The biochemistry and pharmacology of plasma-membrane calcium channels in plants

1992 ◽  
Vol 338 (1283) ◽  
pp. 91-96 ◽  
Keyword(s):  
Plasma Membrane ◽  
Calcium Channels ◽  
Calcium Channel ◽  
Higher Plants ◽  
Binding Protein ◽  
Low Doses ◽  
Specific Effects ◽  
Current State ◽  
Pharmacological Studies ◽  
Biochemical Studies

A review of plasma-membrane calcium channels in higher plants is presented. Data from pharmacological and biochemical studies are used to assess the current state of our knowledge concerning the occurrence of these structures in higher plants. Recent results demonstrate that after purification and reconstitution a phenylalkylamine binding protein will form calcium permeable channels. This result suggests that plants contain structures with some analogy to animal calcium channels. We also suggest that a degree of caution should be observed in the interpretation of results gained in pharmacological studies employing calcium channel active drugs, as it is now clear that even at low doses these com pounds have non-specific effects.

Nuclear membrane R-type calcium channels mediate cytosolic ET-1-induced increase of nuclear calcium in human vascular smooth muscle cells

2015 ◽  
Vol 93 (4) ◽  
pp. 291-297 ◽  
Author(s):  
Ghassan Bkaily ◽  
Levon Avedanian ◽  
Johny Al-Khoury ◽  
Marc Chamoun ◽  
Rana Semaan ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Plasma Membrane ◽  
Steady State ◽  
Calcium Channels ◽  
Calcium Channel ◽  
Vascular Smooth Muscle Cells ◽  
Nuclear Membrane ◽  
Channel Blocker ◽  
Calcium Influx ◽  
Nuclear Calcium

The objective of this work was to verify whether, as in the case of the plasma membrane of human vascular smooth muscle cells (hVSMCs), cytosolic ET-1-induced increase of nuclear calcium is mediated via the activation of calcium influx through the steady-state R-type calcium channel. Pharmacological tools to identify the R-type calcium channels, as well as real 3-D confocal microscopy imaging techniques coupled to calcium fluorescent probes, were used to study the effect of cytosolic ET-1 on nuclear calcium in isolated nuclei of human hepatocytes and plasma membrane perforated hVSMCs. Our results showed that pre-treatment with pertussis toxin (PTX) or cholera toxin (CTX) prevented cytosolic ET-1 (10−9 mol/L) from inducing a sustained increase in nuclear calcium. Furthermore, the L-type calcium channel blocker nifedipine did not prevent cytosolic ET-1 from inducing an increase in nuclear calcium, as opposed to the dual L- and R-type calcium channel blocker isradipine (PN200-110) (in the presence of nifedipine). In conclusion, the preventative effect with PTX and CTX, and the absence of an effect with nifedipine, as well as the blockade by isradipine on cytosolic ET-1-induced increase in nuclear calcium, suggest that this nuclear calcium influx in hVSMCs is due to activation of the steady-state R-type calcium channel. The sarcolemmal and nuclear membrane R-type calcium channels in hVSMCs are involved in ET-1 modulation of vascular tone in physiology and pathology.

Calcium Channels Symposium

1990 ◽  
Vol 68 (11) ◽  
pp. 1472-1473
Author(s):  
C. R. Triggle ◽  
M. Wolowyk
Keyword(s):  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Channels ◽  
Calcium Channel ◽  
Metal Ion ◽  
Striated Muscle ◽  
Calcium Release Channel ◽  
Isolation And Characterization ◽  
Current State ◽  
The University

Calcium is an essential element for just about all cellular processes, and yet abnormally high levels of cellular calcium can cause cell death. The processes that control cellular levels of this metal ion are thus of critical importance to both normal and pathophysiological conditions. Essential in the regulation of intracellular calcium levels are the calcium channels associated with cell membranes, for instance, with the plasma and sarcoplasmic reticulum membranes of muscle cells. In recent years, there has been a tremendous increase in our knowledge of the structure and function of these channels. However, we also now realize that the term "calcium channels" is used to refer to a rather heterogeneous population of entities. In some instances, notably receptor-operated calcium channels, we have only indirect evidence for their existence, whereas with the voltage-dependent channels, considerable information is now available on their comparative physiology, pharmacology, and biochemistry. The main objective of the Symposium presented in Calgary during the 1989 CFBS meeting was to bring together experts in the area of the calcium channels associated with both smooth and striated muscle function so that they could present the current state of knowledge in this area.Dr. David Triggle, from the State University of New York in Buffalo, reviewed the importance of calcium and calcium channels in cellular function and highlighted the pharmacology of calcium channel antagonists particularly with respect to their effects on the L-type calcium channels associated with smooth muscle. Dr. Sidney Fleischer from Vanderbilt University, Nashville, Tennessee, focused on his work associated with the isolation and characterization of the calcium release channel – ryanodine receptor of the sarcoplasmic reticulum from striated muscle. Dr. Fleischer has referred interested readers to his recent review in the 1989 issue of the Annual Reviews of Biophysics and Biophysical Chemistry (18: 333–364). Dr. Balwant Tuana from the University of Ottawa presented an update complemented by original data from his laboratory in the Department of Pharmacology on the current state of knowledge of the structure of the L-type calcium channel associated with both skeletal and cardiac muscle. The last two speakers, Dr. Wayne Giles and Dr. Hamid Akbarali, both from the Department of Medical Physiology at the University of Calgary, completed the program by presenting a review of data concerning the electrical physiological properties of calcium-activated channels in cardiac and smooth muscle. Their manuscript highlights their recent studies, with co-workers in Calgary, of the properties of calcium-activated potassium currents from the human cystic artery.The organizers of this symposium, hosted by the Pharmacological Society of Canada, gratefully acknowledge the financial support of the Alberta Heart and Stroke Foundation, Alberta Heritage Foundation for Medical Research, Canadian Heart and Stroke Foundation, Canadian Federation of Biological Societies, Charles River Laboratories (Canada Ltd.), SynPhar Laboratories Inc., Fisher Scientific Ltd., Novopharm Ltd., and Mandel Scientific Co. Ltd. The artistic contribution from Sylvia Ficken of Medical Audiovisual Services in the Faculty of Medicine at Memorial University of Newfoundland, who drew the symposium logo reproduced on the title page, is also gratefully acknowledged.

scholarly journals Impaired renal calcium absorption in mice lacking calcium channel β3 subunits

2009 ◽  
Vol 87 (7) ◽  
pp. 522-530 ◽  
Author(s):  
José F. Bernardo ◽  
Clara E. Magyar ◽  
W. Bruce Sneddon ◽  
Peter A. Friedman
Keyword(s):  
Plasma Membrane ◽  
Transgenic Mice ◽  
Calcium Channels ◽  
Calcium Channel ◽  
Sodium Excretion ◽  
Calcium Transport ◽  
Calcium Absorption ◽  
Wild Type ◽  
Distal Tubules ◽  
Calbindin D

Transgenic mice lacking calcium channel β3 subunits (CaVβ3) were used to determine the involvement of a multimeric calcium channel in mediating stimulated renal calcium absorption. We measured the ability of calcium channel β3 subunit-null (CaVβ3−/−) and wild-type (CaVβ3+/+) mice to increase renal calcium absorption in response to the calcium-sparing diuretic chlorothiazide (CTZ). Control rates of fractional sodium excretion were comparable in CaVβ3−/− and CaVβ3+/+ mice and CTZ increased sodium excretion similarly in both groups. CTZ enhanced calcium absorption only in wild-type CaVβ3+/+ mice. This effect was specific for diuretics acting on distal tubules because both CaVβ3−/− and CaVβ3+/+ mice responded comparably to furosemide. The absence of β3 subunits resulted in compensatory increases of TrpV5 calcium channels, the plasma membrane Ca-ATPase, NCX1 Na/Ca exchanger protein, and calbindin-D9k but not calbindin-D28k. We conclude that TrpV5 mediates basal renal calcium absorption and that a multimeric calcium channel that includes CaVβ3 mediates stimulated calcium transport.

Localization of Adenosine Triphosphatase Activity in the Phleom of Nicotiana Tabacum

1972 ◽  
Vol 30 ◽  
pp. 230-231
Author(s):  
James Cronshaw ◽  
Jamison E. Gilder
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Higher Plants ◽  
High Surface ◽  
Root Tip ◽  
Animal Cells ◽  
Physiological Processes ◽  
Tip Cells ◽  
Atpase Localization

Adenosine triphosphatase (ATPase) activity has been shown to be associated with numerous physiological processes in both plants and animal cells. Biochemical studies have shown that in higher plants ATPase activity is high in cell wall preparations and is associated with the plasma membrane, nuclei, mitochondria, chloroplasts and lysosomes. However, there have been only a few ATPase localization studies of higher plants at the electron microscope level. Poux (1967) demonstrated ATPase activity associated with most cellular organelles in the protoderm cells of Cucumis roots. Hall (1971) has demonstrated ATPase activity in root tip cells of Zea mays. There was high surface activity largely associated with the plasma membrane and plasmodesmata. ATPase activity was also demonstrated in mitochondria, dictyosomes, endoplasmic reticulum and plastids.

scholarly journals Caenorhabditis elegans Junctophilin has tissue-specific functions and regulates neurotransmission with extended-synaptotagmin

Genetics ◽  
2021 ◽  
Author(s):  
Christopher A Piggott ◽  
Zilu Wu ◽  
Stephen Nurrish ◽  
Suhong Xu ◽  
Joshua M Kaplan ◽  
...  
Keyword(s):  
Calcium Channels ◽  
Calcium Channel ◽  
Tissue Specific ◽  
Voltage Gated ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Pharyngeal Muscles ◽  
Membrane Contact ◽  
Null Mutants

Abstract The junctophilin family of proteins tether together plasma membrane (PM) and endoplasmic reticulum (ER) membranes, and couple PM- and ER-localized calcium channels. Understanding in vivo functions of junctophilins is of great interest for dissecting the physiological roles of ER-PM contact sites. Here, we show that the sole C. elegans junctophilin JPH-1 localizes to discrete membrane contact sites in neurons and muscles and has important tissue-specific functions. jph-1 null mutants display slow growth and development due to weaker contraction of pharyngeal muscles, leading to reduced feeding. In the body wall muscle, JPH-1 co-localizes with the PM-localized EGL-19 voltage-gated calcium channel and ER-localized UNC-68/RyR calcium channel, and is required for animal movement. In neurons, JPH-1 co-localizes with the membrane contact site protein Extended-SYnaptoTagmin 2 (ESYT-2) in soma, and is present near presynaptic release sites. Interestingly, jph-1 and esyt-2 null mutants display mutual suppression in their response to aldicarb, suggesting that JPH-1 and ESYT-2 have antagonistic roles in neuromuscular synaptic transmission. Additionally, we find an unexpected cell non-autonomous effect of jph-1 in axon regrowth after injury. Genetic double mutant analysis suggests that jph-1 functions in overlapping pathways with two PM-localized voltage-gated calcium channels, egl-19 and unc-2, and unc-68/RyR for animal health and development. Finally, we show that jph-1 regulates the colocalization of EGL-19 and UNC-68 and that unc-68/RyR is required for JPH-1 localization to ER-PM puncta. Our data demonstrate important roles for junctophilin in cellular physiology, and also provide insights into how junctophilin functions together with other calcium channels in vivo.

scholarly journals Voltage-gated calcium channel blockers for psychiatric disorders: genomic reappraisal

2019 ◽  
Vol 216 (5) ◽  
pp. 250-253 ◽  
Author(s):  
Paul J. Harrison ◽  
Elizabeth M. Tunbridge ◽  
Annette C. Dolphin ◽  
Jeremy Hall
Keyword(s):  
Calcium Channels ◽  
Calcium Channel ◽  
Psychiatric Disorders ◽  
Calcium Channel Blockers ◽  
Channel Blockers ◽  
Risk Genes ◽  
Voltage Gated ◽  
Voltage Gated Calcium Channels ◽  
Voltage Gated Calcium Channel ◽  
Second Use

SummaryWe reappraise the psychiatric potential of calcium channel blockers (CCBs). First, voltage-gated calcium channels are risk genes for several disorders. Second, use of CCBs is associated with altered psychiatric risks and outcomes. Third, research shows there is an opportunity for brain-selective CCBs, which are better suited to psychiatric indications.

scholarly journals Carbonic Anhydrases in Photosynthesizing Cells of C3 Higher Plants

Metabolites ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 73 ◽  
Author(s):  
Lyudmila Ignatova ◽  
Natalia Rudenko ◽  
Elena Zhurikova ◽  
Maria Borisova-Mubarakshina ◽  
Boris Ivanov
Keyword(s):  
Plasma Membrane ◽  
Carbonic Anhydrase ◽  
Environmental Conditions ◽  
Organic Molecules ◽  
Higher Plants ◽  
C3 Plants ◽  
Coherent System ◽  
Carbonic Anhydrases ◽  
Chloroplast Stroma ◽  
Different Parts

The review presents data on the location, nature, properties, number, and expression of carbonic anhydrase genes in the photosynthesizing cells of C3 plants. The available data about the presence of carbonic anhydrases in plasma membrane, cytoplasm, mitochondria, chloroplast stroma and thylakoids are scrutinized. Special attention was paid to the presence of carbonic anhydrase activities in the different parts of thylakoids, and on collation of sources of these activities with enzymes encoded by the established genes of carbonic anhydrases. The data are presented to show that the consistent incorporation of carbonic anhydrases belonging to different families of these enzymes forms a coherent system of CO2 molecules transport from air to chloroplasts in photosynthesizing cells, where they are included in organic molecules in the carboxylation reaction. It is discussed that the manifestation of the activity of a certain carbonic anhydrase depends on environmental conditions and the stage of ontogenesis.

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