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Greenwald E, Posner C, Bharath A, Lyons A, Salmerón C, Sriram K, Wiley SZ, Insel PA, Zhang J. GPCR Signaling Measurement and Drug Profiling with an Automated Live-Cell Microscopy System. ACS Sens 2023; 8:19-27. [PMID: 36602887 PMCID: PMC9994309 DOI: 10.1021/acssensors.2c01341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A major limitation of time-lapse microscopy combined with fluorescent biosensors, a powerful tool for quantifying spatiotemporal dynamics of signaling in single living cells, is low-experimental throughput. To overcome this limitation, we created a highly customizable, MATLAB-based platform: flexible automated liquid-handling combined microscope (FALCOscope) that coordinates an OpenTrons liquid handler and a fluorescence microscope to automate drug treatments, fluorescence imaging, and single-cell analysis. To test the feasibility of the FALCOscope, we quantified G protein-coupled receptor (GPCR)-stimulated Protein Kinase A activity and cAMP responses to GPCR agonists and antagonists. We also characterized cAMP dynamics induced by GPR68/OGR1, a proton-sensing GPCR, in response to variable extracellular pH values. GPR68-induced cAMP responses were more transient in acidic than neutral pH values, suggesting a pH-dependence for signal attenuation. Ogerin, a GPR68 positive allosteric modulator, enhanced cAMP response most strongly at pH 7.0 and sustained cAMP response for acidic pH values, thereby demonstrating the capability of the FALCOscope to capture allosteric modulation. At a high concentration, ogerin increased cAMP signaling independent of GPR68, likely via phosphodiesterase inhibition. The FALCOscope system thus enables enhanced throughput single-cell dynamic measurements and is a versatile system for interrogating spatiotemporal regulation of signaling molecules in living cells and for drug profiling and screening.
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Affiliation(s)
- Eric Greenwald
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, United States
| | - Clara Posner
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Ananya Bharath
- Department of Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Anne Lyons
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Cristina Salmerón
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, United States
| | - Krishna Sriram
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, United States
| | - Shu Z Wiley
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, United States
| | - Paul A Insel
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, United States.,Department of Medicine, University of California, San Diego, La Jolla, California 92093 United States
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, United States.,Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, United States.,Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
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2
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Imenez Silva PH, Wagner CA. Physiological relevance of proton-activated GPCRs. Pflugers Arch 2022; 474:487-504. [PMID: 35247105 PMCID: PMC8993716 DOI: 10.1007/s00424-022-02671-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 12/12/2022]
Abstract
The detection of H+ concentration variations in the extracellular milieu is accomplished by a series of specialized and non-specialized pH-sensing mechanisms. The proton-activated G protein–coupled receptors (GPCRs) GPR4 (Gpr4), TDAG8 (Gpr65), and OGR1 (Gpr68) form a subfamily of proteins capable of triggering intracellular signaling in response to alterations in extracellular pH around physiological values, i.e., in the range between pH 7.5 and 6.5. Expression of these receptors is widespread for GPR4 and OGR1 with particularly high levels in endothelial cells and vascular smooth muscle cells, respectively, while expression of TDAG8 appears to be more restricted to the immune compartment. These receptors have been linked to several well-studied pH-dependent physiological activities including central control of respiration, renal adaption to changes in acid–base status, secretion of insulin and peripheral responsiveness to insulin, mechanosensation, and cellular chemotaxis. Their role in pathological processes such as the genesis and progression of several inflammatory diseases (asthma, inflammatory bowel disease), and tumor cell metabolism and invasiveness, is increasingly receiving more attention and makes these receptors novel and interesting targets for therapy. In this review, we cover the role of these receptors in physiological processes and will briefly discuss some implications for disease processes.
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Affiliation(s)
- Pedro H Imenez Silva
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland. .,National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland.
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland. .,National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland.
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3
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Kumari P, Bowmik S, Paul SK, Biswas B, Banerjee SK, Murty US, Ravichandiran V, Mohan U. Sortase A: A chemoenzymatic approach for the labeling of cell surfaces. Biotechnol Bioeng 2021; 118:4577-4589. [PMID: 34491580 DOI: 10.1002/bit.27935] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/20/2021] [Accepted: 08/27/2021] [Indexed: 01/31/2023]
Abstract
Sortase A, a transpeptidase enzyme is present in many Gram-positive bacteria and helps in the recruitment of the cell surface proteins. Over the last two decades, Sortase A has become an attractive tool for performing in vivo and in vitro ligations. Sortase A-mediated ligation has continuously been used for its specificity, robustness, and highly efficient nature. These properties make it a popular choice among protein engineers as well as researchers from different fields. In this review, we give an overview of Sortase A-mediated ligation of various molecules on the cell surfaces, which can have diverse applications in interdisciplinary fields.
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Affiliation(s)
- Poonam Kumari
- Department of Biotechnology, National Institute of Pharmaceutical Education & Research (NIPER), Guwahati, Assam, India
| | - Sujoy Bowmik
- Department of Biotechnology, National Institute of Pharmaceutical Education & Research (NIPER), Guwahati, Assam, India
| | - Sudipto Kumar Paul
- Department of Biotechnology, National Institute of Pharmaceutical Education & Research (NIPER), Guwahati, Assam, India
| | - Bidisha Biswas
- Department of Biotechnology, National Institute of Pharmaceutical Education & Research (NIPER), Guwahati, Assam, India
| | - Sanjay K Banerjee
- Department of Biotechnology, National Institute of Pharmaceutical Education & Research (NIPER), Guwahati, Assam, India
| | | | - Velayutham Ravichandiran
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education & Research (NIPER), Kolkata, West Bengal, India
| | - Utpal Mohan
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education & Research (NIPER), Kolkata, West Bengal, India
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4
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Ozkan AD, Gettas T, Sogata A, Phaychanpheng W, Zhou M, Lacroix JJ. Mechanical and chemical activation of GPR68 probed with a genetically encoded fluorescent reporter. J Cell Sci 2021; 134:271846. [PMID: 34322699 DOI: 10.1242/jcs.255455] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 07/17/2021] [Indexed: 12/24/2022] Open
Abstract
G-protein-coupled receptor (GPCR) 68 (GPR68, or OGR1) couples extracellular acidifications and mechanical stimuli to G-protein signaling and plays important roles in vascular physiology, neuroplasticity and cancer progression. Inspired by previous GPCR-based reporters, here, we inserted a cyclic permuted fluorescent protein into the third intracellular loop of GPR68 to create a genetically encoded fluorescent reporter of GPR68 activation we call 'iGlow'. iGlow responds to known physiological GPR68 activators such as fluid shear stress and extracellular acidifications. In addition, iGlow responds to Ogerin, a synthetic GPR68-selective agonist, but not to a non-active Ogerin analog, showing the specificity of iGlow-mediated fluorescence signals. Flow-induced iGlow activation is not eliminated by pharmacological modulation of downstream G-protein signaling, disruption of actin filaments or application of GsMTx4, an inhibitor of certain mechanosensitive ion channels activated by membrane stretch. Deletion of the conserved helix 8, proposed to mediate mechanosensitivity in certain GPCRs, does not eliminate flow-induced iGlow activation. iGlow could be useful to investigate the contribution of GPR68-dependent signaling in health and disease.
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Affiliation(s)
- Alper D Ozkan
- Graduate College of Biomedical Sciences, Western University of Health Sciences, 309 E. Second St, Pomona, CA 91766, USA
| | - Tina Gettas
- Graduate College of Biomedical Sciences, Western University of Health Sciences, 309 E. Second St, Pomona, CA 91766, USA
| | - Audrey Sogata
- Chino Hills High School, 16150 Pomona Rincon Rd, Chino Hills, CA 91709, USA
| | - Wynn Phaychanpheng
- Chino Hills High School, 16150 Pomona Rincon Rd, Chino Hills, CA 91709, USA
| | - Miou Zhou
- Graduate College of Biomedical Sciences, Western University of Health Sciences, 309 E. Second St, Pomona, CA 91766, USA
| | - Jérôme J Lacroix
- Graduate College of Biomedical Sciences, Western University of Health Sciences, 309 E. Second St, Pomona, CA 91766, USA
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5
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Wolf P, Gavins G, Beck‐Sickinger AG, Seitz O. Strategies for Site-Specific Labeling of Receptor Proteins on the Surfaces of Living Cells by Using Genetically Encoded Peptide Tags. Chembiochem 2021; 22:1717-1732. [PMID: 33428317 PMCID: PMC8248378 DOI: 10.1002/cbic.202000797] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/08/2021] [Indexed: 12/14/2022]
Abstract
Fluorescence microscopy imaging enables receptor proteins to be investigated within their biological context. A key challenge is to site-specifically incorporate reporter moieties into proteins without interfering with biological functions or cellular networks. Small peptide tags offer the opportunity to combine inducible labeling with small tag sizes that avoid receptor perturbation. Herein, we review the current state of live-cell labeling of peptide-tagged cell-surface proteins. Considering their importance as targets in medicinal chemistry, we focus on membrane receptors such as G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs). We discuss peptide tags that i) are subject to enzyme-mediated modification reactions, ii) guide the complementation of reporter proteins, iii) form coiled-coil complexes, and iv) interact with metal complexes. Given our own contributions in the field, we place emphasis on peptide-templated labeling chemistry.
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Affiliation(s)
- Philipp Wolf
- Faculty of Life SciencesInstitute of BiochemistryLeipzig UniversityBrüderstrasse 3404103LeipzigGermany
| | - Georgina Gavins
- Faculty of Mathematics and Natural SciencesDepartment of ChemistryHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | - Annette G. Beck‐Sickinger
- Faculty of Life SciencesInstitute of BiochemistryLeipzig UniversityBrüderstrasse 3404103LeipzigGermany
| | - Oliver Seitz
- Faculty of Mathematics and Natural SciencesDepartment of ChemistryHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
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6
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Unraveling the Molecular Nexus between GPCRs, ERS, and EMT. Mediators Inflamm 2021; 2021:6655417. [PMID: 33746610 PMCID: PMC7943314 DOI: 10.1155/2021/6655417] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 02/23/2021] [Accepted: 02/25/2021] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent a large family of transmembrane proteins that transduce an external stimulus into a variety of cellular responses. They play a critical role in various pathological conditions in humans, including cancer, by regulating a number of key processes involved in tumor formation and progression. The epithelial-mesenchymal transition (EMT) is a fundamental process in promoting cancer cell invasion and tumor dissemination leading to metastasis, an often intractable state of the disease. Uncontrolled proliferation and persistent metabolism of cancer cells also induce oxidative stress, hypoxia, and depletion of growth factors and nutrients. These disturbances lead to the accumulation of misfolded proteins in the endoplasmic reticulum (ER) and induce a cellular condition called ER stress (ERS) which is counteracted by activation of the unfolded protein response (UPR). Many GPCRs modulate ERS and UPR signaling via ERS sensors, IRE1α, PERK, and ATF6, to support cancer cell survival and inhibit cell death. By regulating downstream signaling pathways such as NF-κB, MAPK/ERK, PI3K/AKT, TGF-β, and Wnt/β-catenin, GPCRs also upregulate mesenchymal transcription factors including Snail, ZEB, and Twist superfamilies which regulate cell polarity, cytoskeleton remodeling, migration, and invasion. Likewise, ERS-induced UPR upregulates gene transcription and expression of proteins related to EMT enhancing tumor aggressiveness. Though GPCRs are attractive therapeutic targets in cancer biology, much less is known about their roles in regulating ERS and EMT. Here, we will discuss the interplay in GPCR-ERS linked to the EMT process of cancer cells, with a particular focus on oncogenes and molecular signaling pathways.
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7
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Comprehensive Assessment of GPR68 Expression in Normal and Neoplastic Human Tissues Using a Novel Rabbit Monoclonal Antibody. Int J Mol Sci 2019; 20:ijms20215261. [PMID: 31652823 PMCID: PMC6862545 DOI: 10.3390/ijms20215261] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 10/17/2019] [Accepted: 10/22/2019] [Indexed: 02/07/2023] Open
Abstract
GPR68 (OGR1) belongs to the proton-sensing G protein-coupled receptors that are involved in cellular adaptations to pH changes during tumour development. Although expression of GPR68 has been described in many tumour cell lines, little is known about its presence in human tumour entities. We characterised the novel rabbit monoclonal anti-human GPR68 antibody 16H23L16 using various cell lines and tissue specimens. The antibody was then applied to a large series of formalin-fixed, paraffin-embedded normal and neoplastic human tissue samples. Antibody specificity was demonstrated in a Western blot analysis of GPR68-expressing cells using specific siRNAs. Immunocytochemical experiments revealed pH-dependent changes in subcellular localisation of the receptor and internalisation after stimulation with lorazepam. In normal tissue, GPR68 was present in glucagon-producing islet cells, neuroendocrine cells of the intestinal tract, gastric glands, granulocytes, macrophages, muscle layers of arteries and arterioles, and capillaries. GPR68 was also expressed in neuroendocrine tumours, where it may be a positive prognostic factor, in pheochromocytomas, cervical adenocarcinomas, and endometrial cancer, as well as in paragangliomas, medullary thyroid carcinomas, gastrointestinal stromal tumours, and pancreatic adenocarcinomas. Often, tumour capillaries were also strongly GPR68-positive. The novel antibody 16H23L16 will be a valuable tool for basic research and for identifying GPR68-expressing tumours during histopathological examinations.
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8
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Lagadic-Gossmann D, Hardonnière K, Mograbi B, Sergent O, Huc L. Disturbances in H + dynamics during environmental carcinogenesis. Biochimie 2019; 163:171-183. [PMID: 31228544 DOI: 10.1016/j.biochi.2019.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 06/16/2019] [Indexed: 12/24/2022]
Abstract
Despite the improvement of diagnostic methods and anticancer therapeutics, the human population is still facing an increasing incidence of several types of cancers. According to the World Health Organization, this growing trend would be partly linked to our environment, with around 20% of cancers stemming from exposure to environmental contaminants, notably chemicals like polycyclic aromatic hydrocarbons (PAHs). PAHs are widespread pollutants in our environment resulting from incomplete combustion or pyrolysis of organic material, and thus produced by both natural and anthropic sources; notably benzo[a]pyrene (B[a]P), i.e. the prototypical molecule of this family, that can be detected in cigarette smoke, diesel exhaust particles, occupational-related fumes, and grilled food. This molecule is a well-recognized carcinogen belonging to group 1 carcinogens. Indeed, it can target the different steps of the carcinogenic process and all cancer hallmarks. Interestingly, H+ dynamics have been described as key parameters for the occurrence of several, if not all, of these hallmarks. However, information regarding the role of such parameters during environmental carcinogenesis is still very scarce. The present review will thus mainly give an overview of the impact of B[a]P on H+ dynamics in liver cells, and will show how such alterations might impact different aspects related to the finely-tuned balance between cell death and survival processes, thereby likely favoring environmental carcinogenesis. In total, the main objective of this review is to encourage further research in this poorly explored field of environmental molecular toxicology.
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Affiliation(s)
- Dominique Lagadic-Gossmann
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail), UMR_S 1085, F-35000, Rennes, France.
| | - Kévin Hardonnière
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail), UMR_S 1085, F-35000, Rennes, France
| | - Baharia Mograbi
- Institute of Research on Cancer and Ageing of Nice (IRCAN), INSERM U1081, CNRS UMR7284, 2. Université de Nice-Sophia Antipolis, Faculté de Médecine, Centre Antoine Lacassagne, Nice, F-06107, France
| | - Odile Sergent
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail), UMR_S 1085, F-35000, Rennes, France
| | - Laurence Huc
- INRA, ToxAlim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
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9
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Mani I, Pandey KN. Emerging concepts of receptor endocytosis and concurrent intracellular signaling: Mechanisms of guanylyl cyclase/natriuretic peptide receptor-A activation and trafficking. Cell Signal 2019; 60:17-30. [PMID: 30951863 DOI: 10.1016/j.cellsig.2019.03.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/27/2019] [Accepted: 03/28/2019] [Indexed: 12/15/2022]
Abstract
Endocytosis is a prominent clathrin-mediated mechanism for concentrated uptake and internalization of ligand-receptor complexes, also known as cargo. Internalization of cargo is the fundamental mechanism for receptor-dependent regulation of cell membrane function, intracellular signal transduction, and neurotransmission, as well as other biological and physiological activities. However, the intrinsic mechanisms of receptor endocytosis and contemporaneous intracellular signaling are not well understood. We review emerging concepts of receptor endocytosis with concurrent intracellular signaling, using a typical example of guanylyl cyclase/natriuretic peptide receptor-A (NPRA) internalization, subcellular trafficking, and simultaneous generation of second-messenger cGMP and signaling in intact cells. We highlight the role of short-signal motifs located in the carboxyl-terminal regions of membrane receptors during their internalization and subsequent receptor trafficking in organelles that are not traditionally studied in this context, including nuclei and mitochondria. This review sheds light on the importance of future investigations of receptor endocytosis and trafficking in live cells and intact animals in vivo in physiological context.
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Affiliation(s)
- Indra Mani
- Department of Physiology, Tulane University Health Sciences Center and School of Medicine, 1430 Tulane Avenue, New Orleans, Louisiana 70112, United States
| | - Kailash N Pandey
- Department of Physiology, Tulane University Health Sciences Center and School of Medicine, 1430 Tulane Avenue, New Orleans, Louisiana 70112, United States.
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10
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Dai X, Böker A, Glebe U. Broadening the scope of sortagging. RSC Adv 2019; 9:4700-4721. [PMID: 35514663 PMCID: PMC9060782 DOI: 10.1039/c8ra06705h] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 01/31/2019] [Indexed: 01/20/2023] Open
Abstract
Sortases are enzymes occurring in the cell wall of Gram-positive bacteria. Sortase A (SrtA), the best studied sortase class, plays a key role in anchoring surface proteins with the recognition sequence LPXTG covalently to oligoglycine units of the bacterial cell wall. This unique transpeptidase activity renders SrtA attractive for various purposes and motivated researchers to study multiple in vivo and in vitro ligations in the last decades. This ligation technique is known as sortase-mediated ligation (SML) or sortagging and developed to a frequently used method in basic research. The advantages are manifold: extremely high substrate specificity, simple access to substrates and enzyme, robust nature and easy handling of sortase A. In addition to the ligation of two proteins or peptides, early studies already included at least one artificial (peptide equipped) substrate into sortagging reactions - which demonstrates the versatility and broad applicability of SML. Thus, SML is not only a biology-related technique, but has found prominence as a major interdisciplinary research tool. In this review, we provide an overview about the use of sortase A in interdisciplinary research, mainly for protein modification, synthesis of protein-polymer conjugates and immobilization of proteins on surfaces.
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Affiliation(s)
- Xiaolin Dai
- Fraunhofer Institute for Applied Polymer Research IAP Geiselbergstr. 69 14476 Potsdam-Golm Germany
- Lehrstuhl für Polymermaterialien und Polymertechnologie, Universität Potsdam 14476 Potsdam-Golm Germany
| | - Alexander Böker
- Fraunhofer Institute for Applied Polymer Research IAP Geiselbergstr. 69 14476 Potsdam-Golm Germany
- Lehrstuhl für Polymermaterialien und Polymertechnologie, Universität Potsdam 14476 Potsdam-Golm Germany
| | - Ulrich Glebe
- Fraunhofer Institute for Applied Polymer Research IAP Geiselbergstr. 69 14476 Potsdam-Golm Germany
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11
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Wiley SZ, Sriram K, Salmerón C, Insel PA. GPR68: An Emerging Drug Target in Cancer. Int J Mol Sci 2019; 20:E559. [PMID: 30696114 PMCID: PMC6386835 DOI: 10.3390/ijms20030559] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 12/19/2022] Open
Abstract
GPR68 (or ovarian cancer G protein-coupled receptor 1, OGR1) is a proton-sensing G-protein-coupled receptor (GPCR) that responds to extracellular acidity and regulates a variety of cellular functions. Acidosis is considered a defining hallmark of the tumor microenvironment (TME). GPR68 expression is highly upregulated in numerous types of cancer. Emerging evidence has revealed that GPR68 may play crucial roles in tumor biology, including tumorigenesis, tumor growth, and metastasis. This review summarizes current knowledge regarding GPR68-its expression, regulation, signaling pathways, physiological roles, and functions it regulates in human cancers (including prostate, colon and pancreatic cancer, melanoma, medulloblastoma, and myelodysplastic syndrome). The findings provide evidence for GPR68 as a potentially novel therapeutic target but in addition, we note challenges in developing drugs that target GPR68.
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Affiliation(s)
- Shu Z Wiley
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Krishna Sriram
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Cristina Salmerón
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Paul A Insel
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA.
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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12
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Zhao B, Hu T. JTC-801 inhibits the proliferation and metastasis of the Hep G2 hepatoblastoma cell line by regulating the phosphatidylinositol 3-kinase/protein kinase B signalling pathway. Oncol Lett 2018; 17:1939-1945. [PMID: 30675258 DOI: 10.3892/ol.2018.9780] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 09/17/2018] [Indexed: 12/18/2022] Open
Abstract
The increased worldwide mortality rate due to liver cancer may be attributed to the aggressive nature of the disease. Signal transduction through G-protein-coupled receptors (GPCRs) can affect a number of aspects of cancer biology, including invasion, migration and vascular remodelling. JTC-801, a novel GPCR antagonist, has demonstrated promising anticancer effects in adenocarcinoma and osteosarcoma cells. In the present study, the effect of JTC-801 on the proliferation and migration of hepatoblastoma Hep G2 cells was investigated. The Cell Counting Kit-8 assay revealed that JTC-801 markedly suppressed the growth of the Hep G2 cells. Additionally, JTC-801 significantly inhibited cell invasion and migration in a Transwell assay. Furthermore, the expression of anti-apoptotic protein B-cell lymphoma 2 decreased and the expression of the pro-apoptotic proteins active caspase-3 and apoptosis regulator BAX increased in the Hep G2 cells following JTC-801 treatment. Additionally, JTC-801 suppressed the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signalling pathway in the Hep G2 cells. Therefore, the present study revealed that JTC-801 can induce the apoptosis of Hep G2 cells by regulating the PI3K/AKT signalling pathway, which suggests that JTC-801 may be a potential novel drug target for clinical liver cancer treatment.
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Affiliation(s)
- Bufei Zhao
- Department of Hepatopancreatobiliary Surgery, Affiliated Hospital of Beihua University, Jilin 132001, P.R. China
| | - Ting Hu
- Department of Oncology, The First Affiliated Hospital of Changchun University of Chinese Medicine, Changchun, Jilin 130021, P.R. China
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