Referenced in: none

Automatically associated channels: Kv1.2 , Kv2.1

Title: The pore region of the Kv1.2alpha subunit is an important component of recombinant Kv1.2 channel oxygen sensitivity.

Authors: Laura Conforti, Koichi Takimoto, Milan Petrovic, Olaf Pongs, David Millhorn

Journal, date & volume: Biochem. Biophys. Res. Commun., 2003 Jun 27 , 306, 450-6

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/12804584

Abstract
Oxygen-sensitive K(+) channels are important elements in the cellular response to hypoxia. Although much progress has been made in identifying their molecular composition, the structural components associated to their O(2)-sensitivity are not yet understood. Recombinant Kv1.2 currents expressed in Xenopus oocytes are inhibited by a decrease in O(2) availability. On the contrary, heterologous Kv2.1 channels are O(2)-insensitive. To elucidate the protein segment responsible for the O(2)-sensitivity of Kv1.2 channels, we analyzed the response to anoxia of Kv1.2/Kv2.1 chimeric channels. Expression of chimeric Kv2.1 channels each containing the S4, the S1-S3 or the S6-COOH segments of Kv1.2 polypeptide resulted in a K(+) current insensitive to anoxia. In contrast, transferring the S5-S6 segment of Kv1.2 into Kv2.1 produced an O(2)-sensitive K(+) current. Finally, mutating a redox-sensitive methionine residue (M380) of Kv1.2 polypeptide did not affect O(2)-sensitivity. Thus, the pore and its surrounding regions of Kv1.2 polypeptide confer its hypoxic inhibition. This response is independent on the redox modulation of methionine residues in this protein segment.