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Pflügers Archiv

, Volume 436, Issue 4, pp 627–629 | Cite as

Inactivation of expressed and conducting rCx46 hemichannels by phosphorylation

  • A. Ngezahayo
  • C. Zeilinger
  • I. Todt
  • I. Marten
  • H.-A. Kolb
Short Communication

Abstract

 Hemichannels of rat connexin 46 (rCx46) were expressed in Xenopus laevis oocytes and analysed by two-electrode voltage-clamp experiments. It is established that rCx46 hemichannels can be activated at low external Ca2+ and positive membrane potentials. Upon larger depolarizations, the hemichannels of oocytes activate in a time-dependent manner, occasionally followed by a spontaneous inactivation. We found that, in the absence of inactivation, treatment of oocytes with 1-oleoyl-2-acetyl-sn-glycerol (OAG), an activator of protein kinase C (PKC), reversibly reduced the amplitude of the rCx46-mediated current and, after an incubation time of about 30 min, induced inactivation of the voltage-dependent current. After wash-out of OAG the corresponding membrane conductance increased and the inactivation behaviour disappeared. The OAG-induced inactivation, as well as the spontaneous inactivation, could be removed by application of the specific PKC inhibitor calphostin C and also by phloretin. The data provide evidence that the activation and inhibition of PKC affect the rCx46-mediated membrane conductance as well as the voltage-dependent current inactivation in an inverse manner.

Key words Connexin46 expression Hemichannel Inactivation 1-Oleoyl-2-acetyl-sn-glycerol (OAG) Phosphorylation Protein kinases Xenopus oocytes 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • A. Ngezahayo
    • 1
  • C. Zeilinger
    • 1
  • I. Todt
    • 1
  • I. Marten
    • 1
  • H.-A. Kolb
    • 1
  1. 1.Institut für Biophysik, Universität Hannover, Herrenhäuser Strasse 2, D-30419 Hannover, Germany e-mail: kolb@mbox.biophysik.uni-hannover.de Tel.: +49-511-7622608, Fax: +49-511-7622606DE

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