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Goh M, Fu L, Seetoh WG, Koay A, Hua H, Tan SM, Tay SH, Jinfeng EC, Abdullah N, Ng SY, Lakshmanan M, Arumugam P. Mono-2-ethylhexylphthalate (MEHP) is a potent agonist of human TRPA1 channel. Chemosphere 2024; 349:140740. [PMID: 38006918 DOI: 10.1016/j.chemosphere.2023.140740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/27/2023]
Abstract
Phthalates are extensively used as plasticizers in diverse consumer care products but have been reported to cause adverse health effects in humans. A commonly used phthalate, di-2-ethylhexylphthalate (DEHP) causes developmental and reproductive toxicities in humans, but the associated molecular mechanisms are not fully understood. Mono-2-ethylhexylphthalate (MEHP), a hydrolytic product of DEHP generated by cellular esterases, is proposed to be the active toxicant. We conducted a screen for sensory irritants among compounds used in consumer care using an assay for human Transient Receptor Potential A1 (hTRPA1). We have identified MEHP as a potent agonist of hTRPA1. MEHP-induced hTRPA1 activation was blocked by the TRPA1 inhibitor A-967079. Patch clamp assays revealed that MEHP induced inward currents in cells expressing hTRPA1. In addition, the N855S mutation in hTRPA1 associated with familial episodic pain syndrome decreased MEHP-induced hTRPA1 activation. In summary, we report that MEHP is a potent agonist of hTRPA1 which generates new possible mechanisms for toxic effects of phthalates in humans.
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Affiliation(s)
- Megan Goh
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Singapore, 138669
| | - Lin Fu
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Singapore, 138669; Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, Singapore, 138671
| | - Wei-Guang Seetoh
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Singapore, 138669
| | - Ann Koay
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Singapore, 138669
| | - Huang Hua
- National University of Singapore, Department of Physiology, 4 Science Drive 2, Wet Science Building Level 11, Singapore, 117544
| | - Shi Min Tan
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Singapore, 138669
| | - Shermaine Huiping Tay
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Singapore, 138673
| | - Elaine Chin Jinfeng
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Singapore, 138669
| | - Nimo Abdullah
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Singapore, 138669; Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - Shi Yan Ng
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Singapore, 138673
| | - Manikandan Lakshmanan
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Singapore, 138673
| | - Prakash Arumugam
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Singapore, 138669; Nanyang Technological University, School of Biological Sciences, Singapore, 637551.
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2
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Soh R, Fu L, Guo WM, Seetoh WG, Koay A. Inhibitors of human bitter taste receptors from the five-flavour berry, Schisandra chinensis. Food Funct 2023; 14:10700-10708. [PMID: 37986606 DOI: 10.1039/d3fo02303f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The human bitter taste 2 receptor member 16 (TAS2R16) is one of 25 class A G-protein-coupled receptors (GPCRs) and responds to a variety of molecules responsible for the bitter taste sensation perceived in humans. TAS2R16 can be activated by β-glucopyranosides, and its activation can be inhibited by probenecid, a synthetic drug compound used to treat gout. In this study we describe naturally derived compounds which can inhibit the activation of TAS2R16 by salicin in vitro. These compounds belong to the lignan class derived from the fruit of Schisandra chinensis, which is commonly known as the five-flavour berry. We further tested other analogs with this lignan scaffold, found their differential inhibitory activities towards TAS2R16 in vitro, and sought to rationalize the activity using molecular docking of these lignans on a computationally modelled structure of TAS2R16. Selected lignans with inhibitory activity against other TAS2Rs reveal sub-millimolar inhibitory activity towards TAS2R10, TAS2R14, and TAS2R43 in cell-based assays. These compounds with demonstrated in vitro inhibition of bitter taste receptors may serve as tool compounds to investigate the molecular mechanisms of hTAS2Rs biology in gustatory and non-gustatory tissues.
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Affiliation(s)
- Ryan Soh
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01 Nanos, Singapore 138669, Singapore.
| | - Lin Fu
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01 Nanos, Singapore 138669, Singapore.
| | - Wei Mei Guo
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01 Nanos, Singapore 138669, Singapore.
| | - Wei-Guang Seetoh
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01 Nanos, Singapore 138669, Singapore.
| | - Ann Koay
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01 Nanos, Singapore 138669, Singapore.
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Nicholas Chua B, Mei Guo W, Teng Wong H, Siak-Wei Ow D, Leng Ho P, Koh W, Koay A, Tian Wong F. A sweeter future: Using protein language models for exploring sweeter brazzein homologs. Food Chem 2023; 426:136580. [PMID: 37331142 DOI: 10.1016/j.foodchem.2023.136580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/23/2023] [Accepted: 06/06/2023] [Indexed: 06/20/2023]
Abstract
With growing concerns over the health impact of sugar, brazzein offers a viable alternative due to its sweetness, thermostability, and low risk profile. Here, we demonstrated the ability of protein language models to design new brazzein homologs with improved thermostability and potentially higher sweetness, resulting in new diverse optimized amino acid sequences that improve structural and functional features beyond what conventional methods could achieve. This innovative approach resulted in the identification of unexpected mutations, thereby generating new possibilities for protein engineering. To facilitate the characterization of the brazzein mutants, a simplified procedure was developed for expressing and analyzing related proteins. This process involved an efficient purification method using Lactococcus lactis (L. lactis), a generally recognized as safe (GRAS) bacterium, as well as taste receptor assays to evaluate sweetness. The study successfully demonstrated the potential of computational design in producing a more heat-resistant and potentially more palatable brazzein variant, V23.
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Affiliation(s)
- Bryan Nicholas Chua
- Molecular Engineering Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, #07-06, Proteos, Singapore 138673, Republic of Singapore
| | - Wei Mei Guo
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01, Nanos, Singapore 138669, Republic of Singapore
| | - Han Teng Wong
- Molecular Engineering Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, #07-06, Proteos, Singapore 138673, Republic of Singapore
| | - Dave Siak-Wei Ow
- Bioprocessing Technology Institute (BTI), Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, #06-01, Centros, Singapore 138668, Republic of Singapore
| | - Pooi Leng Ho
- Bioprocessing Technology Institute (BTI), Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, #06-01, Centros, Singapore 138668, Republic of Singapore
| | - Winston Koh
- Institute of Bioengineering and Bioimaging (IBB), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #07-01, Nanos, Singapore 138669, Republic of Singapore; Bioinformatics Institute (BII), Agency of Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01, Matrix, Singapore 138671, Republic of Singapore.
| | - Ann Koay
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01, Nanos, Singapore 138669, Republic of Singapore.
| | - Fong Tian Wong
- Molecular Engineering Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, #07-06, Proteos, Singapore 138673, Republic of Singapore; Institute of Sustainability for Chemicals, Energy and Environment (ISCE(2)), Agency for Science, Technology and Research (A*STAR), 8 Biomedical Grove, Neuros, #07-01, Singapore 138665, Republic of Singapore.
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Zhong W, Koay A, Ngo A, Li Y, Nah Q, Wong YH, Chionh YH, Ng HQ, Koh-Stenta X, Poulsen A, Foo K, McBee M, Choong ML, El Sahili A, Kang C, Matter A, Lescar J, Hill J, Dedon P. Targeting the Bacterial Epitranscriptome for Antibiotic Development: Discovery of Novel tRNA-(N 1G37) Methyltransferase (TrmD) Inhibitors. ACS Infect Dis 2019; 5:326-335. [PMID: 30682246 DOI: 10.1021/acsinfecdis.8b00275] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Bacterial tRNA modification synthesis pathways are critical to cell survival under stress and thus represent ideal mechanism-based targets for antibiotic development. One such target is the tRNA-(N1G37) methyltransferase (TrmD), which is conserved and essential in many bacterial pathogens. Here we developed and applied a widely applicable, radioactivity-free, bioluminescence-based high-throughput screen (HTS) against 116350 compounds from structurally diverse small-molecule libraries to identify inhibitors of Pseudomonas aeruginosa TrmD ( PaTrmD). Of 285 compounds passing primary and secondary screens, a total of 61 TrmD inhibitors comprised of more than 12 different chemical scaffolds were identified, all showing submicromolar to low micromolar enzyme inhibitor constants, with binding affinity confirmed by thermal stability and surface plasmon resonance. S-Adenosyl-l-methionine (SAM) competition assays suggested that compounds in the pyridine-pyrazole-piperidine scaffold were substrate SAM-competitive inhibitors. This was confirmed in structural studies, with nuclear magnetic resonance analysis and crystal structures of PaTrmD showing pyridine-pyrazole-piperidine compounds bound in the SAM-binding pocket. Five hits showed cellular activities against Gram-positive bacteria, including mycobacteria, while one compound, a SAM-noncompetitive inhibitor, exhibited broad-spectrum antibacterial activity. The results of this HTS expand the repertoire of TrmD-inhibiting molecular scaffolds that show promise for antibiotic development.
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Affiliation(s)
- Wenhe Zhong
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, 138602 Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, 636921 Singapore
| | - Ann Koay
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Anna Ngo
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Yan Li
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Qianhui Nah
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, 138602 Singapore
| | - Yee Hwa Wong
- NTU Institute of Structural Biology, Nanyang Technological University, 636921 Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore
| | - Yok Hian Chionh
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, 138602 Singapore
| | - Hui Qi Ng
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Xiaoying Koh-Stenta
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Anders Poulsen
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Klement Foo
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Megan McBee
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, 138602 Singapore
| | - Meng Ling Choong
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Abbas El Sahili
- NTU Institute of Structural Biology, Nanyang Technological University, 636921 Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore
| | - Congbao Kang
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Alex Matter
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Julien Lescar
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, 138602 Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, 636921 Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore
| | - Jeffrey Hill
- Experimental Therapeutics Centre, 31 Biopolis Way, #03-01 Nanos, 138669 Singapore
| | - Peter Dedon
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, 138602 Singapore
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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5
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Ngo A, Koay A, Pecquet C, Diaconu CC, Jenkins DA, Shiau AK, Constantinescu SN, Choong ML. Phenotypic Screening for Inhibitors of a Mutant Thrombopoietin Receptor. Methods Mol Biol 2018; 1787:53-66. [PMID: 29736709 DOI: 10.1007/978-1-4939-7847-2_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An inhibitor for the thrombopoietin receptor (TpoR) would be more specific for the treatment of myeloproliferative neoplasms (MPNs) due to constitutively active mutant TpoR compared to the current treatment approach of inhibiting Janus kinase 2 (JAK2). We describe a cell-based high-throughput phenotypic screening approach to identify inhibitors for constitutively active mutant TpoR. A stepwise elimination process is used to differentiate generally cytotoxic compounds from compounds that specifically inhibit growth of cells expressing wild-type TpoR and/or mutant TpoR. We have systematically optimized the phenotypic screening assay and documented in this chapter critical parameters for a successful phenotypic screen, such as cell growth and seeding optimization, plate reproducibility and uniformity studies, and an assay robustness analysis with a pilot screen.
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Affiliation(s)
- Anna Ngo
- Experimental Therapeutics Centre, Agency for Science Technology and Research (A*STAR), Singapore, Singapore
| | - Ann Koay
- Experimental Therapeutics Centre, Agency for Science Technology and Research (A*STAR), Singapore, Singapore
| | - Christian Pecquet
- Ludwig Institute for Cancer Research, Université catholique de Louvain and de Duve Institute, Brussels, Belgium
| | - Carmen C Diaconu
- Stefan S. Nicolau Institute of Virology, Romanian Academy, Bucharest, Romania
| | - David A Jenkins
- Small Molecule Discovery Program, Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Andrew K Shiau
- Small Molecule Discovery Program, Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Stefan N Constantinescu
- Ludwig Institute for Cancer Research, Université catholique de Louvain and de Duve Institute, Brussels, Belgium
| | - Meng Ling Choong
- Experimental Therapeutics Centre, Agency for Science Technology and Research (A*STAR), Singapore, Singapore.
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6
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Gooley PR, Koay A, Mobbs JI. Applications of NMR and ITC for the Study of the Kinetics of Carbohydrate Binding by AMPK β-Subunit Carbohydrate-Binding Modules. Methods Mol Biol 2018; 1732:87-98. [PMID: 29480470 DOI: 10.1007/978-1-4939-7598-3_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Understanding the kinetics of proteins interacting with their ligands is important for characterizing molecular mechanism. However, it can be difficult to determine the extent and nature of these interactions for weakly formed protein-ligand complexes that have lifetimes of micro- to milliseconds. Nuclear magnetic resonance (NMR) spectroscopy is a powerful solution-based method for the atomic-level analysis of molecular interactions on a wide range of timescales, including micro- to milliseconds. Recently the combination of thermodynamic experiments using isothermal titration calorimetry (ITC) with kinetic measurements using ZZ-exchange and CPMG relaxation dispersion NMR spectroscopy have been used to determine the kinetics of weakly interacting protein systems. This chapter describes the application of ITC and NMR to understand the differences in the kinetics of carbohydrate binding by the β1- and β2-carbohydrate-binding modules of AMP-activated protein kinase.
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Affiliation(s)
- Paul R Gooley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia.
| | - Ann Koay
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia.,Experimental Therapeutics Centre, Agency for Science Technology and Research, Singapore, Singapore
| | - Jesse I Mobbs
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia.,Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, VIC, Australia
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Gallagher T, Leahy MF, Darby S, Campbell L, Howman R, Watts S, Vodanovich M, Tovey J, Esson A, Koay A. Assembling a state-wide patient blood management program as a standard of care: the Western Australian experience. ACTA ACUST UNITED AC 2017. [DOI: 10.1111/voxs.12350] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- T. Gallagher
- Department of Health Western Australia; Perth WA Australia
| | - M. F. Leahy
- Fremantle Hospital; Fremantle WA Australia
- Royal Perth Hospital; Perth WA Australia
- PathWest Laboratory Medicine; Perth WA Australia
- The University of Western Australia; Perth WA Australia
| | - S. Darby
- Sir Charles Gairdner Hospital; Nedlands WA Australia
| | - L. Campbell
- Sir Charles Gairdner Hospital; Nedlands WA Australia
| | - R. Howman
- Sir Charles Gairdner Hospital; Nedlands WA Australia
| | - S. Watts
- Sir Charles Gairdner Hospital; Nedlands WA Australia
| | | | - J. Tovey
- Fremantle Hospital; Fremantle WA Australia
| | - A. Esson
- Department of Health Western Australia; Perth WA Australia
| | - A. Koay
- Department of Health Western Australia; Perth WA Australia
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Emanuelle S, Hossain MI, Moller IE, Pedersen HL, van de Meene AML, Doblin MS, Koay A, Oakhill JS, Scott JW, Willats WGT, Kemp BE, Bacic A, Gooley PR, Stapleton DI. SnRK1 from Arabidopsis thaliana is an atypical AMPK. Plant J 2015; 82:183-92. [PMID: 25736509 DOI: 10.1111/tpj.12813] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 02/17/2015] [Accepted: 02/23/2015] [Indexed: 05/05/2023]
Abstract
SNF1-related protein kinase 1 (SnRK1) is the plant orthologue of the evolutionarily-conserved SNF1/AMPK/SnRK1 protein kinase family that contributes to cellular energy homeostasis. Functional as heterotrimers, family members comprise a catalytic α subunit and non-catalytic β and γ subunits; multiple isoforms of each subunit type exist, giving rise to various isoenzymes. The Arabidopsis thaliana genome contains homologues of each subunit type, and, in addition, two atypical subunits, β(3) and βγ, with unique domain architecture, that are found only amongst plants, suggesting atypical heterotrimers. The AtSnRK1 subunit structure was determined using recombinant protein expression and endogenous co-immunoprecipitation, and six unique isoenzyme combinations were identified. Each heterotrimeric isoenzyme comprises a catalytic α subunit together with the unique βγ subunit and one of three non-catalytic β subunits: β(1), β(2) or the plant-specific β(3) isoform. Thus, the AtSnRK1 heterotrimers contain the atypical βγ subunit rather than a conventional γ subunit. Mammalian AMPK heterotrimers are phosphorylated on the T-loop (pThr175/176) within both catalytic a subunits. However, AtSnRK1 is insensitive to AMP and ADP, and is resistant to T-loop dephosphorylation by protein phosphatases, a process that inactivates other SNF1/AMPK family members. In addition, we show that SnRK1 is inhibited by a heat-labile, >30 kDa, soluble proteinaceous factor that is present in the lysate of young rosette leaves. Finally, none of the three SnRK1 carbohydrate-binding modules, located in the β(1), β(2) and βγ subunits, associate with various carbohydrates, including starch, the plant analogue of glycogen to which AMPK binds in vitro. These data clearly demonstrate that AtSnRK1 is an atypical member of the SNF1/AMPK/SnRK1 family.
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Affiliation(s)
- Shane Emanuelle
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of Botany, and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia; Department of Biochemistry & Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia
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Greeve K, Bloomer S, Chellew-Hawley M, Clarnette R, Fortnum D, Garton-Smith J, Harney M, Ibrahim J, Kendall P, Koay A, Moody H, Porter S, Scarff Z, Trevaskis G, Yuen K, Walker H. ADVANCE CARE PLANNING, A STEP-BY-STEP GUIDE FOR HEALTH CARE PROFESSIONALS ASSISTING PATIENTS WITH CHRONIC CONDITIONS TO PLAN FOR CARE TOWARDS END OF LIFE. BMJ Support Palliat Care 2013. [DOI: 10.1136/bmjspcare-2013-000491.77] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Bieri M, Mobbs JI, Koay A, Louey G, Mok YF, Hatters DM, Park JT, Park KH, Neumann D, Stapleton D, Gooley PR. AMP-activated protein kinase β-subunit requires internal motion for optimal carbohydrate binding. Biophys J 2012; 102:305-14. [PMID: 22339867 DOI: 10.1016/j.bpj.2011.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 12/05/2011] [Accepted: 12/09/2011] [Indexed: 01/01/2023] Open
Abstract
AMP-activated protein kinase interacts with oligosaccharides and glycogen through the carbohydrate-binding module (CBM) containing the β-subunit, for which there are two isoforms (β(1) and β(2)). Muscle-specific β(2)-CBM, either as an isolated domain or in the intact enzyme, binds carbohydrates more tightly than the ubiquitous β(1)-CBM. Although residues that contact carbohydrate are strictly conserved, an additional threonine in a loop of β(2)-CBM is concurrent with an increase in flexibility in β(2)-CBM, which may account for the affinity differences between the two isoforms. In contrast to β(1)-CBM, unbound β(2)-CBM showed microsecond-to-millisecond motion at the base of a β-hairpin that contains residues that make critical contacts with carbohydrate. Upon binding to carbohydrate, similar microsecond-to-millisecond motion was observed in this β-hairpin and the loop that contains the threonine insertion. Deletion of the threonine from β(2)-CBM resulted in reduced carbohydrate affinity. Although motion was retained in the unbound state, a significant loss of motion was observed in the bound state of the β(2)-CBM mutant. Insertion of a threonine into the background of β(1)-CBM resulted in increased ligand affinity and flexibility in these loops when bound to carbohydrate. However, these mutations indicate that the additional threonine is not solely responsible for the differences in carbohydrate affinity and protein dynamics. Nevertheless, these results suggest that altered protein dynamics may contribute to differences in the ligand affinity of the two naturally occurring CBM isoforms.
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Affiliation(s)
- Michael Bieri
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
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Koay A, Woodcroft B, Petrie EJ, Yue H, Emanuelle S, Bieri M, Bailey MF, Hargreaves M, Park JT, Park KH, Ralph S, Neumann D, Stapleton D, Gooley PR. AMPK β subunits display isoform specific affinities for carbohydrates. FEBS Lett 2010; 584:3499-503. [DOI: 10.1016/j.febslet.2010.07.015] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Accepted: 07/08/2010] [Indexed: 11/26/2022]
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12
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Scott JW, van Denderen BJW, Jorgensen SB, Honeyman JE, Steinberg GR, Oakhill JS, Iseli TJ, Koay A, Gooley PR, Stapleton D, Kemp BE. Thienopyridone drugs are selective activators of AMP-activated protein kinase beta1-containing complexes. ACTA ACUST UNITED AC 2009; 15:1220-30. [PMID: 19022182 DOI: 10.1016/j.chembiol.2008.10.005] [Citation(s) in RCA: 205] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 09/09/2008] [Accepted: 10/02/2008] [Indexed: 11/29/2022]
Abstract
The AMP-activated protein kinase (AMPK) is an alphabetagamma heterotrimer that plays a pivotal role in regulating cellular and whole-body metabolism. Activation of AMPK reverses many of the metabolic defects associated with obesity and type 2 diabetes, and therefore AMPK is considered a promising target for drugs to treat these diseases. Recently, the thienopyridone A769662 has been reported to directly activate AMPK by an unexpected mechanism. Here we show that A769662 activates AMPK by a mechanism involving the beta subunit carbohydrate-binding module and residues from the gamma subunit but not the AMP-binding sites. Furthermore, A769662 exclusively activates AMPK heterotrimers containing the beta1 subunit. Our findings highlight the regulatory role played by the beta subunit in modulating AMPK activity and the possibility of developing isoform specific therapeutic activators of this important metabolic regulator.
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Affiliation(s)
- John W Scott
- St. Vincent's Institute and Department of Medicine, University of Melbourne, 41 Victoria Parade, Fitzroy 3065, VIC Australia.
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Koay A, Rimmer KA, Mertens HDT, Gooley PR, Stapleton D. Oligosaccharide recognition and binding to the carbohydrate binding module of AMP-activated protein kinase. FEBS Lett 2007; 581:5055-9. [PMID: 17919599 DOI: 10.1016/j.febslet.2007.09.044] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 09/04/2007] [Accepted: 09/20/2007] [Indexed: 11/16/2022]
Abstract
The AMP-activated protein kinase (AMPK) contains a carbohydrate-binding module (beta1-CBM) that is conserved from yeast to mammals. Beta1-CBM has been shown to localize AMPK to glycogen in intact cells and in vitro. Here we use Nuclear Magnetic Resonance spectroscopy to investigate oligosaccharide binding to 15N labelled beta1-CBM. We find that beta1-CBM shows greatest affinity to carbohydrates of greater than five glucose units joined via alpha,1-->4 glycosidic linkages with a single, but not multiple, glucose units in an alpha,1-->6 branch. The near identical chemical shift profile for all oligosaccharides whether cyclic or linear suggest a similar binding conformation and confirms the presence of a single carbohydrate-binding site.
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Affiliation(s)
- Ann Koay
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
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Parker GJ, Koay A, Gilbert-Wilson R, Waddington LJ, Stapleton D. AMP-activated protein kinase does not associate with glycogen alpha-particles from rat liver. Biochem Biophys Res Commun 2007; 362:811-5. [PMID: 17767922 DOI: 10.1016/j.bbrc.2007.08.080] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Accepted: 08/07/2007] [Indexed: 11/28/2022]
Abstract
The AMP-activated protein kinase (AMPK) is heterotrimer consisting of alpha catalytic subunit and beta/gamma regulatory subunits. It acts as a critical focal point for whole body and cellular mechanisms maintaining energy homeostasis by regulating carbohydrate and lipid metabolism, food intake, gene transcription, and protein synthesis. The AMPK beta subunit contains a glycogen-binding domain that has been shown to associate with glycogen particles in vitro and glycogen phosphorylase and glycogen synthase in cultured cells. To determine whether AMPK associates with glycogen particles in vivo, we developed a procedure to purify glycogen alpha-particles to apparent homogeneity from rat liver. Using immunoreactivity and mass spectrometry we determined that AMPK does not associate with the glycogen particle in livers from random-fed rats. This surprising finding indicates that the glycogen-binding properties of the AMPK beta subunit are likely regulated and responsive to the metabolic status of the hepatocyte.
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Affiliation(s)
- Glendon J Parker
- Department of Medicine, Rm 4C464B SOM, 30 N 1900 E, 84132, School of Medicine, University of Utah, Salt Lake City, UT, USA
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