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Membrane polarization in non-neuronal cells as a potential mechanism of metabolic disruption by depolarizing insecticides. Food Chem Toxicol 2022; 160:112804. [PMID: 34990786 DOI: 10.1016/j.fct.2021.112804] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/22/2021] [Accepted: 12/31/2021] [Indexed: 01/01/2023]
Abstract
A significant rise in the incidence of obesity and type 2 diabetes has occurred worldwide in the last two decades. Concurrently, a growing body of evidence suggests a connection between exposure to environmental pollutants, particularly insecticides, and the development of obesity and type 2 diabetes. This review summarizes key evidence of (1) the presence of different types of neuronal receptors - target sites for neurotoxic insecticides - in non-neuronal cells, (2) the activation of these receptors in non-neuronal cells by membrane-depolarizing insecticides, and (3) changes in metabolic functions, including lipid and glucose accumulation, associated with changes in membrane potential. Based on these findings, we propose that changes in membrane potential (Vmem) by certain insecticides serve as a novel regulator of lipid and glucose metabolism in non-excitable cells associated with obesity and type 2 diabetes.
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Kudryavtseva OA, Safina KR, Vakhrusheva OA, Logacheva MD, Penin AA, Neretina TV, Moskalenko VN, Glagoleva ES, Bazykin GA, Kondrashov AS. Genetics of Adaptation of the Ascomycetous Fungus Podospora anserina to Submerged Cultivation. Genome Biol Evol 2019; 11:2807-2817. [PMID: 31529025 PMCID: PMC6786475 DOI: 10.1093/gbe/evz194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2019] [Indexed: 12/02/2022] Open
Abstract
Podospora anserina is a model ascomycetous fungus which shows pronounced phenotypic senescence when grown on solid medium but possesses unlimited lifespan under submerged cultivation. In order to study the genetic aspects of adaptation of P. anserina to submerged cultivation, we initiated a long-term evolution experiment. In the course of the first 4 years of the experiment, 125 single-nucleotide substitutions and 23 short indels were fixed in eight independently evolving populations. Six proteins that affect fungal growth and development evolved in more than one population; in particular, in the G-protein alpha subunit FadA, new alleles fixed in seven out of eight experimental populations, and these fixations affected just four amino acid sites, which is an unprecedented level of parallelism in experimental evolution. Parallel evolution at the level of genes and pathways, an excess of nonsense and missense substitutions, and an elevated conservation of proteins and their sites where the changes occurred suggest that many of the observed fixations were adaptive and driven by positive selection.
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Affiliation(s)
- Olga A Kudryavtseva
- Department of Mycology and Phycology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Ksenia R Safina
- Skolkovo Institute of Science and Technology, Moscow, Russia
- Institute for Information Transmission Problems of the Russian Academy of Sciences, Moscow, Russia
| | - Olga A Vakhrusheva
- Skolkovo Institute of Science and Technology, Moscow, Russia
- Institute for Information Transmission Problems of the Russian Academy of Sciences, Moscow, Russia
| | - Maria D Logacheva
- Skolkovo Institute of Science and Technology, Moscow, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Aleksey A Penin
- Institute for Information Transmission Problems of the Russian Academy of Sciences, Moscow, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Tatiana V Neretina
- Institute for Information Transmission Problems of the Russian Academy of Sciences, Moscow, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- White Sea Biological Station, Lomonosov Moscow State University, Republic of Karelia, Russia
| | | | - Elena S Glagoleva
- Department of Plant Physiology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Georgii A Bazykin
- Skolkovo Institute of Science and Technology, Moscow, Russia
- Institute for Information Transmission Problems of the Russian Academy of Sciences, Moscow, Russia
| | - Alexey S Kondrashov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor
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Adjobo-Hermans MJW, Goedhart J, van Weeren L, Nijmeijer S, Manders EMM, Offermanns S, Gadella TWJ. Real-time visualization of heterotrimeric G protein Gq activation in living cells. BMC Biol 2011; 9:32. [PMID: 21619590 PMCID: PMC3129320 DOI: 10.1186/1741-7007-9-32] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 05/27/2011] [Indexed: 12/28/2022] Open
Abstract
Background Gq is a heterotrimeric G protein that plays an important role in numerous physiological processes. To delineate the molecular mechanisms and kinetics of signalling through this protein, its activation should be measurable in single living cells. Recently, fluorescence resonance energy transfer (FRET) sensors have been developed for this purpose. Results In this paper, we describe the development of an improved FRET-based Gq activity sensor that consists of a yellow fluorescent protein (YFP)-tagged Gγ2 subunit and a Gαq subunit with an inserted monomeric Turquoise (mTurquoise), the best cyan fluorescent protein variant currently available. This sensor enabled us to determine, for the first time, the kon (2/s) of Gq activation. In addition, we found that the guanine nucleotide exchange factor p63RhoGEF has a profound effect on the number of Gq proteins that become active upon stimulation of endogenous histamine H1 receptors. The sensor was also used to measure ligand-independent activation of the histamine H1 receptor (H1R) upon addition of a hypotonic stimulus. Conclusions Our observations reveal that the application of a truncated mTurquoise as donor and a YFP-tagged Gγ2 as acceptor in FRET-based Gq activity sensors substantially improves their dynamic range. This optimization enables the real-time single cell quantification of Gq signalling dynamics, the influence of accessory proteins and allows future drug screening applications by virtue of its sensitivity.
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Affiliation(s)
- Merel J W Adjobo-Hermans
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
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Tsutsumi R, Mistry D, Webster NJG. Signaling responses to pulsatile gonadotropin-releasing hormone in LbetaT2 gonadotrope cells. J Biol Chem 2010; 285:20262-72. [PMID: 20406815 DOI: 10.1074/jbc.m110.132662] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The hypothalamic neuropeptide gonadotropin-releasing hormone (GnRH) is secreted in a pulsatile fashion by hypothalamic neurons, and alterations in pulse frequency and amplitude differentially regulate gonadotropin synthesis and release. In this study, we investigated the kinetics of G(s) and G(q) signaling in response to continuous or pulsatile GnRH using fluorescence resonance energy transfer reporters in live mouse LbetaT2 gonadotrope cells. cAMP and protein kinase A-dependent reporters showed a rapid but transient increase in fluorescence resonance energy transfer signal with increasing doses of constant GnRH, and in contrast diacylglycerol (DAG) and calcium reporters showed a rapid and sustained signal. Multiple pulses of GnRH caused multiple pulses of cAMP and protein kinase A activation without desensitization, but the DAG and calcium reporters were rapidly desensitized resulting in inhibition of calcium and DAG responses. At the transcriptional level, both a cAMP-dependent cAMP-response element reporter and a DAG/calcium-dependent AP-1 reporter showed a pulse frequency-dependent increase in luciferase activity. However, constant GnRH stimulation gave very little cAMP-response element activation but very strong AP-1 activation. Based on these data, we propose that both the GnRH-R-G(s) and G(q) pathways are responsive to pulses of GnRH, but only the G(q) pathway is responsive to constant GnRH. Furthermore, the G(q) pathway is subject to desensitization with multiple GnRH pulses, but the G(s) pathway is not.
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Affiliation(s)
- Rie Tsutsumi
- Medical Research Service, Veterans Affairs San Diego Healthcare System, San Diego, California 92161, USA
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Endogenous RGS proteins attenuate Galpha(i)-mediated lysophosphatidic acid signaling pathways in ovarian cancer cells. Cell Signal 2007; 20:381-9. [PMID: 18083345 DOI: 10.1016/j.cellsig.2007.10.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Accepted: 10/30/2007] [Indexed: 01/06/2023]
Abstract
Lysophosphatidic acid is a bioactive phospholipid that is produced by and stimulates ovarian cancer cells, promoting proliferation, migration, invasion, and survival. Effects of LPA are mediated by cell surface G-protein coupled receptors (GPCRs) that activate multiple heterotrimeric G-proteins. G-proteins are deactivated by Regulator of G-protein Signaling (RGS) proteins. This led us to hypothesize that RGS proteins may regulate G-protein signaling pathways initiated by LPA in ovarian cancer cells. To determine the effect of endogenous RGS proteins on LPA signaling in ovarian cancer cells, we compared LPA activity in SKOV-3 ovarian cancer cells expressing G(i) subunit constructs that are either insensitive to RGS protein regulation (RGSi) or their RGS wild-type (RGSwt) counterparts. Both forms of the G-protein contained a point mutation rendering them insensitive to inhibition with pertussis toxin, and cells were treated with pertussis toxin prior to experiments to eliminate endogenous G(i/o) signaling. The potency and efficacy of LPA-mediated inhibition of forskolin-stimulated adenylyl cyclase activity was enhanced in cells expressing RGSi G(i) proteins as compared to RGSwt G(i). We further showed that LPA signaling that is subject to RGS regulation terminates much faster than signaling thru RGS insensitive G-proteins. Finally, LPA-stimulated SKOV-3 cell migration, as measured in a wound-induced migration assay, was enhanced in cells expressing Galpha(i2) RGSi as compared to cells expressing Galpha(i2) RGSwt, suggesting that endogenous RGS proteins in ovarian cancer cells normally attenuate this LPA effect. These data establish RGS proteins as novel regulators of LPA signaling in ovarian cancer cells.
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Clark MA, Sethi PR, Lambert NA. Active Galpha(q) subunits and M3 acetylcholine receptors promote distinct modes of association of RGS2 with the plasma membrane. FEBS Lett 2007; 581:764-70. [PMID: 17275815 PMCID: PMC1805712 DOI: 10.1016/j.febslet.2007.01.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Revised: 12/12/2006] [Accepted: 01/17/2007] [Indexed: 11/17/2022]
Abstract
RGS proteins accelerate the GTPase activity of heterotrimeric G proteins at the plasma membrane. Association of RGS proteins with the plasma membrane can be mediated by interactions with other membrane proteins and by direct interactions with the lipid bilayer. Here we use fluorescence recovery after photobleaching (FRAP) to characterize interactions between RGS2 and M3 acetylcholine receptors (M3Rs), Galpha subunits and the lipid bilayer. Active Galpha(q) and M3Rs both recruited RGS2-EGFP to the plasma membrane. RGS2-EGFP remained bound to the plasma membrane between interactions with active Galpha(q), but rapidly exchanged between membrane-associated and cytosolic pools when recruited by M3Rs.
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Affiliation(s)
- Michael A Clark
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912, USA
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