Molecularphysiological analysis of calcium-signaling proteins in cardiac sarcoplasmic reticulum

我们研究了在心肌兴奋收缩偶联中起关键作用的心肌肌浆网(SR)蛋白调控的分子机制。钙信号在心脏特性调节中的生理作用：我们研究了抗心肌肌浆网钙信号蛋白之一的磷蛋白单抗对心肌肌浆网钙泵ATPase活性的影响。我们发现，抗体抑制了两个SR蛋白之间的直接蛋白质-蛋白质相互作用(J.Mol。牢房。心脏。23,1223,1991)。我们研究了人工合成的磷蛋白多肽对ATPase的影响。揭示了磷脂酶原对钙泵ATPase的双重调节作用，即对V_&lt；max&gt；的细胞质结构域和对K_&lt；Ca&gt；(J.Biol.化学。267、1647、1992).心肌肌浆网钙调节系统在正常和应激心肌细胞中的病理作用：我们在分离的心肌细胞上建立了细胞内钙含量测定系统，并评估了缺氧和钙超载条件下心肌细胞内钙瞬变的变化。目前，我们正在评估抗磷蛋白单抗和合成肽对钙瞬变的影响。我们正在研究心脏肌浆网钙信号蛋白在正常、应激或心肌收缩的心肌细胞中的表达调节。

We investigated the molecular mechanism of regulation of the proteins of cardiac sarcoplasinic reticulum (SR) which has pivotal role in excitation-contraction coupling of myocardium.1. Physiological roles of Ca signaling in regulation of cardiac property : We investigated the effects of a monoclonal antibody against phospholamban, one of the Ca signaling proteins in cardiac SR, on ATPase activity of cardiac SR Ca pump ATPase. We found that the antibody inhibit the direct protein-protein interaction between the two SR proteins (J. Mol. Cell. Cardiol. 23, 1223, 1991). We investigated the effects of synthetic phospholamban peptides on the ATPase. The dual regulatory effects of pliospholainban on Ca pump ATPase were revealed ; the cytoplasmic domain for V_<max> and the intramembrane domain for K_<Ca> (J. Biol. Chem. 267, 1647, 1992).2. Pathological roles of Ca regulatory system of cardiac SR in normal and stressed inyocytes : We established the intracellular Ca^<2+> content measuring system in isolated cardiac myocyte, and evaluated intracellular Ca^<2+> transients of cardiac myocyte under hypoxia and Ca overload. Currently, we are on the way to evaluate the effect of anti-phospholamban monoclonal antibody and the synthetic peptides on the Ca^<2+> transient. We are examining the regulation of the expression of cardiac SR Ca signaling proteins in normal, stressed, or cardioinyopatliic cardiomyocyte.