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Inositol 1,4,5-Trisphosphate Receptor Type 3 Regulates Neuronal Growth Cone Sensitivity to Guidance Signals. iScience 2020; 23:100963. [PMID: 32199289 PMCID: PMC7082556 DOI: 10.1016/j.isci.2020.100963] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 02/10/2020] [Accepted: 02/29/2020] [Indexed: 11/22/2022] Open
Abstract
During neurodevelopment, the growth cone deciphers directional information from extracellular guidance cues presented as shallow concentration gradients via signal amplification. However, it remains unclear how the growth cone controls this amplification process during its navigation through an environment in which basal cue concentrations vary widely. Here, we identified inositol 1,4,5-trisphosphate (IP3) receptor type 3 as a regulator of axonal sensitivity to guidance cues in vitro and in vivo. Growth cones lacking the type 3 subunit are hypersensitive to nerve growth factor (NGF), an IP3-dependent attractive cue, and incapable of turning toward normal concentration ranges of NGF to which wild-type growth cones respond. This is due to globally, but not asymmetrically, activated Ca2+ signaling in the hypersensitive growth cones. Remarkably, lower NGF concentrations can polarize growth cones for turning if IP3 receptor type 3 is deficient. These data suggest a subtype-specific IP3 receptor function in sensitivity adjustment during axon navigation. IP3 receptor type 3 (IP3R3) controls axonal sensitivity to IP3-based guidance cues IP3R3−/− growth cones are not attracted to NGF due to global Ca2+ responses Lower NGF concentrations can polarize IP3R3−/− growth cones for attractive turning NGF knockdown in vivo can revert abnormal trajectory of IP3R3−/− axons
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2
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Pancreatic Beta Cell G-Protein Coupled Receptors and Second Messenger Interactions: A Systems Biology Computational Analysis. PLoS One 2016; 11:e0152869. [PMID: 27138453 PMCID: PMC4854486 DOI: 10.1371/journal.pone.0152869] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/21/2016] [Indexed: 12/17/2022] Open
Abstract
Insulin secretory in pancreatic beta-cells responses to nutrient stimuli and hormonal modulators include multiple messengers and signaling pathways with complex interdependencies. Here we present a computational model that incorporates recent data on glucose metabolism, plasma membrane potential, G-protein-coupled-receptors (GPCR), cytoplasmic and endoplasmic reticulum calcium dynamics, cAMP and phospholipase C pathways that regulate interactions between second messengers in pancreatic beta-cells. The values of key model parameters were inferred from published experimental data. The model gives a reasonable fit to important aspects of experimentally measured metabolic and second messenger concentrations and provides a framework for analyzing the role of metabolic, hormones and neurotransmitters changes on insulin secretion. Our analysis of the dynamic data provides support for the hypothesis that activation of Ca2+-dependent adenylyl cyclases play a critical role in modulating the effects of glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and catecholamines. The regulatory properties of adenylyl cyclase isoforms determine fluctuations in cytoplasmic cAMP concentration and reveal a synergistic action of glucose, GLP-1 and GIP on insulin secretion. On the other hand, the regulatory properties of phospholipase C isoforms determine the interaction of glucose, acetylcholine and free fatty acids (FFA) (that act through the FFA receptors) on insulin secretion. We found that a combination of GPCR agonists activating different messenger pathways can stimulate insulin secretion more effectively than a combination of GPCR agonists for a single pathway. This analysis also suggests that the activators of GLP-1, GIP and FFA receptors may have a relatively low risk of hypoglycemia in fasting conditions whereas an activator of muscarinic receptors can increase this risk. This computational analysis demonstrates that study of second messenger pathway interactions will improve understanding of critical regulatory sites, how different GPCRs interact and pharmacological targets for modulating insulin secretion in type 2 diabetes.
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Correia J, Michelangeli F, Publicover S. Regulation and roles of Ca2+ stores in human sperm. Reproduction 2015; 150:R65-76. [PMID: 25964382 PMCID: PMC4497595 DOI: 10.1530/rep-15-0102] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/11/2015] [Indexed: 12/16/2022]
Abstract
[Ca(2)(+)]i signalling is a key regulatory mechanism in sperm function. In mammalian sperm the Ca(2)(+)-permeable plasma membrane ion channel CatSper is central to [Ca(2)(+)]i signalling, but there is good evidence that Ca(2)(+) stored in intracellular organelles is also functionally important. Here we briefly review the current understanding of the diversity of Ca(2)(+) stores and the mechanisms for the regulation of their activity. We then consider the evidence for the involvement of these stores in [Ca(2)(+)]i signalling in mammalian (primarily human) sperm, the agonists that may activate these stores and their role in control of sperm function. Finally we consider the evidence that membrane Ca(2)(+) channels and stored Ca(2)(+) may play discrete roles in the regulation of sperm activities and propose a mechanism by which these different components of the sperm Ca(2)(+)-signalling apparatus may interact to generate complex and spatially diverse [Ca(2)(+)]i signals.
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Affiliation(s)
- Joao Correia
- School of BiosciencesUniversity of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | | | - Stephen Publicover
- School of BiosciencesUniversity of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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4
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Song W, Jin XA. Cyclic AMP inhibits neuromuscular junction maturation mediated by intracellular Ca2+. Neurosci Lett 2015; 589:104-9. [PMID: 25596442 DOI: 10.1016/j.neulet.2015.01.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 01/09/2015] [Accepted: 01/12/2015] [Indexed: 11/18/2022]
Abstract
The neuromuscular junction (NMJ) is established through initial contact of motor neuron axon with a skeletal muscle cell and the subsequent synaptic maturation. Previous studies have shown that cyclic AMP (cAMP) enhanced spinal neurons' survival and growth but inhibited synaptogenesis. Here, we find that elevating intracellular cAMP level of presynaptic neurons prevented NMJs from maturation both physiologically and morphologically. Importantly, cytosolic Ca(2+) is essential for the inhibitory effects of cAMP on NMJ maturation. We show that depletion of intracellular Ca(2+) store, rather than extracellular Ca(2+), abolished the cAMP-dependent inhibition of synaptic maturation. Taken together, we demonstrate that Ca(2+) released from intracellular Ca(2+) stores regulates neurotrophic actions on NMJ maturation.
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Affiliation(s)
- Wei Song
- Peking University Health Science Center, Beijing 100191, China; Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China.
| | - Xiwan Albert Jin
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China.
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5
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Meyer D, Voigt A, Widmayer P, Borth H, Huebner S, Breit A, Marschall S, de Angelis MH, Boehm U, Meyerhof W, Gudermann T, Boekhoff I. Expression of Tas1 taste receptors in mammalian spermatozoa: functional role of Tas1r1 in regulating basal Ca²⁺ and cAMP concentrations in spermatozoa. PLoS One 2012; 7:e32354. [PMID: 22427794 PMCID: PMC3303551 DOI: 10.1371/journal.pone.0032354] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 01/25/2012] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND During their transit through the female genital tract, sperm have to recognize and discriminate numerous chemical compounds. However, our current knowledge of the molecular identity of appropriate chemosensory receptor proteins in sperm is still rudimentary. Considering that members of the Tas1r family of taste receptors are able to discriminate between a broad diversity of hydrophilic chemosensory substances, the expression of taste receptors in mammalian spermatozoa was examined. METHODOLOGY/PRINCIPAL FINDINGS The present manuscript documents that Tas1r1 and Tas1r3, which form the functional receptor for monosodium glutamate (umami) in taste buds on the tongue, are expressed in murine and human spermatozoa, where their localization is restricted to distinct segments of the flagellum and the acrosomal cap of the sperm head. Employing a Tas1r1-deficient mCherry reporter mouse strain, we found that Tas1r1 gene deletion resulted in spermatogenic abnormalities. In addition, a significant increase in spontaneous acrosomal reaction was observed in Tas1r1 null mutant sperm whereas acrosomal secretion triggered by isolated zona pellucida or the Ca²⁺ ionophore A23187 was not different from wild-type spermatozoa. Remarkably, cytosolic Ca²⁺ levels in freshly isolated Tas1r1-deficient sperm were significantly higher compared to wild-type cells. Moreover, a significantly higher basal cAMP concentration was detected in freshly isolated Tas1r1-deficient epididymal spermatozoa, whereas upon inhibition of phosphodiesterase or sperm capacitation, the amount of cAMP was not different between both genotypes. CONCLUSIONS/SIGNIFICANCE Since Ca²⁺ and cAMP control fundamental processes during the sequential process of fertilization, we propose that the identified taste receptors and coupled signaling cascades keep sperm in a chronically quiescent state until they arrive in the vicinity of the egg - either by constitutive receptor activity and/or by tonic receptor activation by gradients of diverse chemical compounds in different compartments of the female reproductive tract.
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MESH Headings
- Animals
- Blotting, Western
- Calcium/metabolism
- Cyclic AMP/metabolism
- Female
- Gene Expression
- Humans
- Luminescent Proteins/genetics
- Luminescent Proteins/metabolism
- Male
- Mice
- Mice, 129 Strain
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Microscopy, Confocal
- Models, Biological
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Sperm Head/metabolism
- Spermatozoa/metabolism
- Testis/cytology
- Testis/metabolism
- Red Fluorescent Protein
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Affiliation(s)
- Dorke Meyer
- Walther-Straub Institute of Pharmacology and
Toxicology, Ludwig-Maximilians-University, Munich, Germany
| | - Anja Voigt
- German Institute of Nutrition,
Potsdam-Rehbruecke, Germany
- Institute for Neural Signal Transduction,
Center for Molecular Neurobiology, Hamburg, Germany
| | - Patricia Widmayer
- Institute of Physiology, University of
Hohenheim, Stuttgart, Germany
| | - Heike Borth
- Walther-Straub Institute of Pharmacology and
Toxicology, Ludwig-Maximilians-University, Munich, Germany
| | - Sandra Huebner
- German Institute of Nutrition,
Potsdam-Rehbruecke, Germany
| | - Andreas Breit
- Walther-Straub Institute of Pharmacology and
Toxicology, Ludwig-Maximilians-University, Munich, Germany
| | - Susan Marschall
- Institute of Experimental Genetics,
Helmholtz-Zentrum, Munich, Germany
| | | | - Ulrich Boehm
- Institute for Neural Signal Transduction,
Center for Molecular Neurobiology, Hamburg, Germany
| | | | - Thomas Gudermann
- Walther-Straub Institute of Pharmacology and
Toxicology, Ludwig-Maximilians-University, Munich, Germany
| | - Ingrid Boekhoff
- Walther-Straub Institute of Pharmacology and
Toxicology, Ludwig-Maximilians-University, Munich, Germany
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6
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Chaloux B, Caron AZ, Guillemette G. Protein kinase A increases the binding affinity and the Ca2+ release activity of the inositol 1,4,5-trisphosphate receptor type 3 in RINm5F cells. Biol Cell 2012; 99:379-88. [PMID: 17373911 DOI: 10.1042/bc20060121] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION In endocrine cells, IP(3)R (inositol 1,4,5-trisphosphate receptor), a ligand-gated Ca2+ channel, plays an important role in the control of intracellular Ca2+ concentration. There are three subtypes of IP(3)R that are distributed differentially among cell types. RINm5F cells express almost exclusively the IP(3)R-3 subtype. The purpose of the present study was to investigate the effect of PKA (protein kinase A) on the activity of IP(3)R-3 in RINm5F cells. RESULTS We show that immunoprecipitated IP(3)R-3 is a good substrate for PKA. Using a back-phosphorylation approach, we show that endogenous PKA phosphorylates IP(3)R-3 in intact RINm5F cells. [(3)H]IP(3) (inositol 1,4,5-trisphosphate) binding affinity and IP(3)-induced Ca2+ release activity were enhanced in permeabilized cells that were pre-treated with forskolin or PKA. The PKA-induced enhancement of IP(3)R-3 activity was also observed in intact RINm5F cells stimulated with carbachol and epidermal growth factor, two agonists that use different receptor types to activate phospholipase C. CONCLUSION The results of the present study reveal a converging step where the cAMP and the Ca2+ signalling systems act co-operatively in endocrine cell responses to external stimuli.
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Affiliation(s)
- Benoit Chaloux
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada
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7
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Tovey SC, Dedos SG, Rahman T, Taylor EJA, Pantazaka E, Taylor CW. Regulation of inositol 1,4,5-trisphosphate receptors by cAMP independent of cAMP-dependent protein kinase. J Biol Chem 2010; 285:12979-89. [PMID: 20189985 PMCID: PMC2857138 DOI: 10.1074/jbc.m109.096016] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 02/11/2010] [Indexed: 12/02/2022] Open
Abstract
In HEK cells stably expressing type 1 receptors for parathyroid hormone (PTH), PTH causes a sensitization of inositol 1,4,5-trisphosphate receptors (IP(3)R) to IP(3) that is entirely mediated by cAMP and requires cAMP to pass directly from type 6 adenylyl cyclase (AC6) to IP(3)R2. Using DT40 cells expressing single subtypes of mammalian IP(3)R, we demonstrate that high concentrations of cAMP similarly sensitize all IP(3)R isoforms to IP(3) by a mechanism that does not require cAMP-dependent protein kinase (PKA). IP(3) binding to IP(3)R2 is unaffected by cAMP, and sensitization is not mediated by the site through which ATP potentiates responses to IP(3). In single channel recordings from excised nuclear patches of cells expressing IP(3)R2, cAMP alone had no effect, but it increased the open probability of IP(3)R2 activated by a submaximal concentration of IP(3) alone or in combination with a maximally effective concentration of ATP. These results establish that cAMP itself increases the sensitivity of all IP(3)R subtypes to IP(3). For IP(3)R2, this sensitization results from cAMP binding to a novel site that increases the efficacy of IP(3). Using stably expressed short hairpin RNA to reduce expression of the G-protein, G alpha(s), we demonstrate that attenuation of AC activity by loss of G alpha(s) more substantially reduces sensitization of IP(3)R by PTH than does comparable direct inhibition of AC. This suggests that G alpha(s) may also specifically associate with each AC x IP(3)R complex. We conclude that all three subtypes of IP(3)R are regulated by cAMP independent of PKA. In HEK cells, where IP(3)R2 selectively associates with AC6, G alpha(s) also associates with the AC x IP(3)R signaling junction.
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MESH Headings
- Adenylyl Cyclases/genetics
- Adenylyl Cyclases/metabolism
- Animals
- Cell Line
- Cyclic AMP/genetics
- Cyclic AMP/metabolism
- Cyclic AMP-Dependent Protein Kinases/genetics
- Cyclic AMP-Dependent Protein Kinases/metabolism
- GTP-Binding Protein alpha Subunits/genetics
- GTP-Binding Protein alpha Subunits/metabolism
- Humans
- Inositol 1,4,5-Trisphosphate/genetics
- Inositol 1,4,5-Trisphosphate/metabolism
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- Rats
- Receptor, Parathyroid Hormone, Type 1/genetics
- Receptor, Parathyroid Hormone, Type 1/metabolism
- Signal Transduction/physiology
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Affiliation(s)
- Stephen C. Tovey
- From the Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Skarlatos G. Dedos
- From the Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Taufiq Rahman
- From the Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Emily J. A. Taylor
- From the Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Evangelia Pantazaka
- From the Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Colin W. Taylor
- From the Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
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8
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Gerlyand AM, Sitar DS. Protein kinase inhibition differentially regulates organic cation transport. Can J Physiol Pharmacol 2010; 87:821-30. [PMID: 20052008 DOI: 10.1139/y09-072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Previous studies showed that amantadine transport increased while tetraethylammonium (TEA) transport decreased in kidney tissue from diabetic rats. Changes in transport activity were reversed by exogenous insulin. We hypothesized that this difference in transport regulation is due to differential regulation of different transport systems. Native human embryonic kidney cortex cells (HEK293 cell line) and rat organic cation transporter (rOCT)-transfected cells were used to test the hypothesis. In support of differential regulation, short-term glucose starvation stimulated amantadine transport and inhibited TEA transport, but the effect was bicarbonate-modulated only for amantadine. cAMP analogues inhibited TEA transport while stimulating amantadine transport. This effect was additive to the effect of insulin, and the presence of bicarbonate affected the extent of the change. Our findings indicated that regulation of rOCT 1 and 2 was mediated by transmembrane adenylyl cyclase, and regulation of amantadine transport was mediated by soluble adenylyl cyclase, suggesting that intracellular microdomains of cAMP may be important in determining overall cellular transport for organic cations. Soluble adenylyl cyclase activity is known to be modulated by bicarbonate and lactate. These observations support our hypothesis and reconcile our previous studies demonstrating increased transport affinity for amantadine in the presence of bicarbonate and decreased transport affinity in the presence of lactate.
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Affiliation(s)
- Alexander M Gerlyand
- Department of Pharmacology and Therapeutics, University of Manitoba, A220-753 McDermot Avenue, Winnipeg, MB R3E 0T6, Canada
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9
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Vanderheyden V, Devogelaere B, Missiaen L, De Smedt H, Bultynck G, Parys JB. Regulation of inositol 1,4,5-trisphosphate-induced Ca2+ release by reversible phosphorylation and dephosphorylation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:959-70. [PMID: 19133301 DOI: 10.1016/j.bbamcr.2008.12.003] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 11/27/2008] [Accepted: 12/03/2008] [Indexed: 12/12/2022]
Abstract
The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) is a universal intracellular Ca2+-release channel. It is activated after cell stimulation and plays a crucial role in the initiation and propagation of the complex spatio-temporal Ca2+ signals that control cellular processes as different as fertilization, cell division, cell migration, differentiation, metabolism, muscle contraction, secretion, neuronal processing, and ultimately cell death. To achieve these various functions, often in a single cell, exquisite control of the Ca2+ release is needed. This review aims to highlight how protein kinases and protein phosphatases can interact with the IP3R or with associated proteins and so provide a large potential for fine tuning the Ca2+-release activity and for creating efficient Ca2+ signals in subcellular microdomains.
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Affiliation(s)
- Veerle Vanderheyden
- Laboratory of Molecular and Cellular Signalling, Department Molecular and Cellular Biology, Campus Gasthuisberg O/N1-K. U. Leuven, Herestraat 49-Bus 802, B-3000 Leuven, Belgium
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10
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Barrera NP, Morales B, Villalon M. ATP and adenosine trigger the interaction of plasma membrane IP3 receptors with protein kinase A in oviductal ciliated cells. Biochem Biophys Res Commun 2008; 364:815-21. [PMID: 18163243 DOI: 10.1016/j.bbrc.2007.10.104] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We have demonstrated that adenosine did not produce any change of intracellular free Ca2+ concentration ([Ca2+]i) in oviductal ciliated cells; however, it increased the ATP-induced Ca2+ influx through the activation of protein kinase A (PKA). Uncaging of IP3 and cAMP triggered a larger Ca2+ influx than did IP3 alone. Furthermore, the IP3 effect was abolished by Xestospongin C, an IP3 receptor blocker. Whole-cell recordings demonstrated the presence of an ATP-induced Ca2+ current, and the addition of adenosine increased the peak of this current. This effect was not observed in the presence of H-89, a PKA inhibitor. Using excised macro-patches of plasma membrane, IP3 generated a current, which was higher in the presence of the catalytic PKA subunit and this current was blocked by Xestospongin C. We show here that activation of plasma membrane IP3 receptors directly triggers Ca2+ influx in response to ATP and that these receptors are modulated by adenosine-activated PKA.
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Affiliation(s)
- Nelson P Barrera
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 IEW, United Kingdom.
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11
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Abstract
The inositol 1,4,5-trisphosphate (InsP3) receptors (InsP3Rs) are a family of Ca2+ release channels localized predominately in the endoplasmic reticulum of all cell types. They function to release Ca2+ into the cytoplasm in response to InsP3 produced by diverse stimuli, generating complex local and global Ca2+ signals that regulate numerous cell physiological processes ranging from gene transcription to secretion to learning and memory. The InsP3R is a calcium-selective cation channel whose gating is regulated not only by InsP3, but by other ligands as well, in particular cytoplasmic Ca2+. Over the last decade, detailed quantitative studies of InsP3R channel function and its regulation by ligands and interacting proteins have provided new insights into a remarkable richness of channel regulation and of the structural aspects that underlie signal transduction and permeation. Here, we focus on these developments and review and synthesize the literature regarding the structure and single-channel properties of the InsP3R.
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Affiliation(s)
- J Kevin Foskett
- Department of Physiology, University of Pennsylvania, Philadelphia 19104-6085, USA.
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12
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Soulsby MD, Wojcikiewicz RJH. Calcium mobilization via type III inositol 1,4,5-trisphosphate receptors is not altered by PKA-mediated phosphorylation of serines 916, 934, and 1832. Cell Calcium 2007; 42:261-70. [PMID: 17257671 PMCID: PMC1975771 DOI: 10.1016/j.ceca.2006.12.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 12/01/2006] [Accepted: 12/11/2006] [Indexed: 11/28/2022]
Abstract
Several studies have shown that PKA-mediated phosphorylation of IP3R1 at serines S1588 and S1755 enhances the receptor's ability to mobilize Ca2+. In contrast, much less is known about whether Ca2+ mobilization via IP3R2 and IP3R3 is regulated by PKA. We report here that IP3R2 is only very weakly phosphorylated in response to PKA activation and is probably not a physiological substrate for this kinase. IP3R3, however, is known to be phosphorylated by PKA at three sites (S916, S934, and S1832) and, thus, we examined how phosphorylation of these sites affects Ca2+ mobilization in DT40-3KO cells stably expressing either exogenous wild-type or mutant IP3R3s; an antibody raised against phospho-serine 934 of IP3R3 was used to demonstrate that the exogenous IP3R3s are strongly phosphorylated in response to PKA activation. Surprisingly, our data show that IP3R3-mediated Ca2+ mobilization is unaffected by phosphorylation of S916, S934, and S1832. In contrast, phosphorylation of exogenous IP3R1 (monitored with an antibody against phospho-serine 1755) enhances Ca2+ mobilization, indicating that DT40-3KO cells have the capacity to respond to phosphorylation of IP3Rs. Overall, these data suggest that modification of Ca2+ flux may not be the primary effect of IP3R3 phosphorylation by PKA.
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Affiliation(s)
- M D Soulsby
- Department of Pharmacology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210 2339, USA
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13
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Regimbald-Dumas Y, Arguin G, Fregeau MO, Guillemette G. cAMP-dependent protein kinase enhances inositol 1,4,5-trisphosphate-induced Ca2+ release in AR4-2J cells. J Cell Biochem 2007; 101:609-18. [PMID: 17203464 DOI: 10.1002/jcb.21221] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In non-excitable cells, the inositol 1,4,5-trisphosphate receptor (IP(3)R), a ligand-gated Ca(2+) channel, plays an important role in the control of intracellular Ca(2+). There are three subtypes of IP(3)R that are differentially distributed among cell types. AR4-2J cells express almost exclusively the IP(3)R-2 subtype. The purpose of this study was to investigate the effect of cAMP-dependent protein kinase (PKA) on the activity of IP(3)R-2 in AR4-2J cells. We showed that immunoprecipitated IP(3)R-2 is a good substrate for PKA. Using a back-phosphorylation approach, we showed that endogenous PKA phosphorylates IP(3)R-2 in intact AR4-2J cells. Pretreatment with PKA enhanced IP(3)-induced Ca(2+) release in permeabilized AR4-2J cells. Pretreatment with the cAMP generating agent's forskolin and vasoactive intestinal peptide (VIP) enhanced carbachol (Cch)-induced and epidermal growth factor (EGF)-induced Ca(2+) responses in intact AR4-2J cells. Our results are consistent with an enhancing effect of PKA on IP(3)R-2 activity. This conclusion supports the emerging concept of crosstalk between Ca(2+) signaling and cAMP pathways and thus provides another way by which Ca(2+) signals are finely encoded within non-excitable cells.
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Affiliation(s)
- Yannik Regimbald-Dumas
- Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H5N4, Canada
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14
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Soulsby M, Wojcikiewicz R. The type III inositol 1,4,5-trisphosphate receptor is phosphorylated by cAMP-dependent protein kinase at three sites. Biochem J 2006; 392:493-7. [PMID: 16107208 PMCID: PMC1316288 DOI: 10.1042/bj20051325] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
IP3 (inositol 1,4,5-trisphosphate) receptors form tetrameric, IP3-gated Ca2+ channels in endoplasmic reticulum membranes, and are substrates for several kinases, including PKA (cAMP-dependent protein kinase). Activation of PKA has been reported to either enhance or inhibit type III IP3 receptor Ca2+-channel activity, but, as yet, the sites of phosphorylation remain unknown. Here, we reveal that PKA phosphorylates the type III IP3 receptor at Ser916, Ser934 and Ser1832, and that, intriguingly, each site is located close to a putative surface-exposed peptide loop. Furthermore, we demonstrate that Ser934 is considerably more susceptible to PKA-dependent phoshorylation than either Ser916 or Ser1832. These findings define the sites at which the type III IP3 receptor is phosphorylated by PKA, and provide the basis for exploring the functional consequences of this regulatory event.
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Affiliation(s)
- Matthew D. Soulsby
- Department of Pharmacology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210-2339, U.S.A
| | - Richard J. H. Wojcikiewicz
- Department of Pharmacology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210-2339, U.S.A
- To whom correspondence should be addressed (email )
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15
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Abstract
The endoplasmic reticulum is not the only major agonist-releasable Ca2+ store within cells; it is now clear that virtually all organelles so far studied have the ability to act as mobilizable Ca2+ stores. From recent findings with regard to Ca2+ transportation and Ca2+ homeostasis within a variety of cell organelles such as the mitochondria, nucleus, Golgi and lysosomes, it emerges that many of these organellar Ca2+ stores appear to interact with each other, adding a further level of complexity to Ca2+ signalling events.
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16
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Hsieh JC, Dang HTL, Galligan MA, Whitfield GK, Haussler CA, Jurutka PW, Haussler MR. Phosphorylation of human vitamin D receptor serine-182 by PKA suppresses 1,25(OH)2D3-dependent transactivation. Biochem Biophys Res Commun 2004; 324:801-9. [PMID: 15474498 DOI: 10.1016/j.bbrc.2004.09.139] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Indexed: 01/06/2023]
Abstract
The human vitamin D receptor (hVDR), which is a substrate for several protein kinases, mediates the actions of its 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) ligand to regulate gene expression. To determine the site, and functional impact, of cAMP-dependent protein kinase (PKA)-catalyzed phosphorylation of hVDR, we generated a series of C-terminally truncated and point mutant receptors. Incubation of mutant hVDRs with PKA and [gamma-32P]ATP, in vitro, or overexpressing them in COS-7 kidney cells labeled with [32P]orthophosphate, revealed that serine-182 is the predominant residue in hVDR phosphorylated by PKA. An aspartate substituted mutant (S182D), incorporating a negative charge to mimic phosphorylation, displayed only 50% of the transactivation capacity in response to 1,25(OH)2D3 of either wild-type or an S182A-altered hVDR. When the catalytic subunit of PKA was overexpressed, a similar reduction in wild-type but not S182D hVDR transactivity was observed. In a mammalian two-hybrid system, S182D bound less avidly than wild-type or S182A hVDR to the retinoid X receptor (RXR) heterodimeric partner that co-mediates vitamin D responsive element recognition and transactivation. These data suggest that hVDR serine-182 is a primary site for PKA phosphorylation, an event that leads to an attenuation of both RXR heterodimerization and resultant transactivation of 1,25(OH)2D3 target genes.
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Affiliation(s)
- Jui-Cheng Hsieh
- Department of Biochemistry and Molecular Biophysics, College of Medicine, University of Arizona, Tucson, AZ 85724, USA
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17
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Soulsby MD, Alzayady K, Xu Q, Wojcikiewicz RJH. The contribution of serine residues 1588 and 1755 to phosphorylation of the type I inositol 1,4,5-trisphosphate receptor by PKA and PKG. FEBS Lett 2004; 557:181-4. [PMID: 14741364 DOI: 10.1016/s0014-5793(03)01487-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Type I inositol 1,4,5-trisphosphate receptors can be phosphorylated by cAMP-dependent protein kinase (PKA) and cGMP-dependent protein kinase (PKG). To define the site-specificity of these events we analyzed the phosphorylation of mutant receptors expressed in intact cells. These studies showed that S(1588) and S(1755), the serine residues within kinase consensus sequences, are equally sensitive to PKA, that phosphorylation events at these sites are independent of each other, and that PKG predominantly phosphorylates S(1588). These findings provide the basis for understanding the functional consequences of type I inositol 1,4,5-trisphosphate receptor phosphorylation.
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Affiliation(s)
- Matthew D Soulsby
- Department of Pharmacology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210-2339, USA
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18
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Lu Z, Kolodecik TR, Karne S, Nyce M, Gorelick F. Effect of ligands that increase cAMP on caerulein-induced zymogen activation in pancreatic acini. Am J Physiol Gastrointest Liver Physiol 2003; 285:G822-8. [PMID: 12881228 PMCID: PMC2830556 DOI: 10.1152/ajpgi.00213.2003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The pathological activation of proteases within the pancreatic acinar cell is critical to initiating pancreatitis. Stimulation of acinar cells with supraphysiological concentrations of the CCK analog caerulein (CER) leads to protease activation and pancreatitis. Agents that sensitize the acinar cell to the effects of CCK might contribute to disease. The effects of physiological ligands that increase acinar cell cAMP [secretin, VIP, and pituitary adenylate cyclase activating peptide (PACAP)] on CER-induced responses were examined in isolated rat pancreatic acini. Each ligand sensitized the acinar cell to zymogen activation by physiological concentrations of CER (0.1 nM). VIP and PACAP but not secretin also enhanced activation by supraphysiological concentrations of CER (0.1 muM). A cell-permeable cAMP analog also sensitized the acinar cell to CER-induced activation. The cAMP antagonist Rp-8-Br-cAMP inhibited these sensitizing effects. These findings suggest that ligands that increase acinar cell cAMP levels can sensitize the acinar cell to the effects of CCK-induced zymogen activation.
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Affiliation(s)
- Z Lu
- GI Research Laboratory, Veterans Affairs Healthcare Connecticut, 950 Campbell Ave., West Haven, CT 06516, USA
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19
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Khan SZ, Kirk CJ, Michelangeli F. Alkylphenol endocrine disrupters inhibit IP3-sensitive Ca2+ channels. Biochem Biophys Res Commun 2003; 310:261-6. [PMID: 14521904 DOI: 10.1016/j.bbrc.2003.09.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated the influence of alkylphenol endocrine disrupters and the synthetic estrogen diethylstilbestrol (DES) on inositol-1,4,5-trisphosphate (IP(3))-sensitive Ca(2+) channels from porcine cerebellum and rat testicular membranes. All alkylphenols and DES inhibited the extent of IP(3)-induced Ca(2+) release (IICR) from both cerebellar and testicular microsomes. 4-n-nonylphenol was the most potent compound tested (IC(50), 8 microM). Inhibition of IICR was directly related to the length and hydrophobicity of the alkylphenol side chain. None of the alkylphenols or DES appeared to influence the concentration dependence of IICR nor did they have a significant effect on [3H]IP(3) binding to the membranes. An investigation of the effects of nonylphenol on the transient kinetics of IICR showed that it inhibited the rate constants for both the fast and the slow phases of IICR and also the extent of Ca(2+) release. These results illustrate another mechanism by which these environmental pollutants can disrupt endocrine function without the involvement of estrogen receptors.
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Affiliation(s)
- Shahla Zafar Khan
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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