Respiratory State and Phosphatidylserine Import in Brain Mitochondria In Vitro

Respiratory State and Phosphatidylserine Import in Brain Mitochondria In Vitro The mechanism of phosphatidylserine (PS) movement from donor membranes into rat brain mitochondria was investigated. Mitochondria were incubated with liposomes and subjected to density gradient centrifugation. The energized state was monitored by flow cytometry measuring the fluorescence of membrane-potential-sensitive rhodamine-123 dye. Mitochondria density decreased upon increase of the respiratory rate, as a consequence of their association with liposomes. After interaction of mitochondria with 14C-PS containing liposomes, 14C-PS became a substrate of PS decarboxylase, as monitored by the formation of 14C-phosphatidylethanolamine (PE), indicating translocation of 14C-PS to the inner membrane. The kinetics of 14C-PE formation showed a high rate upon addition of ADP, malate and pyruvate (state 3) compared to control (state 1). In state 3, 14C-PE formation decreased in the presence of NaN3. Mitochondria-associated membranes (MAM) are the major site of PS synthesis. However, their role in the translocation of PS to mitochondria has not been completely elucidated. A crude mitochondrial fraction (P2) containing MAM, synaptosomes and myelin was prelabeled with 14C-PS and incubated in different respiratory states. At a high respiratory rate, low-density labeled mitochondria, whose band overlaps that of synaptosomes, were obtained by centrifugation. A parallel decrease of both radioactivity and protein in MAM fraction was observed, indicating that the association of MAM and mitochondria had occurred. Synthesis and translocation of 14C-PS in P2 membranes were also studied by incubating P2 with 14C-serine. In the resting state 14C-PS accumulated in MAM, indicating that the transfer to mitochondria was a limiting step. In state 3 both the transfer rate of 14C-PS and its conversion to 14C-PE increased. Respiratory mitochondrial activity modulated the association of MAM and mitochondria, triggering a mechanism that allowed the transport of PS across the outer mitochondrial membrane. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Respiratory State and Phosphatidylserine Import in Brain Mitochondria In Vitro

Loading next page...
 
/lp/springer_journal/respiratory-state-and-phosphatidylserine-import-in-brain-mitochondria-kTbU0PxPtk
Publisher
Springer-Verlag
Copyright
Copyright © Inc. by 2000 Springer-Verlag New York
Subject
Life Sciences; Biochemistry, general; Human Physiology
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s002320001011
Publisher site
See Article on Publisher Site

There are no references for this article.

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