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Wijayaratna D, Sacchetta F, Pedraza-González L, Fanelli F, Sugihara T, Koyanagi M, Piyawardana S, Ghotra K, Thotamune W, Terakita A, Olivucci M, Karunarathne A. In-silico predicted mouse melanopsins with blue spectral shifts deliver efficient subcellular signaling. Cell Commun Signal 2024; 22:394. [PMID: 39118111 PMCID: PMC11312219 DOI: 10.1186/s12964-024-01753-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 07/17/2024] [Indexed: 08/10/2024] Open
Abstract
Melanopsin is a photopigment belonging to the G Protein-Coupled Receptor (GPCR) family expressed in a subset of intrinsically photosensitive retinal ganglion cells (ipRGCs) and responsible for a variety of processes. The bistability and, thus, the possibility to function under low retinal availability would make melanopsin a powerful optogenetic tool. Here, we aim to utilize mouse melanopsin to trigger macrophage migration by its subcellular optical activation with localized blue light, while simultaneously imaging the migration with red light. To reduce melanopsin's red light sensitivity, we employ a combination of in silico structure prediction and automated quantum mechanics/molecular mechanics modeling to predict minimally invasive mutations to shift its absorption spectrum towards the shorter wavelength region of the visible spectrum without compromising the signaling efficiency. The results demonstrate that it is possible to achieve melanopsin mutants that resist red light-induced activation but are activated by blue light and display properties indicating preserved bistability. Using the A333T mutant, we show that the blue light-induced subcellular melanopsin activation triggers localized PIP3 generation and macrophage migration, which we imaged using red light, demonstrating the optogenetic utility of minimally engineered melanopsins.
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Affiliation(s)
| | - Filippo Sacchetta
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | | | - Francesca Fanelli
- Department of Life Sciences, Dulbecco Telethon Institute, University of Modena and Reggio Emilia, Modena, I-41125, Italy
| | - Tomohiro Sugihara
- Department of Biology, Osaka Metropolitan University, O 3-3-138 Sugimoto, Sumiyoshi-Ku, Osaka, 558-8585, Japan
| | - Mitsumasa Koyanagi
- Department of Biology, Osaka Metropolitan University, O 3-3-138 Sugimoto, Sumiyoshi-Ku, Osaka, 558-8585, Japan
- The OMU Advanced Research Institute for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan
| | - Senuri Piyawardana
- Department of Chemistry, Saint Louis University, Saint Louis, MO, 63103, USA
| | - Kiran Ghotra
- Department of Biology, Siena Heights University, Adrian, MI, 49221, USA
| | - Waruna Thotamune
- Department of Chemistry, Saint Louis University, Saint Louis, MO, 63103, USA
| | - Akihisa Terakita
- Department of Biology, Osaka Metropolitan University, O 3-3-138 Sugimoto, Sumiyoshi-Ku, Osaka, 558-8585, Japan
- The OMU Advanced Research Institute for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan
| | - Massimo Olivucci
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy.
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA.
| | - Ajith Karunarathne
- Department of Chemistry, Saint Louis University, Saint Louis, MO, 63103, USA.
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2
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Thotamune W, Ubeysinghe S, Shrestha KK, Mostafa ME, Young MC, Karunarathne A. Optical control of cell-surface and endomembrane-exclusive β-adrenergic receptor signaling. J Biol Chem 2024; 300:107481. [PMID: 38901558 PMCID: PMC11304070 DOI: 10.1016/j.jbc.2024.107481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/29/2024] [Accepted: 06/10/2024] [Indexed: 06/22/2024] Open
Abstract
Beta-adrenergic receptors (βARs) are G protein-coupled receptors (GPCRs) that mediate catecholamine hormone-induced stress responses, such as elevation of heart rate. Besides those that are plasma membrane-bound, endomembrane βARs are also signaling competent. Dysregulation of βAR pathways underlies severe pathological conditions. Emerging evidence indicates pathological molecular signatures in deeper endomembrane βARs signaling, likely contributing to conditions such as cardiomyocyte hypertrophy and apoptosis. However, the lack of approaches to control endomembrane β1ARs has impeded linking signaling with pathology. Informed by the β1AR-catecholamine interactions, we engineered an efficient photolabile proligand (OptoIso) to trigger βAR signaling exclusively in endomembrane regions using blue light stimulation. Not only does OptoIso undergo blue light deprotection in seconds, but also efficiently enters cells and allows examination of G protein heterotrimer activation exclusively at endomembranes. OptoIso also allows optical activation of plasma membrane βAR signaling in selected single cells with native fidelity, which can be reversed by terminating blue light. Thus, OptoIso will be a valuable experimental tool to elicit spatial and temporal control of βAR signaling in user-defined endomembrane or plasma membrane regions in unmodified cells with native fidelity.
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Affiliation(s)
- Waruna Thotamune
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri, USA
| | | | - Kendra K Shrestha
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, Toledo, Ohio, USA
| | | | - Michael C Young
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, Toledo, Ohio, USA.
| | - Ajith Karunarathne
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri, USA.
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3
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Thotamune W, Ubeysinghe S, Rajarathna C, Kankanamge D, Olupothage K, Chandu A, Copits BA, Karunarathne A. AGS3-based optogenetic GDI induces GPCR-independent Gβγ signaling and macrophage migration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.04.597473. [PMID: 38895415 PMCID: PMC11185739 DOI: 10.1101/2024.06.04.597473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
G protein-coupled receptors (GPCRs) are efficient Guanine nucleotide exchange factors (GEFs) and exchange GDP to GTP on the Gα subunit of G protein heterotrimers in response to various extracellular stimuli, including neurotransmitters and light. GPCRs primarily broadcast signals through activated G proteins, GαGTP, and free Gβγ, and are major disease drivers. Evidence shows that the ambient low threshold signaling required for cells is likely supplemented by signaling regulators such as non-GPCR GEFs and Guanine nucleotide Dissociation Inhibitors (GDIs). Activators of G protein Signaling 3 (AGS3) are recognized as a GDI involved in multiple health and disease-related processes. Nevertheless, understanding of AGS3 is limited, and no significant information is available on its structure-function relationship or signaling regulation in living cells. Here, we employed in silico structure-guided engineering of a novel optogenetic GDI, based on the AGS3's G protein regulatory (GPR) motif, to understand its GDI activity and induce standalone Gβγ signaling in living cells on optical command. Our results demonstrate that plasma membrane recruitment of OptoGDI efficiently releases Gβγ, and its subcellular targeting generated localized PIP3 and triggered macrophage migration. Therefore, we propose OptoGDI as a powerful tool for optically dissecting GDI-mediated signaling pathways and triggering GPCR-independent Gβγ signaling in cells and in vivo.
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Affiliation(s)
- Waruna Thotamune
- Department of Chemistry, Saint Louis University, Saint Louis, MO 63103, USA
- Institute for Drug and Biotherapeutic Innovation, Saint Louis University, Saint Louis, MO 63103, USA
| | - Sithurandi Ubeysinghe
- Department of Chemistry, Saint Louis University, Saint Louis, MO 63103, USA
- Institute for Drug and Biotherapeutic Innovation, Saint Louis University, Saint Louis, MO 63103, USA
| | - Chathuri Rajarathna
- Department of Chemistry, Saint Louis University, Saint Louis, MO 63103, USA
- Institute for Drug and Biotherapeutic Innovation, Saint Louis University, Saint Louis, MO 63103, USA
| | - Dinesh Kankanamge
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine; St. Louis, MO 63110 USA
| | - Koshala Olupothage
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Aditya Chandu
- Department of Chemistry, Saint Louis University, Saint Louis, MO 63103, USA
| | - Bryan A. Copits
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine; St. Louis, MO 63110 USA
| | - Ajith Karunarathne
- Department of Chemistry, Saint Louis University, Saint Louis, MO 63103, USA
- Institute for Drug and Biotherapeutic Innovation, Saint Louis University, Saint Louis, MO 63103, USA
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4
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Thotamune W, Ubeysinghe S, Shrestha KK, Mostafa ME, Young MC, Karunarathne A. Optical Control of Cell-Surface and Endomembrane-Exclusive β-Adrenergic Receptor Signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580335. [PMID: 38405895 PMCID: PMC10888897 DOI: 10.1101/2024.02.14.580335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Beta-adrenergic receptors (βARs) are G protein-coupled receptors (GPCRs) that mediate catecholamine-induced stress responses, such as heart rate increase and bronchodilation. In addition to signals from the cell surface, βARs also broadcast non-canonical signaling activities from the cell interior membranes (endomembranes). Dysregulation of these receptor pathways underlies severe pathological conditions. Excessive βAR stimulation is linked to cardiac hypertrophy, leading to heart failure, while impaired stimulation causes compromised fight or flight stress responses and homeostasis. In addition to plasma membrane βAR, emerging evidence indicates potential pathological implications of deeper endomembrane βARs, such as inducing cardiomyocyte hypertrophy and apoptosis, underlying heart failure. However, the lack of approaches to control their signaling in subcellular compartments exclusively has impeded linking endomembrane βAR signaling with pathology. Informed by the β1AR-catecholamine interactions, we engineered an efficiently photo-labile, protected hydroxy β1AR pro-ligand (OptoIso) to trigger βAR signaling at the cell surface, as well as exclusive endomembrane regions upon blue light stimulation. Not only does OptoIso undergo blue light deprotection in seconds, but it also efficiently enters cells and allows examination of G protein heterotrimer activation exclusively at endomembranes. In addition to its application in the optical interrogation of βARs in unmodified cells, given its ability to control deep organelle βAR signaling, OptoIso will be a valuable experimental tool.
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Affiliation(s)
- Waruna Thotamune
- Department of Chemistry, Saint Louis University, Saint Louis, MO 63103, USA
| | | | - Kendra K. Shrestha
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, Toledo, OH 43606, USA
| | | | - Michael C. Young
- Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, Toledo, OH 43606, USA
| | - Ajith Karunarathne
- Department of Chemistry, Saint Louis University, Saint Louis, MO 63103, USA
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5
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Ubeysinghe S, Kankanamge D, Thotamune W, Wijayaratna D, Mohan TM, Karunarathne A. Spatiotemporal Optical Control of Gαq-PLCβ Interactions. ACS Synth Biol 2024; 13:242-258. [PMID: 38092428 DOI: 10.1021/acssynbio.3c00490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2023]
Abstract
Cells experience time-varying and spatially heterogeneous chemokine signals in vivo, activating cell surface proteins including G protein-coupled receptors (GPCRs). The Gαq pathway activation by GPCRs is a major signaling axis with broad physiological and pathological significance. Compared with other Gα members, GαqGTP activates many crucial effectors, including PLCβ (Phospholipase Cβ) and Rho GEFs (Rho guanine nucleotide exchange factors). PLCβ regulates many key processes, such as hematopoiesis, synaptogenesis, and cell cycle, and is therefore implicated in terminal-debilitating diseases, including cancer, epilepsy, Huntington's Disease, and Alzheimer's Disease. However, due to a lack of genetic and pharmacological tools, examining how the dynamic regulation of PLCβ signaling controls cellular physiology has been difficult. Since activated PLCβ induces several abrupt cellular changes, including cell morphology, examining how the other pathways downstream of Gq-GPCRs contribute to the overall signaling has also been difficult. Here we show the engineering, validation, and application of a highly selective and efficient optogenetic inhibitor (Opto-dHTH) to completely disrupt GαqGTP-PLCβ interactions reversibly in user-defined cellular-subcellular regions on optical command. Using this newly gained PLCβ signaling control, our data indicate that the molecular competition between RhoGEFs and PLCβ for GαqGTP determines the potency of Gq-GPCR-governed directional cell migration.
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Affiliation(s)
- Sithurandi Ubeysinghe
- Department of Chemistry, Saint Louis University, St. Louis, Missouri 63103, United States
| | - Dinesh Kankanamge
- Pain Center, Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Waruna Thotamune
- Department of Chemistry, Saint Louis University, St. Louis, Missouri 63103, United States
| | - Dhanushan Wijayaratna
- Department of Chemistry, Saint Louis University, St. Louis, Missouri 63103, United States
| | - Thomas M Mohan
- Department of Chemistry, Saint Louis University, St. Louis, Missouri 63103, United States
| | - Ajith Karunarathne
- Department of Chemistry, Saint Louis University, St. Louis, Missouri 63103, United States
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6
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Landge VG, Mishra A, Thotamune W, Bonds AL, Alahakoon I, Karunarathne A, Young MC. Selective C-H Activation of Unprotected Allylamines by Control of Catalyst Speciation. CHEM CATALYSIS 2023; 3:100809. [PMID: 37982045 PMCID: PMC10653252 DOI: 10.1016/j.checat.2023.100809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
An outstanding challenge in the Pd-catalyzed functionalization of allylamines is the control of stereochemistry. Terminal alkenes preferentially undergo Heck-type reactions, while internal alkenes may undergo a mixture of Heck and C-H activation reactions that give mixtures of stereochemical products. In the case of unprotected allylamines, the challenge in achieving C-H activation is that facile in situ formation of Pd nanoparticles leads to preferential formation of trans rather than cis-substituted products. In this study we have demonstrated the feasibility of using mono-protected amino acid (MPAA) ligands as metal protecting groups to prevent aggregation and reduction, allowing the selective synthesis of free cis-arylated allylamines. This method complements Heck-selective methods, allowing complete stereochemical control over the synthesis of cinnamylamines, an important class of amine that can serve as therapeutics directly or as advanced intermediates. To highlight the utility of the methodology, we have demonstrated rapid access to mu opioid receptor ligands.
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Affiliation(s)
- Vinod G. Landge
- Department of Chemistry & Biochemistry, School of Green Chemistry & Engineering, The University of Toledo, Toledo, OH 43606, USA
| | - Ankita Mishra
- Department of Chemistry & Biochemistry, School of Green Chemistry & Engineering, The University of Toledo, Toledo, OH 43606, USA
| | - Waruna Thotamune
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, MO 63103, USA
| | - Audrey L. Bonds
- Department of Chemistry & Biochemistry, School of Green Chemistry & Engineering, The University of Toledo, Toledo, OH 43606, USA
| | - Indunil Alahakoon
- Department of Chemistry & Biochemistry, School of Green Chemistry & Engineering, The University of Toledo, Toledo, OH 43606, USA
| | - Ajith Karunarathne
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, MO 63103, USA
| | - Michael C. Young
- Department of Chemistry & Biochemistry, School of Green Chemistry & Engineering, The University of Toledo, Toledo, OH 43606, USA
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7
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Ubeysinghe S, Kankanamge D, Thotamune W, Wijayaratna D, Mohan TM, Karunarathne A. Spatiotemporal optical control of Gαq-PLCβ interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552801. [PMID: 37609229 PMCID: PMC10441412 DOI: 10.1101/2023.08.10.552801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Cells experience time-varying and spatially heterogeneous chemokine signals in vivo, activating cell surface proteins, including G protein-coupled receptors (GPCRs). The Gαq pathway activation by GPCRs is a major signaling axis with a broad physiological and pathological significance. Compared to other Gα members, GαqGTP activates many crucial effectors, including PLCβ (Phospholipase Cβ) and Rho GEFs (Rho guanine nucleotide exchange factors). PLCβ regulates many key processes, such as hematopoiesis, synaptogenesis, and cell cycle, and is therefore implicated in terminal - debilitating diseases, including cancer, epilepsy, Huntington's Disease, and Alzheimer's Disease. However, due to a lack of genetic and pharmacological tools, examining how the dynamic regulation of PLCβ signaling controls cellular physiology has been difficult. Since activated PLCβ induces several abrupt cellular changes, including cell morphology, examining how the other pathways downstream of Gq-GPCRs contribute to the overall signaling has also been difficult. Here we show the engineering, validation, and application of a highly selective and efficient optogenetic inhibitor (Opto-dHTH) to completely disrupt GαqGTP-PLCβ interactions reversibly in user-defined cellular-subcellular regions on optical command. Using this newly gained PLCβ signaling control, our data indicate that the molecular competition between RhoGEFs and PLCβ for GαqGTP determines the potency of Gq-GPCR-governed directional cell migration.
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8
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Wijayaratna D, Ratnayake K, Ubeysinghe S, Kankanamge D, Tennakoon M, Karunarathne A. The spatial distribution of GPCR and Gβγ activity across a cell dictates PIP3 dynamics. Sci Rep 2023; 13:2771. [PMID: 36797332 PMCID: PMC9935898 DOI: 10.1038/s41598-023-29639-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 02/08/2023] [Indexed: 02/18/2023] Open
Abstract
Phosphatidylinositol (3,4,5) trisphosphate (PIP3) is a plasma membrane-bound signaling phospholipid involved in many cellular signaling pathways that control crucial cellular processes and behaviors, including cytoskeleton remodeling, metabolism, chemotaxis, and apoptosis. Therefore, defective PIP3 signaling is implicated in various diseases, including cancer, diabetes, obesity, and cardiovascular diseases. Upon activation by G protein-coupled receptors (GPCRs) or receptor tyrosine kinases (RTKs), phosphoinositide-3-kinases (PI3Ks) phosphorylate phosphatidylinositol (4,5) bisphosphate (PIP2), generating PIP3. Though the mechanisms are unclear, PIP3 produced upon GPCR activation attenuates within minutes, indicating a tight temporal regulation. Our data show that subcellular redistributions of G proteins govern this PIP3 attenuation when GPCRs are activated globally, while localized GPCR activation induces sustained subcellular PIP3. Interestingly the observed PIP3 attenuation was Gγ subtype-dependent. Considering distinct cell-tissue-specific Gγ expression profiles, our findings not only demonstrate how the GPCR-induced PIP3 response is regulated depending on the GPCR activity gradient across a cell, but also show how diversely cells respond to spatial and temporal variability of external stimuli.
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Affiliation(s)
- Dhanushan Wijayaratna
- grid.267337.40000 0001 2184 944XDepartment of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606 USA ,grid.262962.b0000 0004 1936 9342Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, MO 63103 USA
| | - Kasun Ratnayake
- grid.267337.40000 0001 2184 944XDepartment of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606 USA
| | - Sithurandi Ubeysinghe
- grid.267337.40000 0001 2184 944XDepartment of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606 USA ,grid.262962.b0000 0004 1936 9342Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, MO 63103 USA
| | - Dinesh Kankanamge
- grid.267337.40000 0001 2184 944XDepartment of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606 USA ,grid.4367.60000 0001 2355 7002Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO 63110 USA
| | - Mithila Tennakoon
- grid.267337.40000 0001 2184 944XDepartment of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606 USA ,grid.262962.b0000 0004 1936 9342Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, MO 63103 USA
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH, 43606, USA. .,Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, MO, 63103, USA.
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Xu X, Wu G. Non-canonical Golgi-compartmentalized Gβγ signaling: mechanisms, functions, and therapeutic targets. Trends Pharmacol Sci 2023; 44:98-111. [PMID: 36494204 PMCID: PMC9901158 DOI: 10.1016/j.tips.2022.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 12/13/2022]
Abstract
G protein Gβγ subunits are key mediators of G protein-coupled receptor (GPCR) signaling under physiological and pathological conditions; their inhibitors have been tested for the treatment of human disease. Conventional wisdom is that the Gβγ complex is activated and subsequently exerts its functions at the plasma membrane (PM). Recent studies have revealed non-canonical activation of Gβγ at intracellular organelles, where the Golgi apparatus is a major locale, via translocation or local activation. Golgi-localized Gβγ activates specific signaling cascades and regulates fundamental cell processes such as membrane trafficking, proliferation, and migration. More recent studies have shown that inhibiting Golgi-compartmentalized Gβγ signaling attenuates cardiomyocyte hypertrophy and prostate tumorigenesis, indicating new therapeutic targets. We review novel activation mechanisms and non-canonical functions of Gβγ at the Golgi, and discuss potential therapeutic interventions by targeting Golgi-biased Gβγ-directed signaling.
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Affiliation(s)
- Xin Xu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
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10
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Kankanamge D, Tennakoon M, Karunarathne A, Gautam N. G protein gamma subunit, a hidden master regulator of GPCR signaling. J Biol Chem 2022; 298:102618. [PMID: 36272647 PMCID: PMC9678972 DOI: 10.1016/j.jbc.2022.102618] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 11/21/2022] Open
Abstract
Heterotrimeric G proteins (αβγ subunits) that are activated by G protein-coupled receptors (GPCRs) mediate the biological responses of eukaryotic cells to extracellular signals. The α subunits and the tightly bound βγ subunit complex of G proteins have been extensively studied and shown to control the activity of effector molecules. In contrast, the potential roles of the large family of γ subunits have been less studied. In this review, we focus on present knowledge about these proteins. Induced loss of individual γ subunit types in animal and plant models result in strikingly distinct phenotypes indicating that γ subtypes play important and specific roles. Consistent with these findings, downregulation or upregulation of particular γ subunit types result in various types of cancers. Clues about the mechanistic basis of γ subunit function have emerged from imaging the dynamic behavior of G protein subunits in living cells. This shows that in the basal state, G proteins are not constrained to the plasma membrane but shuttle between membranes and on receptor activation βγ complexes translocate reversibly to internal membranes. The translocation kinetics of βγ complexes varies widely and is determined by the membrane affinity of the associated γ subtype. On translocating, some βγ complexes act on effectors in internal membranes. The variation in translocation kinetics determines differential sensitivity and adaptation of cells to external signals. Membrane affinity of γ subunits is thus a parsimonious and elegant mechanism that controls information flow to internal cell membranes while modulating signaling responses.
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Affiliation(s)
- Dinesh Kankanamge
- Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Mithila Tennakoon
- Department of Chemistry, St Louis University, St Louis, Missouri, USA
| | | | - N Gautam
- Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri, USA; Department of Genetics, Washington University School of Medicine, St Louis, Missouri, USA.
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11
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Tennakoon M, Senarath K, Kankanamge D, Chadee DN, Karunarathne A. A short C-terminal peptide in Gγ regulates Gβγ signaling efficacy. Mol Biol Cell 2021; 32:1446-1458. [PMID: 34106735 PMCID: PMC8351738 DOI: 10.1091/mbc.e20-11-0750] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 05/03/2021] [Accepted: 06/04/2021] [Indexed: 01/03/2023] Open
Abstract
G protein beta-gamma (Gβγ) subunits anchor to the plasma membrane (PM) through the carboxy-terminal (CT) prenyl group in Gγ. This interaction is crucial for the PM localization and functioning of Gβγ, allowing GPCR-G protein signaling to proceed. The diverse Gγ family has 12 members, and we have recently shown that the signaling efficacies of major Gβγ effectors are Gγ-type dependent. This dependency is due to the distinct series of membrane-interacting abilities of Gγ. However, the molecular process allowing for Gβγ subunits to exhibit a discrete and diverse range of Gγ-type-dependent membrane affinities is unclear and cannot be explained using only the type of prenylation. The present work explores the unique designs of membrane-interacting CT residues in Gγ as a major source for this Gγ-type-dependent Gβγ signaling. Despite the type of prenylation, the results show signaling efficacy at the PM, and associated cell behaviors of Gβγ are governed by crucially located specific amino acids in the five to six residue preprenylation region of Gγ. The provided molecular picture of Gγ-membrane interactions may explain how cells gain Gγ-type-dependent G protein-GPCR signaling as well as how Gβγ elicits selective signaling at various subcellular compartments.
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Affiliation(s)
- Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606
| | - Kanishka Senarath
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606
| | - Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606
| | - Deborah N. Chadee
- Department of Biological Sciences, The University of Toledo, Toledo, OH 43606
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606
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12
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Tennakoon M, Senarath K, Kankanamge D, Ratnayake K, Wijayaratna D, Olupothage K, Ubeysinghe S, Martins-Cannavino K, Hébert TE, Karunarathne A. Subtype-dependent regulation of Gβγ signalling. Cell Signal 2021; 82:109947. [PMID: 33582184 PMCID: PMC8026654 DOI: 10.1016/j.cellsig.2021.109947] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 01/04/2023]
Abstract
G protein-coupled receptors (GPCRs) transmit information to the cell interior by transducing external signals to heterotrimeric G protein subunits, Gα and Gβγ subunits, localized on the inner leaflet of the plasma membrane. Though the initial focus was mainly on Gα-mediated events, Gβγ subunits were later identified as major contributors to GPCR-G protein signalling. A broad functional array of Gβγ signalling has recently been attributed to Gβ and Gγ subtype diversity, comprising 5 Gβ and 12 Gγ subtypes, respectively. In addition to displaying selectivity towards each other to form the Gβγ dimer, numerous studies have identified preferences of distinct Gβγ combinations for specific GPCRs, Gα subtypes and effector molecules. Importantly, Gβ and Gγ subtype-dependent regulation of downstream effectors, representing a diverse range of signalling pathways and physiological functions have been found. Here, we review the literature on the repercussions of Gβ and Gγ subtype diversity on direct and indirect regulation of GPCR/G protein signalling events and their physiological outcomes. Our discussion additionally provides perspective in understanding the intricacies underlying molecular regulation of subtype-specific roles of Gβγ signalling and associated diseases.
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Affiliation(s)
- Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Kanishka Senarath
- Genetics and Molecular Biology Unit, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
| | - Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Kasun Ratnayake
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA; Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dhanushan Wijayaratna
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Koshala Olupothage
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Sithurandi Ubeysinghe
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | | | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada.
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA.
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13
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Kankanamge D, Ubeysinghe S, Tennakoon M, Pantula PD, Mitra K, Giri L, Karunarathne A. Dissociation of the G protein βγ from the Gq-PLCβ complex partially attenuates PIP2 hydrolysis. J Biol Chem 2021; 296:100702. [PMID: 33901492 PMCID: PMC8138763 DOI: 10.1016/j.jbc.2021.100702] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 04/09/2021] [Accepted: 04/21/2021] [Indexed: 01/14/2023] Open
Abstract
Phospholipase C β (PLCβ), which is activated by the Gq family of heterotrimeric G proteins, hydrolyzes the inner membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2), generating diacylglycerol and inositol 1,4,5-triphosphate (IP3). Because Gq and PLCβ regulate many crucial cellular processes and have been identified as major disease drivers, activation and termination of PLCβ signaling by the Gαq subunit have been extensively studied. Gq-coupled receptor activation induces intense and transient PIP2 hydrolysis, which subsequently recovers to a low-intensity steady-state equilibrium. However, the molecular underpinnings of this equilibrium remain unclear. Here, we explored the influence of signaling crosstalk between Gq and Gi/o pathways on PIP2 metabolism in living cells using single-cell and optogenetic approaches to spatially and temporally constrain signaling. Our data suggest that the Gβγ complex is a component of the highly efficient lipase GαqGTP-PLCβ-Gβγ. We found that over time, Gβγ dissociates from this lipase complex, leaving the less-efficient GαqGTP-PLCβ lipase complex and allowing the significant partial recovery of PIP2 levels. Our findings also indicate that the subtype of the Gγ subunit in Gβγ fine-tunes the lipase activity of Gq-PLCβ, in which cells expressing Gγ with higher plasma membrane interaction show lower PIP2 recovery. Given that Gγ shows cell- and tissue-specific subtype expression, our findings suggest the existence of tissue-specific distinct Gq-PLCβ signaling paradigms. Furthermore, these results also outline a molecular process that likely safeguards cells from excessive Gq signaling.
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Affiliation(s)
- Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio, USA
| | - Sithurandi Ubeysinghe
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio, USA
| | - Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio, USA
| | - Priyanka Devi Pantula
- Department of Chemical Engineering, Indian Institute of Technology, Hyderabad, Sangareddy, Telangana, India
| | - Kishalay Mitra
- Department of Chemical Engineering, Indian Institute of Technology, Hyderabad, Sangareddy, Telangana, India
| | - Lopamudra Giri
- Department of Chemical Engineering, Indian Institute of Technology, Hyderabad, Sangareddy, Telangana, India
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio, USA.
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14
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Blue light-triggered photochemistry and cytotoxicity of retinal. Cell Signal 2020; 69:109547. [PMID: 31982549 DOI: 10.1016/j.cellsig.2020.109547] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/14/2020] [Accepted: 01/22/2020] [Indexed: 01/08/2023]
Abstract
The chemical- and photo- toxicity of chromophore retinal on cells have long been debated. Although we recently showed that retinal and blue light exposure interrupt cellular signaling, a comprehensive study examining molecular underpinnings of this perturbation and its consequences to cellular fate is lacking. Here, we report molecular evidence for blue light excited-retinal induced oxidative damage of polyunsaturated lipid anchors in membrane-interacting signaling molecules and DNA damage in cells using live-cell imaging and in vitro experimentation. The incurred molecular damage irreversibly disrupted subcellular localization of these molecules, a crucial criterion for their signaling. We further show retinal accumulation in lipid-bilayers of cell membranes could enhance the lifetime of retinal in cells. Comparative response-signatures suggest that retinal triggers reactions upon photoexcitation similar to photodynamic therapy agents and generate reactive oxygen species in cells. Additionally, data also shows that exposing retinal-containing cells to sunlight induces substantial cytotoxicity. Collectively, our results explain a likely in vivo mechanism and reaction conditions under which bio-available retinal in physiological light conditions damages cells.
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15
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Optical approaches for single-cell and subcellular analysis of GPCR-G protein signaling. Anal Bioanal Chem 2019; 411:4481-4508. [PMID: 30927013 DOI: 10.1007/s00216-019-01774-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 01/05/2023]
Abstract
G protein-coupled receptors (GPCRs), G proteins, and their signaling associates are major signal transducers that control the majority of cellular signaling and regulate key biological functions including immune, neurological, cardiovascular, and metabolic processes. These pathways are targeted by over one-third of drugs on the market; however, the current understanding of their function is limited and primarily derived from cell-destructive approaches providing an ensemble of static, multi-cell information about the status and composition of molecules. Spatiotemporal behavior of molecules involved is crucial to understanding in vivo cell behaviors both in health and disease, and the advent of genetically encoded fluorescence proteins and small fluorophore-based biosensors has facilitated the mapping of dynamic signaling in cells with subcellular acuity. Since we and others have developed optogenetic methods to regulate GPCR-G protein signaling in single cells and subcellular regions using dedicated wavelengths, the desire to develop and adopt optogenetically amenable assays to measure signaling has motivated us to take a broader look at the available optical tools and approaches compatible with measuring single-cell and subcellular GPCR-G protein signaling. Here we review such key optical approaches enabling the examination of GPCR, G protein, secondary messenger, and downstream molecules such as kinase and lipid signaling in living cells. The methods reviewed employ both fluorescence and bioluminescence detection. We not only further elaborate the underlying principles of these sensors but also discuss the experimental criteria and limitations to be considered during their use in single-cell and subcellular signal mapping.
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16
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Kankanamge D, Tennakoon M, Weerasinghe A, Cedeno-Rosario L, Chadee DN, Karunarathne A. G protein αq exerts expression level-dependent distinct signaling paradigms. Cell Signal 2019; 58:34-43. [PMID: 30849518 DOI: 10.1016/j.cellsig.2019.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/23/2019] [Accepted: 02/25/2019] [Indexed: 12/16/2022]
Abstract
G protein αq-coupled receptors (Gq-GPCRs) primarily signal through GαqGTP mediated phospholipase Cβ (PLCβ) stimulation and the subsequent hydrolysis of phosphatidylinositol 4, 5 bisphosphate (PIP2). Though Gq-heterotrimer activation results in both GαqGTP and Gβγ, unlike Gi/o-receptors, it is unclear if Gq-coupled receptors employ Gβγ as a major signal transducer. Compared to Gi/o- and Gs-coupled receptors, we observed that most cell types exhibit a limited free Gβγ generation upon Gq-pathway and Gαq/11 heterotrimer activation. We show that cells transfected with Gαq or endogenously expressing more than average-levels of Gαq/11 compared to Gαs and Gαi exhibit a distinct signaling regime primarily characterized by recovery-resistant PIP2 hydrolysis. Interestingly, the elevated Gq-expression is also associated with enhanced free Gβγ generation and signaling. Furthermore, the gene GNAQ, which encodes for Gαq, has recently been identified as a cancer driver gene. We also show that GNAQ is overexpressed in tumor samples of patients with Kidney Chromophobe (KICH) and Kidney renal papillary (KIRP) cell carcinomas in a matched tumor-normal sample analysis, which demonstrates the clinical significance of Gαq expression. Overall, our data indicates that cells usually express low Gαq levels, likely safeguarding cells from excessive calcium as wells as from Gβγ signaling.
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Affiliation(s)
- Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Amila Weerasinghe
- McDonnell Genome Institute, Washington University in St. Louis, St. Louis, MO 63108, USA
| | - Luis Cedeno-Rosario
- Department of Biological Sciences, The University of Toledo, Toledo, OH 43606, USA
| | - Deborah N Chadee
- Department of Biological Sciences, The University of Toledo, Toledo, OH 43606, USA
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA.
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17
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Tennakoon M, Kankanamge D, Senarath K, Fasih Z, Karunarathne A. Statins Perturb G βγ Signaling and Cell Behavior in a G γ Subtype Dependent Manner. Mol Pharmacol 2019; 95:361-375. [PMID: 30765461 DOI: 10.1124/mol.118.114710] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 01/25/2019] [Indexed: 01/08/2023] Open
Abstract
Guanine nucleotide-binding proteins (G proteins) facilitate the transduction of external signals to the cell interior, regulate most eukaryotic signaling, and thus have become crucial disease drivers. G proteins largely function at the inner leaflet of the plasma membrane (PM) using covalently attached lipid anchors. Both small monomeric and heterotrimeric G proteins are primarily prenylated, either with a 15-carbon farnesyl or a 20-carbon geranylgeranyl polyunsaturated lipid. The mevalonate [3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase] pathway synthesizes lipids for G-protein prenylation. It is also the source of the precursor lipids for many biomolecules, including cholesterol. Consequently, the rate-limiting enzymes of the mevalonate pathway are major targets for cholesterol-lowering medications and anticancer drug development. Although prenylated G protein γ (Gγ) is essential for G protein-coupled receptor (GPCR)-mediated signaling, how mevalonate pathway inhibitors, statins, influence subcellular distribution of Gβγ dimer and Gαβγ heterotrimer, as well as their signaling upon GPCR activation, is poorly understood. The present study shows that clinically used statins not only significantly disrupt PM localization of Gβγ but also perturb GPCR-G protein signaling and associated cell behaviors. The results also demonstrate that the efficiency of prenylation inhibition by statins is Gγ subtype-dependent and is more effective toward farnesylated Gγ types. Since Gγ is required for Gβγ signaling and shows a cell- and tissue-specific subtype distribution, the present study can help understand the mechanisms underlying clinical outcomes of statin use in patients. This work also reveals the potential of statins as clinically usable drugs to control selected GPCR-G protein signaling.
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Affiliation(s)
- Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio
| | - Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio
| | - Kanishka Senarath
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio
| | - Zehra Fasih
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio
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18
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Abstract
Photoreceptor chromophore, 11-cis retinal (11CR) and the photoproduct, all-trans retinal (ATR), are present in the retina at higher concentrations and interact with the visual cells. Non-visual cells in the body are also exposed to retinal that enters the circulation. Although the cornea and the lens of the eye are transparent to the blue light region where retinal can absorb and undergo excitation, the reported phototoxicity in the eye has been assigned to lipophilic non-degradable materials known as lipofuscins, which also includes retinal condensation products. The possibility of blue light excited retinal interacting with cells; intercepting signaling in the presence or absence of light has not been explored. Using live cell imaging and optogenetic signaling control, we uncovered that blue light-excited ATR and 11CR irreversibly change/distort plasma membrane (PM) bound phospholipid; phosphatidylinositol 4,5 bisphosphate (PIP2) and disrupt its function. This distortion in PIP2 was independent of visual or non-visual G-protein coupled receptor activation. The change in PIP2 was followed by an increase in the cytosolic calcium, excessive cell shape change, and cell death. Blue light alone or retinal alone did not perturb PIP2 or elicit cytosolic calcium increase. Our data also suggest that photoexcited retinal-induced PIP2 distortion and subsequent oxidative damage incur in the core of the PM. These findings suggest that retinal exerts light sensitivity to both photoreceptor and non-photoreceptor cells, and intercepts crucial signaling events, altering the cellular fate.
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19
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Samaradivakara S, Kankanamge D, Senarath K, Ratnayake K, Karunarathne A. G protein γ (Gγ) subtype dependent targeting of GRK2 to M3 receptor by Gβγ. Biochem Biophys Res Commun 2018; 503:165-170. [PMID: 29864421 DOI: 10.1016/j.bbrc.2018.05.204] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 05/29/2018] [Indexed: 01/09/2023]
Abstract
Interactions of cytosolic G protein coupled receptor kinase 2 (GRK2) with activated G protein coupled receptors (GPCRs) induce receptor phosphorylation and desensitization. GRK2 is recruited to active M3-muscarinic receptors (M3R) with the participation of the receptor, Gαq and Gβγ. Since we have shown that signaling efficacy of Gβγ is governed by its Gγ subtype identity, the present study examined whether recruitment of GRK2 to M3R is also Gγ subtype dependent. To capture the dynamics of GRK2-recruitment concurrently with GPCR-G protein activation, we employed live cell confocal imaging and a novel assay based on Gβγ translocation. Data show that M3R activation-induced GRK2 recruitment is Gγ subtype dependent in which Gβγ dimers with low PM-affinity Gγ9 exhibited a two-fold higher GRK2-recruitment compared to high PM affinity Gγ3 expressing cells. Since 12-mammalian Gγ types exhibit a cell and tissue specific expressions and the PM-affinity of a Gγ is linked to its subtype identity, our results indicate a mechanism by which Gγ profile of a cell controls GRK2 signaling and GPCR desensitization.
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Affiliation(s)
- Saroopa Samaradivakara
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH, 43606, USA
| | - Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH, 43606, USA
| | - Kanishka Senarath
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH, 43606, USA
| | - Kasun Ratnayake
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH, 43606, USA
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH, 43606, USA.
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20
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Kankanamge D, Ratnayake K, Samaradivakara S, Karunarathne A. Melanopsin (Opn4) utilizes Gα i and Gβγ as major signal transducers. J Cell Sci 2018; 131:jcs.212910. [PMID: 29712722 DOI: 10.1242/jcs.212910] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 04/23/2018] [Indexed: 01/16/2023] Open
Abstract
Melanopsin (Opn4), a ubiquitously expressed photoreceptor in all classes of vertebrates, is crucial for both visual and non-visual signaling. Opn4 supports visual functions of the eye by sensing radiance levels and discriminating contrast and brightness. Non-image-forming functions of Opn4 not only regulate circadian behavior, but also control growth and development processes of the retina. It is unclear how a single photoreceptor could govern such a diverse range of physiological functions; a role in genetic hardwiring could be one explanation, but molecular and mechanistic evidence is lacking. In addition to its role in canonical Gq pathway activation, here we demonstrate that Opn4 efficiently activates Gi heterotrimers and signals through the G protein βγ. Compared with the low levels of Gi pathway activation observed for several Gq-coupled receptors, the robust Gαi and Gβγ signaling of Opn4 led to both generation of PIP3 and directional migration of RAW264.7 macrophages. We propose that the ability of Opn4 to signal through Gαi and Gβγ subunits is a major contributor to its functional diversity.
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Affiliation(s)
- Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Kasun Ratnayake
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Saroopa Samaradivakara
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
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21
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Senarath K, Payton JL, Kankanamge D, Siripurapu P, Tennakoon M, Karunarathne A. Gγ identity dictates efficacy of Gβγ signaling and macrophage migration. J Biol Chem 2018; 293:2974-2989. [PMID: 29317505 DOI: 10.1074/jbc.ra117.000872] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 01/04/2018] [Indexed: 11/06/2022] Open
Abstract
G protein βγ subunit (Gβγ) is a major signal transducer and controls processes ranging from cell migration to gene transcription. Despite having significant subtype heterogeneity and exhibiting diverse cell- and tissue-specific expression levels, Gβγ is often considered a unified signaling entity with a defined functionality. However, the molecular and mechanistic basis of Gβγ's signaling specificity is unknown. Here, we demonstrate that Gγ subunits, bearing the sole plasma membrane (PM)-anchoring motif, control the PM affinity of Gβγ and thereby differentially modulate Gβγ effector signaling in a Gγ-specific manner. Both Gβγ signaling activity and the migration rate of macrophages are strongly dependent on the PM affinity of Gγ. We also found that the type of C-terminal prenylation and five to six pre-CaaX motif residues at the PM-interacting region of Gγ control the PM affinity of Gβγ. We further show that the overall PM affinity of the Gβγ pool of a cell type is a strong predictor of its Gβγ signaling-activation efficacy. A kinetic model encompassing multiple Gγ types and parameterized for empirical Gβγ behaviors not only recapitulated experimentally observed signaling of Gβγ, but also suggested a Gγ-dependent, active-inactive conformational switch for the PM-bound Gβγ, regulating effector signaling. Overall, our results unveil crucial aspects of signaling and cell migration regulation by Gγ type-specific PM affinities of Gβγ.
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Affiliation(s)
- Kanishka Senarath
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606
| | - John L Payton
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606
| | - Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606
| | - Praneeth Siripurapu
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606
| | - Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio 43606.
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22
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Ratnayake K, Kankanamge D, Senarath K, Siripurapu P, Weis N, Tennakoon M, Payton JL, Karunarathne A. Measurement of GPCR-G protein activity in living cells. Methods Cell Biol 2017; 142:1-25. [PMID: 28964328 DOI: 10.1016/bs.mcb.2017.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors in eukaryotic genomes. They control a variety of cellular and physiological processes such as hormone secretion and heart rate, and therefore are associated with a majority of pathological conditions including cancer and heart diseases. Currently established assays to measure ligand-induced activation of GPCRs and G proteins possess limitations such as being time consuming, indirect, and expensive. Thus, an efficient method to measure GPCR-G protein activation is required to identify novel pharmacological modulators to control them and gain insights about molecular underpinnings of the associated pathways. Activation of GPCRs induces dissociation of G protein heterotrimers to form GαGTP and free Gβγ. Free Gβγ subunits have been shown to translocate reversibly from the plasma membrane to internal membranes. Gβγ translocation therefore represents the GPCR-G protein activation, and thus, imaging of this process can be used to quantify the kinetics and magnitude of the pathway activation-deactivation in real time in living cells. The objective of this chapter is to elaborate the protocols of (i) generation and optimization of the required sensor constructs; (ii) development of cell culture, transient transfection, imaging, and optogenetic procedures; (iii) imaging and data analysis methods; and (iv) stable cell line generation, pertaining to this assay to measure GPCR-G protein activation.
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Affiliation(s)
| | | | | | | | - Nicole Weis
- The University of Toledo, Toledo, OH, United States
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23
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Siripurapu P, Kankanamge D, Ratnayake K, Senarath K, Karunarathne A. Two independent but synchronized Gβγ subunit-controlled pathways are essential for trailing-edge retraction during macrophage migration. J Biol Chem 2017; 292:17482-17495. [PMID: 28864771 DOI: 10.1074/jbc.m117.787838] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 08/27/2017] [Indexed: 12/25/2022] Open
Abstract
Chemokine-induced directional cell migration is a universal cellular mechanism and plays crucial roles in numerous biological processes, including embryonic development, immune system function, and tissue remodeling and regeneration. During the migration of a stationary cell, the cell polarizes, forms lamellipodia at the leading edge (LE), and triggers the concurrent retraction of the trailing edge (TE). During cell migration governed by inhibitory G protein (Gi)-coupled receptors (GPCRs), G protein βγ (Gβγ) subunits control the LE signaling. Interestingly, TE retraction has been linked to the activation of the small GTPase Ras homolog family member A (RhoA) by the Gα12/13 pathway. However, it is not clear how the activation of Gi-coupled GPCRs at the LE orchestrates the TE retraction in RAW264.7 macrophages. Here, using an optogenetic approach involving an opsin to activate the Gi pathway in defined subcellular regions of RAW cells, we show that in addition to their LE activities, free Gβγ subunits also govern TE retraction by operating two independent, yet synchronized, pathways. The first pathway involves RhoA activation, which prevents dephosphorylation of the myosin light chain, allowing actomyosin contractility to proceed. The second pathway activates phospholipase Cβ and induces myosin light chain phosphorylation to enhance actomyosin contractility through increasing cytosolic calcium. We further show that both of these pathways are essential, and inhibition of either one is sufficient to abolish the Gi-coupled GPCR-governed TE retraction and subsequent migration of RAW cells.
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Affiliation(s)
- Praneeth Siripurapu
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606
| | - Dinesh Kankanamge
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606
| | - Kasun Ratnayake
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606
| | - Kanishka Senarath
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606
| | - Ajith Karunarathne
- From the Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606
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24
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Gupta RK, Swain S, Kankanamge D, Priyanka PD, Singh R, Mitra K, Karunarathne A, Giri L. Comparison of Calcium Dynamics and Specific Features for G Protein-Coupled Receptor-Targeting Drugs Using Live Cell Imaging and Automated Analysis. SLAS DISCOVERY 2017; 22:848-858. [PMID: 28267930 DOI: 10.1177/2472555217693378] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
G protein-coupled receptors (GPCRs) are targets for designing a large fraction of the drugs in the pharmaceutical industry. For GPCR-targeting drug screening using cell-based assays, measurement of cytosolic calcium has been widely used to obtain dose-response profiles. However, it remains challenging to obtain drug-specific features due to cell-to-cell heterogeneity in drug-cell responses obtained from live cell imaging. Here, we present a framework combining live cell imaging of a cell population and a feature extraction method for classification of responses of drugs targeting GPCRs CXCR4 and α2AR. We measured the calcium dynamics using confocal microscopy and compared the responses for SDF-1α and norepinephrine. The results clearly show that the clustering patterns of responses for the two GPCRs are significantly different. Additionally, we show that different drugs targeting the same GPCR induce different calcium response signatures. We also implemented principal component analysis and k means for feature extraction and used nondominated (ND) sorting for ranking a group of drugs at various doses. The presented approach can be used to model a cell population as a mixture of subpopulations. It also offers specific advantages, such as higher spatial resolution, classification of responses, and ranking of drugs, potentially providing a platform for high-content drug screening.
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Affiliation(s)
- Rishikesh Kumar Gupta
- 1 Department of Chemical Engineering, Indian Institute of Technology-Hyderabad, Hyderabad, Telangana, India
| | - Sarpras Swain
- 1 Department of Chemical Engineering, Indian Institute of Technology-Hyderabad, Hyderabad, Telangana, India
| | - Dinesh Kankanamge
- 2 Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH, USA
| | - Pantula Devi Priyanka
- 1 Department of Chemical Engineering, Indian Institute of Technology-Hyderabad, Hyderabad, Telangana, India
| | - Ranjana Singh
- 1 Department of Chemical Engineering, Indian Institute of Technology-Hyderabad, Hyderabad, Telangana, India
| | - Kishalay Mitra
- 1 Department of Chemical Engineering, Indian Institute of Technology-Hyderabad, Hyderabad, Telangana, India
| | - Ajith Karunarathne
- 2 Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH, USA
| | - Lopamudra Giri
- 1 Department of Chemical Engineering, Indian Institute of Technology-Hyderabad, Hyderabad, Telangana, India
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