Gating of maxi channels observed from pseudo-phase portraits

Parsons, Sean P.; Huizinga, Jan D.

doi:10.1152/ajpcell.00378.2012

Cited by 4 publications

(1 citation statement)

References 45 publications

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“…In order to detect the transitions between states, we generated pseudo‐phase portraits of the raw data . The current trace I (t) was normalized for extreme values – maximal ( I max ) and minimal ( I min ) value of current, and divided into N bin = 100 bins according to formula:

I_{normalbin} false(t false) = N_{bin} * (I false(t false) - I_{normalmin}) false/ (I_{normalmax} - I_{normalmin}) .

…”

Section: Resultsmentioning

confidence: 99%

Subconductance states of mitochondrial chloride channels: implication for functionally‐coupled tetramers

Tomasek¹,

Misak

Grman

et al. 2017

FEBS Letters

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Recently, it has been discovered that isoforms of intracellular chloride channels (CLIC) are present in cardiac mitochondria. By reconstituting rat cardiac mitochondrial chloride channels into bilayer lipid membranes, we detected three equally separated subconductance states with conductance increment of 45 pS and < 2% occupancy. The observed rare events of channel decomposition into substates, accompanied by disrupted gating, provide an insight into channel quaternary structure. Our findings suggest that the observed channels work as four functionally coupled subunits with synchronized gating. We discuss the putative connection of channel activity from native mitochondria with the recombinant CLIC channels. However, conclusive evidence is needed to prove this connection.

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I_{normalbin} false(t false) = N_{bin} * (I false(t false) - I_{normalmin}) false/ (I_{normalmax} - I_{normalmin}) .

…”

Section: Resultsmentioning

confidence: 99%

Subconductance states of mitochondrial chloride channels: implication for functionally‐coupled tetramers

Tomasek¹,

Misak

Grman

et al. 2017

FEBS Letters

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The properties, functions, and pathophysiology of maxi-anion channels

Sabirov

Merzlyak

Islam

et al. 2016

Pflugers Arch - Eur J Physiol

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The maxi-anion channels (MACs) with a unitary conductance of 200-500 pS are detected in virtually every part of the whole body and found in cells from mammals to amphibia. The channels are normally silent but can be activated by physiologically/pathophysiologically relevant stimuli, such as osmotic, salt, metabolic, oxidative, and mechanical stresses, receptor activation, serum, heat, and intracellular Ca(2+) rise. In some MACs, protein dephosphorylation is associated with channel activation. Among MACs so far studied, around 60 % (designated here as Maxi-Cl) possess, in common, the following phenotypical biophysical properties: (1) unitary conductance of 300-400 pS, (2) a linear current-voltage relationship, (3) high anion-to-cation selectivity with PCl/Pcation of >8, and (4) inactivation at positive and negative potentials over a certain level (usually ±20 mV). The pore configuration of the Maxi-Cl is asymmetrical with extracellular and intracellular radii of ∼1.42 and ∼1.16 nm, respectively, and a medial constriction down to ∼0.55-0.75 nm. The classical function of MACs is control of membrane potential and fluid movement. Permeability to ATP and glutamate turns MACs to signaling channels in purinergic and glutamatergic signal transduction defining them as a perspective target for drug discovery. The molecular identification is an urgent task that would greatly promote the developments in this field. A possible relationship between these channels and some transporters is discussed.

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Leucine-enriched protein feeding does not impair exercise-induced free fatty acid availability and lipid oxidation: beneficial implications for training in carbohydrate-restricted states

et al. 2014

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Given that the enhanced oxidative adaptations observed when training in carbohydrate (CHO)-restricted states is potentially regulated through free fatty acid (FFA)-mediated signalling and that leucine-rich protein elevates muscle protein synthesis, the present study aimed to test the hypothesis that leucine-enriched protein feeding enhances circulating leucine concentration but does not impair FFA availability or whole body lipid oxidation during exercise. Nine males cycled for 2 h at 70% VO2peak when fasted (PLACEBO) or having consumed a whey protein solution (WHEY) or a leucine-enriched whey protein gel (GEL), administered as 22 g 1 h pre-exercise, 11 g/h during and 22 g 30 min post-exercise. Total leucine administration was 14.4 g and 6.3 in GEL and WHEY, respectively. Mean plasma leucine concentrations were elevated in GEL (P = 0.001) compared with WHEY and PLACEBO (375 ± 100, 272 ± 51, 146 ± 14 µmol L(-1), respectively). No differences (P = 0.153) in plasma FFA (WHEY 0.53 ± 0.30, GEL 0.45 ± 0.25, PLACEBO 0.65 ± 0.30, mmol L(-1)) or whole body lipid oxidation during exercise (WHEY 0.37 ± 0.26, GEL 0.36 ± 0.24, PLACEBO 0.34 ± 0.24 g/min) were apparent between trials, despite elevated (P = 0.001) insulin in WHEY and GEL compared with PLACEBO (38 ± 16, 35 ± 16, 22 ± 11 pmol L(-1), respectively). We conclude that leucine-enriched protein feeding does not impair FFA availability or whole body lipid oxidation during exercise, thus having practical applications for athletes who deliberately train in CHO-restricted states to promote skeletal muscle adaptations

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Gating of maxi channels observed from pseudo-phase portraits

Cited by 4 publications

References 45 publications

Subconductance states of mitochondrial chloride channels: implication for functionally‐coupled tetramers

Subconductance states of mitochondrial chloride channels: implication for functionally‐coupled tetramers

The properties, functions, and pathophysiology of maxi-anion channels

Leucine-enriched protein feeding does not impair exercise-induced free fatty acid availability and lipid oxidation: beneficial implications for training in carbohydrate-restricted states

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