Evidence for direct involvement of the sarcoplasmic reticulum Ca2+‐ATPase in a passive monovalent cation (K+/Na+) exchange

FEBS Letters

de Jesus, Florence¹  Dupont, Yves¹  Cuillel, Martine¹ 

[1]C.E.A., Laboratoire de Biophysique Moléculaire, URA CNRS no. 520, Département de Biologie Moléculaire et Structurale, Centre d'Etudes Nucléaires de Grenoble, Grenoble, France

关键词: Ca2+-ATPase;    Sarcoplasmic reticulum;    K+/Na+ exchange;    Thapsigargin;    Potential sensitive dye;    DiSC3(5);    EGTA;    ethylene glycol-bis(β-aminoethyl ether)-N;    N;    N′;    N′-tetraacetic acid;    ATP;    adenosine-5′-triphosphate;    SR;    sarcoplasmic reticulum;    DMSO;    dimethyl sulfoxide;    DiSC3(5);    3;    3′dipropylthiodicarbocyanine iodide;    MOPS;    3-(N-morpholino)propane-sulfonic acid;   

DOI  :  10.1016/0014-5793(95)01267-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A specific inhibitor of SERCA-pumps, thapsigargin (TG) was used to demonstrate the direct involvement of the SR Ca²⁺-ATPase in passive K⁺/Na⁺ exchange. The K⁺-potential variations across vesicle membranes were measured in the absence of ATP with a fluorescent probe: 3,3′-dipropylthiodicarbocyanine iodide. Addition of EGTA dissipates the K⁺-potential whereas the presence of TG abolishes this effect. Our data prove that the Ca²⁺-ATPase translocates monovalent cations at a rate similar to the E₂→E₁ conformational change.

【 授权许可】

Unknown