Functional differences in Kv1.5 currents expressed in mammalian cell lines are due to the presence of endogenous Kvβ2.1 subunits

Victor N. Uebele, Sarah K. England, Archana Chaudhary, Michael M. Tamkun, Dirk J. Snyders

Research output: Contribution to journalArticlepeer-review

116 Scopus citations

Abstract

The voltage-sensitive currents observed following hKv1.5 α subunit expression in HEK 293 and mouse L-cells differ in the kinetics and voltage dependence of activation and slow inactivation. Molecular cloning, immunopurification, and Western blot analysis demonstrated that an endogenous L-cell Kvβ2.1 subunit assembled with transfected hKv1.5 protein. In contrast, both mRNA and protein analysis failed to detect a β subunit in the HEK 293 cells, suggesting that functional differences observed between these two systems are due to endogenous L-cell Kvβ2.1 expression. In the absence of Kvβ2.1, midpoints for activation and inactivation of hKv1.5 in HEK 299 cells were -0.2 ± 2.0 and -9.6 ± 1.8 mV, respectively. In the presence of Kvβ2.1 these values were -14.1 ± 1.8 and -22.1 ± 3.7 mV, respectively. The β subunit also caused a 1.5-fold increase in the extent of slow inactivation at 50 mV, thus completely reconstituting the L-cell current phenotype in the HEK 293 cells. These results indicate that 1) the Kvβ2.1 subunit can alter Kv1.5 α subunit function, 2) β subunits are not required for α subunit expression, and 3) endogenous β subunits are expressed in heterologous expression systems used to study K + channel function.

Original languageEnglish
Pages (from-to)2406-2412
Number of pages7
JournalJournal of Biological Chemistry
Volume271
Issue number5
DOIs
StatePublished - Feb 2 1996

Fingerprint

Dive into the research topics of 'Functional differences in Kv1.5 currents expressed in mammalian cell lines are due to the presence of endogenous Kvβ2.1 subunits'. Together they form a unique fingerprint.

Cite this