CONTROL MECHANISMS OF CARDIAC PROTEINS AND ENZYMES

该程序涉及结构-功能关系， 几种转运蛋白和酶的正常控制机制， 在心脏生理学中很重要，这些的药理学调节 机制，以及它们在病理生理条件下的变化， 可能由心力衰竭和缺血性心脏病引起的那些。 这些 蛋白质包括质膜NaK-ATP酶、肌膜和肌纤维蛋白。 线粒体Na+/H+、K+/H+反向转运蛋白、线粒体Na+/Ca 2 + 反向转运蛋白，肌膜Na+，Pi-协同转运蛋白，心脏蛋白 磷酸酶及其底物，以及Ca 2+依赖性蛋白酶。 的 参与研究者具有离子转运、膜 生物化学、酶学、生物能量学、分子生物学和遗传学， 免疫学和心脏药理学，将联合收割机， 以下研究：使用心肌肌膜和线粒体 制剂，一些运输蛋白，控制流量的 将表征穿过心脏膜的阳离子和阴离子， 纯化和重组。 这些携带者的基因将被克隆， 并将开发适当的表达系统。 研究 纯化的转运蛋白的结构-功能关系 利用已知的序列，蛋白质结构的改变将通过 突变和化学修饰。 利用封闭的肌膜 囊泡，脂质体中重组的转运蛋白，完整 线粒体，在宿主细胞中表达的突变体，和完整的心肌细胞， 通过生理学方法控制各种离子载体的功能， 将研究调节剂和药理学试剂。 在有关研究中， 通过蛋白质磷酸化来控制心肌功能 去磷酸化，心脏蛋白磷酸酶的表征， 他们的生理底物将尝试，和激素控制的 这些酶将被研究。 为了阐明细胞内 蛋白水解酶在控制心脏蛋白催化剂，相互作用 将研究Ca 2+依赖性蛋白酶及其核底物， 以及这些酶在膜修复过程中的作用， 将研究受损心脏蛋白的周转。

This program is concerned with the structure-function relationships and normal control mechanisms of several transport proteins and enzymes that are important in cardiac physiology, the pharmacologic regulation of these mechanisms, and their alterations under pathophysiologic conditions such as those that may result from heart failure and ischemic heart disease. These proteins include the plasma membrane NaK-ATPase, the sarcolemmal and the mitochondrial Na+/H+, K+/H+ antiporters, the mitochondrial Na+/Ca2+ antiporter, the sarcolemmal Na+, Pi-cotransporter, the cardiac protein phosphatases and their substrates, and the Ca2+-dependent proteases. The participating investigators with expertise in ion transport, membrane biochemistry, enzymology, bioenergetics, molecular biology and genetics, immunology, and cardiac pharmacology, will combine their efforts to conduct the following studies: Using cardiac sarcolemmal and mitochondrial preparations, a number of transport proteins that control the fluxes of cations and anions across the cardiac membranes will be characterized, purified, and reconstituted. The genes for these carriers will be cloned, and appropriate systems for their expressions will be developed. To study the structure-function relationships of the purified transport proteins with known sequences, alterations in protein structure will be made by mutations and chemical modifications. With the use of sealed sarcolemmal vesicles, transport proteins reconstituted in liposomes, intact mitochondria, mutants expressed in host cells, and intact cardiac myocytes, control of the functions of the various ion carriers by physiological regulators and pharmacologic agents will be studied. In studies concerned with the control of myocardial function by protein phosphorylation- dephosphorylation, characterization of cardiac protein phosphatases and their physiological substrates will be attempted, and hormonal control of these enzymes will be explored. To clarify the role of intracellular proteolytic enzymes in control of cardiac protein catabolism, interactions of Ca2+-dependent proteases with their nuclear substrates will be studied, and the role of these enzymes in the processes of membrane repair and turnover of damaged cardiac proteins will be investigated.