scholarly journals The Complex Story of Plant Cyclic Nucleotide-Gated Channels

2021 ◽  
Vol 22 (2) ◽  
pp. 874
Author(s):  
Edwin Jarratt-Barnham ◽  
Limin Wang ◽  
Youzheng Ning ◽  
Julia M. Davies
Keyword(s):  
Arabidopsis Thaliana ◽  
Stress Response ◽  
Complex Formation ◽  
Cyclic Nucleotides ◽  
Cyclic Nucleotide ◽  
Cation Channels ◽  
Cyclic Monophosphate ◽  
Cyclic Nucleotide Gated Channels ◽  
Gated Channel

Plant cyclic nucleotide-gated channels (CNGCs) are tetrameric cation channels which may be activated by the cyclic nucleotides (cNMPs) adenosine 3′,5′-cyclic monophosphate (cAMP) and guanosine 3′,5′-cyclic monophosphate (cGMP). The genome of Arabidopsis thaliana encodes 20 CNGC subunits associated with aspects of development, stress response and immunity. Recently, it has been demonstrated that CNGC subunits form heterotetrameric complexes which behave differently from the homotetramers produced by their constituent subunits. These findings have widespread implications for future signalling research and may help explain how specificity can be achieved by CNGCs that are known to act in disparate pathways. Regulation of complex formation may involve cyclic nucleotide-gated channel-like proteins.

Reconstitution and characterization of two forms of cyclic nucleotide-gated channels from skeletal muscle

1996 ◽  
Vol 271 (6) ◽  
pp. E1051-E1060 ◽  
Author(s):  
L. C. Santy ◽  
G. Guidotti
Keyword(s):  
Skeletal Muscle ◽  
Cyclic Nucleotide ◽  
Rod Outer Segments ◽  
Channel Activity ◽  
Cyclic Monophosphate ◽  
Cyclic Nucleotide Gated Channels ◽  
Muscle Plasma Membrane ◽  
Gated Channel ◽  
Two Peaks

A cyclic nucleotide-gated channel present in skeletal muscle plasma membrane has previously been identified as being responsible for insulin-activated sodium entry into muscle cells (J. E. M. McGeoch and G. Guidotti. J. Biol. Chem. 267:832-841, 1992). We have isolated this channel activity to further study and characterize it. The channel was solubilized from rabbit skeletal muscle sarcolemma and functionally reconstituted into phospholipid vesicles, as assayed by patch-clamp analysis of the reconstituted proteins. Channel activity was isolated by 8-bromo-guanosine 3',5'-cyclic monophosphate affinity chromatography, producing two distinct peaks of cyclic nucleotide-gated channel activity. These two types of channel activity differ in guanosine 3',5'-cyclic monophosphate affinity and in the ability to be opened by adenosine 3',5'-cyclic monophosphate. The cyclic nucleotide-gated channel from rod outer segments also forms two peaks of activity when purified in this manner. The presence of two forms of channel activity could have implications for the mechanism of insulin-activated sodium entry.

Expression of a single gene produces both forms of skeletal muscle cyclic nucleotide-gated channels

1997 ◽  
Vol 273 (6) ◽  
pp. E1140-E1148
Author(s):  
Lorraine C. Santy ◽  
Guido Guidotti
Keyword(s):  
Skeletal Muscle ◽  
Cyclic Nucleotide ◽  
Single Gene ◽  
Rabbit Aorta ◽  
Rabbit Skeletal Muscle ◽  
Channel Activity ◽  
Cyclic Nucleotide Gated Channels ◽  
Gated Channel ◽  
Polymerase Chain ◽  
Two Populations

Cyclic nucleotide-gated cation channels in skeletal muscle are responsible for insulin-activated sodium entry into this tissue (J. E. M. McGeoch and G. Guidotti. J. Biol. Chem. 267: 832–841, 1992). These channels have previously been isolated from rabbit skeletal muscle by 8-bromoguanosine 3′,5′-cyclic monophosphate (8-BrcGMP) affinity chromatography, which separates them into two populations differing in nucleotide affinity [L. C. Santy and G. Guidotti. Am. J. Physiol. 271 ( Endocrinol. Metab. 34): E1051-E1060, 1996]. In this study, a polymerase chain reaction approach was used to identify skeletal muscle cyclic nucleotide-gated channel cDNAs. Rabbit skeletal muscle expresses the same cyclic nucleotide-gated channel as rabbit aorta (M. Biel, W. Altenhofen, R. Hullin, J. Ludwig, M. Freichel, V. Flockerzi, N. Dascal, U. B. Kaupp, and F. Hofmann. FEBS Lett. 329: 134–138, 1993). The entire cDNA for this gene was cloned from rabbit skeletal muscle and an antiserum to this protein produced. Expression of this cDNA produces a 63-kDa protein with cyclic nucleotide-gated channel activity. A similarly sized immunoreactive protein is present in sarcolemma. Purification of the expressed channels reveals that this single gene produces both native skeletal muscle channel populations.

Effects of forskolin and cyclic nucleotides on isometric force in rat aorta

1986 ◽  
Vol 250 (3) ◽  
pp. C468-C473 ◽  
Author(s):  
E. G. McMahon ◽  
R. J. Paul
Keyword(s):  
Cyclic Nucleotides ◽  
Cyclic Nucleotide ◽  
Isometric Force ◽  
Rat Aorta ◽  
Isometric Tension ◽  
Tension Development ◽  
Nucleotide Analogues ◽  
Cyclic Monophosphate ◽  
Contractile System ◽  
Rat Thoracic Aorta

The present study was undertaken to determine the extent to which cyclic nucleotide-induced relaxation in the intact rat aorta is mediated at the level of the contractile system. The relaxant effects of the cyclic nucleotide analogues [8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP) and dibutyryladenosine 3',5'-cyclic monophosphate (DBcAMP)] and forskolin were examined in both the intact vessel and a Triton X-100-skinned preparation of rat thoracic aorta. Relaxation of a norepinephrine-induced contraction was essentially complete 30 min after the addition of 50 microM 8-BrcGMP [% relaxation = 87.2 +/- 4.4% (n = 4)], 100 microM DBcAMP [98.2 +/- 1.2% (n = 4)], and 1 microM forskolin [107.0 +/- 3.3% (n = 5)]. These same doses were ineffective in relaxing precontracted skinned rat aortic rings compared with the relaxation achieved in the intact vessel. The largest relaxation in the skinned aortas was achieved with the addition of 1 microM forskolin [17.4 +/- 1.5% (n = 4)]. The addition of catalytic subunit of cAMP-dependent protein kinase had no effect on isometric tension in the precontracted skinned aorta. Preincubation with the cyclic nucleotide analogues or forskolin in a low-Ca2+ solution (pCa less than 8) was also ineffective in inhibiting subsequent isometric tension development. Our results suggest that only a very small fraction of the relaxation with cyclic nucleotides and forskolin in the intact rat aorta is due to the action of these agents at the level of the contractile system.

scholarly journals The Cyclic Nucleotide-Gated Channel CNGC14 Regulates Root Gravitropism in Arabidopsis thaliana

2015 ◽  
Vol 25 (23) ◽  
pp. 3119-3125 ◽  
Author(s):  
Han-Wei Shih ◽  
Cody L. DePew ◽  
Nathan D. Miller ◽  
Gabriele B. Monshausen
Keyword(s):  
Arabidopsis Thaliana ◽  
Cyclic Nucleotide ◽  
Gated Channel ◽  
Root Gravitropism

scholarly journals Opening Mechanism of a Cyclic Nucleotide–gated Channel Based on Analysis of Single Channels Locked in Each Liganded State

1999 ◽  
Vol 113 (6) ◽  
pp. 873-895 ◽  
Author(s):  
MariaLuisa Ruiz ◽  
Jeffrey W. Karpen
Keyword(s):  
Conformational Change ◽  
Conformational Changes ◽  
Cyclic Nucleotide ◽  
Single Channel ◽  
Kinetic Mechanism ◽  
Fixed Number ◽  
Single Channels ◽  
Cyclic Nucleotide Gated Channels ◽  
Gated Channel ◽  
Conductance States

Cyclic nucleotide–gated channels contain four subunits, each with a binding site for cGMP or cAMP in the cytoplasmic COOH-terminal domain. Previous studies of the kinetic mechanism of activation have been hampered by the complication that ligands are continuously binding and unbinding at each of these sites. Thus, even at the single channel level, it has been difficult to distinguish changes in behavior that arise from a channel with a fixed number of ligands bound from those that occur upon the binding and unbinding of ligands. For example, it is often assumed that complex behaviors like multiple conductance levels and bursting occur only as a consequence of changes in the number of bound ligands. We have overcome these ambiguities by covalently tethering one ligand at a time to single rod cyclic nucleotide–gated channels (Ruiz, ML., and J.W. Karpen. 1997. Nature. 389:389–392). We find that with a fixed number of ligands locked in place the channel freely moves between three conductance states and undergoes bursting behavior. Furthermore, a thorough kinetic analysis of channels locked in doubly, triply, and fully liganded states reveals more than one kinetically distinguishable state at each conductance level. Thus, even when the channel contains a fixed number of bound ligands, it can assume at least nine distinct states. Such complex behavior is inconsistent with simple concerted or sequential allosteric models. The data at each level of liganding can be successfully described by the same connected state model (with different rate constants), suggesting that the channel undergoes the same set of conformational changes regardless of the number of bound ligands. A general allosteric model, which postulates one conformational change per subunit in both the absence and presence of ligand, comes close to providing enough kinetically distinct states. We propose an extension of this model, in which more than one conformational change per subunit can occur during the process of channel activation.

Differential Regulation by Cyclic Nucleotides of the CNGA4 and CNGB1b Subunits in Olfactory Cyclic Nucleotide-Gated Channels

2012 ◽  
Vol 5 (232) ◽  
pp. ra48-ra48 ◽  
Author(s):  
V. Nache ◽  
T. Zimmer ◽  
N. Wongsamitkul ◽  
R. Schmauder ◽  
J. Kusch ◽  
...  
Keyword(s):  
Cyclic Nucleotides ◽  
Cyclic Nucleotide ◽  
Differential Regulation ◽  
Cyclic Nucleotide Gated Channels

Sweet taste transduction in hamster: sweeteners and cyclic nucleotides depolarize taste cells by reducing a K+ current

1996 ◽  
Vol 75 (3) ◽  
pp. 1256-1263 ◽  
Author(s):  
T. A. Cummings ◽  
C. Daniels ◽  
S. C. Kinnamon
Keyword(s):  
Cyclic Nucleotides ◽  
Cyclic Nucleotide ◽  
Taste Receptor ◽  
Reversal Potential ◽  
Taste Cell ◽  
K Channel ◽  
Cyclic Monophosphate ◽  
Taste Cells ◽  
Voltage Dependent ◽  
K Current

1. The gigaseal voltage-clamp technique was used to record responses of hamster taste receptor cells to synthetic sweeteners and cyclic nucleotides. Voltage-dependent currents and steady-state currents were monitored during bath exchanges of saccharin, two high-potency sweeteners, 8-chlorophenylthio-adenosine 3',5'-cyclic monophosphate (8cpt-cAMP), and dibutyryl-guanosine 3',5'-cyclic monophosphate (db-cGMP). 2. Of the 237 fungiform taste cells studied, only one in eight was sweet responsive. Outward currents, both voltage-dependent and resting, were reduced by all of the sweeteners tested in sweet-responsive taste cells, whereas these currents were unaffected by sweeteners in sweet-unresponsive taste cells. 3. In every sweet-responsive cell tested, 8cpt-cAMP and db-cGMP mimicked the response to the sweeteners, but neither nucleotide elicited responses in sweet-unresponsive cells. Thus there was a one-to-one correlation between sweet responsivity and cyclic nucleotide responsivity. 4. Sweet responses showed cross adaptation with cyclic nucleotide responses. This indicates that the same ion channel is modulated by sweeteners and cyclic nucleotides. 5. The sweetener- and cyclic nucleotide-blocked current had an apparent reversal potential of -50 mV, which was close to the potassium reversal potential in these experiments. In addition, there was no effect of sweeteners and cyclic nucleotides in the presence of the K+ channel blocker tetraethylammonium bromide (TEA). These data suggest that block of a resting, TEA-sensitive K+ current is the final common step leading to taste cell depolarization during sweet transduction. 6. These data, together with data from a previous study (Cummings et al. 1993), suggest that both synthetic sweeteners and sucrose utilize second-messenger pathways that block a resting K+ conductance to depolarize the taste cell membrane.

scholarly journals A Cyclic Nucleotide-Gated Channel, HvCNGC2-3, Is Activated by the Co-Presence of Na+ and K+ and Permeable to Na+ and K+ Non-Selectively

Plants ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 61 ◽  
Author(s):  
Izumi Mori ◽  
Yuichi Nobukiyo ◽  
Yoshiki Nakahara ◽  
Mineo Shibasaka ◽  
Takuya Furuichi ◽  
...  
Keyword(s):  
Cyclic Nucleotide ◽  
Expression System ◽  
Reversal Potential ◽  
Amino Acid Replacement ◽  
Bathing Solution ◽  
Xenopus Laevis Oocyte ◽  
Electrophysiological Properties ◽  
Cyclic Monophosphate ◽  
Gated Channel ◽  
Canonical Motif

Cyclic nucleotide-gated channels (CNGCs) have been postulated to contribute significantly in plant development and stress resistance. However, their electrophysiological properties remain poorly understood. Here, we characterized barley CNGC2-3 (HvCNGC2-3) by the two-electrode voltage-clamp technique in the Xenopus laevis oocyte heterologous expression system. Current was not observed in X. laevis oocytes injected with HvCNGC2-3 complementary RNA (cRNA) in a bathing solution containing either Na+ or K+ solely, even in the presence of 8-bromoadenosine 3′,5′-cyclic monophosphate (8Br-cAMP) or 8-bromoguanosine 3′,5′-cyclic monophosphate (8Br-cGMP). A weakly voltage-dependent slow hyperpolarization-activated ion current was observed in the co-presence of Na+ and K+ in the bathing solution and in the presence of 10 µM 8Br-cAMP, but not 8Br-cGMP. Permeability ratios of HvCNGC2-3 to K+, Na+ and Cl− were determined as 1:0.63:0.03 according to reversal-potential analyses. Amino-acid replacement of the unique ion-selective motif of HvCNGC2-3, AQGL, with the canonical motif, GQGL, resulted in the abolition of the current. This study reports a unique two-ion-dependent activation characteristic of the barley CNGC, HvCNGC2-3.

Store-operated Ca2+Influx in Airway Smooth Muscle

2006 ◽  
Vol 105 (5) ◽  
pp. 976-983 ◽  
Author(s):  
Y S. Prakash ◽  
Adeyemi Iyanoye ◽  
Binnaz Ay ◽  
Gary C. Sieck ◽  
Christina M. Pabelick
Keyword(s):  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Airway Smooth Muscle ◽  
Cyclic Nucleotides ◽  
Cyclic Nucleotide ◽  
Cyclopiazonic Acid ◽  
Volatile Anesthetics ◽  
Cyclic Monophosphate ◽  
Beta Agonists ◽  
Nucleotide Inhibition

Background Volatile anesthetics produce bronchodilation in part by depleting sarcoplasmic reticulum Ca stores in airway smooth muscle (ASM). Other bronchodilatory drugs are known to act via cyclic nucleotides (cyclic adenosine 3',5'-cyclic monophosphate, cyclic guanosine 3',5'-cyclic monophosphate). Intracellular Ca regulation in ASM involves plasma membrane Ca influx, including that triggered by sarcoplasmic reticulum Ca depletion (store-operated Ca entry [SOCE]). The authors hypothesized that anesthetics and bronchodilatory agents interact in inhibiting SOCE, thus enhancing ASM relaxation. Methods In enzymatically dissociated porcine ASM cells imaged using fluorescence microscopy, sarcoplasmic reticulum Ca was depleted by 1 microm cyclopiazonic acid in 0 extracellular Ca, nifedipine, and potassium chloride (preventing Ca influx through L-type channels and SOCE). Extracellular Ca was rapidly reintroduced to selectively activate SOCE in the presence or absence of 1 minimum alveolar concentration (MAC) halothane, isoflurane, or sevoflurane. Anesthetic interference with SOCE regulation by cyclic nucleotides was examined by activating SOCE in the presence of (1) 1 microm acetylcholine, (2) 100 microm dibutryl cyclic adenosine 3',5'-cyclic monophosphate, or (3) 100 microm 8-bromo-cyclic guanosine 3',5'-cyclic monophosphate. Results SOCE was enhanced by acetylcholine, whereas volatile anesthetics and both cyclic nucleotides partially inhibited Ca influx. Preexposure to 1 or 2 MAC anesthetic (halothane > isoflurane > sevoflurane) inhibited SOCE. Only halothane and isoflurane inhibited acetylcholine-induced augmentation of Ca influx, and significantly potentiated cyclic nucleotide inhibition such that no influx was observed in the presence of anesthetics and cyclic nucleotides. Conclusions These data indicate that volatile anesthetics prevent sarcoplasmic reticulum refilling by inhibiting SOCE and enhancing cyclic nucleotide blunting of Ca influx in ASM. Such interactions likely result in substantial airway relaxation in the presence of both anesthetics and bronchodilatory agents such as beta agonists or nitric oxide.

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