Troponin I converts the skeletal muscle ryanodine receptor into a rectifying calcium release channel

FEBS Letters

Varsányi, Magdolna²  Herzog, Anke²  Jóna, István³  Szegedi, Csaba¹  Sárközi, Sándor³ 

[1] Cell Physiology Research Group of the Hungarian Academy of Science, H-4012 Debrecen, Hungary;Institut für Physiologische Chemie, Ruhr Universität, D-44780 Bochum, Germany;Department of Physiology, University Medical School, H-4012 Debrecen, Hungary

关键词: Ryanodine receptor;    Calcium release;    Rectifying channel;    Troponin I;    Yeast two-hybrid screen;    Skeletal muscle;    SR;    sarcoplasmic reticulum;    RyR1;    ryanodine receptor;    P o;    open probability of the RyR1;   

DOI  :  10.1016/S0014-5793(02)02463-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The goal of our present studies has been to find novel ryanodine receptor (RyR1) interacting polypeptides that modulate the channel activity from the luminal side of RyR1. Using K⁺ as charge carrier for recording of single channel events here we demonstrate a very unexpected observation that troponin I substantially alters RyR's gating behavior, and that RyR1 in association with troponin I becomes a rectifying Ca²⁺ release channel. Troponin I rapidly locks the RyR1 in a non-conducting state only at a negative holding potential, and only when applied to the luminal side; switching to a positive holding potential results in the channel returning to its original activity, immediately. A hypothesis is proposed to account for how an intraluminally located, positively charged molecule might function as a RyR1 regulator under physiological conditions.

【 授权许可】

Unknown