Ca(2+)-dependent Inactivation of a Cloned Cardiac Ca2+ Channel Alpha 1 Subunit (alpha 1C) Expressed in Xenopus Oocytes

Overview

Journal Biophys J

Publisher Cell Press

Specialty Biophysics

Date 1994 Jun 1

PMID 8075326

Citations 35

Authors

A Neely

R Olcese

X Wei

L Birnbaumer

E Stefani

Affiliations

Soon will be listed here.

Abstract

The alpha 1 subunit of cardiac Ca2+ channel, expressed alone or coexpressed with the corresponding beta subunit in Xenopus laevis oocytes, elicits rapidly inactivating Ca2+ currents. The inactivation has the following properties: 1) It is practically absent in external Ba2+; 2) it increases with Ca2+ current amplitudes; 3) it is faster at more negative potentials for comparable Ca2+ current amplitudes; 4) it is independent of channel density; and 5) it does not require the beta subunit. These findings indicate that the Ca2+ binding site responsible for inactivation is encoded in the alpha 1 subunit and suggest that it is located near the inner channel mouth but outside the membrane electric field.

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