Calmodulin inhibits inositol 1,4,5‐trisphosphate‐induced calcium release through the purified and reconstituted inositol 1,4,5‐trisphosphate receptor type 1

FEBS Letters

Hirota, Junji²  Michikawa, Takayuki¹  Mikoshiba, Katsuhiko²  Furuichi, Teiichi¹  Natsume, Tohru² 

[1] Department of Molecular Neurobiology, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108, Japan;Mikoshiba Calciosignal Net Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Corporation (JST), 2-28-8 Honkomagome, Bunkyo-ku, Tokyo 113-0021, Japan

关键词: Calmodulin;    Inositol 1;    4;    5-trisphosphate;    Inositol 1;    4;    5-trisphosphate receptor;    Surface plasmon resonance;    IP3;    D-myo-inositol 1;    4;    5-trisphosphate;    IP3R;    IP3 receptor;    IP3R1;    IP3R type 1;    IP3R2;    IP3R type 2;    IP3R3;    IP3R type 3;    HEPES;    N-(2-hydroxyethyl) piperizine-N′-2-ethanesulfonic acid;    EGTA;    ethylene glycol-bis(β-amino-ethyl ether) N;    N;    N′;    N′-tetra acetic acid;    IICR;    IP3-induced Ca2+ release;    NHS;    N-hydroxysuccinimide;    EDC;    N-ethyl-N′-(3-diethylaminopropyl)-carbodiimide;   

DOI  :  10.1016/S0014-5793(99)00973-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Our previous studies have demonstrated that calmodulin binds to IP₃R type 1 (IP₃R1) in a Ca²⁺ dependent manner, which suggests that calmodulin regulates the IP₃R1 channel. In the present study, we investigated real-time kinetics of interactions between calmodulin and IP₃R1 as well as effects of calmodulin on IP₃-induced Ca²⁺ release by purified and reconstituted IP₃R1. Kinetic analysis revealed that calmodulin binds to IP₃R1 in a Ca²⁺ dependent manner and that both association and dissociation phase consist of two components with time constants of k _a=4.46×10² and >10⁴ M⁻¹ s⁻¹, k _d=1.44×10⁻² and 1.17×10⁻¹ s⁻¹. The apparent dissociation constant was calculated to be 27.3 μM. The IP₃-induced Ca²⁺ release through the purified and reconstituted IP₃R1 was inhibited by Ca²⁺/calmodulin, in a dose dependent manner. We interpret our findings to mean that calmodulin binds to IP₃R1 in a Ca²⁺ dependent manner to exert inhibitory effect on IP₃R channel activity. This event may be one of the mechanisms governing the negative feedback regulation of IP₃-induced Ca²⁺ release by Ca²⁺.

【 授权许可】

Unknown