%0 Journal Article %1 ngezahayo1998inactivation %A Ngezahayo, A %A Zeilinger, C %A Todt, I %A Marten, I %A Kolb, H A %C Germany %D 1998 %J Pflugers Archiv : European journal of physiology %K imported %N 4 %P 627--629 %R 10.1007/s004240050681 %T Inactivation of expressed and conducting rCx46 hemichannels by phosphorylation %U https://pubmed.ncbi.nlm.nih.gov/9683738 %V 436 %X 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.

@article{ngezahayo1998inactivation, 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.}, added-at = {2024-02-16T14:19:58.000+0100}, address = {Germany}, author = {Ngezahayo, A and Zeilinger, C and Todt, I and Marten, I and Kolb, H A}, biburl = {https://www.bibsonomy.org/bibtex/27d343965361cf1306ee0198ae6c0b418/imarten}, comment = {9683738[pmid]}, description = {Inactivation of expressed and conducting rCx46 hemichannels by phosphorylation - PubMed}, doi = {10.1007/s004240050681}, interhash = {ee50dc4ca887f4ef1e7a8f4deed8953a}, intrahash = {7d343965361cf1306ee0198ae6c0b418}, issn = {14322013}, journal = {Pflugers Archiv : European journal of physiology}, keywords = {imported}, month = jul, number = 4, pages = {627--629}, timestamp = {2024-02-16T14:19:58.000+0100}, title = {Inactivation of expressed and conducting rCx46 hemichannels by phosphorylation}, url = {https://pubmed.ncbi.nlm.nih.gov/9683738}, volume = 436, year = 1998 }