Calcium‐independent activation of skinned cardiac muscle by secophalloidin

FEBS Letters

Theodore, Lou J²  Bukatina, Anna E³  Campbell, Kenneth B¹  Sieck, Gary C³ 

[1] Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164, USA;NeoRx Corporation, 410 West Harrison Street, Seattle, WA 98119, USA;Departments of Anesthesiology, and Physiology and Biophysics, Mayo Foundation, Jo 4-184, 200 First Street SW, Rochester, MN 55905, USA

关键词: Secophalloidin;    Cardiac muscle;    Activation;    Contraction;    Regulation;    SPH;    secophalloidin;    SPH-L;    secophalloidin lactone;    SPH-H-A;    secophalloidin hydroxy acid;    TnC;    troponin C;    BDM;    2;    3-butanedione monoxime;    CDTA;    trans-1;    2-cyclohexanediamine-N;    N;    N′;    N′-tetraacetic acid;   

DOI  :  10.1016/S0014-5793(02)02766-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Thin filament regulation of muscle contraction is believed to be mediated by both Ca²⁺ and strongly bound myosin cross-bridges. We found that secophalloidin (SPH, 5–8 mM) activates cross-bridge cycling without Ca²⁺ causing isometric force comparable to that induced by Ca²⁺. At saturated [SPH], Ca²⁺ further increased force by 20%. SPH-induced force was reversible upon washing with a relaxing solution. However, there was more than 30% irreversible loss in subsequent Ca²⁺-activated force. We hypothesize that SPH activates muscle via strongly bound cross-bridges. SPH-activated contraction provides a new model for studying the role of Ca²⁺ and cross-bridges in muscle regulation.

【 授权许可】

Unknown