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McMahon DB, Carey RM, Kohanski MA, Adappa ND, Palmer JN, Lee RJ. PAR-2-activated secretion by airway gland serous cells: role for CFTR and inhibition by Pseudomonas aeruginosa. Am J Physiol Lung Cell Mol Physiol 2021; 320:L845-L879. [PMID: 33655758 DOI: 10.1152/ajplung.00411.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Airway submucosal gland serous cells are important sites of fluid secretion in conducting airways. Serous cells also express the cystic fibrosis (CF) transmembrane conductance regulator (CFTR). Protease-activated receptor 2 (PAR-2) is a G protein-coupled receptor that activates secretion from intact airway glands. We tested if and how human nasal serous cells secrete fluid in response to PAR-2 stimulation using Ca2+ imaging and simultaneous differential interference contrast imaging to track isosmotic cell shrinking and swelling reflecting activation of solute efflux and influx pathways, respectively. During stimulation of PAR-2, serous cells exhibited dose-dependent increases in intracellular Ca2+. At stimulation levels >EC50 for Ca2+, serous cells simultaneously shrank ∼20% over ∼90 s due to KCl efflux reflecting Ca2+-activated Cl- channel (CaCC, likely TMEM16A)-dependent secretion. At lower levels of PAR-2 stimulation (<EC50 for Ca2+), shrinkage was not evident due to failure to activate CaCC. Low levels of cAMP-elevating VIP receptor (VIPR) stimulation, also insufficient to activate secretion alone, synergized with low-level PAR-2 stimulation to elicit fluid secretion dependent on both cAMP and Ca2+ to activate CFTR and K+ channels, respectively. Polarized cultures of primary serous cells also exhibited synergistic fluid secretion. Pre-exposure to Pseudomonas aeruginosa conditioned media inhibited PAR-2 activation by proteases but not peptide agonists in primary nasal serous cells, Calu-3 bronchial cells, and primary nasal ciliated cells. Disruption of synergistic CFTR-dependent PAR-2/VIPR secretion may contribute to reduced airway surface liquid in CF. Further disruption of the CFTR-independent component of PAR-2-activated secretion by P. aeruginosa may also be important to CF pathophysiology.
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Affiliation(s)
- Derek B McMahon
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Ryan M Carey
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Michael A Kohanski
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Nithin D Adappa
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - James N Palmer
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Robert J Lee
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.,Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
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Thibeault PE, Ramachandran R. Role of the Helix-8 and C-Terminal Tail in Regulating Proteinase Activated Receptor 2 Signaling. ACS Pharmacol Transl Sci 2020; 3:868-882. [PMID: 33073187 DOI: 10.1021/acsptsci.0c00039] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Indexed: 12/11/2022]
Abstract
The C-terminal tail of G-protein-coupled receptors (GPCR) contain important regulatory sites that enable interaction with intracellular signaling effectors. Here we examine the relative contribution of the C-tail serine/threonine phosphorylation sites (Ser383-385, Ser387-Thr392) and the helix-8 palmitoylation site (Cys361) in signaling regulation downstream of the proteolytically activated GPCR, PAR2. We examined Gαq/11-coupled calcium signaling, β-arrestin-1/-2 recruitment, and MAPK activation (p44/42 phosphorylation) by wild-type and mutant receptors expressed in a CRISPR/Cas9 PAR2-knockout HEK-293 cell background with both peptide stimulation of the receptor (SLIGRL-NH2) as well as activation with its endogenous trypsin revealed a tethered ligand. We find that alanine substitution of the membrane proximal serine residues (Ser383-385Ala) had no effect on SLIGRL-NH2- or trypsin-stimulated β-arrestin recruitment. In contrast, alanine substitutions in the Ser387-Thr392 cluster resulted in a large (∼50%) decrease in β-arrestin-1/-2 recruitment triggered by the activating peptide, SLIGRL-NH2, but was without an effect on trypsin-activated β-arrestin-1/-2 recruitment. Additionally, we find that alanine substitution of the helix-8 cysteine residue (Cys361Ala) led to a large decrease in both Gαq/11 coupling and β-arrestin-1/-2 recruitment to PAR2. Furthermore, we show that Gαq/11 inhibition with YM254890, inhibited ERK phosphorylation by PAR2 agonists, while genetic deletion of β-arrestin-1/-2 by CRISPR/Cas9 enhanced MAPK activation. Knockout of β-arrestins also enhanced Gαq/11-mediated calcium signaling. In line with these findings, a C-tail serine/threonine mutant that has decreased β-arrestin recruitment also showed enhanced ERK activation. Thus, our studies point to multiple mechanisms that regulate β-arrestin interaction with PAR2 and highlight differences in regulation of tethered-ligand- and peptide-mediated activation of this receptor.
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Affiliation(s)
- Pierre E Thibeault
- Department of Physiology and Pharmacology, University of Western Ontario, 1151 Richmond Street, London, Ontario N6A5C1, Canada
| | - Rithwik Ramachandran
- Department of Physiology and Pharmacology, University of Western Ontario, 1151 Richmond Street, London, Ontario N6A5C1, Canada
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Jiang H, Zhang X, Chen X, Aramsangtienchai P, Tong Z, Lin H. Protein Lipidation: Occurrence, Mechanisms, Biological Functions, and Enabling Technologies. Chem Rev 2018; 118:919-988. [PMID: 29292991 DOI: 10.1021/acs.chemrev.6b00750] [Citation(s) in RCA: 283] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Protein lipidation, including cysteine prenylation, N-terminal glycine myristoylation, cysteine palmitoylation, and serine and lysine fatty acylation, occurs in many proteins in eukaryotic cells and regulates numerous biological pathways, such as membrane trafficking, protein secretion, signal transduction, and apoptosis. We provide a comprehensive review of protein lipidation, including descriptions of proteins known to be modified and the functions of the modifications, the enzymes that control them, and the tools and technologies developed to study them. We also highlight key questions about protein lipidation that remain to be answered, the challenges associated with answering such questions, and possible solutions to overcome these challenges.
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Affiliation(s)
- Hong Jiang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiaoyu Zhang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiao Chen
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Pornpun Aramsangtienchai
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Zhen Tong
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Hening Lin
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
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Ramachandran R, Altier C, Oikonomopoulou K, Hollenberg MD. Proteinases, Their Extracellular Targets, and Inflammatory Signaling. Pharmacol Rev 2016; 68:1110-1142. [PMID: 27677721 DOI: 10.1124/pr.115.010991] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Given that over 2% of the human genome codes for proteolytic enzymes and their inhibitors, it is not surprising that proteinases serve many physiologic-pathophysiological roles. In this context, we provide an overview of proteolytic mechanisms regulating inflammation, with a focus on cell signaling stimulated by the generation of inflammatory peptides; activation of the proteinase-activated receptor (PAR) family of G protein-coupled receptors (GPCR), with a mechanism in common with adhesion-triggered GPCRs (ADGRs); and by proteolytic ion channel regulation. These mechanisms are considered in the much wider context that proteolytic mechanisms serve, including the processing of growth factors and their receptors, the regulation of matrix-integrin signaling, and the generation and release of membrane-tethered receptor ligands. These signaling mechanisms are relevant for inflammatory, neurodegenerative, and cardiovascular diseases as well as for cancer. We propose that the inflammation-triggering proteinases and their proteolytically generated substrates represent attractive therapeutic targets and we discuss appropriate targeting strategies.
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Affiliation(s)
- Rithwik Ramachandran
- Inflammation Research Network-Snyder Institute for Chronic Disease, Department of Physiology & Pharmacology (R.R., C.A., M.D.H.) and Department of Medicine (M.D.H.),University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada; Department of Pathology and Laboratory Medicine, Toronto Western Hospital, Toronto, Ontario, Canada (K.O.); and Department of Physiology and Pharmacology, Western University, London, Ontario, Canada (R.R.)
| | - Christophe Altier
- Inflammation Research Network-Snyder Institute for Chronic Disease, Department of Physiology & Pharmacology (R.R., C.A., M.D.H.) and Department of Medicine (M.D.H.),University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada; Department of Pathology and Laboratory Medicine, Toronto Western Hospital, Toronto, Ontario, Canada (K.O.); and Department of Physiology and Pharmacology, Western University, London, Ontario, Canada (R.R.)
| | - Katerina Oikonomopoulou
- Inflammation Research Network-Snyder Institute for Chronic Disease, Department of Physiology & Pharmacology (R.R., C.A., M.D.H.) and Department of Medicine (M.D.H.),University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada; Department of Pathology and Laboratory Medicine, Toronto Western Hospital, Toronto, Ontario, Canada (K.O.); and Department of Physiology and Pharmacology, Western University, London, Ontario, Canada (R.R.)
| | - Morley D Hollenberg
- Inflammation Research Network-Snyder Institute for Chronic Disease, Department of Physiology & Pharmacology (R.R., C.A., M.D.H.) and Department of Medicine (M.D.H.),University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada; Department of Pathology and Laboratory Medicine, Toronto Western Hospital, Toronto, Ontario, Canada (K.O.); and Department of Physiology and Pharmacology, Western University, London, Ontario, Canada (R.R.)
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Hamilton JR, Trejo J. Challenges and Opportunities in Protease-Activated Receptor Drug Development. Annu Rev Pharmacol Toxicol 2016; 57:349-373. [PMID: 27618736 DOI: 10.1146/annurev-pharmtox-011613-140016] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protease-activated receptors (PARs) are a unique class of G protein-coupled receptors (GPCRs) that transduce cellular responses to extracellular proteases. PARs have important functions in the vasculature, inflammation, and cancer and are important drug targets. A unique feature of PARs is their irreversible proteolytic mechanism of activation that results in the generation of a tethered ligand that cannot diffuse away. Despite the fact that GPCRs have proved to be the most successful class of druggable targets, the development of agents that target PARs specifically has been challenging. As a consequence, researchers have taken a remarkable diversity of approaches to develop pharmacological entities that modulate PAR function. Here, we present an overview of the diversity of therapeutic agents that have been developed against PARs. We further discuss PAR biased signaling and the influence of receptor compartmentalization, posttranslational modifications, and dimerization, which are important considerations for drug development.
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Affiliation(s)
- Justin R Hamilton
- Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria 3004, Australia
| | - JoAnn Trejo
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093;
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Abstract
Protein S-acylation, the only fully reversible posttranslational lipid modification of proteins, is emerging as a ubiquitous mechanism to control the properties and function of a diverse array of proteins and consequently physiological processes. S-acylation results from the enzymatic addition of long-chain lipids, most typically palmitate, onto intracellular cysteine residues of soluble and transmembrane proteins via a labile thioester linkage. Addition of lipid results in increases in protein hydrophobicity that can impact on protein structure, assembly, maturation, trafficking, and function. The recent explosion in global S-acylation (palmitoyl) proteomic profiling as a result of improved biochemical tools to assay S-acylation, in conjunction with the recent identification of enzymes that control protein S-acylation and de-acylation, has opened a new vista into the physiological function of S-acylation. This review introduces key features of S-acylation and tools to interrogate this process, and highlights the eclectic array of proteins regulated including membrane receptors, ion channels and transporters, enzymes and kinases, signaling adapters and chaperones, cell adhesion, and structural proteins. We highlight recent findings correlating disruption of S-acylation to pathophysiology and disease and discuss some of the major challenges and opportunities in this rapidly expanding field.
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Affiliation(s)
- Luke H Chamberlain
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, United Kingdom; and Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Michael J Shipston
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, United Kingdom; and Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
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Canto I, Trejo J. Palmitoylation of protease-activated receptor-1 regulates adaptor protein complex-2 and -3 interaction with tyrosine-based motifs and endocytic sorting. J Biol Chem 2013; 288:15900-12. [PMID: 23580642 DOI: 10.1074/jbc.m113.469866] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protease-activated receptor-1 (PAR1) is a G protein-coupled receptor for the coagulant protease thrombin. Thrombin binds to and cleaves the N terminus of PAR1, generating a new N terminus that functions as a tethered ligand that cannot diffuse away. In addition to rapid desensitization, PAR1 trafficking is critical for the regulation of cellular responses. PAR1 displays constitutive and agonist-induced internalization. Constitutive internalization of unactivated PAR1 is mediated by the clathrin adaptor protein complex-2 (AP-2), which binds to a distal tyrosine-based motif localized within the C-terminal tail (C-tail) domain. Once internalized, PAR1 is sorted from endosomes to lysosomes via AP-3 interaction with a second C-tail tyrosine motif proximal to the transmembrane domain. However, the regulatory processes that control adaptor protein recognition of PAR1 C-tail tyrosine-based motifs are not known. Here, we report that palmitoylation of PAR1 is critical for regulating proper utilization of tyrosine-based motifs and endocytic sorting. We show that PAR1 is basally palmitoylated at highly conserved C-tail cysteines. A palmitoylation-deficient PAR1 mutant is competent to signal and exhibits a marked increase in constitutive internalization and lysosomal degradation compared with wild type receptor. Intriguingly, enhanced constitutive internalization of PAR1 is mediated by AP-2 and requires the proximal tyrosine-based motif rather than the distal tyrosine motif used by wild type receptor. Moreover, palmitoylation-deficient PAR1 displays increased degradation that is mediated by AP-3. These findings suggest that palmitoylation of PAR1 regulates appropriate utilization of tyrosine-based motifs by adaptor proteins and endocytic trafficking, processes that are critical for maintaining appropriate expression of PAR1 at the cell surface.
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Affiliation(s)
- Isabel Canto
- Biomedical Sciences Graduate Program, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
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Oates J, Watts A. Uncovering the intimate relationship between lipids, cholesterol and GPCR activation. Curr Opin Struct Biol 2011; 21:802-7. [DOI: 10.1016/j.sbi.2011.09.007] [Citation(s) in RCA: 185] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 09/23/2011] [Accepted: 09/29/2011] [Indexed: 11/16/2022]
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The role of palmitoylation in signalling, cellular trafficking and plasma membrane localization of protease-activated receptor-2. PLoS One 2011; 6:e28018. [PMID: 22140500 PMCID: PMC3226677 DOI: 10.1371/journal.pone.0028018] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 10/29/2011] [Indexed: 01/05/2023] Open
Abstract
Protease-activated receptor-2 (PAR2) is a G protein coupled receptor (GPCR) activated by proteolytic cleavage of its amino terminal domain by trypsin-like serine proteases. This irreversible activation mechanism leads to rapid receptor desensitization by internalisation and degradation. We have explored the role of palmitoylation, the post-translational addition of palmitate, in PAR2 signalling, trafficking, cell surface expression and desensitization. Experiments using the palmitoylation inhibitor 2-bromopalmitate indicated that palmitate addition is important in trafficking of PAR2 endogenously expressed by prostate cancer cell lines. This was supported by palmitate labelling using two approaches, which showed that PAR2 stably expressed by CHO-K1 cells is palmitoylated and that palmitoylation occurs on cysteine 361. Palmitoylation is required for optimal PAR2 signalling as Ca2+ flux assays indicated that in response to trypsin agonism, palmitoylation deficient PAR2 is ∼9 fold less potent than wildtype receptor with a reduction of about 33% in the maximum signal induced via the mutant receptor. Confocal microscopy, flow cytometry and cell surface biotinylation analyses demonstrated that palmitoylation is required for efficient cell surface expression of PAR2. We also show that receptor palmitoylation occurs within the Golgi apparatus and is required for efficient agonist-induced rab11a-mediated trafficking of PAR2 to the cell surface. Palmitoylation is also required for receptor desensitization, as agonist-induced β-arrestin recruitment and receptor endocytosis and degradation were markedly reduced in CHO-PAR2-C361A cells compared with CHO-PAR2 cells. These data provide new insights on the life cycle of PAR2 and demonstrate that palmitoylation is critical for efficient signalling, trafficking, cell surface localization and degradation of this receptor.
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