Unusual Slow Gating of Gap Junction Channels in Oocytes Expressing Connexin32 or Its COOH-Terminus Truncated Mutant

Unusual Slow Gating of Gap Junction Channels in Oocytes Expressing Connexin32 or Its... Gap junction channels are gated by a chemical gate and two transjunctional voltage (V j)-sensitive gates: fast and slow. Slow V j gate and chemical gate are believed to be the same. The slow gate closes at the negative side of V j and is mostly inactive without uncouplers or connexin (Cx) mutations. In contrast, our present data indicate otherwise. Oocytes expressing Cx32 were subjected to series of −100 mV V j pulses (12-s duration, 30-s intervals). Both peak (PK) and steady-state (SS) junctional conductances (G j), measured at each pulse, decreased exponentially by 50−60% (tau = ∼1.2 min). G jPK dropped more dramatically, such that G jSS/G jPK increased from 0.4 to 0.6, indicating a drop in V j sensitivity. Less striking effects were obtained with –60 mV pulses. During recovery, G j, measured by applying 20 mV pulses (2-s duration, 30-s intervals), slowly returned to initial values (tau = ∼7 min). With reversal of V j polarity, G jPK briefly increased and G jSS/G jPK decreased, suggesting that V j-dependent hemichannel reopening is faster than hemichannel closing. Similar yet more dramatic results were obtained with COOH-terminus truncated Cx32 (Cx32-D225), a mutant believed to lack fast V j gating. The data indicate that the slow gate of Cx32 is active in the absence of uncouplers or mutations and displays unusual V j behavior. Based on previous evidence for direct calmodulin (CaM) involvement in chemical/slow gating, this may also be CaM-mediated. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Unusual Slow Gating of Gap Junction Channels in Oocytes Expressing Connexin32 or Its COOH-Terminus Truncated Mutant

Loading next page...
Copyright © 2007 by Springer Science+Business Media, LLC
Life Sciences; Human Physiology ; Biochemistry, general
Publisher site
See Article on Publisher Site


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


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.



billed annually
Start Free Trial

14-day Free Trial