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Koussis K, Haase S, Withers-Martinez C, Flynn HR, Kunzelmann S, Christodoulou E, Ibrahim F, Skehel M, Baker DA, Blackman MJ. Activation loop phosphorylation and cGMP saturation of PKG regulate egress of malaria parasites. PLoS Pathog 2024; 20:e1012360. [PMID: 38935780 PMCID: PMC11236177 DOI: 10.1371/journal.ppat.1012360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 07/10/2024] [Accepted: 06/20/2024] [Indexed: 06/29/2024] Open
Abstract
The cGMP-dependent protein kinase (PKG) is the sole cGMP sensor in malaria parasites, acting as an essential signalling hub to govern key developmental processes throughout the parasite life cycle. Despite the importance of PKG in the clinically relevant asexual blood stages, many aspects of malarial PKG regulation, including the importance of phosphorylation, remain poorly understood. Here we use genetic and biochemical approaches to show that reduced cGMP binding to cyclic nucleotide binding domain B does not affect in vitro kinase activity but prevents parasite egress. Similarly, we show that phosphorylation of a key threonine residue (T695) in the activation loop is dispensable for kinase activity in vitro but is essential for in vivo PKG function, with loss of T695 phosphorylation leading to aberrant phosphorylation events across the parasite proteome and changes to the substrate specificity of PKG. Our findings indicate that Plasmodium PKG is uniquely regulated to transduce signals crucial for malaria parasite development.
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Affiliation(s)
- Konstantinos Koussis
- Malaria Biochemistry Laboratory, Francis Crick Institute, London, United Kingdom
| | - Silvia Haase
- Host-Pathogen Interactions in Cryptosporidiosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | | | - Helen R. Flynn
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Simone Kunzelmann
- Structural Biology Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Evangelos Christodoulou
- Structural Biology Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Fairouz Ibrahim
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Mark Skehel
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - David A. Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Michael J. Blackman
- Malaria Biochemistry Laboratory, Francis Crick Institute, London, United Kingdom
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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2
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Ong HW, Adderley J, Tobin AB, Drewry DH, Doerig C. Parasite and host kinases as targets for antimalarials. Expert Opin Ther Targets 2023; 27:151-169. [PMID: 36942408 DOI: 10.1080/14728222.2023.2185511] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
INTRODUCTION The deployment of Artemisinin-based combination therapies and transmission control measures led to a decrease in the global malaria burden over the recent decades. Unfortunately, this trend is now reversing, in part due to resistance against available treatments, calling for the development of new drugs against untapped targets to prevent cross-resistance. AREAS COVERED In view of their demonstrated druggability in noninfectious diseases, protein kinases represent attractive targets. Kinase-focussed antimalarial drug discovery is facilitated by the availability of kinase-targeting scaffolds and large libraries of inhibitors, as well as high-throughput phenotypic and biochemical assays. We present an overview of validated Plasmodium kinase targets and their inhibitors, and briefly discuss the potential of host cell kinases as targets for host-directed therapy. EXPERT OPINION We propose priority research areas, including (i) diversification of Plasmodium kinase targets (at present most efforts focus on a very small number of targets); (ii) polypharmacology as an avenue to limit resistance (kinase inhibitors are highly suitable in this respect); and (iii) preemptive limitation of resistance through host-directed therapy (targeting host cell kinases that are required for parasite survival) and transmission-blocking through targeting sexual stage-specific kinases as a strategy to protect curative drugs from the spread of resistance.
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Affiliation(s)
- Han Wee Ong
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC USA
| | - Jack Adderley
- Department of Laboratory Medicine, School of Health and Biomedical Sciences, Rmit University, Bundoora VIC Australia
| | - Andrew B Tobin
- Advanced Research Centre, University of Glasgow, Glasgow, UK
| | - David H Drewry
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC USA
| | - Christian Doerig
- Department of Laboratory Medicine, School of Health and Biomedical Sciences, Rmit University, Bundoora VIC Australia
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3
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Balestra AC, Koussis K, Klages N, Howell SA, Flynn HR, Bantscheff M, Pasquarello C, Perrin AJ, Brusini L, Arboit P, Sanz O, Castaño LPB, Withers-Martinez C, Hainard A, Ghidelli-Disse S, Snijders AP, Baker DA, Blackman MJ, Brochet M. Ca 2+ signals critical for egress and gametogenesis in malaria parasites depend on a multipass membrane protein that interacts with PKG. SCIENCE ADVANCES 2021; 7:7/13/eabe5396. [PMID: 33762339 PMCID: PMC7990342 DOI: 10.1126/sciadv.abe5396] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 02/05/2021] [Indexed: 06/12/2023]
Abstract
Calcium signaling regulated by the cGMP-dependent protein kinase (PKG) controls key life cycle transitions in the malaria parasite. However, how calcium is mobilized from intracellular stores in the absence of canonical calcium channels in Plasmodium is unknown. Here, we identify a multipass membrane protein, ICM1, with homology to transporters and calcium channels that is tightly associated with PKG in both asexual blood stages and transmission stages. Phosphoproteomic analyses reveal multiple ICM1 phosphorylation events dependent on PKG activity. Stage-specific depletion of Plasmodium berghei ICM1 prevents gametogenesis due to a block in intracellular calcium mobilization, while conditional loss of Plasmodium falciparum ICM1 is detrimental for the parasite resulting in severely reduced calcium mobilization, defective egress, and lack of invasion. Our findings suggest that ICM1 is a key missing link in transducing PKG-dependent signals and provide previously unknown insights into atypical calcium homeostasis in malaria parasites essential for pathology and disease transmission.
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Affiliation(s)
- Aurélia C Balestra
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Konstantinos Koussis
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
| | - Natacha Klages
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Steven A Howell
- Mass Spectrometry Proteomics Platform, The Francis Crick Institute, London, UK
| | - Helen R Flynn
- Mass Spectrometry Proteomics Platform, The Francis Crick Institute, London, UK
| | - Marcus Bantscheff
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline, 69117 Heidelberg, Germany
| | - Carla Pasquarello
- Proteomics Core Facility, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Abigail J Perrin
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Lorenzo Brusini
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Patrizia Arboit
- Proteomics Core Facility, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Olalla Sanz
- Diseases of the Developing World Global Health Pharma Unit, GlaxoSmithKline, 28760 Tres Cantos, Spain
| | | | | | - Alexandre Hainard
- Proteomics Core Facility, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Sonja Ghidelli-Disse
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline, 69117 Heidelberg, Germany
| | | | - David A Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Michael J Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Mathieu Brochet
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland.
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Nofal SD, Patel A, Blackman MJ, Flueck C, Baker DA. Plasmodium falciparum Guanylyl Cyclase-Alpha and the Activity of Its Appended P4-ATPase Domain Are Essential for cGMP Synthesis and Blood-Stage Egress. mBio 2021; 12:e02694-20. [PMID: 33500341 PMCID: PMC7858053 DOI: 10.1128/mbio.02694-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/19/2020] [Indexed: 12/16/2022] Open
Abstract
Guanylyl cyclases (GCs) synthesize cyclic GMP (cGMP) and, together with cyclic nucleotide phosphodiesterases, are responsible for regulating levels of this intracellular messenger which mediates myriad functions across eukaryotes. In malaria parasites (Plasmodium spp), as well as their apicomplexan and ciliate relatives, GCs are associated with a P4-ATPase-like domain in a unique bifunctional configuration. P4-ATPases generate membrane bilayer lipid asymmetry by translocating phospholipids from the outer to the inner leaflet. Here, we investigate the role of Plasmodium falciparum guanylyl cyclase alpha (GCα) and its associated P4-ATPase module, showing that asexual blood-stage parasites lacking both the cyclase and P4-ATPase domains are unable to egress from host erythrocytes. GCα-null parasites cannot synthesize cGMP or mobilize calcium, a cGMP-dependent protein kinase (PKG)-driven requirement for egress. Using chemical complementation with a cGMP analogue and point mutagenesis of a crucial conserved residue within the P4-ATPase domain, we show that P4-ATPase activity is upstream of and linked to cGMP synthesis. Collectively, our results demonstrate that GCα is a critical regulator of PKG and that its associated P4-ATPase domain plays a primary role in generating cGMP for merozoite egress.IMPORTANCE The clinical manifestations of malaria arise due to successive rounds of replication of Plasmodium parasites within red blood cells. Once mature, daughter merozoites are released from infected erythrocytes to invade new cells in a tightly regulated process termed egress. Previous studies have shown that the activation of cyclic GMP (cGMP) signaling is critical for initiating egress. Here, we demonstrate that GCα, a unique bifunctional enzyme, is the sole enzyme responsible for cGMP production during the asexual blood stages of Plasmodium falciparum and is required for the cellular events leading up to merozoite egress. We further demonstrate that in addition to the GC domain, the appended ATPase-like domain of GCα is also involved in cGMP production. Our results highlight the critical role of GCα in cGMP signaling required for orchestrating malaria parasite egress.
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Affiliation(s)
- Stephanie D Nofal
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Avnish Patel
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Michael J Blackman
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Christian Flueck
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - David A Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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5
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Brochet M, Balestra AC, Brusini L. cGMP homeostasis in malaria parasites-The key to perceiving and integrating environmental changes during transmission to the mosquito. Mol Microbiol 2020; 115:829-838. [PMID: 33112460 DOI: 10.1111/mmi.14633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/22/2022]
Abstract
Malaria-causing parasites are transmitted from humans to mosquitoes when developmentally arrested gametocytes are taken up by a female Anopheles during a blood meal. The changes in environment from human to mosquito activate gametogenesis, including a drop in temperature, a rise in pH, and a mosquito-derived molecule, xanthurenic acid. Signaling receptors have not been identified in malaria parasites but mounting evidence indicates that cGMP homeostasis is key to sensing extracellular cues in gametocytes. Low levels of cGMP maintained by phosphodiesterases prevent precocious activation of gametocytes in the human blood. Upon ingestion, initiation of gametogenesis depends on the activation of a hybrid guanylyl cyclase/P4-ATPase. Elevated cGMP levels lead to the rapid mobilization of intracellular calcium that relies upon the activation of both cGMP-dependent protein kinase and phosphoinositide phospholipase C. Once calcium is released, a cascade of phosphorylation events mediated by calcium-dependent protein kinases and phosphatases regulates the cellular processes required for gamete formation. cGMP signaling also triggers timely egress from the host cell at other life cycle stages of malaria parasites and in Toxoplasma gondii, a related apicomplexan parasite. This suggests that cGMP signaling is a versatile platform transducing external cues into calcium signals at important decision points in the life cycle of apicomplexan parasites.
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Affiliation(s)
- Mathieu Brochet
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Aurélia C Balestra
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Lorenzo Brusini
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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6
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Bisio H, Soldati-Favre D. Signaling Cascades Governing Entry into and Exit from Host Cells by Toxoplasma gondii. Annu Rev Microbiol 2020; 73:579-599. [PMID: 31500539 DOI: 10.1146/annurev-micro-020518-120235] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Apicomplexa phylum includes a large group of obligate intracellular protozoan parasites responsible for important diseases in humans and animals. Toxoplasma gondii is a widespread parasite with considerable versatility, and it is capable of infecting virtually any warm-blooded animal, including humans. This outstanding success can be attributed at least in part to an efficient and continuous sensing of the environment, with a ready-to-adapt strategy. This review updates the current understanding of the signals governing the lytic cycle of T. gondii, with particular focus on egress from infected cells, a key step for balancing survival, multiplication, and spreading in the host. We cover the recent advances in the conceptual framework of regulation of microneme exocytosis that ensures egress, motility, and invasion. Particular emphasis is given to the trigger molecules and signaling cascades regulating exit from host cells.
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Affiliation(s)
- Hugo Bisio
- Département de Microbiologie et Médecine Moléculaire, Centre Médical Universitaire, Université de Genève, 1211 Geneva 4, Switzerland;
| | - Dominique Soldati-Favre
- Département de Microbiologie et Médecine Moléculaire, Centre Médical Universitaire, Université de Genève, 1211 Geneva 4, Switzerland;
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7
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Koussis K, Withers-Martinez C, Baker DA, Blackman MJ. Simultaneous multiple allelic replacement in the malaria parasite enables dissection of PKG function. Life Sci Alliance 2020; 3:e201900626. [PMID: 32179592 PMCID: PMC7081069 DOI: 10.26508/lsa.201900626] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 01/28/2023] Open
Abstract
Over recent years, a plethora of new genetic tools has transformed conditional engineering of the malaria parasite genome, allowing functional dissection of essential genes in the asexual and sexual blood stages that cause pathology or are required for disease transmission, respectively. Important challenges remain, including the desirability to complement conditional mutants with a correctly regulated second gene copy to confirm that observed phenotypes are due solely to loss of gene function and to analyse structure-function relationships. To meet this challenge, here we combine the dimerisable Cre (DiCre) system with the use of multiple lox sites to simultaneously generate multiple recombination events of the same gene. We focused on the Plasmodium falciparum cGMP-dependent protein kinase (PKG), creating in parallel conditional disruption of the gene plus up to two allelic replacements. We use the approach to demonstrate that PKG has no scaffolding or adaptor role in intraerythrocytic development, acting solely at merozoite egress. We also show that a phosphorylation-deficient PKG is functionally incompetent. Our method provides valuable new tools for analysis of gene function in the malaria parasite.
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Affiliation(s)
| | | | - David A Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Michael J Blackman
- Malaria Biochemistry Laboratory, Francis Crick Institute, London, UK
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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8
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Calamera G, Li D, Ulsund AH, Kim JJ, Neely OC, Moltzau LR, Bjørnerem M, Paterson D, Kim C, Levy FO, Andressen KW. FRET-based cyclic GMP biosensors measure low cGMP concentrations in cardiomyocytes and neurons. Commun Biol 2019; 2:394. [PMID: 31701023 PMCID: PMC6820734 DOI: 10.1038/s42003-019-0641-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 10/02/2019] [Indexed: 01/13/2023] Open
Abstract
Several FRET (fluorescence resonance energy transfer)-based biosensors for intracellular detection of cyclic nucleotides have been designed in the past decade. However, few such biosensors are available for cGMP, and even fewer that detect low nanomolar cGMP concentrations. Our aim was to develop a FRET-based cGMP biosensor with high affinity for cGMP as a tool for intracellular signaling studies. We used the carboxyl-terminal cyclic nucleotide binding domain of Plasmodium falciparum cGMP-dependent protein kinase (PKG) flanked by different FRET pairs to generate two cGMP biosensors (Yellow PfPKG and Red PfPKG). Here, we report that these cGMP biosensors display high affinity for cGMP (EC50 of 23 ± 3 nM) and detect cGMP produced through soluble guanylyl cyclase and guanylyl cyclase A in stellate ganglion neurons and guanylyl cyclase B in cardiomyocytes. These biosensors are therefore optimal tools for real-time measurements of low concentrations of cGMP in living cells.
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Affiliation(s)
- Gaia Calamera
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
- Center for Heart Failure Research, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Dan Li
- Department of Physiology, Anatomy and Genetics, Oxford University, Oxford, UK
| | - Andrea Hembre Ulsund
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
- Center for Heart Failure Research, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Jeong Joo Kim
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX USA
| | - Oliver C. Neely
- Department of Physiology, Anatomy and Genetics, Oxford University, Oxford, UK
| | - Lise Román Moltzau
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
- Center for Heart Failure Research, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Marianne Bjørnerem
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
- Center for Heart Failure Research, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - David Paterson
- Department of Physiology, Anatomy and Genetics, Oxford University, Oxford, UK
| | - Choel Kim
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX USA
| | - Finn Olav Levy
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
- Center for Heart Failure Research, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Kjetil Wessel Andressen
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
- Center for Heart Failure Research, University of Oslo and Oslo University Hospital, Oslo, Norway
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9
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Jillapalli R, Narwal SK, Kolli SK, Mastan BS, Segireddy RR, Dey S, Srivastava PN, Mishra S, Kumar KA. A Plasmodium berghei putative serine-threonine kinase 2 ( PBANKA_0311400) is required for late liver stage development and timely initiation of blood stage infection. Biol Open 2019; 8:bio.042028. [PMID: 31444161 PMCID: PMC6737972 DOI: 10.1242/bio.042028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In Plasmodium, protein kinases govern key biological processes of the parasite life cycle involved in the establishment of infection, dissemination and sexual reproduction. The rodent malaria model Plasmodium berghei encodes for 66 putative eukaryotic protein kinases (ePKs) as identified through modelling domain signatures and are highly conserved in Plasmodium falciparum. We report here the functional characterisation of a putative serine-threonine kinase PBANKA_0311400 identified in this kinome analysis and designate it as Pbstk2. To elucidate its role, we knocked out Pbstk2 locus and performed a detailed phenotypic analysis at different life cycle stages. The Pbstk2 knockout (KO) was not compromised in asexual blood stage propagation, transmission and development in the mosquito vector. The Pbstk2 KO produced viable salivary gland sporozoites that successfully transformed into exo-erythrocytic forms (EEFs) and were morphologically indistinguishable from wild-type GFP (WT GFP) with regard to size and shape until 48 h. An intravenous dose of 1×103Pbstk2 KO sporozoites in C57BL/6 mice failed to establish blood stage infection and a higher dose of 5X103 showed a 2–3 day delay in prepatency as compared to WT GFP parasites. Consistent with such an observation, analysis of in vitro EEF development at 62 h revealed that the hepatic merozoite numbers were reduced to nearly 40% as compared to WT GFP and showed meagre expression of MSP1. Our studies provide evidence for the role of PbSTK2 in late liver stage development and for the successful establishment of a timely blood stage infection. Summary: Requirement of a putative serine threonine kinase 2 (PBANKA_0311400) for Plasmodium berghei liver stage development.
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Affiliation(s)
- Ravi Jillapalli
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Sunil Kumar Narwal
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Surendra Kumar Kolli
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Babu S Mastan
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Rameswara Reddy Segireddy
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Sandeep Dey
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | | | - Satish Mishra
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Kota Arun Kumar
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
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10
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Plasmodium falciparum histidine triad protein and calmodulin modulates calcium homeostasis and intracellular proteolysis. Biochem Biophys Res Commun 2018; 503:722-728. [DOI: 10.1016/j.bbrc.2018.06.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 06/13/2018] [Indexed: 10/28/2022]
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11
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Baker DA, Drought LG, Flueck C, Nofal SD, Patel A, Penzo M, Walker EM. Cyclic nucleotide signalling in malaria parasites. Open Biol 2018; 7:rsob.170213. [PMID: 29263246 PMCID: PMC5746546 DOI: 10.1098/rsob.170213] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/28/2017] [Indexed: 12/22/2022] Open
Abstract
The cyclic nucleotides 3′, 5′-cyclic adenosine monophosphate (cAMP) and 3′, 5′-cyclic guanosine monophosphate (cGMP) are intracellular messengers found in most animal cell types. They usually mediate an extracellular stimulus to drive a change in cell function through activation of their respective cyclic nucleotide-dependent protein kinases, PKA and PKG. The enzymatic components of the malaria parasite cyclic nucleotide signalling pathways have been identified, and the genetic and biochemical studies of these enzymes carried out to date are reviewed herein. What has become very clear is that cyclic nucleotides play vital roles in controlling every stage of the complex malaria parasite life cycle. Our understanding of the involvement of cyclic nucleotide signalling in orchestrating the complex biology of malaria parasites is still in its infancy, but the recent advances in our genetic tools and the increasing interest in signalling will deliver more rapid progress in the coming years.
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Affiliation(s)
- David A Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Laura G Drought
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Christian Flueck
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Stephanie D Nofal
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Avnish Patel
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Maria Penzo
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK.,Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760, Madrid, Spain
| | - Eloise M Walker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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12
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Abstract
Cyclic GMP (cGMP)-dependent protein kinase (protein kinase G [PKG]) is essential for microneme secretion, motility, invasion, and egress in apicomplexan parasites, However, the separate roles of two isoforms of the kinase that are expressed by some apicomplexans remain uncertain. Despite having identical regulatory and catalytic domains, PKGI is plasma membrane associated whereas PKGII is cytosolic in Toxoplasma gondii. To determine whether these isoforms are functionally distinct or redundant, we developed an auxin-inducible degron (AID) tagging system for conditional protein depletion in T. gondii. By combining AID regulation with genome editing strategies, we determined that PKGI is necessary and fully sufficient for PKG-dependent cellular processes. Conversely, PKGII is functionally insufficient and dispensable in the presence of PKGI. The difference in functionality mapped to the first 15 residues of PKGI, containing a myristoylated Gly residue at position 2 that is critical for membrane association and PKG function. Collectively, we have identified a novel requirement for cGMP signaling at the plasma membrane and developed a new system for examining essential proteins in T. gondii. Toxoplasma gondii is an obligate intracellular apicomplexan parasite and important clinical and veterinary pathogen that causes toxoplasmosis. Since apicomplexans can only propagate within host cells, efficient invasion is critically important for their life cycles. Previous studies using chemical genetics demonstrated that cyclic GMP signaling through protein kinase G (PKG)-controlled invasion by apicomplexan parasites. However, these studies did not resolve functional differences between two compartmentalized isoforms of the kinase. Here we developed a conditional protein regulation tool to interrogate PKG isoforms in T. gondii. We found that the cytosolic PKG isoform was largely insufficient and dispensable. In contrast, the plasma membrane-associated isoform was necessary and fully sufficient for PKG function. Our studies identify the plasma membrane as a key location for PKG activity and provide a broadly applicable system for examining essential proteins in T. gondii.
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Phosphoproteomics reveals malaria parasite Protein Kinase G as a signalling hub regulating egress and invasion. Nat Commun 2015; 6:7285. [PMID: 26149123 PMCID: PMC4507021 DOI: 10.1038/ncomms8285] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 04/26/2015] [Indexed: 12/19/2022] Open
Abstract
Our understanding of the key phosphorylation-dependent signalling pathways in the human malaria parasite, Plasmodium falciparum, remains rudimentary. Here we address this issue for the essential cGMP-dependent protein kinase, PfPKG. By employing chemical and genetic tools in combination with quantitative global phosphoproteomics, we identify the phosphorylation sites on 69 proteins that are direct or indirect cellular targets for PfPKG. These PfPKG targets include proteins involved in cell signalling, proteolysis, gene regulation, protein export and ion and protein transport, indicating that cGMP/PfPKG acts as a signalling hub that plays a central role in a number of core parasite processes. We also show that PfPKG activity is required for parasite invasion. This correlates with the finding that the calcium-dependent protein kinase, PfCDPK1, is phosphorylated by PfPKG, as are components of the actomyosin complex, providing mechanistic insight into the essential role of PfPKG in parasite egress and invasion.
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Perspective on computational and structural aspects of kinase discovery from IPK2014. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1595-604. [PMID: 25861861 DOI: 10.1016/j.bbapap.2015.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/29/2015] [Accepted: 03/30/2015] [Indexed: 01/16/2023]
Abstract
Recent advances in understanding the activity and selectivity of kinase inhibitors and their relationships to protein structure are presented. Conformational selection in kinases is studied from empirical, data-driven and simulation approaches. Ligand binding and its affinity are, in many cases, determined by the predetermined active and inactive conformation of kinases. Binding affinity and selectivity predictions highlight the current state of the art and advances in computational chemistry as it applies to kinase inhibitor discovery. Kinome wide inhibitor profiling and cell panel profiling lead to a better understanding of selectivity and allow for target validation and patient tailoring hypotheses. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases.
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15
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Kim JJ, Flueck C, Franz E, Sanabria-Figueroa E, Thompson E, Lorenz R, Bertinetti D, Baker DA, Herberg FW, Kim C. Crystal structures of the carboxyl cGMP binding domain of the Plasmodium falciparum cGMP-dependent protein kinase reveal a novel capping triad crucial for merozoite egress. PLoS Pathog 2015; 11:e1004639. [PMID: 25646845 PMCID: PMC4412288 DOI: 10.1371/journal.ppat.1004639] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 12/20/2014] [Indexed: 01/05/2023] Open
Abstract
The Plasmodium falciparum cGMP-dependent protein kinase (PfPKG) is a key regulator across the malaria parasite life cycle. Little is known about PfPKG’s activation mechanism. Here we report that the carboxyl cyclic nucleotide binding domain functions as a “gatekeeper” for activation by providing the highest cGMP affinity and selectivity. To understand the mechanism, we have solved its crystal structures with and without cGMP at 2.0 and 1.9 Å, respectively. These structures revealed a PfPKG-specific capping triad that forms upon cGMP binding, and disrupting the triad reduces kinase activity by 90%. Furthermore, mutating these residues in the parasite prevents blood stage merozoite egress, confirming the essential nature of the triad in the parasite. We propose a mechanism of activation where cGMP binding allosterically triggers the conformational change at the αC-helix, which bridges the regulatory and catalytic domains, causing the capping triad to form and stabilize the active conformation. Malaria causes up to a million fatalities per year worldwide. Most of these deaths are caused by Plasmodium falciparum, which has a complex life cycle in both humans and mosquitoes. One key regulator of this process is P. falciparum cGMP-dependent protein kinase (PfPKG), the main effector of the cGMP-signaling pathway. Specifically blocking this kinase stops both replication and transmission of the parasites, suggesting that PfPKG is a promising drug target. Here we identified the carboxyl cGMP-binding domain of PfPKG serving as a gatekeeper for activation of the entire kinase by having the highest affinity and selectivity for cGMP. High-resolution crystal structures with and without cGMP allowed us to identify a novel cGMP capping triad that dynamically forms upon binding cGMP and stabilizes the activated conformation. Mutation of the capping triad forming residues not only reduces its kinase activity, but also prevents blood stage merozoite egress, demonstrating its crucial role in PfPKG activation.
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Affiliation(s)
- Jeong Joo Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | - Christian Flueck
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Eugen Franz
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | | | - Eloise Thompson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Robin Lorenz
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | - Daniela Bertinetti
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | - David A. Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Choel Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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16
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Tewari R, Patzewitz EM, Poulin B, Stewart L, Baker DA. Development of a transgenic Plasmodium berghei line (Pb pfpkg) expressing the P. falciparum cGMP-dependent protein kinase, a novel antimalarial drug target. PLoS One 2014; 9:e96923. [PMID: 24805991 PMCID: PMC4013051 DOI: 10.1371/journal.pone.0096923] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 04/12/2014] [Indexed: 11/18/2022] Open
Abstract
With the inevitable selection of resistance to antimalarial drugs in treated populations, there is a need for new medicines to enter the clinic and new targets to progress through the drug discovery pipeline. In this study we set out to develop a transgenic rodent model for testing inhibitors of the Plasmodium falciparum cyclic GMP-dependent kinase in vivo. A model was needed that would allow us to investigate whether differences in amino acid sequence of this enzyme between species influences in vivo efficacy. Here we report the successful development of a transgenic P. berghei line in which the cyclic GMP-dependent protein kinase (PKG) was replaced by the P. falciparum orthologue. We demonstrate that the P. falciparum orthologue was able to functionally complement the endogenous P. berghei pkg gene throughout blood stage development and early sexual development. However, subsequent development in the mosquito was severely compromised. We show that this is due to a defect in the female lineage of the transgenic by using genetic crosses with both male and female deficient P. berghei lines. This defect could be due to expression of a female-specific target in the mosquito stages of P. berghei that cannot be phosphorylated by the P. falciparum kinase. Using a previously reported anti-coccidial inhibitor of the cyclic GMP-dependent protein kinase, we show no difference in in vivo efficacy between the transgenic and control P. berghei lines. This in vivo model will be useful for screening future generations of cyclic GMP-dependent protein kinase inhibitors and allowing us to overcome any species-specific differences in the enzyme primary sequence that would influence in vivo efficacy in the rodent model. The approach will also be applicable to in vivo testing of other antimalarial compounds where the target is known.
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Affiliation(s)
- Rita Tewari
- Centre for Genetics and Genomics, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom
- * E-mail: (RT); (DAB)
| | - Eva-Maria Patzewitz
- Centre for Genetics and Genomics, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Benoit Poulin
- Centre for Genetics and Genomics, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Lindsay Stewart
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - David A. Baker
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail: (RT); (DAB)
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17
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Targeting Plasmodium falciparum protein kinases with adenosine analogue-oligoarginine conjugates. Exp Parasitol 2014; 138:55-62. [PMID: 24534615 DOI: 10.1016/j.exppara.2014.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 12/03/2013] [Accepted: 02/05/2014] [Indexed: 11/22/2022]
Abstract
During the last decade, a vast number of inhibitors, ligands and fluorescent probes have evolved for mammalian protein kinases; however, the suitability of these compounds for studies of evolutionarily divergent eukaryotes has mostly been left beyond the scope of research. Here, we examined whether adenosine analogue-oligoarginine conjugates that had been extensively characterized as efficient inhibitors of the human protein kinases are applicable for targeting Plasmodium protein kinases. We demonstrated that ARCs were not only able to bind to and inhibit a representative member of Plasmodium falciparum kinome (cGMP-dependent protein kinase) in biochemical assay, but also affected the general phosphorylation levels in parasites released from the infected red blood cells upon saponin treatment. These findings urge advantaging of already existing biochemical tools, whose initially generic, but intrinsically "tunable" selectivity profiles could be used for dissection of signaling pathways outside the initially defined group of biological targets.
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Patzewitz EM, Guttery DS, Poulin B, Ramakrishnan C, Ferguson DJP, Wall RJ, Brady D, Holder AA, Szöőr B, Tewari R. An ancient protein phosphatase, SHLP1, is critical to microneme development in Plasmodium ookinetes and parasite transmission. Cell Rep 2013; 3:622-9. [PMID: 23434509 PMCID: PMC3617505 DOI: 10.1016/j.celrep.2013.01.032] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 11/30/2012] [Accepted: 01/28/2013] [Indexed: 12/24/2022] Open
Abstract
Signaling pathways controlled by reversible protein phosphorylation (catalyzed by kinases and phosphatases) in the malaria parasite Plasmodium are of great interest, for both increased understanding of parasite biology and identification of novel drug targets. Here, we report a functional analysis in Plasmodium of an ancient bacterial Shewanella-like protein phosphatase (SHLP1) found only in bacteria, fungi, protists, and plants. SHLP1 is abundant in asexual blood stages and expressed at all stages of the parasite life cycle. shlp1 deletion results in a reduction in ookinete (zygote) development, microneme formation, and complete ablation of oocyst formation, thereby blocking parasite transmission. This defect is carried by the female gamete and can be rescued by direct injection of mutant ookinetes into the mosquito hemocoel, where oocysts develop. This study emphasizes the varied functions of SHLP1 in Plasmodium ookinete biology and suggests that it could be a novel drug target for blocking parasite transmission.
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Affiliation(s)
- Eva-Maria Patzewitz
- Centre for Genetics and Genomics, School of Biology, Queens Medical Centre, University of Nottingham, Nottingham NG2 7UH, UK
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Wolfertstetter S, Huettner JP, Schlossmann J. cGMP-Dependent Protein Kinase Inhibitors in Health and Disease. Pharmaceuticals (Basel) 2013; 6:269-86. [PMID: 24275951 PMCID: PMC3816681 DOI: 10.3390/ph6020269] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 01/23/2013] [Accepted: 02/05/2013] [Indexed: 02/05/2023] Open
Abstract
cGMP-dependent protein kinases (PKG) exhibit diverse physiological functions in the mammalian system e.g., in vascular and gastrointestinal smooth muscles, in platelets, in kidney, in bone growth, nociception and in the central nervous system. Furthermore, PKG were found in insects and in the malaria parasite Plasmodium falciparum. Two different genes of PKG exist: a) the PKG-I gene that is expressed as cytosolic PKG-Iα or PKG-Iβ isoform, and b) the PKG-II gene, which expresses the membrane associated PKG-II protein. The enzyme kinetics, the localization and the substrates of these PKG enzymes differ utilizing different physiological functions. Various inhibitors of PKG were developed directed against diverse functional regions of the kinase. These inhibitors of PKG have been used to analyse the specific functions of these enzymes. The review article will summarize these different inhibitors regarding their specificity and their present applications in vitro and in vivo. Furthermore, it will be discussed that the distinct inhibition of the PKG enzymes could be used as a valuable pharmacological target e.g., in the treatment of cardiovascular diseases, diarrhea, cancer or malaria.
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Affiliation(s)
- Stefanie Wolfertstetter
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University Regensburg, Universitätsstr. 31, 93053 Regensburg, Germany.
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