Regulation of calcium signalling by adenine-based second messengers

2007 ◽  
Vol 35 (1) ◽  
pp. 109-114 ◽  
Author(s):  
R. Fliegert ◽  
A. Gasser ◽  
A.H. Guse
Keyword(s):  
Transient Receptor Potential ◽  
Second Messengers ◽  
Calcium Signalling ◽  
Receptor Potential ◽  
Cell Types ◽  
Cellular Systems ◽  
Membrane Receptors ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor ◽  
Plasma Membrane Receptors

cADPR [cyclic ADPR (ADP-ribose)], NAADP (nicotinic acid–adenine dinucleotide phosphate) and ADPR belong to the family of adenine-containing second messengers. They are metabolically related and are all involved in the regulation of cellular Ca2+ homoeostasis. Activation of specific plasma membrane receptors is connected to cADPR formation in many cell types and tissues. In contrast receptor-mediated formation of NAADP and ADPR has been shown only in a few selected cellular systems. The intracellular Ca2+ channel triggered by cADPR is the RyR (ryanodine receptor); in the case of NAADP, both activation of RyR and a novel Ca2+ channel have been proposed. In contrast, ADPR opens the non-specific cation channel TRPM2 [TRP (transient receptor potential) melastatin 2] that belongs to the TRP family of ion channels.

TRPC1: a core component of store-operated calcium channels

2007 ◽  
Vol 35 (1) ◽  
pp. 96-100 ◽  
Author(s):  
I.S. Ambudkar
Keyword(s):  
Calcium Release ◽  
Transient Receptor Potential ◽  
Calcium Signalling ◽  
Receptor Potential ◽  
Cell Types ◽  
Surface Expression ◽  
Membrane Microdomains ◽  
Store Operated Calcium Entry ◽  
Transient Receptor ◽  
And Function

The TRPC (transient receptor potential canonical) proteins are activated in response to agonist-stimulated PIP2 (phosphatidylinositol 4,5-bisphosphate) hydrolysis and have been suggested as candidate components of the elusive SOC (store-operated calcium channel). TRPC1 is currently the strongest candidate component of SOC. Endogenous TRPC1 has been shown to contribute to SOCE (store-operated calcium entry) in several different cell types. However, the mechanisms involved in the regulation of TRPC1 and its exact physiological function have yet to be established. Studies from our laboratory and several others have demonstrated that TRPC1 is assembled in a signalling complex with key calcium signalling proteins in functionally specific plasma membrane microdomains. Furthermore, critical interactions between TRPC1 monomers as well as interactions between TRPC1 and other proteins determine the surface expression and function of TRPC1-containing channels. Recent studies have revealed novel regulators of TRPC1-containing SOCs and have demonstrated a common molecular basis for the regulation of CRAC (calcium-release-activated calcium) and SOC channels. In the present paper, we will revisit the role of TRPC1 in SOCE and discuss how studies with TRPC1 provide an experimental basis for validating the mechanism of SOCE.

scholarly journals TRPM6 N-Terminal CaM- and S100A1-Binding Domains

2019 ◽  
Vol 20 (18) ◽  
pp. 4430 ◽  
Author(s):  
Monika Zouharova ◽  
Petr Herman ◽  
Kateřina Hofbauerová ◽  
Jiri Vondrasek ◽  
Kristyna Bousova
Keyword(s):  
Calcium Binding ◽  
Transient Receptor Potential ◽  
Calcium Signalling ◽  
Receptor Potential ◽  
Basic Amino Acid ◽  
Binding Domain ◽  
Specific Domain ◽  
Binding Domains ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

Transient receptor potential (TRPs) channels are crucial downstream targets of calcium signalling cascades. They can be modulated either by calcium itself and/or by calcium-binding proteins (CBPs). Intracellular messengers usually interact with binding domains present at the most variable TRP regions—N- and C-cytoplasmic termini. Calmodulin (CaM) is a calcium-dependent cytosolic protein serving as a modulator of most transmembrane receptors. Although CaM-binding domains are widespread within intracellular parts of TRPs, no such binding domain has been characterised at the TRP melastatin member—the transient receptor potential melastatin 6 (TRPM6) channel. Another CBP, the S100 calcium-binding protein A1 (S100A1), is also known for its modulatory activities towards receptors. S100A1 commonly shares a CaM-binding domain. Here, we present the first identified CaM and S100A1 binding sites at the N-terminal of TRPM6. We have confirmed the L520-R535 N-terminal TRPM6 domain as a shared binding site for CaM and S100A1 using biophysical and molecular modelling methods. A specific domain of basic amino acid residues (R526/R531/K532/R535) present at this TRPM6 domain has been identified as crucial to maintain non-covalent interactions with the ligands. Our data unambiguously confirm that CaM and S100A1 share the same binding domain at the TRPM6 N-terminus although the ligand-binding mechanism is different.

Abstract P153: Crosstalk Between Vascular Redox and Calcium Signalling in Hypertension Involves Transient Receptor Potential Melastatin 2 (TRPM2) Channel

Hypertension ◽  
2018 ◽  
Vol 72 (Suppl_1) ◽  
Author(s):  
Rhéure Alves-Lopes ◽  
Karla B Neves ◽  
Aikaterini Anagnostopoulou ◽  
Silvia Lacchini ◽  
Augusto C Montezano ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Calcium Signalling ◽  
Receptor Potential ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channel ◽  
Transient Receptor

scholarly journals A key role for Mg2+ in TRPM7's control of ROS levels during cell stress

2012 ◽  
Vol 445 (3) ◽  
pp. 441-448 ◽  
Author(s):  
Hsiang-Chin Chen ◽  
Li-Ting Su ◽  
Omayra González-Pagán ◽  
Jeffrey D. Overton ◽  
Loren W. Runnels
Keyword(s):  
Cell Survival ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Cell Types ◽  
Cell Stress ◽  
Mitogen Activated Protein Kinase ◽  
Ros Generation ◽  
Dependent Manner ◽  
Transient Receptor Potential Melastatin ◽  
Transient Receptor

The TRPM7 (transient receptor potential melastatin 7) channel has been shown to play a pivotal role in cell survival during brain ischaemia as well as in the survival of other cell types challenged with apoptotic stimuli. Ca2+ is thought to be central to the channel's ability to regulate ROS (reactive oxygen species) production. However, channel-mediated entry of Mg2+ and Zn2+ have also been implicated in cell death. In the present study, we show that depletion of TRPM7 by RNA interference in fibroblasts increases cell resistance to apoptotic stimuli by decreasing ROS levels in an Mg2+-dependent manner. Depletion of TRPM7 lowered cellular Mg2+, decreased the concentration of ROS and lessened p38 MAPK (mitogen-activated protein kinase) and JNK (c-Jun N-terminal kinase) activation as well as decreased caspase 3 activation and PARP [poly(ADP-ribose) polymerase] cleavage in response to apoptotic stimuli. Re-expression of TRPM7 or of a kinase-inactive mutant of TRPM7 in TRPM7-knockdown cells increased cellular Mg2+ and ROS levels, as did expression of the Mg2+ transporter SLC41A2 (solute carrier family 41 member 2). In addition, expression of SLC41A2 increased the sensitivity of TRPM7-knockdown cells to apoptotic stimuli and boosted ROS generation in response to cell stress. Taken together, these data uncover an essential role for Mg2+ in TRPM7's control of cell survival and in the regulation of cellular ROS levels.

scholarly journals Visualizing structural transitions of ligand-dependent gating of the TRPM2 channel

2019 ◽  
Author(s):  
Ying Yin ◽  
Mengyu Wu ◽  
Allen L. Hsu ◽  
William F. Borschel ◽  
Mario J. Borgnia ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Cell Types ◽  
Structural Transitions ◽  
Cryo Electron Microscopy ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channel ◽  
Ligand Free ◽  
Transient Receptor ◽  
Open States

AbstractThe calcium-permeable transient receptor potential melastatin 2 (TRPM2) channel plays a key role in redox sensation in many cell types 1–3. Channel activation requires binding of both ADP-ribose (ADPR) 2,4–6 and Ca2+ 7. The recently published TRPM2 structures from Danio rerio in the ligand-free and in the ADPR/Ca2+-bound conditions represent the channel in closed and open states, which uncover substantial tertiary and quaternary conformational rearrangements 8. However, it is unclear how these rearrangements occur within the tetrameric channel during channel gating. Here we report two cryo-electron microscopy structures of TRPM2 from the same species in complex with Ca2+ alone, and with both ADPR and Ca2+, determined to an overall resolution of ~3.8 Å and ~4.2 Å respectively. In comparison with the published results, our studies capture TRPM2 in two-fold symmetric intermediate states, offering a glimpse of the structural transitions within the tetramer that bridge the closed and open conformations.

Inositol lipids and TRPC channel activation

2007 ◽  
Vol 74 ◽  
pp. 37-45 ◽  
Author(s):  
James W. Putney
Keyword(s):  
Plasma Membrane ◽  
Phospholipase C ◽  
Transient Receptor Potential ◽  
Calcium Signalling ◽  
Receptor Potential ◽  
Breakdown Product ◽  
Channel Activation ◽  
Inositol Lipids ◽  
Transient Receptor ◽  
Secondary Mechanism

The original hypothesis put forth by Bob Michell in his seminal 1975 review held that inositol lipid breakdown was involved in the activation of plasma membrane calcium channels or ‘gates’. Subsequently, it was demonstrated that while the interposition of inositol lipid breakdown upstream of calcium signalling was correct, it was predominantly the release of Ca2+ that was activated, through the formation of Ins(1,4,5)P3. Ca2+ entry across the plasma membrane involved a secondary mechanism signalled in an unknown manner by depletion of intracellular Ca2+ stores. In recent years, however, additional non-store-operated mechanisms for Ca2+ entry have emerged. In many instances, these pathways involve homologues of the Drosophila trp (transient receptor potential) gene. In mammalian systems there are seven members of the TRP superfamily, designated TRPC1–TRPC7, which appear to be reasonably close structural and functional homologues of Drosophila TRP. Although these channels can sometimes function as store-operated channels, in the majority of instances they function as channels more directly linked to phospholipase C activity. Three members of this family, TRPC3, 6 and 7, are activated by the phosphoinositide breakdown product, diacylglycerol. Two others, TRPC4 and 5, are also activated as a consequence of phospholipase C activity, although the precise substrate or product molecules involved are still unclear. Thus the TRPCs represent a family of ion channels that are directly activated by inositol lipid breakdown, confirming Bob Michell's original prediction 30 years ago.

The TRPM7 Channel in the Nervous and Cardiovascular Systems

2020 ◽  
Vol 21 (10) ◽  
pp. 985-992 ◽  
Author(s):  
Koichi Inoue ◽  
Zhi-Gang Xiong ◽  
Takatoshi Ueki
Keyword(s):  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Kinase Domain ◽  
Cellular Functions ◽  
Transient Receptor Potential Melastatin ◽  
Cation Permeability ◽  
Cardiovascular Systems ◽  
Transient Receptor ◽  
Excitatory Responses ◽  
Dual Operations

: Transient receptor potential melastatin 7 (TRPM7), along with the closely related TRPM6, are unique channels that have dual operations: cation permeability and kinase activity. In contrast to the limited tissue distribution of TRPM6, TRPM7 is widely expressed among tissues and is therefore implicated in a variety of cellular functions physiologically and pathophysiologically. The discovery of TRPM7’s unique structure imparting dual ion channel and kinase activities shed light onto novel and peculiar biological functions, such as Mg2+ homeostasis, cellular Ca2+ flickering, and even intranuclear transcriptional regulation by a cleaved kinase domain translocated to nuclei. Interestingly, at a higher level, TRPM7 participates in several biological processes in the nervous and cardiovascular systems, in which excitatory responses in neurons and cardiomyocytes are critical for their function. Here, we review the roles of TRPM7 in cells involved in the nervous and cardiovascular systems and discuss its potential as a future therapeutic target.

Pharmacological Inhibition of Transient Receptor Potential Melastatin 2 (TRPM2) Channels Attenuates Diabetes-induced Cognitive Deficits in Rats: A Mechanistic Study

2020 ◽  
Vol 17 (3) ◽  
pp. 249-258 ◽  
Author(s):  
Pavan Thapak ◽  
Mahendra Bishnoi ◽  
Shyam S. Sharma
Keyword(s):  
Cognitive Impairment ◽  
Cognitive Deficits ◽  
Ache Activity ◽  
Transient Receptor Potential ◽  
Mrna Level ◽  
Receptor Potential ◽  
Transient Receptor Potential Melastatin ◽  
Trpm2 Channels ◽  
Transient Receptor ◽  
Gsk 3Β

Background: Diabetes is a chronic metabolic disorder affecting the central nervous system. A growing body of evidence has depicted that high glucose level leads to the activation of the transient receptor potential melastatin 2 (TRPM2) channels. However, there are no studies targeting TRPM2 channels in diabetes-induced cognitive decline using a pharmacological approach. Objective: The present study intended to investigate the effects of 2-aminoethoxydiphenyl borate (2-APB), a TRPM2 inhibitor, in diabetes-induced cognitive impairment. Methods: Streptozotocin (STZ, 50 mg/kg, i.p.) was used to induce diabetes in rats. Animals were randomly divided into the treatment group, model group and age-matched control and pre se group. 2-APB treatment was given for three weeks to the animals. After 10 days of behavioural treatment, parameters were performed. Animals were sacrificed at 10th week of diabetic induction and the hippocampus and cortex were isolated. After that, protein and mRNA expression study was performed in the hippocampus. Acetylcholinesterase (AchE) activity was done in the cortex. Results: : Our study showed the 10th week diabetic animals developed cognitive impairment, which was evident from the behavioural parameters. Diabetic animals depicted an increase in the TRPM2 mRNA and protein expression in the hippocampus as well as increased AchE activity in the cortex. However, memory associated proteins were down-regulated, namely Ca2+/calmodulin-dependent protein kinase II (CaMKII-Thr286), glycogen synthase kinase 3 beta (GSK-3β-Ser9), cAMP response element-binding protein (CREB-Ser133), and postsynaptic density protein 95 (PSD-95). Gene expression of parvalbumin, calsequestrin and brain-derived neurotrophic factor (BDNF) were down-regulated while mRNA level of calcineurin A/ protein phosphatase 3 catalytic subunit alpha (PPP3CA) was upregulated in the hippocampus of diabetic animals. A three-week treatment with 2-APB significantly ameliorated the alteration in behavioural cognitive parameters in diabetic rats. Moreover, 2-APB also down-regulated the expression of TRPM2 mRNA and protein in the hippocampus as well as AchE activity in the cortex of diabetic animals as compared to diabetic animals. Moreover, the 2-APB treatment also upregulated the CaMKII (Thr-286), GSK-3β (Ser9), CREB (Ser133), and PSD-95 expression and mRNA levels of parvalbumin, calsequestrin, and BDNF while mRNA level of calcineurin A was down-regulated in the hippocampus of diabetic animals. Conclusion: : This study confirms the ameliorative effect of TRPM2 channel inhibitor in the diabetes- induced cognitive deficits. Inhibition of TRPM2 channels reduced the calcium associated downstream signaling and showed a neuroprotective effect of TRPM2 channels in diabetesinduced cognitive impairment.

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