic transport, and peroxisomal oxidation of toxic branched-chain fatty acids derived from dietary phytol. Since male wild-type (WT) mice express markedly higher levels of these proteins than females, the impact of ablating both genes (TKO) was examined in phytol-fed males. In WT males, high phytol diet alone had little impact on whole body weight and did not alter the proportion of lean tissue mass (LTM) versus fat tissue mass (FTM). TKO conferred on dietary phytol the ability to induce weight loss as well as reduce liver weight, FTM, and even more so LTM. Concomitantly TKO induced hepatic lipid accumulation, preferentially threefold increased phospholipid (PL) at the expense of decreased triacylglycerol (TG) and total cholesterol. Increased PL was associated with upregulation of membrane fatty acid transport/translocase proteins (FATP 2,4), cytosolic fatty acid/fatty acyl-CoA binding proteins (FABP2, ACBP), and the rate limiting enzyme in PL synthesis (Gpam). Decreased TG and cholesterol levels were not attributable to altered levels in respective synthetic enzymes or nuclear receptors. These data suggest that the higher level of Fabp1 and Scp2/Scpx gene products in WT males was protective against deleterious effects of dietary phytol, but TKO significantly exacerbated phytol effects in males.
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Affiliation(s)
- Danilo Landrock
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TVMC, College Station, TX, 77843-4467, USA
| | - Sherrelle Milligan
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TVMC, College Station, TX, 77843-4467, USA
| | - Gregory G Martin
- Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Avery L McIntosh
- Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Kerstin K Landrock
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TVMC, College Station, TX, 77843-4467, USA
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Ann B Kier
- Department of Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, TVMC, College Station, TX, 77843-4467, USA.
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22
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Storey SM, Huang H, McIntosh AL, Martin GG, Kier AB, Schroeder F. Impact of Fabp1/Scp-2/Scp-x gene ablation (TKO) on hepatic phytol metabolism in mice. J Lipid Res 2017; 58:1153-1165. [PMID: 28411199 DOI: 10.1194/jlr.m075457] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/07/2017] [Indexed: 01/19/2023] Open
Abstract
Studies in vitro have suggested that both sterol carrier protein-2/sterol carrier protein-x (Scp-2/Scp-x) and liver fatty acid binding protein [Fabp1 (L-FABP)] gene products facilitate hepatic uptake and metabolism of lipotoxic dietary phytol. However, interpretation of physiological function in mice singly gene ablated in the Scp-2/Scp-x has been complicated by concomitant upregulation of FABP1. The work presented herein provides several novel insights: i) An 8-anilino-1-naphthalenesulfonic acid displacement assay showed that neither SCP-2 nor L-FABP bound phytol, but both had high affinity for its metabolite, phytanic acid; ii) GC-MS studies with phytol-fed WT and Fabp1/Scp-2/SCP-x gene ablated [triple KO (TKO)] mice showed that TKO exacerbated hepatic accumulation of phytol metabolites in vivo in females and less so in males. Concomitantly, dietary phytol increased hepatic levels of total long-chain fatty acids (LCFAs) in both male and female WT and TKO mice. Moreover, in both WT and TKO female mice, dietary phytol increased hepatic ratios of saturated/unsaturated and polyunsaturated/monounsaturated LCFAs, while decreasing the peroxidizability index. However, in male mice, dietary phytol selectively increased the saturated/unsaturated ratio only in TKO mice, while decreasing the peroxidizability index in both WT and TKO mice. These findings suggested that: 1) SCP-2 and FABP1 both facilitated phytol metabolism after its conversion to phytanic acid; and 2) SCP-2/SCP-x had a greater impact on hepatic phytol metabolism than FABP1.
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Affiliation(s)
- Stephen M Storey
- Departments of Physiology and Pharmacology Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
| | - Huan Huang
- Departments of Physiology and Pharmacology Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
| | - Avery L McIntosh
- Departments of Physiology and Pharmacology Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
| | - Gregory G Martin
- Departments of Physiology and Pharmacology Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
| | - Ann B Kier
- Pathobiology, Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
| | - Friedhelm Schroeder
- Departments of Physiology and Pharmacology Texas A&M Veterinary Medical Center, Texas A&M University, College Station, TX 77843
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23
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Becchetti A, Crescioli S, Zanieri F, Petroni G, Mercatelli R, Coppola S, Gasparoli L, D'Amico M, Pillozzi S, Crociani O, Stefanini M, Fiore A, Carraresi L, Morello V, Manoli S, Brizzi MF, Ricci D, Rinaldi M, Masi A, Schmidt T, Quercioli F, Defilippi P, Arcangeli A. The conformational state of hERG1 channels determines integrin association, downstream signaling, and cancer progression. Sci Signal 2017; 10:10/473/eaaf3236. [PMID: 28377405 DOI: 10.1126/scisignal.aaf3236] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ion channels regulate cell proliferation, differentiation, and migration in normal and neoplastic cells through cell-cell and cell-extracellular matrix (ECM) transmembrane receptors called integrins. K+ flux through the human ether-à-go-go-related gene 1 (hERG1) channel shapes action potential firing in excitable cells such as cardiomyocytes. Its abundance is often aberrantly high in tumors, where it modulates integrin-mediated signaling. We found that hERG1 interacted with the β1 integrin subunit at the plasma membrane of human cancer cells. This interaction was not detected in cardiomyocytes because of the presence of the hERG1 auxiliary subunit KCNE1 (potassium voltage-gated channel subfamily E regulatory subunit 1), which blocked the β1 integrin-hERG1 interaction. Although open hERG1 channels did not interact as strongly with β1 integrins as did closed channels, current flow through hERG1 channels was necessary to activate the integrin-dependent phosphorylation of Tyr397 in focal adhesion kinase (FAK) in both normal and cancer cells. In immunodeficient mice, proliferation was inhibited in breast cancer cells expressing forms of hERG1 with impaired K+ flow, whereas metastasis of breast cancer cells was reduced when the hERG1/β1 integrin interaction was disrupted. We conclude that the interaction of β1 integrins with hERG1 channels in cancer cells stimulated distinct signaling pathways that depended on the conformational state of hERG1 and affected different aspects of tumor progression.
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Affiliation(s)
- Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
| | - Silvia Crescioli
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Francesca Zanieri
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Giulia Petroni
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Raffaella Mercatelli
- Consiglio Nazionale delle Ricerche-Istituto Nazionale di Ottica, Via N. Carrara 1, 50019 Sesto Fiorentino, Italy
| | - Stefano Coppola
- Physics of Life Processes, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, Netherlands
| | - Luca Gasparoli
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Massimo D'Amico
- Di.V.A.L. Toscana SRL, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Serena Pillozzi
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Olivia Crociani
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Matteo Stefanini
- Di.V.A.L. Toscana SRL, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Antonella Fiore
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Laura Carraresi
- Di.V.A.L. Toscana SRL, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Virginia Morello
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy
| | - Sagar Manoli
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Maria Felice Brizzi
- Department of Medical Sciences, University of Torino, Corso Dogliotti 14, 10126 Torino, Italy
| | - Davide Ricci
- Department of Surgical Sciences, University of Torino, Corso Dogliotti 14, 10126 Torino, Italy
| | - Mauro Rinaldi
- Department of Surgical Sciences, University of Torino, Corso Dogliotti 14, 10126 Torino, Italy
| | - Alessio Masi
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy
| | - Thomas Schmidt
- Physics of Life Processes, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, Netherlands
| | - Franco Quercioli
- Consiglio Nazionale delle Ricerche-Istituto Nazionale di Ottica, Via N. Carrara 1, 50019 Sesto Fiorentino, Italy
| | - Paola Defilippi
- Physics of Life Processes, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, Netherlands
| | - Annarosa Arcangeli
- Department of Experimental and Clinical Medicine, University of Firenze, Viale G.B. Morgagni 50, 50134 Firenze, Italy.
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24
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Milligan S, Martin GG, Landrock D, McIntosh AL, Mackie JT, Schroeder F, Kier AB. Impact of dietary phytol on lipid metabolism in SCP2/SCPX/L-FABP null mice. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:291-304. [PMID: 27940000 PMCID: PMC5266609 DOI: 10.1016/j.bbalip.2016.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/15/2016] [Accepted: 12/04/2016] [Indexed: 12/20/2022]
Abstract
In vitro studies suggest that liver fatty acid binding protein (L-FABP) and sterol carrier protein-2/sterol carrier protein-x (SCP2/SCPx) gene products facilitate uptake and metabolism and detoxification of dietary-derived phytol in mammals. However, concomitant upregulation of L-FABP in SCP2/SCPx null mice complicates interpretation of their physiological phenotype. Therefore, the impact of ablating both the L-FABP gene and SCP2/SCPx gene (L-FABP/SCP2/SCPx null or TKO) was examined in phytol-fed female wild-type (WT) and TKO mice. TKO increased hepatic total lipid accumulation, primarily phospholipid, by mechanisms involving increased hepatic levels of proteins in the phospholipid synthetic pathway. Concomitantly, TKO reduced expression of proteins in targeting fatty acids towards the triacylglycerol synthetic pathway. Increased hepatic lipid accumulation was not associated with any concomitant upregulation of membrane fatty acid transport/translocase proteins involved in fatty acid uptake (FATP2, FATP4, FATP5 or GOT) or cytosolic proteins involved in fatty acid intracellular targeting (ACBP). In addition, TKO exacerbated dietary phytol-induced whole body weight loss, especially lean tissue mass. Since individually ablating SCPx or SCP2/SCPx elicited concomitant upregulation of L-FABP, these findings with TKO mice help to resolve the contributions of SCP2/SCPx gene ablation on dietary phytol-induced whole body and hepatic lipid phenotype independent of concomitant upregulation of L-FABP.
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Affiliation(s)
- Sherrelle Milligan
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Gregory G Martin
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Danilo Landrock
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Avery L McIntosh
- Department of Physiology/Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4466, USA
| | - John T Mackie
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
| | - Friedhelm Schroeder
- Department of Physiology/Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4466, USA
| | - Ann B Kier
- Department of Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA.
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25
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Silva JG, Martins NP, Henriques R, Soares H. HIV-1 Nef Impairs the Formation of Calcium Membrane Territories Controlling the Signaling Nanoarchitecture at the Immunological Synapse. THE JOURNAL OF IMMUNOLOGY 2016; 197:4042-4052. [PMID: 27798165 DOI: 10.4049/jimmunol.1601132] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/16/2016] [Indexed: 12/21/2022]
Abstract
The ability of HIV-1 to replicate and to establish long-term reservoirs is strongly influenced by T cell activation. Through the use of membrane-tethered, genetically encoded calcium (Ca2+) indicators, we were able to detect for the first time, to our knowledge, the formation of Ca2+ territories and determine their role in coordinating the functional signaling nanostructure of the synaptic membrane. Consequently, we report a previously unknown immune subversion mechanism involving HIV-1 exploitation, through its Nef accessory protein, of the interconnectivity among three evolutionarily conserved cellular processes: vesicle traffic, signaling compartmentalization, and the second messenger Ca2+ We found that HIV-1 Nef specifically associates with the traffic regulators MAL and Rab11b compelling the vesicular accumulation of Lck. Through its association with MAL and Rab11b, Nef co-opts Lck switchlike function driving the formation Ca2+ membrane territories, which, in turn, control the fusion of LAT-transporting Rab27 and Rab37 vesicles and the formation of LAT nanoclusters at the immunological synapse. Consequently, HIV-1 Nef disengages TCR triggering from the generation of p-LAT and p-SLP nanoclusters driving TCR signal amplification and diversification. Altogether our results indicate that HIV-1 exploits the interconnectivity among vesicle traffic, Ca2+ membrane territories, and signaling nanoclusters to modulate T cell signaling and function.
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Affiliation(s)
- Joana G Silva
- Immunobiology and Pathogenesis Group, Chronic Diseases Research Center, NOVA Medical School, NOVA University of Lisbon, 1150-082 Lisbon, Portugal
| | - Nuno P Martins
- Unit of Imaging and Cytometry, Gulbenkian Institute for Science, 2780-156 Oeiras, Portugal
| | - Ricardo Henriques
- Quantitative Imaging and Nanobiophysics Group, Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, United Kingdom; and.,Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Helena Soares
- Immunobiology and Pathogenesis Group, Chronic Diseases Research Center, NOVA Medical School, NOVA University of Lisbon, 1150-082 Lisbon, Portugal;
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26
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Mazumder P, Prajapati S, Bapat R, Moradian-Oldak J. Amelogenin-Ameloblastin Spatial Interaction around Maturing Enamel Rods. J Dent Res 2016; 95:1042-8. [PMID: 27146703 PMCID: PMC4959624 DOI: 10.1177/0022034516645389] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Amelogenin and ameloblastin are 2 extracellular matrix proteins that are essential for the proper development of enamel. We recently reported that amelogenin and ameloblastin colocalized during the secretory stage of enamel formation when nucleation of enamel crystallites occurs. Direct interactions between the 2 proteins have been also demonstrated in our in vitro studies. Here, we explore interactions between their fragments during enamel maturation. We applied in vivo immunofluorescence imaging, quantitative co-localization analysis, and a new FRET (fluorescence resonance energy transfer) technique to demonstrate ameloblastin and amelogenin interaction in the maturing mouse enamel. Using immunochemical analysis of protein samples extracted from 8-d-old (P8) first molars from mice as a model for maturation-stage enamel, we identified the ~17-kDa ameloblastin (Ambn-N) and the TRAP (tyrosine-rich amelogenin peptide) fragments. We used Ambn-N18 and Ambn-M300 antibodies raised against the N-terminal and C-terminal segments of ameloblastin, as well as Amel-FL and Amel-C19 antibodies against full-length recombinant mouse amelogenin (rM179) and C-terminal amelogenin, respectively. In transverse sections, co-localization images of N-terminal fragments of amelogenin and ameloblastin around the prism boundary revealed the "fish net" pattern of the enamel matrix. Using in vivo FRET microscopy, we further demonstrated spatial interactions between amelogenin and ameloblastin N-terminal fragments. In the maturing mouse enamel, the association of these residual protein fragments created a discontinuity between enamel rods, which we suggest is important for support and maintenance of enamel rods and eventual contribution to unique enamel mechanical properties. We present data that support cooperative functions of enamel matrix proteins in mediating the structural hierarchy of enamel and that contribute to our efforts to design and develop enamel biomimetic material.
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Affiliation(s)
- P Mazumder
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - S Prajapati
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - R Bapat
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - J Moradian-Oldak
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
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27
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Sroka R, Van Lint J, Katz SF, Schneider MR, Kleger A, Paschke S, Seufferlein T, Eiseler T. Cortactin is a scaffolding platform for the E-cadherin adhesion complex and is regulated by protein kinase D1 phosphorylation. J Cell Sci 2016; 129:2416-29. [PMID: 27179075 DOI: 10.1242/jcs.184721] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 04/28/2016] [Indexed: 12/12/2022] Open
Abstract
Dynamic regulation of cell-cell adhesion by the coordinated formation and dissolution of E-cadherin-based adherens junctions is crucial for tissue homeostasis. The actin-binding protein cortactin interacts with E-cadherin and enables F-actin accumulation at adherens junctions. Here, we were interested to study the broader functional interactions of cortactin in adhesion complexes. In line with literature, we demonstrate that cortactin binds to E-cadherin, and that a posttranslational modification of cortactin, RhoA-induced phosphorylation by protein kinase D1 (PKD1; also known as PRKD1) at S298, impairs adherens junction assembly and supports their dissolution. Two new S298-phosphorylation-dependent interactions were also identified, namely, that phosphorylation of cortactin decreases its interaction with β-catenin and the actin-binding protein vinculin. In addition, binding of vinculin to β-catenin, as well as linkage of vinculin to F-actin, are also significantly compromised upon phosphorylation of cortactin. Accordingly, we found that regulation of cell-cell adhesion by phosphorylation of cortactin downstream of RhoA and PKD1 is vitally dependent on vinculin-mediated protein interactions. Thus, cortactin, unexpectedly, is an important integration node for the dynamic regulation of protein complexes during breakdown and formation of adherens junctions.
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Affiliation(s)
- Robert Sroka
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm 89081, Germany
| | - Johan Van Lint
- Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, Campus Gasthuisberg O/N1 - Herestraat 49 bus 901, Leuven 3000, Belgium
| | - Sarah-Fee Katz
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm 89081, Germany
| | - Marlon R Schneider
- Department for Animal Breeding and Biotechnology, LMU Munich, Gene Center, Feodor-Lynen-Str. 25, Munich 81377, Germany
| | - Alexander Kleger
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm 89081, Germany
| | - Stephan Paschke
- Department of Visceral Surgery, Ulm University, Albert-Einstein-Allee 23, Ulm 89081, Germany
| | - Thomas Seufferlein
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm 89081, Germany
| | - Tim Eiseler
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm 89081, Germany
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28
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Zhou M, Li Q, Wang R. Current Experimental Methods for Characterizing Protein-Protein Interactions. ChemMedChem 2016; 11:738-56. [PMID: 26864455 PMCID: PMC7162211 DOI: 10.1002/cmdc.201500495] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 01/08/2016] [Indexed: 12/14/2022]
Abstract
Protein molecules often interact with other partner protein molecules in order to execute their vital functions in living organisms. Characterization of protein-protein interactions thus plays a central role in understanding the molecular mechanism of relevant protein molecules, elucidating the cellular processes and pathways relevant to health or disease for drug discovery, and charting large-scale interaction networks in systems biology research. A whole spectrum of methods, based on biophysical, biochemical, or genetic principles, have been developed to detect the time, space, and functional relevance of protein-protein interactions at various degrees of affinity and specificity. This article presents an overview of these experimental methods, outlining the principles, strengths and limitations, and recent developments of each type of method.
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Affiliation(s)
- Mi Zhou
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Collaborative Innovation Center of Chemistry for Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai, 200032, People's Republic of China
| | - Qing Li
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Collaborative Innovation Center of Chemistry for Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai, 200032, People's Republic of China
| | - Renxiao Wang
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Collaborative Innovation Center of Chemistry for Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai, 200032, People's Republic of China.
- State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Avenida Wai Long, Macau, 999078, People's Republic of China.
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29
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Zhou M, Li Q, Wang R. Current Experimental Methods for Characterizing Protein-Protein Interactions. ChemMedChem 2016. [PMID: 26864455 DOI: 10.1002/cmdc.201500495.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Protein molecules often interact with other partner protein molecules in order to execute their vital functions in living organisms. Characterization of protein-protein interactions thus plays a central role in understanding the molecular mechanism of relevant protein molecules, elucidating the cellular processes and pathways relevant to health or disease for drug discovery, and charting large-scale interaction networks in systems biology research. A whole spectrum of methods, based on biophysical, biochemical, or genetic principles, have been developed to detect the time, space, and functional relevance of protein-protein interactions at various degrees of affinity and specificity. This article presents an overview of these experimental methods, outlining the principles, strengths and limitations, and recent developments of each type of method.
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Affiliation(s)
- Mi Zhou
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Collaborative Innovation Center of Chemistry for Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai, 200032, People's Republic of China
| | - Qing Li
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Collaborative Innovation Center of Chemistry for Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai, 200032, People's Republic of China
| | - Renxiao Wang
- State Key Laboratory of Bioorganic & Natural Products Chemistry, Collaborative Innovation Center of Chemistry for Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd, Shanghai, 200032, People's Republic of China. .,State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Avenida Wai Long, Macau, 999078, People's Republic of China.
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30
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Martin GG, Landrock D, Landrock KK, Howles PN, Atshaves BP, Kier AB, Schroeder F. Relative contributions of L-FABP, SCP-2/SCP-x, or both to hepatic biliary phenotype of female mice. Arch Biochem Biophys 2015; 588:25-32. [PMID: 26541319 PMCID: PMC4683591 DOI: 10.1016/j.abb.2015.10.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/20/2015] [Accepted: 10/28/2015] [Indexed: 01/01/2023]
Abstract
Both sterol carrier protein-2/sterol carrier protein-x (SCP-2/SCP-x) and liver fatty acid binding protein (L-FABP) have been proposed to function in hepatobiliary bile acid metabolism/accumulation. To begin to address this issue, the impact of ablating L-FABP (LKO) or SCP-2/SCP-x (DKO) individually or both together (TKO) was examined in female mice. Biliary bile acid levels were decreased in LKO, DKO, and TKO mice; however, hepatic bile acid concentration was decreased in LKO mice only. In contrast, biliary phospholipid level was decreased only in TKO mice, while biliary cholesterol levels were unaltered regardless of phenotype. The loss of either or both genes increased hepatic expression of the major bile acid synthetic enzymes (CYP7A1 and/or CYP27A1). Loss of L-FABP and/or SCP-2/SCP-x genes significantly altered the molecular composition of biliary bile acids, but not the proportion of conjugated/unconjugated bile acids or overall bile acid hydrophobicity index. These data suggested that L-FABP was more important in hepatic retention of bile acids, while SCP-2/SCP-x more broadly affected biliary bile acid and phospholipid levels.
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Affiliation(s)
- Gregory G Martin
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, USA
| | - Danilo Landrock
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467, USA
| | - Kerstin K Landrock
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, USA
| | - Philip N Howles
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45219, USA
| | - Barbara P Atshaves
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467, USA
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466, USA.
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Eiseler T, Wille C, Koehler C, Illing A, Seufferlein T. Protein Kinase D2 Assembles a Multiprotein Complex at the Trans-Golgi Network to Regulate Matrix Metalloproteinase Secretion. J Biol Chem 2015; 291:462-77. [PMID: 26507660 DOI: 10.1074/jbc.m115.673582] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Indexed: 11/06/2022] Open
Abstract
Vesicle formation and fission are tightly regulated at the trans-Golgi network (TGN) during constitutive secretion. Two major protein families regulate these processes: members of the adenosyl-ribosylation factor family of small G-proteins (ARFs) and the protein kinase D (PKD) family of serine/threonine kinases. The functional relationship between these two key regulators of protein transport from the TGN so far is elusive. We here demonstrate the assembly of a novel functional protein complex at the TGN and its key members: cytosolic PKD2 binds ARF-like GTPase (ARL1) and shuttles ARL1 to the TGN. ARL1, in turn, localizes Arfaptin2 to the TGN. At the TGN, where PKD2 interacts with active ARF1, PKD2, and ARL1 are required for the assembly of a complex comprising of ARF1 and Arfaptin2 leading to secretion of matrix metalloproteinase-2 and -7. In conclusion, our data indicate that PKD2 is a core factor in the formation of this multiprotein complex at the TGN that controls constitutive secretion of matrix metalloproteinase cargo.
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Affiliation(s)
- Tim Eiseler
- From the Department of Internal Medicine I, Ulm University, Albert Einstein Allee 23, D-89081 Ulm, Germany and
| | - Christoph Wille
- From the Department of Internal Medicine I, Ulm University, Albert Einstein Allee 23, D-89081 Ulm, Germany and
| | - Conny Koehler
- the Department of Internal Medicine I, Martin-Luther University Halle-Wittenberg, Ernst-Grube, Strasse 40, D-06120 Halle (Saale), Germany
| | - Anett Illing
- From the Department of Internal Medicine I, Ulm University, Albert Einstein Allee 23, D-89081 Ulm, Germany and
| | - Thomas Seufferlein
- From the Department of Internal Medicine I, Ulm University, Albert Einstein Allee 23, D-89081 Ulm, Germany and
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32
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Ma L, Yang F, Zheng J. Application of fluorescence resonance energy transfer in protein studies. J Mol Struct 2014; 1077:87-100. [PMID: 25368432 DOI: 10.1016/j.molstruc.2013.12.071] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Since the physical process of fluorescence resonance energy transfer (FRET) was elucidated more than six decades ago, this peculiar fluorescence phenomenon has turned into a powerful tool for biomedical research due to its compatibility in scale with biological molecules as well as rapid developments in novel fluorophores and optical detection techniques. A wide variety of FRET approaches have been devised, each with its own advantages and drawbacks. Especially in the last decade or so, we are witnessing a flourish of FRET applications in biological investigations, many of which exemplify clever experimental design and rigorous analysis. Here we review the current stage of FRET methods development with the main focus on its applications in protein studies in biological systems, by summarizing the basic components of FRET techniques, most established quantification methods, as well as potential pitfalls, illustrated by example applications.
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Affiliation(s)
- Linlin Ma
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA 95616, USA ; Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Fan Yang
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA 95616, USA
| | - Jie Zheng
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA 95616, USA
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33
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A mechanistic framework for noncell autonomous stem cell induction in Arabidopsis. Proc Natl Acad Sci U S A 2014; 111:14619-24. [PMID: 25246576 DOI: 10.1073/pnas.1406446111] [Citation(s) in RCA: 216] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cell-cell communication is essential for multicellular development and, consequently, evolution has brought about an array of distinct mechanisms serving this purpose. Consistently, induction and maintenance of stem cell fate by noncell autonomous signals is a feature shared by many organisms and may depend on secreted factors, direct cell-cell contact, matrix interactions, or a combination of these mechanisms. Although many basic cellular processes are well conserved between animals and plants, cell-to-cell signaling is one function where substantial diversity has arisen between the two kingdoms of life. One of the most striking differences is the presence of cytoplasmic bridges, called plasmodesmata, which facilitate the exchange of molecules between neighboring plant cells and provide a unique route for cell-cell communication in the plant lineage. Here, we provide evidence that the stem cell inducing transcription factor WUSCHEL (WUS), expressed in the niche, moves to the stem cells via plasmodesmata in a highly regulated fashion and that this movement is required for WUS function and, thus, stem cell activity in Arabidopsis thaliana. We show that cell context-independent mobility is encoded in the WUS protein sequence and mediated by multiple domains. Finally, we demonstrate that parts of the protein that restrict movement are required for WUS homodimerization, suggesting that formation of WUS dimers might contribute to the regulation of apical stem cell activity.
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34
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Fereidouni F, Blab GA, Gerritsen HC. Phasor based analysis of FRET images recorded using spectrally resolved lifetime imaging. Methods Appl Fluoresc 2014; 2:035001. [DOI: 10.1088/2050-6120/2/3/035001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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35
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Biomolecular dynamics and binding studies in the living cell. Phys Life Rev 2014; 11:1-30. [DOI: 10.1016/j.plrev.2013.11.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 11/20/2013] [Indexed: 11/22/2022]
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36
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Domoszlai T, Martincuks A, Fahrenkamp D, Schmitz-Van de Leur H, Küster A, Müller-Newen G. Consequences of the disease-related L78R mutation for dimerization and activity of STAT3. J Cell Sci 2014; 127:1899-910. [DOI: 10.1242/jcs.137422] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
STAT3 (signal transducer and activator of transcription 3) is a transcription factor centrally involved in diverse processes including hematopoiesis, immunity and cancer progression. In response to cytokine stimulation STAT3 is activated through phosphorylation of a single tyrosine residue. The phosphorylated STAT3 dimers are stabilized by intermolecular SH2 domain/phosphotyrosine interactions. These activated dimers accumulate in the nucleus and bind to specific DNA sequences resulting in target gene expression. We analysed and compared the structural organizations of the unphosphorylated latent and phosphorylated activated STAT3 dimers using Förster resonance energy transfer (FRET) in fixed and living cells. The latent dimers are stabilized by homotypic interactions between the N-terminal domains. A somatic mutation (L78R) found in inflammatory hepatocellular adenomas (IHCA) which is located in the N-terminal domain of STAT3 disturbs latent dimer formation. Applying intramolecular FRET we verify a functional role of the SH2 domain in latent dimer formation suggesting the parallel orientation of the protomers in the latent STAT3 dimer similar to activated STAT3 dimers but in contrast to the latent dimers of STAT1 and STAT5. Our findings reveal unique structural characteristics of STAT3 within the STAT family and contribute to the understanding of the L78R mutation found in IHCA.
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37
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Zeug A, Stawarski M, Bieganska K, Korotchenko S, Wlodarczyk J, Dityatev A, Ponimaskin E. Current microscopic methods for the neural ECM analysis. PROGRESS IN BRAIN RESEARCH 2014; 214:287-312. [PMID: 25410363 DOI: 10.1016/b978-0-444-63486-3.00013-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The extracellular matrix (ECM) occupies the space between both neurons and glial cells and thus provides a microenvironment that regulates multiple aspects of neural activities. Because of the vital role of ECM as a natural environment of cells in vivo, there is a growing interest to develop methodology allowing for the detailed structural and functional analyses of ECM. In this chapter, we provide the detailed overview of current microscopic methods used for ECM analysis and also describe general labeling strategies for ECM visualization. Since ECM remodeling involves the proteolytic cleavage of ECM, we will also describe current experimental approaches to image the proteolytic reorganization and/or degradation of ECM. The special focus of this chapter is set to the application of Förster resonance energy transfer-based approaches to monitor intracellular and extracellular matrix functions with high spatiotemporal resolution.
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Affiliation(s)
- Andre Zeug
- Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Michal Stawarski
- Laboratory of Cell Biophysics, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | | | - Svetlana Korotchenko
- Laboratory for Brain Extracellular Matrix Research, University of Nizhny Novgorod, Nizhny Novgorod, Russia; Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy; Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy
| | - Jakub Wlodarczyk
- Laboratory of Cell Biophysics, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Alexander Dityatev
- Laboratory for Brain Extracellular Matrix Research, University of Nizhny Novgorod, Nizhny Novgorod, Russia; Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy; Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy; Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Magdeburg, Germany
| | - Evgeni Ponimaskin
- Cellular Neurophysiology, Hannover Medical School, Hannover, Germany.
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38
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Grecco HE, Bastiaens PIH. Quantifying cellular dynamics by fluorescence resonance energy transfer (FRET) microscopy. ACTA ACUST UNITED AC 2013; Chapter 5:Unit5.22. [PMID: 23559306 DOI: 10.1002/0471142301.ns0522s63] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The cell is a spatially organized system whose function emerges from the complex interaction of molecular components. Such local interaction of nanometer-sized molecules generates patterns that span throughout the cell. Those patterns, in turn, regulate the molecular interactions. Understanding such simultaneous bidirectional causation requires quantifying the spatio-temporal progression of biochemical reactions in the context of a living cell. Due to its ability to resolve micrometer-sized structures, biological microscopy has been instrumental to the discovery and understanding of living systems. Functional fluorescence microscopy allows a cellular dynamic topographic map of proteins to be overlaid with topological information on the causality that determines protein state. Here we describe how Förster/fluorescence resonance energy transfer (FRET) can be used to measure the phosphorylation state of proteins in the context of the cell.
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Affiliation(s)
- Hernán E Grecco
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
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39
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Ciccotosto GD, Kozer N, Chow TTY, Chon JWM, Clayton AHA. Aggregation distributions on cells determined by photobleaching image correlation spectroscopy. Biophys J 2013; 104:1056-64. [PMID: 23473488 DOI: 10.1016/j.bpj.2013.01.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 12/17/2012] [Accepted: 01/02/2013] [Indexed: 11/29/2022] Open
Abstract
The organization of molecules into macromolecular (nanometer scale), supramolecular complexes (submicron-to-micron scale), and within subcellular domains, is an important architectural principle of cellular biology and biochemistry. Determining the precise nature and distribution of complexes within the cellular milieu is a challenging biophysical problem. Time-series analysis of laser scanning confocal microscopy images by image correlation spectroscopy (ICS) or fluctuation moments methods provides information on aggregation, flow, and dynamics of fluorescently tagged macromolecules. All the methods to date require a brightness standard to relate the experimental data to absolute aggregation. In this article, we show that ICS as a function of gradual photobleaching is a sensitive indicator of aggregation distribution on the submicron scale. Specifically, in photobleaching ICS, the extent of nonlinearity of the apparent cluster density as a function of bleaching is related to the size of clusters. The analysis is tested using computer simulations on model aggregate systems and then applied to an experimental determination of Aβ peptide aggregation on nerve cells. The analysis reveals time-dependent increases in Aβ1-42 peptide aggregation. Globally, the datasets could be described by a monomer-dimer-tetramer-hexamer or a monomer-dimer-trimer-pentamer model. The results demonstrate the utility of photobleaching with ICS for determining aggregation states on the supramolecular scale in intact cells without the requirement for a brightness standard.
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Affiliation(s)
- Giuseppe D Ciccotosto
- Department of Pathology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Australia
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40
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Zeug A, Woehler A, Neher E, Ponimaskin EG. Quantitative intensity-based FRET approaches--a comparative snapshot. Biophys J 2013. [PMID: 23199910 DOI: 10.1016/j.bpj.2012.09.031] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Förster resonance energy transfer (FRET) has become an important tool for analyzing different aspects of interactions among biological macromolecules in their native environments. FRET analysis has also been successfully applied to study the spatiotemporal regulation of various cellular processes using genetically encoded FRET-based biosensors. A variety of procedures have been described for measuring FRET efficiency or the relative abundance of donor-acceptor complexes, based on analysis of the donor fluorescence lifetime or the spectrally resolved fluorescence intensity. The latter methods are preferable if one wants to not only quantify the apparent FRET efficiencies but also calculate donor-acceptor stoichiometry and observe fast dynamic changes in the interactions among donor and acceptor molecules in live cells. This review focuses on a comparison of the available intensity-based approaches used to measure FRET. We discuss their strengths and weaknesses in terms of FRET quantification, and provide several examples of biological applications.
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Affiliation(s)
- André Zeug
- Cellular Neurophysiology, Center of Physiology, Hannover Medical School, Hannover, Germany
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41
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Yu H, Zhang J, Li H, Chen T. Ma-PbFRET: multiple acceptors FRET measurement based on partial acceptor photobleaching. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2013; 19:171-179. [PMID: 23347498 DOI: 10.1017/s1431927612014079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Fluorescence resonance energy transfer (FRET) measurement based on partial acceptor photobleaching (PbFRET) is easy to implement without external references. However, the current PbFRET methods are inapplicable to the construct with multiple acceptors, which largely increase the Förster distance. Here, we proposed a linear theory for the dependence of the acceptor photobleaching probability of construct with multiple acceptors on the photobleaching degree (x) and developed a multiple acceptors PbFRET method (Ma-PbFRET) to measure the FRET efficiency of construct with multiple acceptors (n) by measuring the fluorescence intensities of both donor and acceptor channels before and after acceptor photobleaching. The Ma-PbFRET method was validated by measuring the FRET efficiency of construct with two or three acceptors under different x in living cells. Our experimental results demonstrate that the Ma-PbFRET method is capable of exactly quantifying the FRET efficiency of construct with multiple acceptors, providing a simple and powerful tool to investigate the assembly/disassembly of biomolecular complexes with larger distance in living cells.
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Affiliation(s)
- Huaina Yu
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China
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42
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Li H, Yu H, Chen T. Partial acceptor photobleaching-based quantitative FRET method completely overcoming emission spectral crosstalks. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:1021-1029. [PMID: 23026309 DOI: 10.1017/s1431927612001110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Based on the quantitative fluorescence resonance energy transfer (FRET) method named PbFRET we reported recently, we herein developed a partial acceptor photobleaching-based quantitative FRET algorithm named B-PbFRET method. B-PbFRET overcomes not only the acceptor excitation crosstalk and donor emission spectral crosstalk but also the acceptor emission spectral crosstalk that harasses previous methods including fluorescence lifetime (FLIM), fluorescence recovery of donor after acceptor photobleaching, and acceptor sensitized emission (SE)-based methods. B-PbFRET method is implemented by simultaneously measuring the fluorescence intensity of both donor and acceptor channels at donor excitation before and after partial acceptor photobleaching, and it can directly measure the FRET efficiency (E) without any verified references. Based on the theoretical analysis of B-PbFRET, we also developed a more straightforward correction method named C-PbFRET to obtain the absolute E from the value measured by PbFRET for a given donor-acceptor pair. We validated both B-PbFRET and C-PbFRET methods by measuring the E of two linked constructs, 18AA and SCAT3 proteins, in single living cells, and our data demonstrated that both B-PbFRET and C-PbFRET methods can directly measure the absolute E of the linked constructs inside living cells under different degrees of acceptor emission spectral crosstalk.
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Affiliation(s)
- Huali Li
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China
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43
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Subach OM, Entenberg D, Condeelis JS, Verkhusha VV. A FRET-facilitated photoswitching using an orange fluorescent protein with the fast photoconversion kinetics. J Am Chem Soc 2012; 134:14789-99. [PMID: 22900938 DOI: 10.1021/ja3034137] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fluorescent proteins photoswitchable with noncytotoxic light irradiation and spectrally distinct from multiple available photoconvertible green-to-red probes are in high demand. We have developed a monomeric fluorescent protein, called PSmOrange2, which is photoswitchable with blue light from an orange (ex./em. at 546 nm/561 nm) to a far-red (ex./em. at 619 nm/651 nm) form. Compared to another orange-to-far-red photoconvertable variant, PSmOrange2 has blue-shifted photoswitching action spectrum, 9-fold higher photoconversion contrast, and up to 10-fold faster photoswitching kinetics. This results in the 4-fold more PSmOrange2 molecules being photoconverted in mammalian cells. Compared to common orange fluorescent proteins, such as mOrange, the orange form of PSmOrange has substantially higher photostability allowing its use in multicolor imaging applications to track dynamics of multiple populations of intracellular objects. The PSmOrange2 photochemical properties allow its efficient photoswitching with common two-photon lasers and, moreover, via Förster resonance energy transfer (FRET) from green fluorescent donors. We have termed the latter effect a FRET-facilitated photoswitching and demonstrated it using several sets of interacting proteins. The enhanced photoswitching properties of PSmOrange2 make it a superior photoconvertable protein tag for flow cytometry, conventional microscopy, and two-photon imaging of live cells.
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Affiliation(s)
- Oksana M Subach
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
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44
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McIntosh AL, Senthivinayagam S, Moon KC, Gupta S, Lwande JS, Murphy CC, Storey SM, Atshaves BP. Direct interaction of Plin2 with lipids on the surface of lipid droplets: a live cell FRET analysis. Am J Physiol Cell Physiol 2012; 303:C728-42. [PMID: 22744009 DOI: 10.1152/ajpcell.00448.2011] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Despite increasing awareness of the health risks associated with excess lipid storage in cells and tissues, knowledge of events governing lipid exchange at the surface of lipid droplets remains unclear. To address this issue, fluorescence resonance energy transfer (FRET) was performed to examine live cell interactions of Plin2 with lipids involved in maintaining lipid droplet structure and function. FRET efficiencies (E) between CFP-labeled Plin2 and fluorescently labeled phosphatidylcholine, sphingomyelin, stearic acid, and cholesterol were quantitated on a pixel-by-pixel basis to generate FRET image maps that specified areas with high E (>60%) in lipid droplets. The mean E and the distance R between the probes indicated a high yield of energy transfer and demonstrated molecular distances on the order of 44-57 Å, in keeping with direct molecular contact. In contrast, FRET between CFP-Plin2 and Nile red was not detected, indicating that the CFP-Plin2/Nile red interaction was beyond FRET proximity (>100 Å). An examination of the effect of Plin2 on cellular metabolism revealed that triacylglycerol, fatty acid, and cholesteryl ester content increased while diacylglycerol remained constant in CFP-Plin2-overexpressing cells. Total phospholipids also increased, reflecting increased phosphatidylcholine and sphingomyelin. Consistent with these results, expression levels of enzymes involved in triacylglycerol, cholesteryl ester, and phospholipid synthesis were significantly upregulated in CFP-Plin2-expressing cells while those associated with lipolysis either decreased or were unaffected. Taken together, these data show for the first time that Plin2 interacts directly with lipids on the surface of lipid droplets and influences levels of key enzymes and lipids involved in maintaining lipid droplet structure and function.
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Affiliation(s)
- Avery L McIntosh
- Dept. of Biochemistry and Molecular Biology, Michigan State Univ., East Lansing, MI 48824, USA
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45
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Ishikawa-Ankerhold HC, Ankerhold R, Drummen GPC. Advanced fluorescence microscopy techniques--FRAP, FLIP, FLAP, FRET and FLIM. Molecules 2012; 17:4047-132. [PMID: 22469598 PMCID: PMC6268795 DOI: 10.3390/molecules17044047] [Citation(s) in RCA: 284] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 03/21/2012] [Accepted: 03/21/2012] [Indexed: 12/19/2022] Open
Abstract
Fluorescence microscopy provides an efficient and unique approach to study fixed and living cells because of its versatility, specificity, and high sensitivity. Fluorescence microscopes can both detect the fluorescence emitted from labeled molecules in biological samples as images or photometric data from which intensities and emission spectra can be deduced. By exploiting the characteristics of fluorescence, various techniques have been developed that enable the visualization and analysis of complex dynamic events in cells, organelles, and sub-organelle components within the biological specimen. The techniques described here are fluorescence recovery after photobleaching (FRAP), the related fluorescence loss in photobleaching (FLIP), fluorescence localization after photobleaching (FLAP), Förster or fluorescence resonance energy transfer (FRET) and the different ways how to measure FRET, such as acceptor bleaching, sensitized emission, polarization anisotropy, and fluorescence lifetime imaging microscopy (FLIM). First, a brief introduction into the mechanisms underlying fluorescence as a physical phenomenon and fluorescence, confocal, and multiphoton microscopy is given. Subsequently, these advanced microscopy techniques are introduced in more detail, with a description of how these techniques are performed, what needs to be considered, and what practical advantages they can bring to cell biological research.
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Affiliation(s)
- Hellen C. Ishikawa-Ankerhold
- Ludwig Maximilian University of Munich, Institute of Anatomy and Cell Biology, Schillerstr. 42, 80336 München, Germany
| | - Richard Ankerhold
- Carl Zeiss Microimaging GmbH, Kistlerhofstr. 75, 81379 München, Germany
| | - Gregor P. C. Drummen
- Bionanoscience and Bio-Imaging Program, Cellular Stress and Ageing Program, Bio&Nano-Solutions, Helmutstr. 3A, 40472 Düsseldorf, Germany
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46
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Kraft LJ, Kenworthy AK. Imaging protein complex formation in the autophagy pathway: analysis of the interaction of LC3 and Atg4B(C74A) in live cells using Förster resonance energy transfer and fluorescence recovery after photobleaching. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:011008. [PMID: 22352642 PMCID: PMC3380812 DOI: 10.1117/1.jbo.17.1.011008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 09/28/2011] [Accepted: 09/29/2011] [Indexed: 05/31/2023]
Abstract
The protein microtubule-associated protein 1, light chain 3 (LC3) functions in autophagosome formation and plays a central role in the autophagy pathway. Previously, we found LC3 diffuses more slowly in cells than is expected for a freely diffusing monomer, suggesting it may constitutively associate with a macromolecular complex containing other protein components of the pathway. In the current study, we used Förster resonance energy transfer (FRET) microscopy and fluorescence recovery after photobleaching (FRAP) to investigate the interactions of LC3 with Atg4B(C74A), a catalytically inactive mutant of the cysteine protease involved in lipidation and de-lipidation of LC3, as a model system to probe protein complex formation in the autophagy pathway. We show Atg4B(C74A) is in FRET proximity with LC3 in both the cytoplasm and nucleus of living cells, consistent with previous biochemical evidence that suggests these proteins directly interact. In addition, overexpressed Atg4B(C74A) diffuses significantly more slowly than predicted based on its molecular weight, and its translational diffusion coefficient is significantly slowed upon coexpression with LC3 to match that of LC3 itself. Taken together, these results suggest Atg4B(C74A) and LC3 are contained within the same multiprotein complex and that this complex exists in both the cytoplasm and nucleoplasm of living cells.
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Affiliation(s)
- Lewis J. Kraft
- Vanderbilt University School of Medicine, Chemical and Physical Biology Program, Nashville, Tennessee 37232
| | - Anne K. Kenworthy
- Vanderbilt University School of Medicine, Chemical and Physical Biology Program, Nashville, Tennessee 37232
- Vanderbilt University School of Medicine, Department of Molecular Physiology and Biophysics, Nashville, Tennessee 37232
- Vanderbilt University School of Medicine, Department of Cell and Developmental Biology, Nashville, Tennessee 37232
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Abstract
Biological research has always tremendously benefited from the development of key methodology. In fact, it was the advent of microscopy that shaped our understanding of cells as the fundamental units of life. Microscopic techniques are still central to the elucidation of biological units and processes, but equally important are methods that allow access to the dimension of time, to investigate the dynamics of molecular functions and interactions. Here, fluorescence spectroscopy with its sensitivity to access the single-molecule level, and its large temporal resolution, has been opening up fully new perspectives for cell biology. Here we summarize the key fluorescent techniques used to study cellular dynamics, with the focus on lipid and membrane systems.
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48
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Okumoto K, Kametani Y, Fujiki Y. Two proteases, trypsin domain-containing 1 (Tysnd1) and peroxisomal lon protease (PsLon), cooperatively regulate fatty acid β-oxidation in peroxisomal matrix. J Biol Chem 2011; 286:44367-79. [PMID: 22002062 DOI: 10.1074/jbc.m111.285197] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The molecular mechanisms underlying protein turnover and enzyme regulation in the peroxisomal matrix remain largely unknown. Trypsin domain-containing 1 (Tysnd1) and peroxisomal Lon protease (PsLon) are newly identified peroxisomal matrix proteins that harbor both a serine protease-like domain and a peroxisome-targeting signal 1 (PTS1) sequence. Tysnd1 processes several PTS1-containing proteins and cleaves N-terminal presequences from PTS2-containing protein precursors. Here we report that knockdown of Tysnd1, but not PsLon, resulted in accumulation of endogenous β-oxidation enzymes in their premature form. The protease activity of Tysnd1 was inactivated by intermolecular self-conversion of the 60-kDa form to 15- and 45-kDa chains, which were preferentially degraded by PsLon. Peroxisomal β-oxidation of a very long fatty acid was significantly decreased by knockdown of Tysnd1 and partially lowered by PsLon knockdown. Taken together, these data suggest that Tysnd1 is a key regulator of the peroxisomal β-oxidation pathway via proteolytic processing of β-oxidation enzymes. The proteolytic activity of oligomeric Tysnd1 is in turn controlled by self-cleavage of Tysnd1 and degradation of Tysnd1 cleavage products by PsLon.
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Affiliation(s)
- Kanji Okumoto
- Department of Biology, Faculty of Sciences, Kyushu University Graduate School, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
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49
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Hostetler HA, Lupas D, Tan Y, Dai J, Kelzer MS, Martin GG, Woldegiorgis G, Kier AB, Schroeder F. Acyl-CoA binding proteins interact with the acyl-CoA binding domain of mitochondrial carnitine palmitoyl transferase I. Mol Cell Biochem 2011; 355:135-48. [PMID: 21541677 DOI: 10.1007/s11010-011-0847-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 04/20/2011] [Indexed: 12/16/2022]
Abstract
Although the rate limiting step in mitochondrial fatty acid oxidation, catalyzed by carnitine palmitoyl transferase I (CPTI), utilizes long-chain fatty acyl-CoAs (LCFA-CoA) as a substrate, how LCFA-CoA is transferred to CPTI remains elusive. Based on secondary structural predictions and conserved tryptophan residues, the cytoplasmic C-terminal domain was hypothesized to be the LCFA-CoA binding site and important for interaction with cytoplasmic LCFA-CoA binding/transport proteins to provide a potential route for LCFA-CoA transfer. To begin to address this question, the cytoplasmic C-terminal region of liver CPTI (L-CPTI) was recombinantly expressed and purified. Data herein showed for the first time that the L-CPTI C-terminal 89 residues were sufficient for high affinity binding of LCFA-CoA (K (d) = 2-10 nM) and direct interaction with several cytoplasmic LCFA-CoA binding proteins (K (d) < 10 nM), leading to enhanced CPTI activity. Furthermore, alanine substitutions for tryptophan in L-CPTI (W391A and W452A) altered secondary structure, decreased binding affinity for LCFA-CoA, and almost completely abolished L-CPTI activity, suggesting that these amino acids may be important for ligand stabilization necessary for L-CPTI activity. Moreover, while decreased activity of the W452A mutant could be explained by decreased binding of lipid binding proteins, W391 itself seems to be important for activity. These data suggest that both interactions with lipid binding proteins and the peptide itself are important for optimal enzyme activity.
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Affiliation(s)
- Heather A Hostetler
- Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, TX 77843-4466, USA
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Sahoo H. Förster resonance energy transfer – A spectroscopic nanoruler: Principle and applications. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2011. [DOI: 10.1016/j.jphotochemrev.2011.05.001] [Citation(s) in RCA: 217] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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