Change in Surface Charge of Sarcoplasmic Reticulum Membrane May Elicit Conformational Change in Sulfhydryl Groups of Membrane Proteins to Release Calcium

Abstract

A lipophilic anion, tetraphenylboron (TPB^-)-induced Ca²⁺ release from fragmented sarcoplasmic reticulum (SR) of frog skeletal muscle was monitored by chlortetracycline fluorescence. TPB^- caused change in surface charge of the membrane and in the protein conformation with a time course similar to that of the Ca²⁺ release. Tetraphenylarsonium (TPA⁺) inhibited these effects of TPB^-. Change in surface charge of SR is suggested to cause conformational change in SR membrane proteins, and then result in Ca²⁺ release from the SR.