Functional identification of ATP-sensitive K+ uniporter in mitochondria from sugar beet taproot

Functional identification of ATP-sensitive K+ uniporter in mitochondria from sugar beet taproot Mitochondria isolated from sugar beet (Beta vulgaris L.) taproot were shown to swell spontaneously after the transfer from a sucrose-containing isolation medium to isoosmotic potassium chloride solutions. The kinetics of this process was strongly retarded after the replacement of potassium with sodium in the incubation medium and was substantially stimulated by the electron-transport chain activity and valinomycin. At neutral pH of the incubation medium, the rate of K+-dependent swelling of mitochondria decreased by 30–50% after adding 1 mM ATP but was insensitive to other nucleotides (GTP, UTP, and CTP). In the medium acidified to pH 6.0, the addition of ATP caused shrinkage of mitochondria that had been swollen in the KCl medium. In the absence of this nucleotide, the kinetics of K+-dependent swelling of mitochondria was considerably decelerated upon the acidification of the incubation medium. The effects of ATP were independent of the presence or absence of oligomycin and atractyloside. However, the ATP-dependent shrinkage of mitochondria was inhibited in the presence of quinine, and this agent also inhibited K+-dependent swelling of organelles in potassium acetate solutions. The presence of K+ ions in the incubation medium caused a rapid dissipation of the mitochondrial membrane potential (Δψ) that was generated during succinate oxidation. The addition of ATP to the reaction medium resulted in the oligomycin-insensitive restoration of Δψ. The results are regarded as evidence that the membrane of taproot mitochondria is endowed with functionally active ATP-sensitive K+ uniporter. This system is likely to represent a K+ channel that catalyzes the electrogenic transfer of potassium ions to the mitochondrial matrix. It is supposed that the membrane of taproot mitochondria also contains a quinine-sensitive K+/H+ antiporter that catalyzes the efflux of potassium from the matrix or, on the contrary, the accumulation of K+ in the presence of potassium acetate. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Russian Journal of Plant Physiology Springer Journals

Functional identification of ATP-sensitive K+ uniporter in mitochondria from sugar beet taproot

Loading next page...
 
/lp/springer_journal/functional-identification-of-atp-sensitive-k-uniporter-in-mitochondria-sb3FBD0pXz
Publisher
Nauka/Interperiodica
Copyright
Copyright © 2005 by MAIK “Nauka/Interperiodica”
Subject
Life Sciences; Plant Sciences; Plant Physiology
ISSN
1021-4437
eISSN
1608-3407
D.O.I.
10.1007/s11183-005-0027-4
Publisher site
See Article on Publisher Site

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • No expiration
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches

$49/month

Start Free Trial

14-day Free Trial

Best Deal — 39% off

Annual Plan

  • All the features of the Professional Plan, but for 39% off!
  • Billed annually
  • No expiration
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.

$588

$360/year

billed annually
Start Free Trial

14-day Free Trial