Calpain proteolysis of free and bound forms of calponin, a troponin T‐like protein in smooth muscle

FEBS Letters

Ozawa, Kazue³  Abe, Masahiro²  Tsunekawa, Shoji¹  Hiwada, Kunio²  Murachi, Takashi¹  Takahashi, Katsuhito² 

[1] Department of Clinical Science and Laboratory Medicine, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606, Japan;Second Department of Internal Medicine, Ehime University School of Medicine, Onsen-gun, Ehime 791-02, Japan;Second Department of Surgery, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606, Japan

关键词: Calpain;    Proteolysis;    Smooth muscle;    Calmodulin-binding protein;    Troponin T;    Thin filament;   

DOI  :  10.1016/0014-5793(89)80783-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Calponin, a novel homologue of troponin T, purified from chicken gizzard was found to be one of the most susceptible proteins among smooth muscle contraction-associated proteins to hydrolysis by calpain I purified from human red blood cells. The high susceptibility of calponin was comparable to that reported for troponin T. The rate of degradation of calponin, unlike caldesmon and myosin light chain kinase, was accelerated when bound to calmodulin. When calponin existed as a bound form in both reconstituted actin filament and native thin filament, the rate of proteolysis was markedly retarded, indicating close association of calponin with actin filament. These observations are compatible with the view that calponin is an integral part of the actin-linked contractile machinery in smooth muscle.

【 授权许可】

Unknown