BK Channels – Focus on Polyamines, Ethanol/Acetaldehyde and Hydrogen Sulfide (H2S)

Hermann, Anton; Ситдикова, Г. Ф.; Weiger, Thomas

doi:10.5772/35179

Cited by 6 publications

(6 citation statements)

References 255 publications

(250 reference statements)

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“…The conductance of single BK channels is up to 300 pS and hence comprises the largest single-channel conductance of all K + channels. To date a vast amount of information has been gathered regarding their biophysical, structural and functional, physiological, pathophysiological and pharmacological properties (recently reviewed in [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]). BK channels are usually synergistically activated by both—Ca 2+ /Mg 2+ —metal ions and by membrane voltage.…”

Section: Ca 2+ -Activated K + mentioning

confidence: 99%

Oxidative Stress and Maxi Calcium-Activated Potassium (BK) Channels

2015

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All cells contain ion channels in their outer (plasma) and inner (organelle) membranes. Ion channels, similar to other proteins, are targets of oxidative impact, which modulates ion fluxes across membranes. Subsequently, these ion currents affect electrical excitability, such as action potential discharge (in neurons, muscle, and receptor cells), alteration of the membrane resting potential, synaptic transmission, hormone secretion, muscle contraction or coordination of the cell cycle. In this chapter we summarize effects of oxidative stress and redox mechanisms on some ion channels, in particular on maxi calcium-activated potassium (BK) channels which play an outstanding role in a plethora of physiological and pathophysiological functions in almost all cells and tissues. We first elaborate on some general features of ion channel structure and function and then summarize effects of oxidative alterations of ion channels and their functional consequences.

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Section: Ca 2+ -Activated K + mentioning

confidence: 99%

Oxidative Stress and Maxi Calcium-Activated Potassium (BK) Channels

2015

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“…BK channels are present in a great variety of non-excitable and excitable cells. Recent detailed studies of BK channels created a vast amount of knowledge regarding their biophysical, structural and functional, physiological, pathophysiological, and pharmacological properties (reviewed in: Ghatta et al, 2006 ; Salkoff et al, 2006 ; Cui et al, 2009 ; Berkefeld et al, 2010 ; Cui, 2010 ; Grimm and Sansom, 2010 ; Hill et al, 2010 ; Lee and Cui, 2010 ; Stojilkovic et al, 2010 ; Wu et al, 2010 ; Hermann et al, 2012a ). BK channels are essential in controlling electrical activity of cells, hormone secretion, vasoregulation, auditory tuning of the hair cells or circadian rhythm generation and participate in mediating drug actions such as ethanol or acetaldehyde.…”

Section: Introductionmentioning

confidence: 99%

Phosphorylation of BK channels modulates the sensitivity to hydrogen sulfide (H2S)

et al. 2014

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Introduction: Gases, such as nitric oxide (NO), carbon monoxide (CO), or hydrogen sulfide (H2S), termed gasotransmitters, play an increasingly important role in understanding of how electrical signaling of cells is modulated. H2S is well-known to act on various ion channels and receptors. In a previous study we reported that H2S increased calcium-activated potassium (BK) channel activity.Aims: The goal of the present study is to investigate the modulatory effect of BK channel phosphorylation on the action of H2S on the channel as well as to recalculate and determine the H2S concentrations in aqueous sodium hydrogen sulfide (NaHS) solutions.Methods: Single channel recordings of GH3, GH4, and GH4 STREX cells were used to analyze channel open probability, amplitude, and open dwell times. H2S was measured with an anion selective electrode.Results: The concentration of H2S produced from NaHS was recalculated taking pH, temperature salinity of the perfusate, and evaporation of H2S into account. The results indicate that from a concentration of 300 μM NaHS, only 11–13%, i.e., 34–41 μM is effective as H2S in solution. GH3, GH4, and GH4 STREX cells respond differently to phosphorylation. BK channel open probability (Po) of all cells lines used was increased by H2S in ATP-containing solutions. PKA prevented the action of H2S on channel Po in GH4 and GH4 STREX, but not in GH3 cells. H2S, high significantly increased Po of all PKG pretreated cells. In the presence of PKC, which lowers channel activity, H2S increased channel Po of GH4 and GH4 STREX, but not those of GH3 cells. H2S increased open dwell times of GH3 cells in the absence of ATP significantly. A significant increase of dwell times with H2S was also observed in the presence of okadaic acid.Conclusions: Our results suggest that phosphorylation by PKG primes the channels for H2S activation and indicate that channel phosphorylation plays an important role in the response to H2S.

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“…Since there are many channels within a membrane, the equilibrium between these conformational states determines the amount of current that flows across the membrane as a function of time. Importantly, channel gating is initiated by: (i) changes of the voltage across the membrane, (ii) binding of ligands such as neurotransmitters, hormones, intracellular messengers (e.g., Ca 2+ , cyclic nucleotides), (iii) mechanical stress to the protein or via the cytoskeleton linked to channels, or (iv) covalent modifications such as protein phosphorylation, carboxylation, or sulfuration (Levitan, 1999 ; Hermann et al, 2012 ). Ion channels can be blocked by chemical agents or by peptide toxins, which can be used for separation of ion currents or for identification of certain types of channels.…”

Section: Ion Channelsmentioning

confidence: 99%

“…(c) “Big (large or maxi) conductance K + channels (big K, BK)” with a γ of 100–300 pS are activated by Ca 2+ /Mg 2+ ions and membrane voltage synergistically. These channels are specifically blocked by iberiotoxin and modulated by a great variety of compounds such as ethanol, polyamines, or gasotransmitters (Weiger and Hermann, 1994 , 2009 ; Jakab et al, 1997 ; Hermann et al, 2012 ). The various types of SK, IK, or BK channels can be expressed alone or in combination in many cells and tissues, as in the nervous or the vascular system.…”

Section: S100s and K + Channelsmentioning

confidence: 99%

S100 Calcium Binding Proteins and Ion Channels

Hermann¹,

Donato²,

Weiger³

et al. 2012

Front. Pharmacol.

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S100 Ca2+-binding proteins have been associated with a multitude of intracellular Ca2+-dependent functions including regulation of the cell cycle, cell differentiation, cell motility and apoptosis, modulation of membrane–cytoskeletal interactions, transduction of intracellular Ca2+ signals, and in mediating learning and memory. S100 proteins are fine tuned to read the intracellular free Ca2+ concentration and affect protein phosphorylation, which makes them candidates to modulate certain ion channels and neuronal electrical behavior. Certain S100s are secreted from cells and are found in extracellular fluids where they exert unique extracellular functions. In addition to their neurotrophic activity, some S100 proteins modulate neuronal electrical discharge activity and appear to act directly on ion channels. The first reports regarding these effects suggested S100-mediated alterations in Ca2+ fluxes, K+ currents, and neuronal discharge activity. Recent reports revealed direct and indirect interactions with Ca2+, K+, Cl−, and ligand activated channels. This review focuses on studies of the physical and functional interactions of S100 proteins and ion channels.

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BK Channels – Focus on Polyamines, Ethanol/Acetaldehyde and Hydrogen Sulfide (H2S)

Cited by 6 publications

References 255 publications

Oxidative Stress and Maxi Calcium-Activated Potassium (BK) Channels

Oxidative Stress and Maxi Calcium-Activated Potassium (BK) Channels

Phosphorylation of BK channels modulates the sensitivity to hydrogen sulfide (H2S)

S100 Calcium Binding Proteins and Ion Channels

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