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Hepatocellular differentiation status is characterized by distinct subnuclear localization and form of the chanzyme TRPM7. Differentiation 2017; 96:15-25. [PMID: 28609676 DOI: 10.1016/j.diff.2017.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 05/14/2017] [Accepted: 06/05/2017] [Indexed: 11/20/2022]
Abstract
The channel-kinase TRPM7 is important for the survival, proliferation, and differentiation, of many cell types. Both plasma membrane channel activity and kinase function are implicated in these roles. Channel activity is greater in less differentiated hepatoma cells compared with non-dividing, terminally differentiated adult hepatocytes, suggesting differences in protein expression and/or localization. We used electrophysiological and immunofluorescence approaches to establish whether hepatocellular differentiation is associated with altered TRPM7 expression. Mean outward current decreased by 44% in WIF-B hepatoma cells incubated with the established hepatic differentiating factors oncostatin M/dexamethasone for 1-8 days. Pre-incubation with pyridone 6, a pan-JAK inhibitor, blocked the current reduction. An antibody targeted to the C-terminus of TRPM7 labelled the cytoplasm in WIF-B cells and intact rat liver. Significant label also localized to the nuclear envelope (NE), with relatively more detected in adult hepatocytes compared with WIF-B cells. Hepatoma cells also exhibited nucleoplasmic labelling with intense signal in the nucleolus. The endogenous labelling pattern closely resembles that of HEK293T cells heterologously expressing a TRPM7 kinase construct containing a putative nucleolar localization sequence. These results suggest that TRPM7 form and distribution between the plasma membrane and nucleus, rather than expression, is altered in parallel with differentiation status in rat hepatic cells.
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102
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Abstract
The calcium signal is a powerful and multifaceted tool by which cells can achieve specific outcomes. Cellular machinery important in tumour progression is often driven or influenced by changes in calcium ions; in some cases this regulation occurs within spatially defined regions. Over the past decade there has been a deeper understanding of how calcium signalling is remodelled in some cancers and the consequences of calcium signalling on key events such as proliferation, invasion and sensitivity to cell death. Specific calcium signalling pathways have also now been identified as playing important roles in the establishment and maintenance of multidrug resistance and the tumour microenvironment.
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Affiliation(s)
- Gregory R Monteith
- The School of Pharmacy, Pharmacy Australia Centre of Excellence, The University of Queensland, Brisbane, Queensland 4102, Australia
- Mater Research Institute, The University of Queensland, Brisbane, Queensland 4102, Australia
- Translational Research Institute, Brisbane, Queensland 4102, Australia
| | - Natalia Prevarskaya
- Institut National de la Santé et de la Recherche Médicale U1003, Laboratoire de Physiologie Cellulaire, Equipe labellisée par la Ligue contre le cancer, and Universite de Lille 1, Villeneuve d'Ascq, F-59650, France
| | - Sarah J Roberts-Thomson
- The School of Pharmacy, Pharmacy Australia Centre of Excellence, The University of Queensland, Brisbane, Queensland 4102, Australia
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103
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Faouzi M, Kilch T, Horgen FD, Fleig A, Penner R. The TRPM7 channel kinase regulates store-operated calcium entry. J Physiol 2017; 595:3165-3180. [PMID: 28130783 DOI: 10.1113/jp274006] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 01/20/2017] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Pharmacological and molecular inhibition of transient receptor potential melastatin 7 (TRPM7) reduces store-operated calcium entry (SOCE). Overexpression of TRPM7 in TRPM7-/- cells restores SOCE. TRPM7 is not a store-operated calcium channel. TRPM7 kinase rather than channel modulates SOCE. TRPM7 channel activity contributes to the maintenance of store Ca2+ levels at rest. ABSTRACT The transient receptor potential melastatin 7 (TRPM7) is a protein that combines an ion channel with an intrinsic kinase domain, enabling it to modulate cellular functions either by conducting ions through the pore or by phosphorylating downstream proteins via its kinase domain. In the present study, we report store-operated calcium entry (SOCE) as a novel target of TRPM7 kinase activity. TRPM7-deficient chicken DT40 B lymphocytes exhibit a strongly impaired SOCE compared to wild-type cells as a result of reduced calcium release activated calcium currents, and independently of potassium channel regulation, membrane potential changes or changes in cell-cycle distribution. Pharmacological blockade of TRPM7 with NS8593 or waixenicin A in wild-type B lymphocytes results in a significant decrease in SOCE, confirming that TRPM7 activity is acutely linked to SOCE, without TRPM7 representing a store-operated channel itself. Using kinase-deficient mutants, we find that TRPM7 regulates SOCE through its kinase domain. Furthermore, Ca2+ influx through TRPM7 is essential for the maintenance of endoplasmic reticulum Ca2+ concentration in resting cells, and for the refilling of Ca2+ stores after a Ca2+ signalling event. We conclude that the channel kinase TRPM7 and SOCE are synergistic mechanisms regulating intracellular Ca2+ homeostasis.
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Affiliation(s)
- Malika Faouzi
- Centre for Biomedical Research, The Queen's Medical Centre, University of Hawaii Cancer Centre and John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - Tatiana Kilch
- Centre for Biomedical Research, The Queen's Medical Centre, University of Hawaii Cancer Centre and John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - F David Horgen
- Laboratory of Marine Biological Chemistry, Department of Natural Sciences, Hawaii Pacific University, Kaneohe, HI, USA
| | - Andrea Fleig
- Centre for Biomedical Research, The Queen's Medical Centre, University of Hawaii Cancer Centre and John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
| | - Reinhold Penner
- Centre for Biomedical Research, The Queen's Medical Centre, University of Hawaii Cancer Centre and John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, USA
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104
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Mass Spectrometric Analysis of TRPM6 and TRPM7 Phosphorylation Reveals Regulatory Mechanisms of the Channel-Kinases. Sci Rep 2017; 7:42739. [PMID: 28220887 PMCID: PMC5318989 DOI: 10.1038/srep42739] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/12/2017] [Indexed: 01/23/2023] Open
Abstract
TRPM7 and TRPM6 were the first identified bifunctional channels to contain their own kinase domains, but how these channel-kinases are regulated is poorly understood. Previous studies identified numerous phosphorylation sites on TRPM7, but very little is known about TRPM6 phosphorylation or sites on TRPM7 transphosphorylated by TRPM6. Our mass spectrometric analysis of homomeric and heteromeric TRPM7 and TRPM6 channels identified phosphorylation sites on both proteins, as well as several prominent sites on TRPM7 that are commonly modified through autophosphorylation and transphosphorylation by TRPM6. We conducted a series of amino acid substitution analyses and identified S1777, in TRPM7’s catalytic domain, and S1565, in TRPM7’s exchange domain that mediates kinase dimerization, as potential regulatory sites. The phosphomimetic S1777D substitution disrupted catalytic activity, most likely by causing an electrostatic perturbation at the active site. The S1565D phosphomimetic substitution also inactivated the kinase but did so without interfering with kinase dimerization. Molecular modeling indicates that phosphorylation of S1565 is predicted to structurally affect TRPM7’s functionally conserved N/D loop, which is thought to influence the access of substrate to the active site pocket. We propose that phosphorylation of S1565 within the exchange domain functions as a regulatory switch to control TRPM7 catalytic activity.
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105
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The different expression of TRPM7 and MagT1 impacts on the proliferation of colon carcinoma cells sensitive or resistant to doxorubicin. Sci Rep 2017; 7:40538. [PMID: 28094304 PMCID: PMC5240092 DOI: 10.1038/srep40538] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 12/07/2016] [Indexed: 01/16/2023] Open
Abstract
The processes leading to anticancer drug resistance are not completely unraveled. To get insights into the underlying mechanisms, we compared colon carcinoma cells sensitive to doxorubicin with their resistant counterpart. We found that resistant cells are growth retarded, and show staminal and ultrastructural features profoundly different from sensitive cells. The resistant phenotype is accompanied by the upregulation of the magnesium transporter MagT1 and the downregulation of the ion channel kinase TRPM7. We demonstrate that the different amounts of TRPM7 and MagT1 account for the different proliferation rate of sensitive and resistant colon carcinoma cells. It remains to be verified whether they are also involved in the control of other “staminal” traits.
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106
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Mobile zinc increases rapidly in the retina after optic nerve injury and regulates ganglion cell survival and optic nerve regeneration. Proc Natl Acad Sci U S A 2017; 114:E209-E218. [PMID: 28049831 DOI: 10.1073/pnas.1616811114] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Retinal ganglion cells (RGCs), the projection neurons of the eye, cannot regenerate their axons once the optic nerve has been injured and soon begin to die. Whereas RGC death and regenerative failure are widely viewed as being cell-autonomous or influenced by various types of glia, we report here that the dysregulation of mobile zinc (Zn2+) in retinal interneurons is a primary factor. Within an hour after the optic nerve is injured, Zn2+ increases several-fold in retinal amacrine cell processes and continues to rise over the first day, then transfers slowly to RGCs via vesicular release. Zn2+ accumulation in amacrine cell processes involves the Zn2+ transporter protein ZnT-3, and deletion of slc30a3, the gene encoding ZnT-3, promotes RGC survival and axon regeneration. Intravitreal injection of Zn2+ chelators enables many RGCs to survive for months after nerve injury and regenerate axons, and enhances the prosurvival and regenerative effects of deleting the gene for phosphatase and tensin homolog (pten). Importantly, the therapeutic window for Zn2+ chelation extends for several days after nerve injury. These results show that retinal Zn2+ dysregulation is a major factor limiting the survival and regenerative capacity of injured RGCs, and point to Zn2+ chelation as a strategy to promote long-term RGC protection and enhance axon regeneration.
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107
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Sturgeon M, Wu P, Cornell R. SLC41A1 and TRPM7 in magnesium homeostasis and genetic risk for Parkinson's disease. JOURNAL OF NEUROLOGY & NEUROMEDICINE 2016; 1:23-28. [PMID: 31187092 PMCID: PMC6557452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder of the central nervous system with a clinically heterogeneous presentation that includes progressive loss of dopaminergic (DA) neurons in the substantia nigra. A minority of PD cases are familial and are caused by mutations in single genes. Most cases, however, are idiopathic PD, a complex multifactorial disorder with environmental and genetic contributors to etiology. Here, we first briefly summarize published evidence that among environmental contributors is dietary deficiency of magnesium. We then review genetic data suggesting that mutations in genes encoding two proteins contributing to cellular magnesium homeostasis confer risk for PD or other Parkinsonian conditions. First, the gene encoding magnesium transporter SLC41A1 is, among others, a candidate for the causative gene in the PARK16 locus where variation is associated with risk for idiopathic Parkinsonian disease. Studies of the function of SLC41A1 in animal models are needed to test whether this protein has a role in maintenance of dopaminergic neurons. Second, in a small study, a hypomorphic variant of TRPM7, a magnesium-permeable channel, was over-represented in cases of amyotrophic lateral sclerosis/ Parkinson dementia complex versus controls from the same ethnic group. Although this association was not detected in a second study, in zebrafish Trpm7 is necessary for terminal differentiation and reduction of toxin-sensitivity in dopaminergic neurons. Overall, epidemiological results support the possibility that mutations in genes relevant to magnesium homeostasis would alter PD risk, but deeper genetic analyses of PD patients are necessary to confirm whether SLC41A1 and TRPM7 are among such genes.
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Affiliation(s)
- Morgan Sturgeon
- Molecular and Cell Biology Graduate Program, University of Iowa, Iowa City, Iowa
| | - Perry Wu
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, Iowa
| | - Robert Cornell
- Molecular and Cell Biology Graduate Program, University of Iowa, Iowa City, Iowa
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, Iowa
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108
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Carvacho I, Ardestani G, Lee HC, McGarvey K, Fissore RA, Lykke-Hartmann K. TRPM7-like channels are functionally expressed in oocytes and modulate post-fertilization embryo development in mouse. Sci Rep 2016; 6:34236. [PMID: 27681336 PMCID: PMC5041074 DOI: 10.1038/srep34236] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 09/05/2016] [Indexed: 01/16/2023] Open
Abstract
The Transient Receptor Potential (TRP) channels are a family of cationic ion channels widely distributed in mammalian tissues. In general, the global genetic disruption of individual TRP channels result in phenotypes associated with impairment of a particular tissue and/or organ function. An exception is the genetic ablation of the TRP channel TRPM7, which results in early embryonic lethality. Nevertheless, the function of TRPM7 in oocytes, eggs and pre-implantation embryos remains unknown. Here, we described an outward rectifying non-selective current mediated by a TRP ion channel in immature oocytes (germinal vesicle stage), matured oocytes (metaphase II eggs) and 2-cell stage embryos. The current is activated by specific agonists and inhibited by distinct blockers consistent with the functional expression of TRPM7 channels. We demonstrated that the TRPM7-like channels are homo-tetramers and their activation mediates calcium influx in oocytes and eggs, which is fundamental to support fertilization and egg activation. Lastly, we showed that pharmacological inhibition of the channel function delays pre-implantation embryo development and reduces progression to the blastocyst stage. Our data demonstrate functional expression of TRPM7-like channels in mouse oocytes, eggs and embryos that may play an essential role in the initiation of embryo development.
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Affiliation(s)
- Ingrid Carvacho
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark.,Department of Biology and Chemistry, Faculty of Basic Sciences, Universidad Católica del Maule, 3480112 Talca, Chile
| | - Goli Ardestani
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
| | - Hoi Chang Lee
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
| | - Kaitlyn McGarvey
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
| | - Rafael A Fissore
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
| | - Karin Lykke-Hartmann
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark.,Aarhus Institute of Advanced Studies (AIAS), Aarhus University, DK-8000 Aarhus C, Denmark
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109
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Iordanov I, Mihályi C, Tóth B, Csanády L. The proposed channel-enzyme transient receptor potential melastatin 2 does not possess ADP ribose hydrolase activity. eLife 2016; 5. [PMID: 27383051 PMCID: PMC4974056 DOI: 10.7554/elife.17600] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 07/05/2016] [Indexed: 11/21/2022] Open
Abstract
Transient Receptor Potential Melastatin 2 (TRPM2) is a Ca2+-permeable cation channel essential for immunocyte activation, insulin secretion, and postischemic cell death. TRPM2 is activated by ADP ribose (ADPR) binding to its C-terminal cytosolic NUDT9-homology (NUDT9H) domain, homologous to the soluble mitochondrial ADPR pyrophosphatase (ADPRase) NUDT9. Reported ADPR hydrolysis classified TRPM2 as a channel-enzyme, but insolubility of isolated NUDT9H hampered further investigations. Here we developed a soluble NUDT9H model using chimeric proteins built from complementary polypeptide fragments of NUDT9H and NUDT9. When expressed in E.coli, chimeras containing up to ~90% NUDT9H sequence remained soluble and were affinity-purified. In ADPRase assays the conserved Nudix-box sequence of NUDT9 proved essential for activity (kcat~4-9s-1), that of NUDT9H did not support catalysis. Replacing NUDT9H in full-length TRPM2 with soluble chimeras retained ADPR-dependent channel gating (K1/2~1-5 μM), confirming functionality of chimeric domains. Thus, TRPM2 is not a 'chanzyme'. Chimeras provide convenient soluble NUDT9H models for structural/biochemical studies. DOI:http://dx.doi.org/10.7554/eLife.17600.001 Ion channels are proteins that allow specific charged particles to move across the membranes of cells – for example to travel in or out of a cell, or between different parts of the same cell. Almost all ion channels are gated, meaning that they can open and close in response to different signals. For instance, so-called ligand gated channels open in response to binding of some small molecule, known as the "ligand". A small number of channel proteins are also enzymes, meaning that they are able to catalyze chemical reactions, and these channel-enzymes are often referred to as “chanzymes”. TRPM2 is an ion channel found in humans that opens when a small molecule called ADPR binds to a portion of the channel inside the cell. This channel is also thought to be a chanzyme because the part that binds to ADPR is similar to an enzyme called NUDT9. The NUDT9 enzyme converts ADPR into two other chemicals. When studied in biochemical assays, the enzyme-like part of TRPM2 – which contains a segment called a “Nudix box” – appeared to act in the same way, although this activity was not linked to the opening and closing of the TRPM2 channel. Iordanov et al. set out to re-examine whether TRPM2 is actually an enzyme by comparing the activity of NUDT9 to the enzyme-like part of TRPM2. To test an enzyme’s activity, it typically needs to be dissolved in water. However, the enzyme-like part of TRPM2 does not dissolve, and so it could not be tested directly. Instead, Iordanov et al. identified which parts of TRPM2 make it insoluble and replaced them with the equivalent parts from NUDT9 to create several new proteins. For all the proteins tested, only those with the Nudix box from NUDT9 were active enzymes, while those with the Nudix box from TRPM2 were not. Iordanov et al. conclude that TRPM2 is a ligand gated channel and not a chanzyme, and that the experimental conditions used in previous biochemical assays, and not TRPM2 activity, led to the breakdown of ADPR. Finally, the TRPM2 channel is involved in cell damage following heart attacks or stroke and may contribute to Alzheimer’s disease, Parkinson’s disease and bipolar disorder as well. As such, knowing how TRMP2 behaves could guide efforts to develop new drugs for these illnesses. DOI:http://dx.doi.org/10.7554/eLife.17600.002
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Affiliation(s)
- Iordan Iordanov
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary.,MTA-SE Ion Channel Research Group, Semmelweis University, Budapest, Hungary
| | - Csaba Mihályi
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary.,MTA-SE Ion Channel Research Group, Semmelweis University, Budapest, Hungary
| | - Balázs Tóth
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary.,MTA-SE Ion Channel Research Group, Semmelweis University, Budapest, Hungary
| | - László Csanády
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary.,MTA-SE Ion Channel Research Group, Semmelweis University, Budapest, Hungary
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110
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Vrenken KS, Jalink K, van Leeuwen FN, Middelbeek J. Beyond ion-conduction: Channel-dependent and -independent roles of TRP channels during development and tissue homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1436-46. [DOI: 10.1016/j.bbamcr.2015.11.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 10/26/2015] [Accepted: 11/11/2015] [Indexed: 01/09/2023]
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111
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Ye Q, Yang Y, van Staalduinen L, Crawley SW, Liu L, Brennan S, Côté GP, Jia Z. Structure of the Dictyostelium Myosin-II Heavy Chain Kinase A (MHCK-A) α-kinase domain apoenzyme reveals a novel autoinhibited conformation. Sci Rep 2016; 6:26634. [PMID: 27211275 PMCID: PMC4876393 DOI: 10.1038/srep26634] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 05/04/2016] [Indexed: 02/06/2023] Open
Abstract
The α-kinases are a family of a typical protein kinases present in organisms ranging from protozoa to mammals. Here we report an autoinhibited conformation for the α-kinase domain of Dictyostelium myosin-II heavy chain kinase A (MHCK-A) in which nucleotide binding to the catalytic cleft, located at the interface between an N-terminal and C-terminal lobe, is sterically blocked by the side chain of a conserved arginine residue (Arg592). Previous α-kinase structures have shown that an invariant catalytic aspartic acid residue (Asp766) is phosphorylated. Unexpectedly, in the autoinhibited conformation the phosphoryl group is transferred to the adjacent Asp663, creating an interaction network that stabilizes the autoinhibited state. The results suggest that Asp766 phosphorylation may play both catalytic and regulatory roles. The autoinhibited structure also provides the first view of a phosphothreonine residue docked into the phospho-specific allosteric binding site (Pi-pocket) in the C-lobe of the α-kinase domain.
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Affiliation(s)
- Qilu Ye
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Yidai Yang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Laura van Staalduinen
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Scott William Crawley
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Linda Liu
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Stephanie Brennan
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Graham P Côté
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
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112
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Zierler S, Sumoza-Toledo A, Suzuki S, Dúill FÓ, Ryazanova LV, Penner R, Ryazanov AG, Fleig A. TRPM7 kinase activity regulates murine mast cell degranulation. J Physiol 2016; 594:2957-70. [PMID: 26660477 DOI: 10.1113/jp271564] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/10/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The Mg(2+) and Ca(2+) conducting transient receptor potential melastatin 7 (TRPM7) channel-enzyme (chanzyme) has been implicated in immune cell function. Mice heterozygous for a TRPM7 kinase deletion are hyperallergic, while mice with a single point mutation at amino acid 1648, silencing kinase activity, are not. As mast cell mediators trigger allergic reactions, we here determine the function of TRPM7 in mast cell degranulation and histamine release. Our data establish that TRPM7 kinase activity regulates mast cell degranulation and release of histamine independently of TRPM7 channel function. Our findings suggest a regulatory role of TRPM7 kinase activity on intracellular Ca(2+) and extracellular Mg(2+) sensitivity of mast cell degranulation. ABSTRACT Transient receptor potential melastatin 7 (TRPM7) is a divalent ion channel with a C-terminally located α-kinase. Mice heterozygous for a TRPM7 kinase deletion (TRPM7(+/∆K) ) are hypomagnesaemic and hyperallergic. In contrast, mice carrying a single point mutation at amino acid 1648, which silences TRPM7 kinase activity (TRPM7(KR) ), are not hyperallergic and are resistant to systemic magnesium (Mg(2+) ) deprivation. Since allergic reactions are triggered by mast cell-mediated histamine release, we investigated the function of TRPM7 on mast cell degranulation and histamine release using wild-type (TRPM7(+/+) ), TRPM7(+/∆K) and TRPM7(KR) mice. We found that degranulation and histamine release proceeded independently of TRPM7 channel function. Furthermore, extracellular Mg(2+) assured unperturbed IgE-DNP-dependent exocytosis, independently of TRPM7. However, impairment of TRPM7 kinase function suppressed IgE-DNP-dependent exocytosis, slowed the cellular degranulation rate, and diminished the sensitivity to intracellular calcium (Ca(2+) ) in G protein-induced exocytosis. In addition, G protein-coupled receptor (GPCR) stimulation revealed strong suppression of histamine release, whereas removal of extracellular Mg(2+) caused the phenotype to revert. We conclude that the TRPM7 kinase activity regulates murine mast cell degranulation by changing its sensitivity to intracellular Ca(2+) and affecting granular mobility and/or histamine contents.
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Affiliation(s)
- Susanna Zierler
- Center for Biomedical Research, The Queen's Medical Center and University of Hawaii John A. Burns School of Medicine and Cancer Center, Honolulu, HI, 96813, USA.,Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Adriana Sumoza-Toledo
- Center for Biomedical Research, The Queen's Medical Center and University of Hawaii John A. Burns School of Medicine and Cancer Center, Honolulu, HI, 96813, USA.,Instituto de Investigaciones Médico-Biológicas, Universidad Veracruzana, Colonia Centro CP 91700, Veracruz, Mexico
| | - Sayuri Suzuki
- Center for Biomedical Research, The Queen's Medical Center and University of Hawaii John A. Burns School of Medicine and Cancer Center, Honolulu, HI, 96813, USA
| | - Fionán Ó Dúill
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Lillia V Ryazanova
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA
| | - Reinhold Penner
- Center for Biomedical Research, The Queen's Medical Center and University of Hawaii John A. Burns School of Medicine and Cancer Center, Honolulu, HI, 96813, USA
| | - Alexey G Ryazanov
- Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA
| | - Andrea Fleig
- Center for Biomedical Research, The Queen's Medical Center and University of Hawaii John A. Burns School of Medicine and Cancer Center, Honolulu, HI, 96813, USA
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113
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Schäfer S, Ferioli S, Hofmann T, Zierler S, Gudermann T, Chubanov V. Mibefradil represents a new class of benzimidazole TRPM7 channel agonists. Pflugers Arch 2015; 468:623-34. [PMID: 26669310 DOI: 10.1007/s00424-015-1772-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 12/02/2015] [Accepted: 12/04/2015] [Indexed: 01/16/2023]
Abstract
Transient receptor potential cation channel, subfamily M, member 7 (TRPM7) is a bi-functional protein comprising an ion channel moiety covalently linked to a protein kinase domain. Currently, the prevailing view is that a decrease in the cytosolic Mg(2+) concentration leads to activation of divalent cation-selective TRPM7 currents. TRPM7 plays a role in immune responses, hypotension, tissue fibrosis, and tumor progression and, therefore, represents a new promising therapeutic target. Because of the dearth of pharmacological tools, our mechanistic understanding of the role of TRPM7 in physiology and pathophysiology still lags behind. Therefore, we have recently carried out a high throughput screen for small-molecule activators of TRPM7. We have characterized the phenanthrene naltriben as a first stimulatory agonist of the TRPM7 channel. Surprisingly, the effect of naltriben on TRPM7 was found to be unaffected by the physiological levels of cytosolic Mg(2+). Here, we demonstrate that mibefradil and NNC 50-0396, two benzimidazole relatives of the TRPM7 inhibitor NS8593, are positive modulators of TRPM7. Using Ca(2+) imaging and the patch-clamp technique, we show that mibefradil activates TRPM7-mediated Ca(2+) entry and whole-cell currents. The response to mibefradil was fast, reversible, and reproducible. In contrast to naltriben, mibefradil efficiently activates TRPM7 currents only at physiological intracellular Mg(2+) concentrations, and its stimulatory effect was fully abrogated by high internal Mg(2+) levels. Consequently, a TRPM7 variant harboring a gain-of-function mutation was insensitive to further mibefradil activation. Finally, we observed that the effect of mibefradil was selective for TRPM7 when various TRP channels were tested. Taken together, mibefradil acts as a Mg(2+)-regulated agonist of the TRPM7 channel and, hence, uncovers a new class of TRPM7 agonists.
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Affiliation(s)
- Sebastian Schäfer
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany
| | - Silvia Ferioli
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany
| | - Thomas Hofmann
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany
| | - Susanna Zierler
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany
| | - Thomas Gudermann
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany
- Comprehensive Pneumology Center Munich (CPC-M), German Center for Lung Research, Munich, Germany
- DZHK (German Centre for Cardiovascular Research), Munich Heart Alliance, Munich, Germany
| | - Vladimir Chubanov
- Walther-Straub-Institute of Pharmacology and Toxicology, University of Munich, Goethestrasse 33, 80336, Munich, Germany.
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114
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Castiglioni S, Cazzaniga A, Trapani V, Cappadone C, Farruggia G, Merolle L, Wolf FI, Iotti S, Maier JAM. Magnesium homeostasis in colon carcinoma LoVo cells sensitive or resistant to doxorubicin. Sci Rep 2015; 5:16538. [PMID: 26563869 PMCID: PMC4643312 DOI: 10.1038/srep16538] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 10/15/2015] [Indexed: 11/12/2022] Open
Abstract
Neoplastic cells accumulate magnesium, an event which provides selective advantages and is frequently associated with TRPM7 overexpression. Little is known about magnesium homeostasis in drug-resistant cancer cells. Therefore, we used the colon cancer LoVo cell model and compared doxorubicin-resistant to sensitive cells. In resistant cells the concentration of total magnesium is higher while its influx capacity is lower than in sensitive cells. Accordingly, resistant cells express lower amounts of the TRPM6 and 7, both involved in magnesium transport. While decreased TRPM6 levels are due to transcriptional regulation, post-transcriptional events are involved in reducing the amounts of TRPM7. Indeed, the calpain inhibitor calpeptin markedly increases the levels of TRPM7 in resistant cells. In doxorubicin-sensitive cells, silencing TRPM7 shifts the phenotype to one more similar to resistant cells, since in these cells silencing TRPM7 significantly decreases the influx of magnesium, increases its intracellular concentration and increases resistance to doxorubicin. On the other hand, calpain inhibition upregulates TRPM7, decreases intracellular magnesium and enhances the sensitivity to doxorubicin of resistant LoVo cells. We conclude that in LoVo cells drug resistance is associated with alteration of magnesium homeostasis through modulation of TRPM7. Our data suggest that TRPM7 expression may be an additional undisclosed player in chemoresistance.
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Affiliation(s)
- Sara Castiglioni
- Dipartimento di Scienze Biomediche e Cliniche L. Sacco, Università di Milano, Via G.B. Grassi 74, Milano I-20157
| | - Alessandra Cazzaniga
- Dipartimento di Scienze Biomediche e Cliniche L. Sacco, Università di Milano, Via G.B. Grassi 74, Milano I-20157
| | - Valentina Trapani
- Istituto di Patologia Generale, Facoltà di Medicina, Università Cattolica del Sacro Cuore, Largo F. Vito 1, Roma I-00168
| | - Concettina Cappadone
- Dipartimento di Farmacia e Biotecnologie, Università Alma Mater di Bologna, Via San Donato 19/2, Bologna I-40127
| | - Giovanna Farruggia
- Dipartimento di Farmacia e Biotecnologie, Università Alma Mater di Bologna, Via San Donato 19/2, Bologna I-40127
- Istituto Nazionale Biostrutture e Biosistemi, Viale delle Medaglie d’oro 305, Roma I-00136
| | - Lucia Merolle
- Dipartimento di Farmacia e Biotecnologie, Università Alma Mater di Bologna, Via San Donato 19/2, Bologna I-40127
| | - Federica I. Wolf
- Istituto di Patologia Generale, Facoltà di Medicina, Università Cattolica del Sacro Cuore, Largo F. Vito 1, Roma I-00168
| | - Stefano Iotti
- Dipartimento di Farmacia e Biotecnologie, Università Alma Mater di Bologna, Via San Donato 19/2, Bologna I-40127
- Istituto Nazionale Biostrutture e Biosistemi, Viale delle Medaglie d’oro 305, Roma I-00136
| | - Jeanette A M Maier
- Dipartimento di Scienze Biomediche e Cliniche L. Sacco, Università di Milano, Via G.B. Grassi 74, Milano I-20157
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115
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Mechanosensitive TRPM7 mediates shear stress and modulates osteogenic differentiation of mesenchymal stromal cells through Osterix pathway. Sci Rep 2015; 5:16522. [PMID: 26558702 PMCID: PMC4642269 DOI: 10.1038/srep16522] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 10/13/2015] [Indexed: 01/13/2023] Open
Abstract
Microenvironments that modulate fate commitments of mesenchymal stromal cells (MSCs) are composed of chemical and physical cues, but the latter ones are much less investigated. Here we demonstrate that intermittent fluid shear stress (IFSS), a potent and physiologically relevant mechanical stimulus, regulates osteogenic differentiation of MSCs through Transient receptor potential melastatin 7 (TRPM7)-Osterix axis. Immunostaining showed the localization of TRPM7 near or at cell membrane upon IFSS, and calcium imaging analysis demonstrated the transient increase of cytosolic free calcium. Expressions of osteogenic marker genes including Osterix, but not Runx2, were upregulated after three-hour IFSS. Phosphorylation of p38 and Smad1/5 was promoted by IFSS as well. TRPM7 gene knockdown abolished the promotion of bone-related gene expressions and phosphorylation. We illustrate that TRPM7 is mechanosensitive to shear force of 1.2 Pa, which is much lower than 98 Pa pressure loading reported recently, and mediates distinct mechanotransduction pathways. Additionally, our results suggest the differential roles of TRPM7 in endochondral and intramembranous ossification. Together, this study elucidates the mechanotransduction in MSCs fate commitments and displays an efficient mechano-modulation for MSCs osteogenic differentiation. Such findings should be taken into consideration when designing relevant scaffolds and microfluidic devices for osteogenic induction in the future.
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116
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Yang Y, Ye Q, Jia Z, Côté GP. Characterization of the Catalytic and Nucleotide Binding Properties of the α-Kinase Domain of Dictyostelium Myosin-II Heavy Chain Kinase A. J Biol Chem 2015; 290:23935-46. [PMID: 26260792 DOI: 10.1074/jbc.m115.672410] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Indexed: 11/06/2022] Open
Abstract
The α-kinases are a widely expressed family of serine/threonine protein kinases that exhibit no sequence identity with conventional eukaryotic protein kinases. In this report, we provide new information on the catalytic properties of the α-kinase domain of Dictyostelium myosin-II heavy chain kinase-A (termed A-CAT). Crystallization of A-CAT in the presence of MgATP yielded structures with AMP or adenosine in the catalytic cleft together with a phosphorylated Asp-766 residue. The results show that the β- and α-phosphoryl groups are transferred either directly or indirectly to the catalytically essential Asp-766. Biochemical assays confirmed that A-CAT hydrolyzed ATP, ADP, and AMP with kcat values of 1.9, 0.6, and 0.32 min(-1), respectively, and showed that A-CAT can use ADP to phosphorylate peptides and proteins. Binding assays using fluorescent 2'/3'-O-(N-methylanthraniloyl) analogs of ATP and ADP yielded Kd values for ATP, ADP, AMP, and adenosine of 20 ± 3, 60 ± 20, 160 ± 60, and 45 ± 15 μM, respectively. Site-directed mutagenesis showed that Glu-713, Leu-716, and Lys-645, all of which interact with the adenine base, were critical for nucleotide binding. Mutation of the highly conserved Gln-758, which chelates a nucleotide-associated Mg(2+) ion, eliminated catalytic activity, whereas loss of the highly conserved Lys-722 and Arg-592 decreased kcat values for kinase and ATPase activities by 3-6-fold. Mutation of Asp-663 impaired kinase activity to a much greater extent than ATPase, indicating a specific role in peptide substrate binding, whereas mutation of Gln-768 doubled ATPase activity, suggesting that it may act to exclude water from the active site.
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Affiliation(s)
- Yidai Yang
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Qilu Ye
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Zongchao Jia
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Graham P Côté
- From the Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
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117
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Abstract
Calcium (Ca2+) and magnesium (Mg2+) ions have been shown to play an important role in regulating various neuronal functions. In the present review we focus on the emerging role of transient potential melastatin-7 (TRPM7) channel in not only regulating Ca2+ and Mg2+ homeostasis necessary for biological functions, but also how alterations in TRPM7 function/expression could induce neurodegeneration. Although eight TRPM channels have been identified, the channel properties, mode of activation, and physiological responses of various TRPM channels are quite distinct. Among the known 8 TRPM channels only TRPM6 and TRPM7 channels are highly permeable to both Ca2+ and Mg2+; however here we will only focus on TRPM7 as unlike TRPM6, TRPM7 channels are abundantly expressed in neuronal cells. Importantly, the discrepancy in TRPM7 channel function and expression leads to various neuronal diseases such as Alzheimer disease (AD) and Parkinson disease (PD). Further, it is emerging as a key factor in anoxic neuronal death and in other neurodegenerative disorders. Thus, by understanding the precise involvement of the TRPM7 channels in different neurodegenerative diseases and by understanding the factors that regulate TRPM7 channels, we could uncover new strategies in the future that could evolve as new drug therapeutic targets for effective treatment of these neurodegenerative diseases.
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Affiliation(s)
- Yuyang Sun
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
| | - Pramod Sukumaran
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
| | - Anne Schaar
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
| | - Brij B Singh
- a Department of Basic Science ; School of Medicine and Health Sciences, University of North Dakota ; Grand Forks , ND USA
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118
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Banerji J. Asparaginase treatment side-effects may be due to genes with homopolymeric Asn codons (Review-Hypothesis). Int J Mol Med 2015; 36:607-26. [PMID: 26178806 PMCID: PMC4533780 DOI: 10.3892/ijmm.2015.2285] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 07/15/2015] [Indexed: 12/14/2022] Open
Abstract
The present treatment of childhood T-cell leukemias involves the systemic administration of prokary-otic L-asparaginase (ASNase), which depletes plasma Asparagine (Asn) and inhibits protein synthesis. The mechanism of therapeutic action of ASNase is poorly understood, as are the etiologies of the side-effects incurred by treatment. Protein expression from genes bearing Asn homopolymeric coding regions (N-hCR) may be particularly susceptible to Asn level fluctuation. In mammals, N-hCR are rare, short and conserved. In humans, misfunctions of genes encoding N-hCR are associated with a cluster of disorders that mimic ASNase therapy side-effects which include impaired glycemic control, dislipidemia, pancreatitis, compromised vascular integrity, and neurological dysfunction. This paper proposes that dysregulation of Asn homeostasis, potentially even by ASNase produced by the microbiome, may contribute to several clinically important syndromes by altering expression of N-hCR bearing genes. By altering amino acid abundance and modulating ribosome translocation rates at codon repeats, the microbiomic environment may contribute to genome decoding and to shaping the proteome. We suggest that impaired translation at poly Asn codons elevates diabetes risk and severity.
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Affiliation(s)
- Julian Banerji
- Center for Computational and Integrative Biology, MGH, Simches Research Center, Boston, MA 02114, USA
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119
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Mori Y, Takahashi N, Polat OK, Kurokawa T, Takeda N, Inoue M. Redox-sensitive transient receptor potential channels in oxygen sensing and adaptation. Pflugers Arch 2015; 468:85-97. [PMID: 26149285 PMCID: PMC4700073 DOI: 10.1007/s00424-015-1716-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/22/2015] [Indexed: 12/14/2022]
Abstract
Regulation of ion channels is central to the mechanisms that underlie immediate acute physiological responses to changes in the availability of molecular oxygen (O2). A group of cation-permeable channels that are formed by transient receptor potential (TRP) proteins have been characterized as exquisite sensors of redox reactive species and as efficient actuators of electric/ionic signals in vivo. In this review, we first discuss how redox-sensitive TRP channels such as TRPA1 have recently emerged as sensors of the relatively inert oxidant O2. With regard to the physiological significance of O2 sensor TRP channels, vagal TRPA1 channels are mainly discussed with respect to their role in respiratory regulation in comparison with canonical pathways in glomus cells of the carotid body, which is a well-established O2-sensing organ. TRPM7 channels are discussed regarding hypoxia-sensing function in ischemic cell death. Also, ubiquitous expression of TRPA1 and TRPM7 together with their physiological relevance in the body is examined. Finally, based upon these studies on TRP channels, we propose a hypothesis of “O2 remodeling.” The hypothesis is that cells detect deviation of O2 availability from appropriate levels via sensors and adjust local O2 environments in vivo by controlling supply and consumption of O2 via pathways comprising cellular signals and transcription factors downstream of sensors, which consequently optimize physiological functions. This new insight into O2 adaptation through ion channels, particularly TRPs, may foster a paradigm shift in our understanding in the biological significance of O2.
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Affiliation(s)
- Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
- Laboratory of Environmental Systems Biology, Department of Technology and Ecology, Hall of Global Environmental Studies, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
| | - Nobuaki Takahashi
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Onur Kerem Polat
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Tatsuki Kurokawa
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Norihiko Takeda
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Masahiro Inoue
- Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, Higashinari-ku, Osaka, 537-8511, Japan
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120
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Earley S, Brayden JE. Transient receptor potential channels in the vasculature. Physiol Rev 2015; 95:645-90. [PMID: 25834234 DOI: 10.1152/physrev.00026.2014] [Citation(s) in RCA: 301] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The mammalian genome encodes 28 distinct members of the transient receptor potential (TRP) superfamily of cation channels, which exhibit varying degrees of selectivity for different ionic species. Multiple TRP channels are present in all cells and are involved in diverse aspects of cellular function, including sensory perception and signal transduction. Notably, TRP channels are involved in regulating vascular function and pathophysiology, the focus of this review. TRP channels in vascular smooth muscle cells participate in regulating contractility and proliferation, whereas endothelial TRP channel activity is an important contributor to endothelium-dependent vasodilation, vascular wall permeability, and angiogenesis. TRP channels are also present in perivascular sensory neurons and astrocytic endfeet proximal to cerebral arterioles, where they participate in the regulation of vascular tone. Almost all of these functions are mediated by changes in global intracellular Ca(2+) levels or subcellular Ca(2+) signaling events. In addition to directly mediating Ca(2+) entry, TRP channels influence intracellular Ca(2+) dynamics through membrane depolarization associated with the influx of cations or through receptor- or store-operated mechanisms. Dysregulation of TRP channels is associated with vascular-related pathologies, including hypertension, neointimal injury, ischemia-reperfusion injury, pulmonary edema, and neurogenic inflammation. In this review, we briefly consider general aspects of TRP channel biology and provide an in-depth discussion of the functions of TRP channels in vascular smooth muscle cells, endothelial cells, and perivascular cells under normal and pathophysiological conditions.
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Affiliation(s)
- Scott Earley
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada; and Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont
| | - Joseph E Brayden
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada; and Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont
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121
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Yue Z, Xie J, Yu AS, Stock J, Du J, Yue L. Role of TRP channels in the cardiovascular system. Am J Physiol Heart Circ Physiol 2015; 308:H157-82. [PMID: 25416190 PMCID: PMC4312948 DOI: 10.1152/ajpheart.00457.2014] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/14/2014] [Indexed: 12/12/2022]
Abstract
The transient receptor potential (TRP) superfamily consists of a large number of nonselective cation channels with variable degree of Ca(2+)-permeability. The 28 mammalian TRP channel proteins can be grouped into six subfamilies: canonical, vanilloid, melastatin, ankyrin, polycystic, and mucolipin TRPs. The majority of these TRP channels are expressed in different cell types including both excitable and nonexcitable cells of the cardiovascular system. Unlike voltage-gated ion channels, TRP channels do not have a typical voltage sensor, but instead can sense a variety of other stimuli including pressure, shear stress, mechanical stretch, oxidative stress, lipid environment alterations, hypertrophic signals, and inflammation products. By integrating multiple stimuli and transducing their activity to downstream cellular signal pathways via Ca(2+) entry and/or membrane depolarization, TRP channels play an essential role in regulating fundamental cell functions such as contraction, relaxation, proliferation, differentiation, and cell death. With the use of targeted deletion and transgenic mouse models, recent studies have revealed that TRP channels are involved in numerous cellular functions and play an important role in the pathophysiology of many diseases in the cardiovascular system. Moreover, several TRP channels are involved in inherited diseases of the cardiovascular system. This review presents an overview of current knowledge concerning the physiological functions of TRP channels in the cardiovascular system and their contributions to cardiovascular diseases. Ultimately, TRP channels may become potential therapeutic targets for cardiovascular diseases.
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Affiliation(s)
- Zhichao Yue
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Jia Xie
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Albert S Yu
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Jonathan Stock
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Jianyang Du
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Lixia Yue
- Calhoun Cardiology Center, Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut
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122
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Elucidating the role of the TRPM7 alpha-kinase: TRPM7 kinase inactivation leads to magnesium deprivation resistance phenotype in mice. Sci Rep 2014; 4:7599. [PMID: 25534891 PMCID: PMC4274504 DOI: 10.1038/srep07599] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 12/03/2014] [Indexed: 12/20/2022] Open
Abstract
TRPM7 is an unusual bi-functional protein containing an ion channel covalently linked to a protein kinase domain. TRPM7 is implicated in regulating cellular and systemic magnesium homeostasis. While the biophysical properties of TRPM7 ion channel and its function are relatively well characterized, the function of the TRPM7 enzymatically active kinase domain is not understood yet. To investigate the physiological role of TRPM7 kinase activity, we constructed mice carrying an inactive TRPM7 kinase. We found that these mice were resistant to dietary magnesium deprivation, surviving three times longer than wild type mice; also they displayed decreased chemically induced allergic reaction. Interestingly, mutant mice have lower magnesium bone content compared to wild type mice when fed regular diet; unlike wild type mice, mutant mice placed on magnesium-depleted diet did not alter their bone magnesium content. Furthermore, mouse embryonic fibroblasts isolated from TRPM7 kinase-dead animals exhibited increased resistance to magnesium deprivation and oxidative stress. Finally, electrophysiological data revealed that the activity of the kinase-dead TRPM7 channel was not significantly altered. Together, our results suggest that TRPM7 kinase is a sensor of magnesium status and provides coordination of cellular and systemic responses to magnesium deprivation.
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123
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Turlova E, Bae CYJ, Deurloo M, Chen W, Barszczyk A, Horgen FD, Fleig A, Feng ZP, Sun HS. TRPM7 Regulates Axonal Outgrowth and Maturation of Primary Hippocampal Neurons. Mol Neurobiol 2014; 53:595-610. [PMID: 25502295 DOI: 10.1007/s12035-014-9032-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 11/30/2014] [Indexed: 11/25/2022]
Abstract
Transient receptor potential melastatin 7 (TRPM7) is a calcium-permeable divalent cation channel and mediates neuronal cell death under ischemic stresses. In this study, we investigated the contribution of TRPM7 to neuronal development in mouse primary hippocampal neurons. We demonstrated that TRPM7 channels are highly expressed in the tips of the growth cone. Either knockdown of TRPM7 with target-specific shRNA or blocking channel conductance by a specific blocker waixenicin A enhanced axonal outgrowth in culture. Blocking TRPM7 activity by waixenicin A reduced calcium influx and accelerated the polarization of the hippocampal neurons as characterized by the development of distinct axons and dendrites. Furthermore, TRPM7 coprecipitated and colocalized with F-actin and α-actinin-1 at the growth cone. We conclude that calcium influx through TRPM7 inhibits axonal outgrowth and maturation by regulating the F-actin and α-actinin-1 protein complex. Inhibition of TRPM7 channel promotes axonal outgrowth, suggesting its therapeutic potential in neurodegenerative disorders.
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Affiliation(s)
- Ekaterina Turlova
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Christine Y J Bae
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Marielle Deurloo
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Wenliang Chen
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Andrew Barszczyk
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - F David Horgen
- College of Natural and Computational Sciences, Hawaii Pacific University, Kaneohe, HI, 96744, USA
| | - Andrea Fleig
- Center for Biomedical Research, The Queen's Medical Center, Honolulu, HI, 96720, USA
- University of Hawaii Cancer Center and John A. Burns School of Medicine, Honolulu, HI, 96720, USA
| | - Zhong-Ping Feng
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
| | - Hong-Shuo Sun
- Department of Surgery, Faculty of Medicine, University of Toronto, 1132 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Department of Physiology, Faculty of Medicine, University of Toronto, 3306 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Department of Pharmacology & Toxicology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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124
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Natural and Synthetic Modulators of the TRPM7 Channel. Cells 2014; 3:1089-101. [PMID: 25437439 PMCID: PMC4276914 DOI: 10.3390/cells3041089] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 11/16/2022] Open
Abstract
Transient receptor potential cation channel subfamily M member 7 (TRPM7) is a bi-functional protein comprising a TRP ion channel segment linked to an α-type protein kinase domain. Genetic inactivation of TRPM7 revealed its central role in magnesium metabolism, cell motility, proliferation and differentiation. TRPM7 is associated with anoxic neuronal death, cardiac fibrosis and tumor progression highlighting TRPM7 as a new drug target. Recently, several laboratories have independently identified pharmacological compounds inhibiting or activating the TRPM7 channel. The recently found TRPM7 modulators were used as new experimental tools to unravel cellular functions of the TRPM7 channel. Here, we provide a concise overview of this emerging field.
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125
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Visser D, Middelbeek J, van Leeuwen FN, Jalink K. Function and regulation of the channel-kinase TRPM7 in health and disease. Eur J Cell Biol 2014; 93:455-65. [DOI: 10.1016/j.ejcb.2014.07.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 06/24/2014] [Accepted: 07/01/2014] [Indexed: 11/30/2022] Open
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126
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Yee NS, Kazi AA, Yee RK. Cellular and Developmental Biology of TRPM7 Channel-Kinase: Implicated Roles in Cancer. Cells 2014; 3:751-77. [PMID: 25079291 PMCID: PMC4197629 DOI: 10.3390/cells3030751] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/15/2014] [Accepted: 07/15/2014] [Indexed: 12/29/2022] Open
Abstract
The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a ubiquitously expressed cation-permeable ion channel with intrinsic kinase activity that plays important roles in various physiological functions. Biochemical and electrophysiological studies, in combination with molecular analyses of TRPM7, have generated insights into its functions as a cellular sensor and transducer of physicochemical stimuli. Accumulating evidence indicates that TRPM7 channel-kinase is essential for cellular processes, such as proliferation, survival, differentiation, growth, and migration. Experimental studies in model organisms, such as zebrafish, mouse, and frog, have begun to elucidate the pleiotropic roles of TRPM7 during embryonic development from gastrulation to organogenesis. Aberrant expression and/or activity of the TRPM7 channel-kinase have been implicated in human diseases including a variety of cancer. Studying the functional roles of TRPM7 and the underlying mechanisms in normal cells and developmental processes is expected to help understand how TRPM7 channel-kinase contributes to pathogenesis, such as malignant neoplasia. On the other hand, studies of TRPM7 in diseases, particularly cancer, will help shed new light in the normal functions of TRPM7 under physiological conditions. In this article, we will provide an updated review of the structural features and biological functions of TRPM7, present a summary of current knowledge of its roles in development and cancer, and discuss the potential of TRPM7 as a clinical biomarker and therapeutic target in malignant diseases.
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Affiliation(s)
- Nelson S Yee
- Division of Hematology-Oncology, Department of Medicine, Penn State College of Medicine, Program of Experimental Therapeutics, Penn State Hershey Cancer Institute, Penn State Milton S, Hershey Medical Center, Pennsylvania State University, Hershey, PA 17033, USA.
| | - Abid A Kazi
- Division of Hematology-Oncology, Department of Medicine, Penn State College of Medicine, Program of Experimental Therapeutics, Penn State Hershey Cancer Institute, Penn State Milton S, Hershey Medical Center, Pennsylvania State University, Hershey, PA 17033, USA.
| | - Rosemary K Yee
- Schreyer Honors College, Pennsylvania State University, University Park, PA 16802, USA; Penn State Harrisburg School of Humanities, Pennsylvania State University, Middletown, PA 17057, USA.
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Kinase cut-and-run. Nat Chem Biol 2014. [DOI: 10.1038/nchembio.1567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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