Remodeling of ryanodine receptor isoform 1 channel regulates the sweet and umami perception of Rattus norvegicus

Sweet and umami are respectively elicited by sweet/umami receptor on the tongue and palate epithelium. However, the molecular machinery allowing to taste reaction remains incompletely understood. Through a phosphoproteomic approach, we found the key proteins that trigger taste mechanisms based on the phosphorylation cascades. Thereinto, ryanodine receptor isoform 1 (RYR1) was further verified by sensor and behaviors assay. A model proposing RYR1-mediated sweet/umami signaling: RYR1 channel which mediates Ca2+ release from the endoplasmic reticulum is closed by its dephosphorylation in the bud tissue after umami/sweet treatment. And the alteration of Ca2+ content in the cytosol induces a transient membrane depolarization and generates cell current for taste signaling transduction. We demonstrate that RYR1 is a new channel in regulation of sweet/umami signaling transduction and also propose a metabolic clock notion based on sweet/umami sensing. Our study provides a rich fundamental for a system-level understanding of taste perception mechanism.

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Efficient High-Throughput Screening by Endoplasmic Reticulum Ca2+ Measurement to Identify Inhibitors of Ryanodine Receptor Ca2+-Release Channels

Molecular Pharmacology ◽

10.1124/mol.117.111468 ◽

2018 ◽

Vol 94 (1) ◽

pp. 722-730 ◽

Cited By ~ 15

Author(s):

Takashi Murayama ◽

Nagomi Kurebayashi ◽

Mari Ishigami-Yuasa ◽

Shuichi Mori ◽

Yukina Suzuki ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Ryanodine Receptor ◽

High Throughput ◽

High Throughput Screening

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Abstract 11423: Mitochondrial Calcium Flux Modulates Pacemaker Activity in Mouse Stem Cell Derived Cardiomyocytes

Circulation ◽

10.1161/circ.130.suppl_2.11423 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

An Xie ◽

Anyu Zhou ◽

Hong Liu ◽

Guangbin Shi ◽

Kenneth R Boheler ◽

...

Keyword(s):

Ryanodine Receptor ◽

Mrna Level ◽

Embryonic Stem ◽

Calcium Flux ◽

Pacemaker Activity ◽

Receptor Subtypes ◽

Ip3 Receptors ◽

Cell Current ◽

Beating Rate

INTRODUCTION: Ca2+ release from sarcoplasmic reticulum (SR) is known to contribute to the pacemaker activity in embryonic stem cells (ESC) derived cardiomyocytes (CMs). Mitochondria are known to participate in Ca2+ cycling. Nevertheless, the role of mitochondria in pacemaker activity is unclear. We studied the role of mitochondrial Ca2+ flux in spontaneously activity of ESC derived CMs. METHODS: CMs were derived from Wt and ryanodine receptor type 2 knockout (RYR2-/-) mouse ESC. Action potentials (APs) were recorded by perforated whole-cell current-clamp. Cytoplasmic and mitochondrial Ca2+ transients were determined by Fluo-4 and Rhod-2 respectively. Mitochondrial Ca2+ uniporter (MCU) siRNA was used. The mRNA level was evaluated by qPCR. RESULTS: As predicted, SR Ca2+ handling inhibitors, 10 μM ryanodine and 2 μM 2-APB, reduced spontaneous beating rate to 56% and 73% respectively in Wt CMs. Inhibition of mitochondrial Ca2+ flux by 10 μM Ru360 showed a similar inhibition effect on the pacemaker activity as 2 μM 2-APB in Wt CMs. To isolate the mitochondrial component, we used RYR2-/- CMs. In these cells, MCU inhibition by pharmacological or molecular biological means reduced beating rate. The MCU mRNA decreased by 96% after MCU siRNA silence 72 hrs (p<0.01). AP and mitochondrial Ca2+ transient synchronous recording revealed that the reduction of spontaneous beating rate accompanied with the depressed mitochondrial Ca2+ uptaking and releasing. In RyR2-/- CMs, 2 μM 2-APB could significantly lower the spontaneous beating rate. While 2 μM 2-APB was applied to MCU silenced RyR2-/- CMs, the beating rate couldn’t be slowed down further. This indicated IP3 receptors reduced spontaneous beating rate via MCU. Thapsigargin could substantially slow down beating rate like 2-APB. Caffeine depletion experiments showed other ryanodine receptor subtypes didn’t contribute Ca2+ release in RyR2-/- CMs. A L-type Ca2+ channel block, 10 μM nifedipine, couldn’t reduce beating frequency. This indicated spontaneous beating rate is Ca2+ influx independent in RyR2-/- CMs. CONCLUSIONS: Mitochondrial Ca2+ handling plays an important role in decreasing spontaneous beating rate. IP3R reduced spontaneous beating rate through MCU.

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Red and near-infrared light evokes Ca2+ influx, endoplasmic reticulum release and membrane depolarization in neurons and cancer cells

Journal of Photochemistry and Photobiology B Biology ◽

10.1016/j.jphotobiol.2020.112088 ◽

2021 ◽

Vol 214 ◽

pp. 112088

Author(s):

Iuliia Golovynska ◽

Sergii Golovynskyi ◽

Yurii V. Stepanov ◽

Liudmyla I. Stepanova ◽

Junle Qu ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Cancer Cells ◽

Near Infrared ◽

Membrane Depolarization ◽

Infrared Light ◽

Near Infrared Light

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cADP-ribose releases Ca2+ from cardiac sarcoplasmic reticulum independently of ryanodine receptor

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1997.273.3.h1082 ◽

1997 ◽

Vol 273 (3) ◽

pp. H1082-H1089 ◽

Cited By ~ 9

Author(s):

P. Lahouratate ◽

J. Guibert ◽

J. F. Faivre

Keyword(s):

Endoplasmic Reticulum ◽

Sarcoplasmic Reticulum ◽

Ryanodine Receptor ◽

Sea Urchin ◽

Calcium Release ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Cardiac Sarcoplasmic Reticulum ◽

Consistent Effect ◽

Cyclic Adp Ribose

Cyclic ADP-ribose (cADPR), an endogenous metabolite of beta-NAD+, activates Ca2+ release from endoplasmic reticulum in sea urchin eggs via the ryanodine receptor (RyR) pathway. A similar role has been proposed in cardiac sarcoplasmic reticulum (SR), although this remains controversial. We therefore investigated the ability of cADPR to induce Ca2+ release from canine cardiac SR microsomes using fluo 3 to monitor extravesicular Ca2+ concentration. We found that cADPR induced Ca2+ release in a concentration-dependent manner, whereas neither its precursor, NAD+, nor its metabolite, ADP-ribose, elicited a consistent effect. In addition, an additive effect on calcium release between cADPR and 9-Me-7-Br-eudistomin-D (MBED), an activator of RyR, was found as well as no cross-desensitization between cADPR and MBED. Specific blockers of the RyR did not abolish the cADPR-induced Ca2+ release. These results provide evidence for cADPR-induced Ca2+ release from dog cardiac SR via a novel mechanism which is independent of RyR activation.

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Ryanodine Receptor-1 Mediated Endoplasmic Reticulum - Mitochondrial Calcium Transfer in High-Grade Serous Ovarian Cancer Cells (HGSOC)

Biophysical Journal ◽

10.1016/j.bpj.2019.11.2295 ◽

2020 ◽

Vol 118 (3) ◽

pp. 404a-405a

Author(s):

Kay-Pong D. Yip ◽

Byeong-Jik Cha ◽

Omkar Paudel ◽

Samuel C. Mok ◽

James S. Sham

Keyword(s):

Ovarian Cancer ◽

Endoplasmic Reticulum ◽

Cancer Cells ◽

Ryanodine Receptor ◽

Ovarian Cancer Cells ◽

Mitochondrial Calcium ◽

High Grade ◽

Serous Ovarian Cancer ◽

Ryanodine Receptor 1

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Syntaxin 17 Is Abundant in Steroidogenic Cells and Implicated in Smooth Endoplasmic Reticulum Membrane Dynamics

Molecular Biology of the Cell ◽

10.1091/mbc.11.8.2719 ◽

2000 ◽

Vol 11 (8) ◽

pp. 2719-2731 ◽

Cited By ~ 62

Author(s):

Martin Steegmaier ◽

Viola Oorschot ◽

Judith Klumperman ◽

Richard H. Scheller

Keyword(s):

Endoplasmic Reticulum ◽

Smooth Endoplasmic Reticulum ◽

Regulatory Protein ◽

Cell Types ◽

Membrane Dynamics ◽

Endoplasmic Reticulum Membrane ◽

Steroidogenic Cell ◽

Molecular Machinery ◽

Intermediate Compartment ◽

Steroidogenic Cells

The endoplasmic reticulum (ER) consists of subcompartments that have distinct protein constituents, morphological appearances, and functions. To understand the mechanisms that regulate the intricate and dynamic organization of the endoplasmic reticulum, it is important to identify and characterize the molecular machinery involved in the assembly and maintenance of the different subcompartments. Here we report that syntaxin 17 is abundantly expressed in steroidogenic cell types and specifically localizes to smooth membranes of the ER. By immunoprecipitation analyses, syntaxin 17 exists in complexes with a syntaxin regulatory protein, rsly1, and/or two intermediate compartment SNARE proteins, rsec22b and rbet1. Furthermore, we found that syntaxin 17 is anchored to the smooth endoplasmic reticulum through an unusual mechanism, requiring two adjacent hydrophobic domains near its carboxyl terminus. Converging lines of evidence indicate that syntaxin 17 functions in a vesicle-trafficking step to the smooth-surfaced tubular ER membranes that are abundant in steroidogenic cells.

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Distribution of Retention Signals to the Endoplasmic Reticulum in the Type 1 Ryanodine Receptor (Ca2+ Release Channel)

The Showa University Journal of Medical Sciences ◽

10.15369/sujms1989.18.171 ◽

2006 ◽

Vol 18 (4) ◽

pp. 171-178

Author(s):

Takashi MAKINO ◽

Hideto OYAMADA ◽

Yusuke UBUKATA ◽

Katsuji OGUCHI

Keyword(s):

Endoplasmic Reticulum ◽

Ryanodine Receptor ◽

Release Channel

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3D visualisation of the cardiac ryanodine receptor clusters and the molecular-scale fraying of dyads

10.1101/2021.10.21.462365 ◽

2021 ◽

Author(s):

Thomas M. D. Sheard ◽

Miriam E. Hurley ◽

Andrew J Smith ◽

John Colyer ◽

Ed White ◽

...

Keyword(s):

Right Ventricular ◽

Ryanodine Receptor ◽

Ventricular Myocytes ◽

Three Dimensional ◽

Super Resolution ◽

Structural Protein ◽

3D Visualisation ◽

Central Regions ◽

Molecular Machinery ◽

Receptor Clusters

Clusters of ryanodine receptor calcium channels (RyRs) form the primary molecular machinery in cardiomyocytes. Various adaptations of super-resolution microscopy have revealed intricate details of the structure, molecular composition and locations of these couplons. However, most optical super-resolution techniques lack the capacity for three-dimensional (3D) visualisation. Enhanced Expansion Microscopy (EExM) offers resolution (in-plane and axially) sufficient to spatially resolve individual proteins within peripheral couplons and within dyads located in the interior. We have combined immunocytochemistry and immunohistochemistry variations of EExM with 3D visualisation to examine the complex topologies, geometries and molecular sub-domains within RyR clusters. We observed that peripheral couplons exhibit variable co-clustering ratios and patterns between RyR and the structural protein, junctophilin-2 (JPH2). Dyads possessed sub-domains of JPH2 which occupied the central regions of the RyR cluster, whilst the poles were typically devoid of JPH2 and broader, and likely specialise in turnover and remodelling of the cluster. In right ventricular myocytes from rats with monocrotaline-induced right ventricular failure, we observed hallmarks of RyR cluster fragmentation accompanied by similar fragmentations of the JPH2 sub-domains. We hypothesise that the frayed morphology of RyRs in close proximity to fragmented JPH2 structural sub-domains may form the primordial foci of RyR mobilisation and dyad remodelling.

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Effect of caffeine and coffee diets on calcium signalling in rat hippocampal neurons

Fiziolohichnyĭ zhurnal ◽

10.15407/fz67.04.037 ◽

2021 ◽

Vol 67 (4) ◽

pp. 37-43

Author(s):

V.M. Shkryl ◽

◽

T.G. Turytska ◽

V.A. Yavorsky ◽

V.P. Lyashenko ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Calcium Level ◽

Hippocampal Neurons ◽

Ryanodine Receptors ◽

Calcium Signalling ◽

Membrane Depolarization ◽

Calcium Mobilization ◽

High Concentration ◽

Excitability Of Neurons

The effects of long-lasting high concentration coffee and caffeine diets on calcium mobilization in rat hippocampal neurons were studied. Changes in the basal calcium level in the hippocampal neurons of control and experimental rats kept on a coffee or caffeine diet were measured. We also recorded the changes in the Ca2+ transients’ amplitude evoked by membrane depolarization or emptying the Ca2+ depot of the endoplasmic reticulum (ER) induced by caffeine activator of the ryanodine receptors. In rats on a coffee or caffeine diet, the basal Ca2+ level was increased by 7.4% and 11%, respectively, compared to control animals. In these groups, the amplitude of Ca2+ transients increased by 70% and 90%, respectively, of the basal level in response to the membrane depolarization. In the same groups, the amount of Ca2+ released from the ER was increased by two and three times, respectively, compared to the control after activation of ryanodine receptors. We concluded that long-term coffee and caffeine diets in rats cause a significant disruption of the hippocampal neurons’ endoplasmic reticulum function. The diets evoke an increase in Ca2+ concentration in the neurons and an excessive release of Ca2+ in response to excitation. The latter can lead to increased excitability of neurons and their further death from excessive Ca2+ levels.

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