Cytoplasmic and extracellular IsK peptides activate endogenous K+ and Cl- channels in Xenopus oocytes: Evidence for regulatory function

Iris Ben-Efraim, Yechiel Shai*, Bernard Attali

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

IsK is a 14.5-kDa type III membrane glycoprotein which induces slowly activating K+ and Cl- currents when expressed in Xenopus oocytes and HEK 293 cells. Recently, mutagenesis experiments identified amino-and carboxyl- terminal domains of IsK as critical for induction of Cl- and K+ currents, respectively. This hypothesis was tested by examining effects of synthetic IsK hydrophilic peptides on untreated Xenopus oocytes. In agreement with IsK membrane topology, we show here that peptides derived from carboxyl and amino termini are sufficient to activate slow K+ and Cl- channels whose biophysical and pharmacological characteristics are similar to those exhibited by the native IsK protein. That data provide further evidence that IsK is a regulatory subunit of pro-existing silent channel complexes rather than a channel per se.

Original languageEnglish
Pages (from-to)8768-8771
Number of pages4
JournalJournal of Biological Chemistry
Volume271
Issue number15
DOIs
StatePublished - 12 Apr 1996
Externally publishedYes

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