Macroscopic and single-channel properties of a cloned human heart L-type Ca2+ channel α1 subunit expressed in Xenopus oocytes were studied and the effects of a cardiac β subunit were evaluated. The α1 subunit expressed current with much slower activation and inactivation kinetics than native cells. The β subunit increased the current amplitude and accelerated both activation and inactivation rates. Single-channel analysis revealed that the β subunit increased the probability of channel opening and shifted the voltage-dependence to more negative potentials without affecting conductance or open time. The data suggest that the β subunit modulates macroscopic current by increasing the probability of channel opening and shifting the voltage-dependence of the channel.
|Number of pages||7|
|Journal||Biochemical and biophysical research communications|
|Publication status||Published - 1993 Nov 15|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology