1
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Walker V. The Intricacies of Renal Phosphate Reabsorption-An Overview. Int J Mol Sci 2024; 25:4684. [PMID: 38731904 PMCID: PMC11083860 DOI: 10.3390/ijms25094684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 05/13/2024] Open
Abstract
To maintain an optimal body content of phosphorus throughout postnatal life, variable phosphate absorption from food must be finely matched with urinary excretion. This amazing feat is accomplished through synchronised phosphate transport by myriads of ciliated cells lining the renal proximal tubules. These respond in real time to changes in phosphate and composition of the renal filtrate and to hormonal instructions. How they do this has stimulated decades of research. New analytical techniques, coupled with incredible advances in computer technology, have opened new avenues for investigation at a sub-cellular level. There has been a surge of research into different aspects of the process. These have verified long-held beliefs and are also dramatically extending our vision of the intense, integrated, intracellular activity which mediates phosphate absorption. Already, some have indicated new approaches for pharmacological intervention to regulate phosphate in common conditions, including chronic renal failure and osteoporosis, as well as rare inherited biochemical disorders. It is a rapidly evolving field. The aim here is to provide an overview of our current knowledge, to show where it is leading, and where there are uncertainties. Hopefully, this will raise questions and stimulate new ideas for further research.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton S016 6YD, UK
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2
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Aydin A, Klenk C, Nemec K, Işbilir A, Martin LM, Zauber H, Rrustemi T, Toka HR, Schuster H, Gong M, Stricker S, Bock A, Bähring S, Selbach M, Lohse MJ, Luft FC. ADAM19 cleaves the PTH receptor and associates with brachydactyly type E. Life Sci Alliance 2024; 7:e202302400. [PMID: 38331475 PMCID: PMC10853454 DOI: 10.26508/lsa.202302400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 01/25/2024] [Accepted: 01/25/2024] [Indexed: 02/10/2024] Open
Abstract
Brachydactyly type E (BDE), shortened metacarpals, metatarsals, cone-shaped epiphyses, and short stature commonly occurs as a sole phenotype. Parathyroid hormone-like protein (PTHrP) has been shown to be responsible in all forms to date, either directly or indirectly. We used linkage and then whole genome sequencing in a small pedigree, to elucidate BDE and identified a truncated disintegrin-and-metalloproteinase-19 (ADAM19) allele in all affected family members, but not in nonaffected persons. Since we had shown earlier that the extracellular domain of the parathyroid hormone receptor (PTHR1) is subject to an unidentified metalloproteinase cleavage, we tested the hypothesis that ADAM19 is a sheddase for PTHR1. WT ADAM19 cleaved PTHR1, while mutated ADAM-19 did not. We mapped the cleavage site that we verified with mass spectrometry between amino acids 64-65. ADAM-19 cleavage increased Gq and decreased Gs activation. Moreover, perturbed PTHR1 cleavage by ADAM19 increased ß-arrestin2 recruitment, while cAMP accumulation was not altered. We suggest that ADAM19 serves as a regulatory element for PTHR1 and could be responsible for BDE. This sheddase may affect other PTHrP or PTH-related functions.
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Affiliation(s)
- Atakan Aydin
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- https://ror.org/001w7jn25 Experimental and Clinical Research Center, A Cooperation Between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin, Berlin, Germany
| | - Christoph Klenk
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Katarina Nemec
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
- Department of Structural Biology and Center of Excellence for Data-Driven Discovery, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Ali Işbilir
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Lisa M Martin
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Henrik Zauber
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Trendelina Rrustemi
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Hakan R Toka
- https://ror.org/001w7jn25 Experimental and Clinical Research Center, A Cooperation Between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin, Berlin, Germany
| | - Herbert Schuster
- https://ror.org/001w7jn25 Experimental and Clinical Research Center, A Cooperation Between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin, Berlin, Germany
| | - Maolian Gong
- https://ror.org/001w7jn25 Experimental and Clinical Research Center, A Cooperation Between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin, Berlin, Germany
| | - Sigmar Stricker
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Andreas Bock
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Sylvia Bähring
- https://ror.org/001w7jn25 Experimental and Clinical Research Center, A Cooperation Between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin, Berlin, Germany
| | - Matthias Selbach
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Martin J Lohse
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- ISAR Bioscience Institute, Munich, Germany
| | - Friedrich C Luft
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- https://ror.org/001w7jn25 Experimental and Clinical Research Center, A Cooperation Between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin, Berlin, Germany
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3
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Pizzoni A, Zhang X, Altschuler DL. From membrane to nucleus: A three-wave hypothesis of cAMP signaling. J Biol Chem 2024; 300:105497. [PMID: 38016514 PMCID: PMC10788541 DOI: 10.1016/j.jbc.2023.105497] [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: 09/18/2023] [Revised: 11/14/2023] [Accepted: 11/19/2023] [Indexed: 11/30/2023] Open
Abstract
For many decades, our understanding of G protein-coupled receptor (GPCR) activity and cyclic AMP (cAMP) signaling was limited exclusively to the plasma membrane. However, a growing body of evidence has challenged this view by introducing the concept of endocytosis-dependent GPCR signaling. This emerging paradigm emphasizes not only the sustained production of cAMP but also its precise subcellular localization, thus transforming our understanding of the spatiotemporal organization of this process. Starting from this alternative point of view, our recent work sheds light on the role of an endocytosis-dependent calcium release from the endoplasmic reticulum in the control of nuclear cAMP levels. This is achieved through the activation of local soluble adenylyl cyclase, which in turn regulates the activation of local protein kinase A (PKA) and downstream transcriptional events. In this review, we explore the dynamic evolution of research on cyclic AMP signaling, including the findings that led us to formulate the novel three-wave hypothesis. We delve into how we abandoned the paradigm of cAMP generation limited to the plasma membrane and the changing perspectives on the rate-limiting step in nuclear PKA activation.
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Affiliation(s)
- Alejandro Pizzoni
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Xuefeng Zhang
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Daniel L Altschuler
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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4
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Ripoll L, von Zastrow M. Spatial organization of adenylyl cyclase and its impact on dopamine signaling in neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.06.570478. [PMID: 38106018 PMCID: PMC10723477 DOI: 10.1101/2023.12.06.570478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The cAMP cascade is widely recognized to transduce its physiological effects locally through spatially limited cAMP gradients. However, little is known about how the adenylyl cyclase enzymes, which initiate cAMP gradients, are localized. Here we answer this question in physiologically relevant striatal neurons and delineate how AC localization impacts downstream signaling functions. We show that the major striatal AC isoforms are differentially sorted between ciliary and extraciliary domains of the plasma membrane, and that AC9 is uniquely targeted to endosomes. We identify key sorting determinants in the N-terminal cytoplasmic domain responsible for isoform-specific localization. We also show that AC9-containing endosomes accumulate activated dopamine receptors and form an elaborately intertwined network with juxtanuclear PKA stores bound to Golgi membranes. Finally, we show that endosomal localization is critical for AC9 to selectively elevate PKA activity in the nucleus relative to the cytoplasm. These results reveal a precise spatial landscape of the cAMP cascade in neurons and a key role of AC localization in directing downstream signal transduction to the nucleus.
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5
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Eiger DS, Hicks C, Gardner J, Pham U, Rajagopal S. Location bias: A "Hidden Variable" in GPCR pharmacology. Bioessays 2023; 45:e2300123. [PMID: 37625014 DOI: 10.1002/bies.202300123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/09/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of transmembrane receptors and primarily signal through two main effector proteins: G proteins and β-arrestins. Many agonists of GPCRs promote "biased" responses, in which different cellular signaling pathways are activated with varying efficacies. The mechanisms underlying biased signaling have not been fully elucidated, with many potential "hidden variables" that regulate this behavior. One contributor is "location bias," which refers to the generation of unique signaling cascades from a given GPCR depending upon the cellular location at which the receptor is signaling. Here, we review evidence that GPCRs are expressed at and traffic to various subcellular locations and discuss how location bias can impact the pharmacologic properties and characterization of GPCR agonists. We also evaluate how differences in subcellular environments can modulate GPCR signaling, highlight the physiological significance of subcellular GPCR signaling, and discuss the therapeutic potential of exploiting GPCR location bias.
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Affiliation(s)
- Dylan Scott Eiger
- Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Chloe Hicks
- Trinity College, Duke University, Durham, North Carolina, USA
| | - Julia Gardner
- Trinity College, Duke University, Durham, North Carolina, USA
| | - Uyen Pham
- Department of Biochemistry, Duke University, Durham, North Carolina, USA
| | - Sudarshan Rajagopal
- Department of Biochemistry, Duke University, Durham, North Carolina, USA
- Department of Medicine, Duke University, Durham, North Carolina, USA
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6
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Vilardaga JP, Clark LJ, White AD, Sutkeviciute I, Lee JY, Bahar I. Molecular Mechanisms of PTH/PTHrP Class B GPCR Signaling and Pharmacological Implications. Endocr Rev 2023; 44:474-491. [PMID: 36503956 PMCID: PMC10461325 DOI: 10.1210/endrev/bnac032] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 11/14/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
The classical paradigm of G protein-coupled receptor (GPCR) signaling via G proteins is grounded in a view that downstream responses are relatively transient and confined to the cell surface, but this notion has been revised in recent years following the identification of several receptors that engage in sustained signaling responses from subcellular compartments following internalization of the ligand-receptor complex. This phenomenon was initially discovered for the parathyroid hormone (PTH) type 1 receptor (PTH1R), a vital GPCR for maintaining normal calcium and phosphate levels in the body with the paradoxical ability to build or break down bone in response to PTH binding. The diverse biological processes regulated by this receptor are thought to depend on its capacity to mediate diverse modes of cyclic adenosine monophosphate (cAMP) signaling. These include transient signaling at the plasma membrane and sustained signaling from internalized PTH1R within early endosomes mediated by PTH. Here we discuss recent structural, cell signaling, and in vivo studies that unveil potential pharmacological outputs of the spatial versus temporal dimension of PTH1R signaling via cAMP. Notably, the combination of molecular dynamics simulations and elastic network model-based methods revealed how precise modulation of PTH signaling responses is achieved through structure-encoded allosteric coupling within the receptor and between the peptide hormone binding site and the G protein coupling interface. The implications of recent findings are now being explored for addressing key questions on how location bias in receptor signaling contributes to pharmacological functions, and how to drug a difficult target such as the PTH1R toward discovering nonpeptidic small molecule candidates for the treatment of metabolic bone and mineral diseases.
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Affiliation(s)
- Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Lisa J Clark
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Alex D White
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Ieva Sutkeviciute
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Ji Young Lee
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Ivet Bahar
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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7
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Subramaniam G, Schleicher K, Kovanich D, Zerio A, Folkmanaite M, Chao YC, Surdo NC, Koschinski A, Hu J, Scholten A, Heck AJ, Ercu M, Sholokh A, Park KC, Klussmann E, Meraviglia V, Bellin M, Zanivan S, Hester S, Mohammed S, Zaccolo M. Integrated Proteomics Unveils Nuclear PDE3A2 as a Regulator of Cardiac Myocyte Hypertrophy. Circ Res 2023; 132:828-848. [PMID: 36883446 PMCID: PMC10045983 DOI: 10.1161/circresaha.122.321448] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/09/2023]
Abstract
BACKGROUND Signaling by cAMP is organized in multiple distinct subcellular nanodomains regulated by cAMP-hydrolyzing PDEs (phosphodiesterases). Cardiac β-adrenergic signaling has served as the prototypical system to elucidate cAMP compartmentalization. Although studies in cardiac myocytes have provided an understanding of the location and properties of a handful of cAMP subcellular compartments, an overall view of the cellular landscape of cAMP nanodomains is missing. METHODS Here, we combined an integrated phosphoproteomics approach that takes advantage of the unique role that individual PDEs play in the control of local cAMP, with network analysis to identify previously unrecognized cAMP nanodomains associated with β-adrenergic stimulation. We then validated the composition and function of one of these nanodomains using biochemical, pharmacological, and genetic approaches and cardiac myocytes from both rodents and humans. RESULTS We demonstrate the validity of the integrated phosphoproteomic strategy to pinpoint the location and provide critical cues to determine the function of previously unknown cAMP nanodomains. We characterize in detail one such compartment and demonstrate that the PDE3A2 isoform operates in a nuclear nanodomain that involves SMAD4 (SMAD family member 4) and HDAC-1 (histone deacetylase 1). Inhibition of PDE3 results in increased HDAC-1 phosphorylation, leading to inhibition of its deacetylase activity, derepression of gene transcription, and cardiac myocyte hypertrophic growth. CONCLUSIONS We developed a strategy for detailed mapping of subcellular PDE-specific cAMP nanodomains. Our findings reveal a mechanism that explains the negative long-term clinical outcome observed in patients with heart failure treated with PDE3 inhibitors.
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Affiliation(s)
- Gunasekaran Subramaniam
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
| | - Katharina Schleicher
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
| | - Duangnapa Kovanich
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
- Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, the Netherlands (D.K., A.S., A.J.R.H.)
- Centre for Vaccine Development, Institute of Molecular Biosciences, Mahidol University, Thailand (D.K.)
| | - Anna Zerio
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
| | - Milda Folkmanaite
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
| | - Ying-Chi Chao
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
| | - Nicoletta C. Surdo
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
- Now with Neuroscience Institute, National Research Council of Italy (CNR), Padova (N.C.S.)
| | - Andreas Koschinski
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
| | - Jianshu Hu
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
| | - Arjen Scholten
- Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, the Netherlands (D.K., A.S., A.J.R.H.)
| | - Albert J.R. Heck
- Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, the Netherlands (D.K., A.S., A.J.R.H.)
| | - Maria Ercu
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association and German Centre for Cardiovascular Research, Partner Site Berlin (M.E., A.S., E.K.)
| | - Anastasiia Sholokh
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association and German Centre for Cardiovascular Research, Partner Site Berlin (M.E., A.S., E.K.)
| | - Kyung Chan Park
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
| | - Enno Klussmann
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association and German Centre for Cardiovascular Research, Partner Site Berlin (M.E., A.S., E.K.)
| | - Viviana Meraviglia
- Department of Anatomy and Embryology, Leiden University Medical Center, the Netherlands (V.M., M.B.)
| | - Milena Bellin
- Department of Anatomy and Embryology, Leiden University Medical Center, the Netherlands (V.M., M.B.)
- Department of Biology, University of Padua, Italy (M.B.)
- Veneto Institute of Molecular Medicine, Padua, Italy (M.B.)
| | - Sara Zanivan
- Cancer Research UK Beatson Institute, Glasgow, United Kingdom (S.Z.)
- Institute of Cancer Sciences, University of Glasgow, United Kingdom (S.Z.)
| | - Svenja Hester
- Department of Biochemistry (S.H., S.M.), University of Oxford, United Kingdom
| | - Shabaz Mohammed
- Department of Biochemistry (S.H., S.M.), University of Oxford, United Kingdom
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics (G.S., K.S., D.K., A.Z., M.F., Y.-C.C., N.C.S., A.K., J.H., K.C.P., M.Z.), University of Oxford, United Kingdom
- Oxford NIHR Biomedical Research Centre (M.Z.)
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8
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Soluble cyclase-mediated nuclear cAMP synthesis is sufficient for cell proliferation. Proc Natl Acad Sci U S A 2023; 120:e2208749120. [PMID: 36656863 PMCID: PMC9942871 DOI: 10.1073/pnas.2208749120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
cAMP, a key player in many physiological processes, was classically considered to originate solely from the plasma membrane (PM). This view was recently challenged by observations showing that upon internalization GsPCRs can sustain signaling from endosomes and/or the trans-Golgi network (TGN). In this new view, after the first PM-generated cAMP wave, the internalization of GsPCRs and ACs generates a second wave that was strictly associated with nuclear transcriptional events responsible for triggering specific biological responses. Here, we report that the endogenously expressed TSHR, a canonical GsPCR, triggers an internalization-dependent, calcium-mediated nuclear sAC activation that drives PKA activation and CREB phosphorylation. Both pharmacological and genetic sAC inhibition, which did not affect the cytosolic cAMP levels, blunted nuclear cAMP accumulation, PKA activation, and cell proliferation, while an increase in nuclear sAC expression significantly enhanced cell proliferation. Furthermore, using novel nuclear-targeted optogenetic actuators, we show that light-stimulated nuclear cAMP synthesis can mimic the proliferative action of TSH by activating PKA and CREB. Therefore, based on our results, we propose a novel three-wave model in which the "third" wave of cAMP is generated by nuclear sAC. Despite being downstream of events occurring at the PM (first wave) and endosomes/TGN (second wave), the nuclear sAC-generated cAMP (third wave) is sufficient and rate-limiting for thyroid cell proliferation.
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9
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Fasciani I, Carli M, Petragnano F, Colaianni F, Aloisi G, Maggio R, Scarselli M, Rossi M. GPCRs in Intracellular Compartments: New Targets for Drug Discovery. Biomolecules 2022; 12:1343. [PMID: 36291552 PMCID: PMC9599219 DOI: 10.3390/biom12101343] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 09/16/2022] [Accepted: 09/17/2022] [Indexed: 08/02/2023] Open
Abstract
The architecture of eukaryotic cells is defined by extensive membrane-delimited compartments, which entails separate metabolic processes that would otherwise interfere with each other, leading to functional differences between cells. G protein-coupled receptors (GPCRs) are the largest class of cell surface receptors, and their signal transduction is traditionally viewed as a chain of events initiated from the plasma membrane. Furthermore, their intracellular trafficking, internalization, and recycling were considered only to regulate receptor desensitization and cell surface expression. On the contrary, accumulating data strongly suggest that GPCRs also signal from intracellular compartments. GPCRs localize in the membranes of endosomes, nucleus, Golgi and endoplasmic reticulum apparatuses, mitochondria, and cell division compartments. Importantly, from these sites they have shown to orchestrate multiple signals that regulate different cell pathways. In this review, we summarize the current knowledge of this fascinating phenomenon, explaining how GPCRs reach the intracellular sites, are stimulated by the endogenous ligands, and their potential physiological/pathophysiological roles. Finally, we illustrate several mechanisms involved in the modulation of the compartmentalized GPCR signaling by drugs and endogenous ligands. Understanding how GPCR signaling compartmentalization is regulated will provide a unique opportunity to develop novel pharmaceutical approaches to target GPCRs and potentially lead the way towards new therapeutic approaches.
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Affiliation(s)
- Irene Fasciani
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Marco Carli
- Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
| | - Francesco Petragnano
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Francesco Colaianni
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Gabriella Aloisi
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Roberto Maggio
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Marco Scarselli
- Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
| | - Mario Rossi
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
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10
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Peña KA, White AD, Savransky S, Castillo IP, Jean-Alphonse FG, Gardella TJ, Sutkeviciute I, Vilardaga JP. Biased GPCR signaling by the native parathyroid hormone-related protein 1-141 relative to its N-terminal fragment 1-36. J Biol Chem 2022; 298:102332. [PMID: 35933010 PMCID: PMC9437850 DOI: 10.1016/j.jbc.2022.102332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Abstract
The parathyroid hormone (PTH)–related protein (PTHrP) is indispensable for the development of mammary glands, placental calcium ion transport, tooth eruption, bone formation and bone remodeling, and causes hypercalcemia in patients with malignancy. Although mature forms of PTHrP in the body consist of splice variants of 139, 141, and 173 amino acids, our current understanding on how endogenous PTHrP transduces signals through its cognate G-protein coupled receptor (GPCR), the PTH type 1 receptor (PTHR), is largely derived from studies done with its N-terminal fragment, PTHrP1-36. Here, we demonstrate using various fluorescence imaging approaches at the single cell level to measure kinetics of (i) receptor activation, (ii) receptor signaling via Gs and Gq, and (iii) receptor internalization and recycling that the native PTHrP1-141 displays biased agonist signaling properties that are not mimicked by PTHrP1-36. Although PTHrP1–36 induces transient cAMP production, acute intracellular Ca2+ (iCa2+) release and β-arrestin recruitment mediated by ligand–PTHR interactions at the plasma membrane, PTHrP1-141 triggers sustained cAMP signaling from the plasma membrane and fails to stimulate iCa2+ release and recruit β-arrestin. Furthermore, we show that the molecular basis for biased signaling differences between PTHrP1-36 and properties of native PTHrP1-141 are caused by the stabilization of a singular PTHR conformation and PTHrP1-141 sensitivity to heparin, a sulfated glycosaminoglycan. Taken together, our results contribute to a better understanding of the biased signaling process of a native protein hormone acting in conjunction with a GPCR.
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Affiliation(s)
- Karina A Peña
- Department of Pharmacology and Chemical Biology, Pittsburgh PA 15261, USA
| | - Alex D White
- Department of Pharmacology and Chemical Biology, Pittsburgh PA 15261, USA
| | - Sofya Savransky
- Department of Pharmacology and Chemical Biology, Pittsburgh PA 15261, USA; Graduate Program in Molecular Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh PA 15261, USA
| | | | | | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Ieva Sutkeviciute
- Department of Pharmacology and Chemical Biology, Pittsburgh PA 15261, USA
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11
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Treyball A, Bergeron AC, Brooks DJ, Langlais AL, Hashmi H, Nagano K, Barlow D, Neilson RJ, Roy TA, Nevola KT, Houseknecht KL, Baron R, Bouxsein ML, Guntur AR, Motyl KJ. Propranolol Promotes Bone Formation and Limits Resorption Through Novel Mechanisms During Anabolic Parathyroid Hormone Treatment in Female C57BL/6J Mice. J Bone Miner Res 2022; 37:954-971. [PMID: 35122666 PMCID: PMC9098680 DOI: 10.1002/jbmr.4523] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 01/15/2022] [Accepted: 01/30/2022] [Indexed: 11/09/2022]
Abstract
Although the nonselective β-blocker, propranolol, improves bone density with parathyroid hormone (PTH) treatment in mice, the mechanism of this effect is unclear. To address this, we used a combination of in vitro and in vivo approaches to address how propranolol influences bone remodeling in the context of PTH treatment. In female C57BL/6J mice, intermittent PTH and propranolol administration had complementary effects in the trabecular bone of the distal femur and fifth lumbar vertebra (L5 ), with combination treatment achieving microarchitectural parameters beyond that of PTH alone. Combined treatment improved the serum bone formation marker, procollagen type 1 N propeptide (P1NP), but did not impact other histomorphometric parameters relating to osteoblast function at the L5 . In vitro, propranolol amplified the acute, PTH-induced, intracellular calcium signal in osteoblast-like cells. The most striking finding, however, was suppression of PTH-induced bone resorption. Despite this, PTH-induced receptor activator of nuclear factor κ-B ligand (RANKL) mRNA and protein levels were unaltered by propranolol, which led us to hypothesize that propranolol could act directly on osteoclasts. Using in situ methods, we found Adrb2 expression in osteoclasts in vivo, suggesting β-blockers may directly impact osteoclasts. Consistent with this, we found propranolol directly suppresses osteoclast differentiation in vitro. Taken together, this work suggests a strong anti-osteoclastic effect of nonselective β-blockers in vivo, indicating that combining propranolol with PTH could be beneficial to patients with extremely low bone density. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Annika Treyball
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA
| | - Audrey C Bergeron
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA
| | - Daniel J Brooks
- Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Audrie L Langlais
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Hina Hashmi
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA
| | - Kenichi Nagano
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - Deborah Barlow
- Department of Biomedical Sciences, University of New England, Biddeford, ME, USA
| | - Ryan J Neilson
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA
| | - Tyler A Roy
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA
| | - Kathleen T Nevola
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA.,Tufts Graduate School of Biomedical Sciences, Tufts University, Boston, MA, USA
| | - Karen L Houseknecht
- Department of Biomedical Sciences, University of New England, Biddeford, ME, USA
| | - Roland Baron
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - Mary L Bouxsein
- Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, MA, USA.,Department of Orthopedic Surgery, Harvard Medical School, Boston, MA, USA
| | - Anyonya R Guntur
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA.,Tufts University School of Medicine, Tufts University, Boston, MA, USA
| | - Katherine J Motyl
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA.,Tufts University School of Medicine, Tufts University, Boston, MA, USA
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12
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Sutkeviciute I, Lee JY, White AD, Maria CS, Peña KA, Savransky S, Doruker P, Li H, Lei S, Kaynak B, Tu C, Clark LJ, Sanker S, Gardella TJ, Chang W, Bahar I, Vilardaga JP. Precise druggability of the PTH type 1 receptor. Nat Chem Biol 2022; 18:272-280. [PMID: 34949836 PMCID: PMC8891041 DOI: 10.1038/s41589-021-00929-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 10/20/2021] [Indexed: 12/23/2022]
Abstract
Class B G protein-coupled receptors (GPCRs) are notoriously difficult to target by small molecules because their large orthosteric peptide-binding pocket embedded deep within the transmembrane domain limits the identification and development of nonpeptide small molecule ligands. Using the parathyroid hormone type 1 receptor (PTHR) as a prototypic class B GPCR target, and a combination of molecular dynamics simulations and elastic network model-based methods, we demonstrate that PTHR druggability can be effectively addressed. Here we found a key mechanical site that modulates the collective dynamics of the receptor and used this ensemble of PTHR conformers to identify selective small molecules with strong negative allosteric and biased properties for PTHR signaling in cell and PTH actions in vivo. This study provides a computational pipeline to detect precise druggable sites and identify allosteric modulators of PTHR signaling that could be extended to GPCRs to expedite discoveries of small molecules as novel therapeutic candidates.
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Affiliation(s)
- Ieva Sutkeviciute
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Ji Young Lee
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Alex D White
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Christian Santa Maria
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, University of California, San Francisco, CA, USA
| | - Karina A Peña
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sofya Savransky
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Graduate Program in Molecular Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Pemra Doruker
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Hongchun Li
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Research Center for Computer-Aided Drug Discovery, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Beijing, China
| | - Saifei Lei
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Center for Pharmacogenetics, University of Pittsburgh, School of Pharmacy, Pittsburgh, PA, USA
| | - Burak Kaynak
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Chialing Tu
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, University of California, San Francisco, CA, USA
| | - Lisa J Clark
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Biological Chemistry, University of California, Los Angeles, CA, USA
| | - Subramaniam Sanker
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Wenhan Chang
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, University of California, San Francisco, CA, USA
| | - Ivet Bahar
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Jean-Pierre Vilardaga
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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13
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White AD, Peña KA, Clark LJ, Maria CS, Liu S, Jean-Alphonse FG, Lee JY, Lei S, Cheng Z, Tu CL, Fang F, Szeto N, Gardella TJ, Xiao K, Gellman SH, Bahar I, Sutkeviciute I, Chang W, Vilardaga JP. Spatial bias in cAMP generation determines biological responses to PTH type 1 receptor activation. Sci Signal 2021; 14:eabc5944. [PMID: 34609896 PMCID: PMC8682804 DOI: 10.1126/scisignal.abc5944] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- Alex D White
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.,Graduate Program in Molecular Pharmacology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Karina A Peña
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Lisa J Clark
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.,Graduate Program in Molecular Biology and Structural Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Christian Santa Maria
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, and University of California, San Francisco, CA 94158, USA
| | - Shi Liu
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Frédéric G Jean-Alphonse
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Ji Young Lee
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Saifei Lei
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Zhiqiang Cheng
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, and University of California, San Francisco, CA 94158, USA
| | - Chia-Ling Tu
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, and University of California, San Francisco, CA 94158, USA
| | - Fei Fang
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Nicholas Szeto
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, and University of California, San Francisco, CA 94158, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Kunhong Xiao
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Samuel H Gellman
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Ivet Bahar
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Ieva Sutkeviciute
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Wenhan Chang
- Endocrine Research Unit, Department of Veterans Affairs Medical Center, and University of California, San Francisco, CA 94158, USA
| | - Jean-Pierre Vilardaga
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
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14
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Li M, Li M, Guo J. Molecular Mechanism of Ca 2+ in the Allosteric Regulation of Human Parathyroid Hormone Receptor-1. J Chem Inf Model 2021; 62:5110-5119. [PMID: 34464108 DOI: 10.1021/acs.jcim.1c00471] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Parathyroid hormone (PTH) is an endogenous ligand that activates the PTH type 1 receptor (PTH1R) signaling. Ca2+, a common second messenger, acts as an allosteric regulator for prolonging the activation of PTH1R. However, a clear picture of the underlying allosteric mechanism is still missing. Herein, extensive molecular dynamics (MD) simulations are performed for PTH1R-PTH complexes with and without Ca2+ ions, allowing us to delineate the molecular details of calcium-induced allostery. Our results indicate that acidic residues in the extracellular loop 1 (ECL1) (D251, E252, E254, and E258-E260) and PTH (E19 and E22) serve as key determinants for local Ca2+-coupling structures and rigidity of ECL1. Moreover, the binding of Ca2+ induces conformational changes of transmembrane domain 6/7 (TM6/7) that are related to PTH1R activation and strengthens the residue-residue communication within PTH and TMD allosterically. Moreover, our results demonstrate that the presence of Ca2+ ions potentiates the interaction between PTH and PTH1R via steered molecular dynamics (SMD) simulations, while the point mutation in the PTH (PTHR25C) weakens the binding of PTH and PTH1R. These results support that Ca2+ ions might further prolong the residence time of PTH on PTH1R and facilitate the positive allostery of PTH1R. Together, the present work provides new insights into the allosteric regulation mechanism of GPCRs induced by ions and related drug design targeting the PTH1R allosteric pathway.
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Affiliation(s)
- Mengrong Li
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Miaomiao Li
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Jingjing Guo
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
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15
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Jean-Alphonse FG, Sposini S. Confocal and TIRF microscopy based approaches to visualize arrestin trafficking in living cells. Methods Cell Biol 2021; 166:179-203. [PMID: 34752332 DOI: 10.1016/bs.mcb.2021.06.009] [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: 01/04/2023]
Abstract
Arrestins are key proteins that serve as versatile scaffolds to control and mediate G protein coupled receptors (GPCR) activity. Arrestin control of GPCR functions involves their recruitment from the cytosol to plasma membrane-localized GPCRs and to endosomal compartments, where they mediate internalization, sorting and signaling of GPCRs. Several methods can be used to monitor trafficking of arrestins; however, live fluorescence imaging remains the method of choice to both assess arrestin recruitment to ligand-activated receptors and to monitor its dynamic subcellular localization. Here, we present two approaches based on Total Internal Fluorescence (TIRF) microscopy and confocal microscopy to visualize arrestin trafficking in live cells in real time and to assess their co-localization with the GPCR of interest and their localization at specific subcellular locations.
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Affiliation(s)
- Frédéric Gaëtan Jean-Alphonse
- CNRS, IFCE, INRAE, Université de Tours, PRC, Nouzilly, France; Université Paris-Saclay, Inria, Inria Saclay-Île-de-France, Palaiseau, France
| | - Silvia Sposini
- Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom; University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, Bordeaux, France.
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16
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Senese NB, Rasenick MM. Antidepressants Produce Persistent G α s-Associated Signaling Changes in Lipid Rafts after Drug Withdrawal. Mol Pharmacol 2021; 100:66-81. [PMID: 34011569 DOI: 10.1124/molpharm.120.000226] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/10/2021] [Indexed: 12/14/2022] Open
Abstract
Termination of antidepressant therapy often has negative consequences. Although symptoms of antidepressant withdrawal are widely recognized, the molecular processes that underlie them are not well characterized. We show that certain aspects of Gα s signaling remain suppressed after antidepressant withdrawal, even after others have reverted to baseline. Antidepressant treatment causes translocation of Gα s protein from lipid rafts to nonraft membrane regions. This results in augmented Gα s signaling, including facilitated activation of adenylyl cyclase and increased cAMP accumulation. Using CC6 or SK-N-SH cells and a lipid raft-localized cAMP sensor, we show that Gα s signaling is reduced in lipid rafts, even while signaling is enhanced elsewhere in the cell. These signaling changes mirror the changes in Gα s localization observed after antidepressant treatment. Furthermore, we show that suppression of Gα s signaling in lipid rafts persists at least 24 hours after cessation of antidepressant treatment. Gα s localization was quantified after membrane isolation and sequential detergent extraction. We show that suppression of lipid raft Gα s signaling persists for an extended time period after antidepressant withdrawal, whereas increased nonraft membrane Gα s signaling reverts partially or fully upon cessation of antidepressant treatment. Translocation of Gα s out of lipid rafts is also persistent. These events may reflect cellular adaptations to antidepressant treatment that contribute to antidepressant discontinuation syndromes and may aid in the discovery of new treatments and strategies to mitigate the symptoms of depression and antidepressant withdrawal. SIGNIFICANCE STATEMENT: This work explores, for the first time, the effects of antidepressants on Gα s signaling after drug withdrawal. This provides novel insight into the cellular and molecular processes affected by antidepressant drugs and their persistence after discontinuation of treatment.
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Affiliation(s)
- Nicolas B Senese
- Departments of Psychiatry and Physiology and Biophysics, University of Illinois Chicago, Chicago, Illinois, and Jesse Brown VA Medical Center, Chicago, Illinois
| | - Mark M Rasenick
- Departments of Psychiatry and Physiology and Biophysics, University of Illinois Chicago, Chicago, Illinois, and Jesse Brown VA Medical Center, Chicago, Illinois
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17
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Mehta S, Zhang J. Biochemical Activity Architectures Visualized-Using Genetically Encoded Fluorescent Biosensors to Map the Spatial Boundaries of Signaling Compartments. Acc Chem Res 2021; 54:2409-2420. [PMID: 33949851 DOI: 10.1021/acs.accounts.1c00056] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
All biological processes arise through the coordinated actions of biochemical pathways. How such functional diversity is achieved by a finite cast of molecular players remains a central mystery in biology. Spatial compartmentation-the idea that biochemical activities are organized around discrete spatial domains within cells-was first proposed nearly 40 years ago and has become firmly rooted in our understanding of how biochemical pathways are regulated to ensure specificity. However, directly interrogating spatial compartmentation and its mechanistic origins has only really become possible in the last 20 or so years, following technological advances such as the development of genetically encoded fluorescent biosensors. These powerful molecular tools permit a direct, real-time visualization of dynamic biochemical processes in native biological contexts, and they are essential for probing the spatial regulation of biochemical activities. In this Account, we review our lab's efforts in developing and using biosensors to map the spatial compartmentation of intracellular signaling pathways and illuminate key mechanisms that establish the boundaries of an intricate biochemical activity architecture. We first discuss the role of regulatory fences, wherein the dynamic activation and deactivation of diffusible messengers produce diverse signaling compartments. For example, we used biosensors for the Ca2+ effector calmodulin and its downstream target calcineurin to reveal a spatial gradient of calmodulin that controls the temporal dynamics of calcineurin signaling. Our studies using cyclic adenosine monophosphate (cAMP) biosensors have similarly elucidated fenced cAMP domains generated by competing production and degradation pathways, ranging in size from cell-spanning gradients to nanoscale hotspots. Second, we describe the role played by intracellular membranes in creating unique signaling platforms with distinctive pathway regulation, as revealed through studies using subcellularly targeted fluorescent biosensors. Using biosensors to visualize subcellular extracellular response kinase (ERK) pathway activity, for example, led us to discover a local signaling circuit that mediates distinct plasma membrane ERK dynamics versus global ERK signaling. Similarly, our work developing biosensors to monitor the subcellular mechanistic target of rapamycin complex 1 (mTORC1) signaling allowed us to not only clarify the presence of mTORC1 activity in the nucleus but also identify a novel mechanism governing the activation of mTORC1 in this location. Finally, we detail how molecular assemblies enable the precise spatial tuning of biochemical activity, through investigations enabled by cutting-edge advances in biosensor design. We recently identified liquid-liquid phase separation as a major factor in cAMP compartmentation aided by a new strategy for targeting biosensors to endogenously expressed proteins via genome editing, for instance, and have also been able to directly visualize nanometer-scale protein kinase signalosomes using an entirely new class of biosensors specifically developed for the dynamic super-resolution imaging of live-cell biochemical activities. Our work provides key insights into the molecular logic of spatially regulated signaling and lays the foundation for a broader exploration of biochemical activity architectures across multiple spatial scales.
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Affiliation(s)
- Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, United States
| | - Jin Zhang
- Departments of Pharmacology, Bioengineering, and Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
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18
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DeNies MS, Smrcka AV, Schnell S, Liu AP. β-arrestin mediates communication between plasma membrane and intracellular GPCRs to regulate signaling. Commun Biol 2020; 3:789. [PMID: 33339901 PMCID: PMC7749148 DOI: 10.1038/s42003-020-01510-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 11/16/2020] [Indexed: 01/14/2023] Open
Abstract
It has become increasingly apparent that G protein-coupled receptor (GPCR) localization is a master regulator of cell signaling. However, the molecular mechanisms involved in this process are not well understood. To date, observations of intracellular GPCR activation can be organized into two categories: a dependence on OCT3 cationic channel-permeable ligands or the necessity of endocytic trafficking. Using CXC chemokine receptor 4 (CXCR4) as a model, we identified a third mechanism of intracellular GPCR signaling. We show that independent of membrane permeable ligands and endocytosis, upon stimulation, plasma membrane and internal pools of CXCR4 are post-translationally modified and collectively regulate EGR1 transcription. We found that β-arrestin-1 (arrestin 2) is necessary to mediate communication between plasma membrane and internal pools of CXCR4. Notably, these observations may explain that while CXCR4 overexpression is highly correlated with cancer metastasis and mortality, plasma membrane localization is not. Together these data support a model where a small initial pool of plasma membrane-localized GPCRs are capable of activating internal receptor-dependent signaling events. DeNies et al. identify a new mechanism of intracellular GPCR signalling. Using CXC chemokine receptor 4 (CXCR4) as a model, they show that upon stimulation with receptor agonists that not only plasma membrane-localized receptors, but also intracellular CXCR4 molecules are post-translationally modified and regulate transcription. This study suggests that a small pool of plasma membrane-localized GPCRs can activate internal receptor-dependent signaling, and that β-arrestin-1 mediates this activation.
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Affiliation(s)
- Maxwell S DeNies
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA
| | - Alan V Smrcka
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Santiago Schnell
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA.,Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Computational Medicine & Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Allen P Liu
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA. .,Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA. .,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA. .,Department of Biophysics, University of Michigan, Ann Arbor, MI, USA.
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19
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Sutkeviciute I, Vilardaga JP. Structural insights into emergent signaling modes of G protein-coupled receptors. J Biol Chem 2020; 295:11626-11642. [PMID: 32571882 DOI: 10.1074/jbc.rev120.009348] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 06/21/2020] [Indexed: 12/21/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent the largest family of cell membrane proteins, with >800 GPCRs in humans alone, and recognize highly diverse ligands, ranging from photons to large protein molecules. Very important to human medicine, GPCRs are targeted by about 35% of prescription drugs. GPCRs are characterized by a seven-transmembrane α-helical structure, transmitting extracellular signals into cells to regulate major physiological processes via heterotrimeric G proteins and β-arrestins. Initially viewed as receptors whose signaling via G proteins is delimited to the plasma membrane, it is now recognized that GPCRs signal also at various intracellular locations, and the mechanisms and (patho)physiological relevance of such signaling modes are actively investigated. The propensity of GPCRs to adopt different signaling modes is largely encoded in the structural plasticity of the receptors themselves and of their signaling complexes. Here, we review emerging modes of GPCR signaling via endosomal membranes and the physiological implications of such signaling modes. We further summarize recent structural insights into mechanisms of GPCR activation and signaling. We particularly emphasize the structural mechanisms governing the continued GPCR signaling from endosomes and the structural aspects of the GPCR resensitization mechanism and discuss the recently uncovered and important roles of lipids in these processes.
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Affiliation(s)
- Ieva Sutkeviciute
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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20
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G q/11-dependent regulation of endosomal cAMP generation by parathyroid hormone class B GPCR. Proc Natl Acad Sci U S A 2020; 117:7455-7460. [PMID: 32184323 DOI: 10.1073/pnas.1918158117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
cAMP production upon activation of Gs by G protein-coupled receptors has classically been considered to be plasma membrane-delimited, but a shift in this paradigm has occurred in recent years with the identification of several receptors that continue to signal from early endosomes after internalization. The molecular mechanisms regulating this aspect of signaling remain incompletely understood. Here, we investigated the role of Gq/11 activation by the parathyroid hormone (PTH) type 1 receptor (PTHR) in mediating endosomal cAMP responses. Inhibition of Gq/11 signaling by FR900359 markedly reduced the duration of PTH-induced cAMP production, and this effect was mimicked in cells lacking endogenous Gαq/11 We determined that modulation of cAMP generation by Gq/11 occurs at the level of the heterotrimeric G protein via liberation of cell surface Gβγ subunits, which, in turn, act in a phosphoinositide-3 kinase-dependent manner to promote the assembly of PTHR-βarrestin-Gβγ signaling complexes that mediate endosomal cAMP responses. These results unveil insights into the spatiotemporal regulation of Gs-dependent cAMP signaling.
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Sutkeviciute I, Clark LJ, White AD, Gardella TJ, Vilardaga JP. PTH/PTHrP Receptor Signaling, Allostery, and Structures. Trends Endocrinol Metab 2019; 30:860-874. [PMID: 31699241 PMCID: PMC6857722 DOI: 10.1016/j.tem.2019.07.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/09/2019] [Accepted: 07/12/2019] [Indexed: 02/08/2023]
Abstract
The parathyroid hormone (PTH) type 1 receptor (PTHR) is the canonical G protein-coupled receptor (GPCR) for PTH and PTH-related protein (PTHrP) and the key regulator of calcium homeostasis and bone turnover. PTHR function is critical for human health to maintain homeostatic control of ionized serum Ca2+ levels and has several unusual signaling features, such as endosomal cAMP signaling, that are well-studied but not structurally understood. In this review, we discuss how recently solved high resolution near-atomic structures of hormone-bound PTHR in its inactive and active signaling states and discovery of extracellular Ca2+ allosterism shed light on the structural basis for PTHR signaling and function.
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Affiliation(s)
- Ieva Sutkeviciute
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Lisa J Clark
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Graduate Program in Molecular Biophysics and Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Alex D White
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Graduate Program in Molecular Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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AKAP95 Organizes a Nuclear Microdomain to Control Local cAMP for Regulating Nuclear PKA. Cell Chem Biol 2019; 26:885-891.e4. [PMID: 30982750 DOI: 10.1016/j.chembiol.2019.03.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 01/27/2019] [Accepted: 03/01/2019] [Indexed: 12/25/2022]
Abstract
Contrary to the classic model of protein kinase A (PKA) residing outside of the nucleus, we identify a nuclear signaling complex that consists of AKAP95, PKA, and PDE4D5 and show that it forms a functional cyclic AMP (cAMP) signaling microdomain. Locally generated cAMP can accumulate within the vicinity of this complex; however, when cAMP is generated at the plasma membrane, PDE4 serves as a local sink and PDE3 as a barrier to prevent accumulation of cAMP within the microdomain as a means of controlling activation of tethered nuclear PKA.
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Zhang M, Yang H, Wan X, Lu L, Zhang J, Zhang H, Ye T, Liu Q, Xie M, Liu X, Yu S, Guo S, Chang W, Wang M. Prevention of Injury-Induced Osteoarthritis in Rodent Temporomandibular Joint by Targeting Chondrocyte CaSR. J Bone Miner Res 2019; 34:726-738. [PMID: 30496623 PMCID: PMC6482062 DOI: 10.1002/jbmr.3643] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 11/13/2018] [Accepted: 11/14/2018] [Indexed: 01/21/2023]
Abstract
Traumatic joint injuries produce osteoarthritic cartilage manifesting accelerated chondrocyte terminal differentiation and matrix degradation via unknown cellular and molecular mechanisms. Here we report the ability of biomechanical stress to increase expression of the calcium-sensing receptor (CaSR), a pivotal driver of chondrocyte terminal differentiation, in cultured chondrogenic cells subjected to fluid flow shear stress (FFSS) and in chondrocytes of rodent temporomandibular joint (TMJ) cartilage subjected to unilateral anterior cross-bite (UAC). In cultured ATDC5 cells or TMJ chondrocytes, FFSS induced Ca2+ loading and CaSR localization in endoplasmic reticulum (ER), casually accelerating cell differentiation that could be abrogated by emptying ER Ca2+ stores or CaSR knockdown. Likewise, acute chondrocyte-specific Casr knockout (KO) prevented the UAC-induced acceleration of chondrocyte terminal differentiation and matrix degradation in TMJ cartilage in mice. More importantly, local injections of CaSR antagonist, NPS2143, replicated the effects of Casr KO in preventing the development of osteoarthritic phenotypes in TMJ cartilage of the UAC-treated rats. Our study revealed a novel pathological action of CaSR in development of osteoarthritic cartilage due to aberrant mechanical stimuli and supports a therapeutic potential of calcilytics in preventing osteoarthritis in temporomandibular joints by targeting the CaSR. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Mian Zhang
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Hongxu Yang
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Xianghong Wan
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Lei Lu
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Jing Zhang
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Hongyun Zhang
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Tao Ye
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Qian Liu
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Mianjiao Xie
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Xiaodong Liu
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Shibin Yu
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Shaoxiong Guo
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
| | - Wenhan Chang
- Endocrine Research Unit, Department of Veterans Affairs Medical Center and Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Meiqing Wang
- State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, the Fourth Military Medical University, Xi'an, China
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Localised GPCR signalling as revealed by FRET biosensors. Curr Opin Cell Biol 2019; 57:48-56. [DOI: 10.1016/j.ceb.2018.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 11/05/2018] [Accepted: 11/05/2018] [Indexed: 12/20/2022]
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Abstract
The parathyroid hormone (PTH) and its related peptide (PTHrP) activate PTH receptor (PTHR) signaling, but only the PTH sustains GS-mediated adenosine 3',5'-cyclic monophosphate (cAMP) production after PTHR internalization into early endosomes. The mechanism of this unexpected behavior for a G-protein-coupled receptor is not fully understood. Here, we show that extracellular Ca2+ acts as a positive allosteric modulator of PTHR signaling that regulates sustained cAMP production. Equilibrium and kinetic studies of ligand-binding and receptor activation reveal that Ca2+ prolongs the residence time of ligands on the receptor, thus, increasing both the duration of the receptor activation and the cAMP signaling. We further find that Ca2+ allostery in the PTHR is strongly affected by the point mutation recently identified in the PTH (PTHR25C) as a new cause of hypocalcemia in humans. Using high-resolution and mass accuracy mass spectrometry approaches, we identified acidic clusters in the receptor's first extracellular loop as key determinants for Ca2+ allosterism and endosomal cAMP signaling. These findings coupled to defective Ca2+ allostery and cAMP signaling in the PTHR by hypocalcemia-causing PTHR25C suggest that Ca2+ allostery in PTHR signaling may be involved in primary signaling processes regulating calcium homeostasis.
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Landomiel F, De Pascali F, Raynaud P, Jean-Alphonse F, Yvinec R, Pellissier LP, Bozon V, Bruneau G, Crépieux P, Poupon A, Reiter E. Biased Signaling and Allosteric Modulation at the FSHR. Front Endocrinol (Lausanne) 2019; 10:148. [PMID: 30930853 PMCID: PMC6425863 DOI: 10.3389/fendo.2019.00148] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 02/19/2019] [Indexed: 12/12/2022] Open
Abstract
Knowledge on G protein-coupled receptor (GPCRs) structure and mechanism of activation has profoundly evolved over the past years. The way drugs targeting this family of receptors are discovered and used has also changed. Ligands appear to bind a growing number of GPCRs in a competitive or allosteric manner to elicit balanced signaling or biased signaling (i.e., differential efficacy in activating or inhibiting selective signaling pathway(s) compared to the reference ligand). These novel concepts and developments transform our understanding of the follicle-stimulating hormone (FSH) receptor (FSHR) biology and the way it could be pharmacologically modulated in the future. The FSHR is expressed in somatic cells of the gonads and plays a major role in reproduction. When compared to classical GPCRs, the FSHR exhibits intrinsic peculiarities, such as a very large NH2-terminal extracellular domain that binds a naturally heterogeneous, large heterodimeric glycoprotein, namely FSH. Once activated, the FSHR couples to Gαs and, in some instances, to other Gα subunits. G protein-coupled receptor kinases and β-arrestins are also recruited to this receptor and account for its desensitization, trafficking, and intracellular signaling. Different classes of pharmacological tools capable of biasing FSHR signaling have been reported and open promising prospects both in basic research and for therapeutic applications. Here we provide an updated review of the most salient peculiarities of FSHR signaling and its selective modulation.
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Du Y, Yan T, Zhou L, Yin W, Lu J. A single-nucleotide polymorphism of the beta 2-adrenergic receptor gene can predict pathological complete response to taxane- and platinum-based neoadjuvant chemotherapy in breast cancer. BREAST CANCER-TARGETS AND THERAPY 2018; 10:201-206. [PMID: 30568487 PMCID: PMC6267711 DOI: 10.2147/bctt.s189197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Background Germline genetic polymorphisms in certain genes are associated with the response to anthracycline- and taxane-based neoadjuvant chemotherapy in breast cancer (BC). This translational study aims to evaluate the potential role of rs1042713 in the beta 2-adrenergic receptor (ADRB2) gene in predicting pathological complete responses (pCRs) to taxane- and platinum-based neoadjuvant chemotherapy in locally advanced breast cancer (LABC). Materials and methods The distribution frequencies of rs1042713 were genotyped in LABC patients who received taxane- and platinum-based neoadjuvant chemotherapy. Associations between tumor-relevant biomarkers, genotypes and pCRs were evaluated using Student’s t-test for continuous variables and Chi-square or Fisher’s exact test for categorical variables. For univariate analysis, the relationship between the rs1042713 polymorphism and pCR was analyzed by Chi-square or Fisher’s exact test. The modified ORs with their 95% CIs were calculated by a multivariate logistic regression analysis to explore the association between genotype and pCR. Results There was a significant correlation of the rs1042713 genotype with estrogen receptor (ER) status (P=0.008). Significant differences were detected in the rs1042713 genotypes of pCR and non-pCR patients (P=0.046). The pCR rate was 18.2% in patients with ADRB2 rs1042713 AA genotypes and 38.7% in AG+GG genotypes. Women carrying the AG+GG (OR=2.91, 95% CI: 1.02–8.29, P=0.046) genotype had a higher pCR rate than those with the AA genotype. Conclusion rs1042713, which is located in the ADRB2 gene, could predict pCR to taxane-and platinum-based neoadjuvant chemotherapy in LABC. This finding suggests that rs1042713 could play a potential role as a predictive marker in clinical settings.
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Affiliation(s)
- Yueyao Du
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China, ;
| | - Tingting Yan
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China, ;
| | - Liheng Zhou
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China, ;
| | - Wenjin Yin
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China, ;
| | - Jinsong Lu
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China, ;
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Greenwald EC, Mehta S, Zhang J. Genetically Encoded Fluorescent Biosensors Illuminate the Spatiotemporal Regulation of Signaling Networks. Chem Rev 2018; 118:11707-11794. [PMID: 30550275 DOI: 10.1021/acs.chemrev.8b00333] [Citation(s) in RCA: 295] [Impact Index Per Article: 49.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cellular signaling networks are the foundation which determines the fate and function of cells as they respond to various cues and stimuli. The discovery of fluorescent proteins over 25 years ago enabled the development of a diverse array of genetically encodable fluorescent biosensors that are capable of measuring the spatiotemporal dynamics of signal transduction pathways in live cells. In an effort to encapsulate the breadth over which fluorescent biosensors have expanded, we endeavored to assemble a comprehensive list of published engineered biosensors, and we discuss many of the molecular designs utilized in their development. Then, we review how the high temporal and spatial resolution afforded by fluorescent biosensors has aided our understanding of the spatiotemporal regulation of signaling networks at the cellular and subcellular level. Finally, we highlight some emerging areas of research in both biosensor design and applications that are on the forefront of biosensor development.
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Affiliation(s)
- Eric C Greenwald
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Sohum Mehta
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Jin Zhang
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
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Mechanisms of signalling and biased agonism in G protein-coupled receptors. Nat Rev Mol Cell Biol 2018; 19:638-653. [DOI: 10.1038/s41580-018-0049-3] [Citation(s) in RCA: 323] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Integration of GPCR Signaling and Sorting from Very Early Endosomes via Opposing APPL1 Mechanisms. Cell Rep 2018; 21:2855-2867. [PMID: 29212031 PMCID: PMC5732320 DOI: 10.1016/j.celrep.2017.11.023] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/18/2017] [Accepted: 11/03/2017] [Indexed: 01/10/2023] Open
Abstract
Endocytic trafficking is a critical mechanism for cells to decode complex signaling pathways, including those activated by G-protein-coupled receptors (GPCRs). Heterogeneity in the endosomal network enables GPCR activity to be spatially restricted between early endosomes (EEs) and the recently discovered endosomal compartment, the very early endosome (VEE). However, the molecular machinery driving GPCR activity from the VEE is unknown. Using luteinizing hormone receptor (LHR) as a prototype GPCR for this compartment, along with additional VEE-localized GPCRs, we identify a role for the adaptor protein APPL1 in rapid recycling and endosomal cAMP signaling without impacting the EE-localized β2-adrenergic receptor. LHR recycling is driven by receptor-mediated Gαs/cAMP signaling from the VEE and PKA-dependent phosphorylation of APPL1 at serine 410. Receptor/Gαs endosomal signaling is localized to microdomains of heterogeneous VEE populations and regulated by APPL1 phosphorylation. Our study uncovers a highly integrated inter-endosomal communication system enabling cells to tightly regulate spatially encoded signaling. GPCRs that internalize to very early endosomes (VEEs) require APPL1 to recycle Receptor recycling is driven by cAMP/PKA to phosphorylate serine 410 on APPL1 cAMP signaling from GPCRs, such as LHR, occurs from distinct VEE microdomains APPL1 limits VEE cAMP signaling via opposing mechanisms required for GPCR sorting
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English EJ, Mahn SA, Marchese A. Endocytosis is required for C XC chemokine receptor type 4 (CXCR4)-mediated Akt activation and antiapoptotic signaling. J Biol Chem 2018; 293:11470-11480. [PMID: 29899118 DOI: 10.1074/jbc.ra118.001872] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/07/2018] [Indexed: 11/06/2022] Open
Abstract
Signaling activated by binding of the CXC motif chemokine ligand 12 (CXCL12) to its cognate G protein-coupled receptor (GPCR), chemokine CXC motif receptor 4 (CXCR4), is linked to metastatic disease. However, the mechanisms governing CXCR4 signaling remain poorly understood. Here, we show that endocytosis and early endosome antigen 1 (EEA1), which is part of the endosome fusion machinery, are required for CXCL12-mediated AKT Ser/Thr kinase (Akt) signaling selective for certain Akt substrates. Pharmacological inhibition of endocytosis partially attenuated CXCL12-induced phosphorylation of Akt, but not phosphorylation of ERK-1/2. Similarly, phosphorylation of Akt, but not ERK-1/2, stimulated by CXCL13, the cognate ligand for the chemokine receptor CXCR5, was also attenuated by inhibited endocytosis. Furthermore, siRNA-mediated depletion of the Rab5-effector EEA1, but not of adaptor protein, phosphotyrosine-interacting with PH domain and leucine zipper 1 (APPL1), partially attenuated Akt, but not ERK-1/2, phosphorylation promoted by CXCR4. Attenuation of Akt phosphorylation through inhibition of endocytosis or EEA1 depletion was associated with reduced signaling to Akt substrate forkhead box O1/3a but not the Akt substrates TSC complex subunit 2 or glycogen synthase kinase 3β. This suggested that endocytosis and endosomes govern discrete aspects of CXCR4- or CXCR5-mediated Akt signaling. Consistent with this hypothesis, depletion of EEA1 reduced the ability of CXCL12 to attenuate apoptosis in suspended, but not adherent, HeLa cells. Our results suggest a mechanism whereby compartmentalized chemokine-mediated Akt signaling from endosomes suppresses the cancer-related process known as anoikis. Targeting this signaling pathway may help inhibit metastatic cancer involving receptors such as CXCR4.
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Affiliation(s)
- Elizabeth J English
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Sarah A Mahn
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Adriano Marchese
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226.
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Hanyaloglu AC. Advances in Membrane Trafficking and Endosomal Signaling of G Protein-Coupled Receptors. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 339:93-131. [PMID: 29776606 DOI: 10.1016/bs.ircmb.2018.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The integration of GPCR signaling with membrane trafficking, as a single orchestrated system, is a theme increasingly evident with the growing reports of GPCR endosomal signaling. Once viewed as a mechanism to regulate cell surface heterotrimeric G protein signaling, the endocytic trafficking system is complex, highly compartmentalized, yet deeply interconnected with cell signaling. The organization of receptors into distinct plasma membrane signalosomes, biochemically distinct endosomal populations, endosomal microdomains, and its communication with distinct subcellular organelles such as the Golgi provides multiple unique signaling platforms that are critical for specifying receptor function physiologically and pathophysiologically. In this chapter I discuss our emerging understanding in the endocytic trafficking systems employed by GPCRs and their novel roles in spatial control of signaling. Given the extensive roles that GPCRs play in vivo, these evolving models are starting to provide mechanistic understanding of distinct diseases and provide novel therapeutic avenues that are proving to be viable targets.
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Affiliation(s)
- Aylin C Hanyaloglu
- Institute of Reproductive and Developmental Biology, Department of Surgery and Cancer, Imperial College London, London, United Kingdom.
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Eichel K, von Zastrow M. Subcellular Organization of GPCR Signaling. Trends Pharmacol Sci 2018; 39:200-208. [PMID: 29478570 PMCID: PMC5830169 DOI: 10.1016/j.tips.2017.11.009] [Citation(s) in RCA: 156] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 11/26/2017] [Accepted: 11/27/2017] [Indexed: 01/09/2023]
Abstract
G protein-coupled receptors (GPCRs) comprise a large and diverse class of signal-transducing receptors that undergo dynamic and isoform-specific membrane trafficking. GPCRs thus have an inherent potential to initiate or regulate signaling reactions from multiple membrane locations. This review discusses emerging insights into the subcellular organization of GPCR function in mammalian cells, focusing on signaling transduced by heterotrimeric G proteins and β-arrestins. We summarize recent evidence indicating that GPCR-mediated activation of G proteins occurs not only from the plasma membrane (PM) but also from endosomes and Golgi membranes and that β-arrestin-dependent signaling can be transduced from the PM by β-arrestin trafficking to clathrin-coated pits (CCPs) after dissociation from a ligand-activated GPCR.
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Affiliation(s)
- Kelsie Eichel
- Program in Biochemistry and Molecular Biology, University of California, San Francisco School of Medicine, San Francisco, CA 94158, USA
| | - Mark von Zastrow
- Department of Psychiatry, University of California, San Francisco School of Medicine, San Francisco, CA 94158, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco School of Medicine, San Francisco, CA 94158, USA.
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Evolving View of Membrane Trafficking and Signaling Systems for G Protein-Coupled Receptors. ENDOCYTOSIS AND SIGNALING 2018; 57:273-299. [DOI: 10.1007/978-3-319-96704-2_10] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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35
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Spatial encryption of G protein-coupled receptor signaling in endosomes; Mechanisms and applications. Biochem Pharmacol 2017; 143:1-9. [DOI: 10.1016/j.bcp.2017.04.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/25/2017] [Indexed: 01/14/2023]
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36
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Grundmann M, Kostenis E. Temporal Bias: Time-Encoded Dynamic GPCR Signaling. Trends Pharmacol Sci 2017; 38:1110-1124. [PMID: 29074251 DOI: 10.1016/j.tips.2017.09.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/24/2017] [Accepted: 09/25/2017] [Indexed: 12/21/2022]
Abstract
Evidence suggests that cells can time-encode signals for secure transport and perception of information, and it appears that this dynamic signaling is a common principle of nature to code information in time. G-protein-coupled receptor (GPCR) signaling networks are no exception as their composition and signal transduction appear temporally flexible. In this review, we discuss the potential mechanisms by which GPCRs code biological information in time to create 'temporal bias.' We highlight dynamic signaling patterns from the second messenger to the receptor-ligand level and shed light on the dynamics of G-protein cycles, the kinetics of ligand-receptor interaction, and the occurrence of distinct signaling waves within the cell. A dynamic feature such as temporal bias adds to the complexity of GPCR signaling bias and gives rise to the question whether this trait could be exploited to gain control over time-encoded cell physiology.
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Affiliation(s)
- Manuel Grundmann
- Molecular-, Cellular- and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Nussallee 6, 53115 Bonn, Germany; Kidney Disease Research, Bayer Pharma AG, Aprather Weg 18a, 42113 Wuppertal, Germany
| | - Evi Kostenis
- Molecular-, Cellular- and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Nussallee 6, 53115 Bonn, Germany.
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37
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Halls ML, Canals M. Genetically Encoded FRET Biosensors to Illuminate Compartmentalised GPCR Signalling. Trends Pharmacol Sci 2017; 39:148-157. [PMID: 29054309 DOI: 10.1016/j.tips.2017.09.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/07/2017] [Accepted: 09/27/2017] [Indexed: 01/17/2023]
Abstract
Genetically encoded Förster resonance energy transfer (FRET) biosensors have been instrumental to our understanding of how intracellular signalling is organised and regulated within cells. In the last decade, the toolbox, dynamic range and applications of these sensors have expanded beyond basic cell biology applications. In particular, FRET biosensors have shed light onto the mechanisms that control the intracellular organisation of G protein-coupled receptor (GPCR) signalling and have allowed the visualisation of signalling events with unprecedented temporal and spatial resolution. Here we review the use of these sensors in the GPCR field and how it has already provided invaluable advances towards our understanding of the complexity of GPCR signalling.
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Affiliation(s)
- Michelle L Halls
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
| | - Meritxell Canals
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
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Kittikulsuth W, Friedman PA, van Hoek A, Gao Y, Kohan DE. Identification of adenylyl cyclase isoforms mediating parathyroid hormone- and calcitonin-stimulated cyclic AMP accumulation in distal tubule cells. BMC Nephrol 2017; 18:292. [PMID: 28882112 PMCID: PMC5590165 DOI: 10.1186/s12882-017-0712-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 09/04/2017] [Indexed: 11/23/2022] Open
Abstract
Background The distal convoluted tubule (DCT) is an important nephron site for parathyroid hormone (PTH) and calcitonin regulation of urinary divalent cation excretion. These hormones exert their effects on the DCT in substantial part through activation of adenylyl cyclase (AC); however, it is unknown which AC isoforms are involved. Methods To examine this, two mouse DCT cell lines were studied: 209 and D1 cells. AC isoform mRNA expression was analyzed by real-time PCR. Cyclic AMP was measured using enzyme immunoassay. Results Calcitonin, but not PTH, stimulated cAMP accumulation in 209 cells, while PTH, but not calcitonin, increased cAMP content in D1 cells. Both cell types expressed AC3, AC4, AC6, AC7, and AC9 mRNA; in both cell types, AC6 mRNA was most abundant, followed by AC9, then AC3 and AC7, with relatively very small amounts of AC4 mRNA. Microdissected mouse DCT had a similar pattern of AC isoform mRNA expression although AC5 mRNA was detected. Individual siRNA knockdown of AC6 and AC9 reduced calcitonin-stimulated cAMP accumulation in 209 cells and PTH-induced cAMP levels in D1 cells. Knockdown of AC3 had no effect on hormonal augmentation of cAMP in either cell line. Surprisingly, knockdown of AC7 increased calcitonin-induced cAMP accumulation in 209 cells as well as PTH-stimulated cAMP content in D1 cells. Conclusions Taken together, these findings indicate that AC6 and AC9 mediate calcitonin- and PTH-stimulated cAMP accumulation in DCT cells, while activation of AC7 may paradoxically reduce the stimulatory effects of PTH and calcitonin on cultured DCT cAMP levels.
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Affiliation(s)
- Wararat Kittikulsuth
- Division of Nephrology, University of Utah Health Sciences Center, 1900 E 30 N, Salt Lake City, UT, 84132, USA
| | - Peter A Friedman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alfred van Hoek
- Department of Neurology, University of Utah Health Sciences Center, Salt Lake City, UT, USA
| | - Yang Gao
- Division of Nephrology, University of Utah Health Sciences Center, 1900 E 30 N, Salt Lake City, UT, 84132, USA
| | - Donald E Kohan
- Division of Nephrology, University of Utah Health Sciences Center, 1900 E 30 N, Salt Lake City, UT, 84132, USA. .,Salt Lake Veterans Affairs Medical Center, Salt Lake City, UT, USA.
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Inda C, Armando NG, Dos Santos Claro PA, Silberstein S. Endocrinology and the brain: corticotropin-releasing hormone signaling. Endocr Connect 2017; 6:R99-R120. [PMID: 28710078 PMCID: PMC5551434 DOI: 10.1530/ec-17-0111] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 07/14/2017] [Indexed: 01/01/2023]
Abstract
Corticotropin-releasing hormone (CRH) is a key player of basal and stress-activated responses in the hypothalamic-pituitary-adrenal axis (HPA) and in extrahypothalamic circuits, where it functions as a neuromodulator to orchestrate humoral and behavioral adaptive responses to stress. This review describes molecular components and cellular mechanisms involved in CRH signaling downstream of its G protein-coupled receptors (GPCRs) CRHR1 and CRHR2 and summarizes recent findings that challenge the classical view of GPCR signaling and impact on our understanding of CRHRs function. Special emphasis is placed on recent studies of CRH signaling that revealed new mechanistic aspects of cAMP generation and ERK1/2 activation in physiologically relevant contexts of the neurohormone action. In addition, we present an overview of the pathophysiological role of the CRH system, which highlights the need for a precise definition of CRHRs signaling at molecular level to identify novel targets for pharmacological intervention in neuroendocrine tissues and specific brain areas involved in CRH-related disorders.
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Affiliation(s)
- Carolina Inda
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck SocietyBuenos Aires, Argentina
- DFBMCFacultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Natalia G Armando
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck SocietyBuenos Aires, Argentina
| | - Paula A Dos Santos Claro
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck SocietyBuenos Aires, Argentina
| | - Susana Silberstein
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck SocietyBuenos Aires, Argentina
- DFBMCFacultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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Abstract
All cellular behaviors arise through the coordinated actions of numerous intracellular biochemical pathways. Over the past 20 years, efforts to probe intracellular biochemical processes have undergone a fundamental transformation brought about by advances in fluorescence imaging, such as the development of genetically encoded fluorescent reporters and new imaging technologies; the impact of these approaches on our understanding of the molecular underpinnings of biological function cannot be understated. In particular, the ability to obtain information on the spatiotemporal regulation of biochemical processes unfolding in real time in the native context of a living cell has crystallized the view, long a matter of speculation, that cells achieve specific biological outcomes through the imposition of spatial control over the distribution of various biomolecules, and their associated biochemical activities, within the cellular environment. Indeed, the compartmentalization of biochemical activities by cells is now known to be pervasive and to span a multitude of spatial scales, from the length of a cell to just a few enzymes. In this Perspective, part of this special issue on "Seeing into cells", we highlight several recent imaging studies that provide detailed insights into not just where molecules are but where molecules are active within cells, offering a glimpse into the emerging view of biochemical activity architecture as a complement to the physical architecture of a cell.
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Affiliation(s)
- Sohum Mehta
- Department of Pharmacology, 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 Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine , Baltimore, Maryland 21205, United States
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Ni Q, Mehta S, Zhang J. Live-cell imaging of cell signaling using genetically encoded fluorescent reporters. FEBS J 2017; 285:203-219. [PMID: 28613457 DOI: 10.1111/febs.14134] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/19/2017] [Accepted: 06/09/2017] [Indexed: 12/31/2022]
Abstract
Synergistic advances in fluorescent protein engineering and live-cell imaging techniques in recent years have fueled the concurrent development and application of genetically encoded fluorescent reporters that are tailored for tracking signaling dynamics in living systems over multiple length and time scales. These biosensors are uniquely suited for this challenging task, owing to their specificity, sensitivity, and versatility, as well as to the noninvasive and nondestructive nature of fluorescence and the power of genetic encoding. Over the past 10 years, a growing number of fluorescent reporters have been developed for tracking a wide range of biological signals in living cells and animals, including second messenger and metabolite dynamics, enzyme activation and activity, and cell cycle progression and neuronal activity. Many of these biosensors are gaining wide use and are proving to be indispensable for unraveling the complex biological functions of individual signaling molecules in their native environment, the living cell, shedding new light on the structural and molecular underpinnings of cell signaling. In this review, we highlight recent advances in protein engineering that are likely to help expand and improve the design and application of these valuable tools. We then turn our focus to specific examples of live-cell imaging using genetically encoded fluorescent reporters as an important platform for advancing our understanding of G protein-coupled receptor signaling and neuronal activity.
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Affiliation(s)
- Qiang Ni
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA.,Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD, USA
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Mamonova T, Zhang Q, Chandra M, Collins BM, Sarfo E, Bu Z, Xiao K, Bisello A, Friedman PA. Origins of PDZ Binding Specificity. A Computational and Experimental Study Using NHERF1 and the Parathyroid Hormone Receptor. Biochemistry 2017; 56:2584-2593. [PMID: 28376304 DOI: 10.1021/acs.biochem.7b00078] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Na+/H+ exchanger regulatory factor-1 (NHERF1) is a scaffolding protein containing two PSD95/discs large protein/ZO1 (PDZ) domains that modifies the signaling, trafficking, and function of the parathyroid hormone receptor (PTHR), a family B G-protein-coupled receptor. PTHR and NHERF1 bind through a PDZ-ligand-recognition mechanism. We show that PTH elicits phosphorylation of Thr591 in the canonical -ETVM binding motif of PTHR. Conservative substitution of Thr591 with Cys does not affect PTH(1-34)-induced cAMP production or binding of PTHR to NHERF1. The findings suggested the presence of additional sites upstream of the PDZ-ligand motif through which the two proteins interact. Structural determinants outside the canonical NHERF1 PDZ-PTHR interface that influence binding have not been characterized. We used molecular dynamics (MD) simulation to predict residues involved in these interactions. Simulation data demonstrate that the negatively charged Glu side chains at positions -3, -5, and -6 upstream of the PDZ binding motif are involved in PDZ-PTHR recognition. Engineered mutant peptides representing the PTHR C-terminal region were used to measure the binding affinity with NHERF1 PDZ domains. Comparable micromolar affinities for peptides of different length were confirmed by fluorescence polarization, isothermal titration calorimetry, and surface plasmon resonance. Binding affinities measured for Ala variants validate MD simulations. The linear relation between the change in enthalpy and entropy following Ala substitutions at upstream positions -3, -5, and -6 of the PTHR peptide provides a clear example of the thermodynamic compensation rule. Overall, our data highlight sequences in PTHR that contribute to NHERF1 interaction and can be altered to prevent phosphorylation-mediated inhibition.
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Affiliation(s)
| | | | - Mintu Chandra
- Institute for Molecular Bioscience, The University of Queensland , St. Lucia, Brisbane, Queensland 4072, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland , St. Lucia, Brisbane, Queensland 4072, Australia
| | - Edward Sarfo
- Department of Chemistry, City College of New York , New York, New York 10031, United States
| | - Zimei Bu
- Department of Chemistry, City College of New York , New York, New York 10031, United States
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