Xenbase is experiencing difficulties due to technical problems with the University of Calgary IT infrastructure and may go temporarily offline.

Click on this message to dismiss it.
Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
J Biol Chem. July 6, 2001; 276 (27): 24449-52.

Block of Kcnk3 by protons. Evidence that 2-P-domain potassium channel subunits function as homodimers.

Lopes CM , Zilberberg N , Goldstein SA .

KCNK subunits have two pore-forming P domains and four predicted transmembrane segments. To assess the number of subunits in each pore, we studied external proton block of Kcnk3, a subunit prominent in rodent heart and brain. Consistent with a pore-blocking mechanism, inhibition was dependent on voltage, potassium concentration, and a histidine in the first P domain (P1H). Thus, at pH 6.8 with 20 mm potassium half the current passed by P1H channels was blocked (apparently via two sites approximately 10% into the electrical field) whereas channels with an asparagine substitution (P1N) were fully active. Furthermore, pore blockade by barium was sensitive to pH in P1H but not P1N channels. Although linking two Kcnk3 subunits in tandem to produce P1H-P1H and P1N-P1N channels bearing four P domains did not alter these attributes, the mixed tandems P1H-P1N and P1N-P1H were half-blocked at pH approximately 6.4, apparently via a single site. This implicates a dimeric structure for Kcnk3 channels with two (and only two) P1 domains in each pore and argues that P2 domains also contribute to pore formation.

PubMed ID: 11358956
Article link: J Biol Chem.

Genes referenced: kcnk3

My Xenbase: [ Log-in / Register ]
version: [3.11.2]

Major funding for Xenbase is provided by the National Institute of Child Health and Human Development, grant P41 HD064556