CALMODULIN-DEPENDENT PROTEIN KINASE II IN HEART CALCIUM CHANNEL REGULATION

钙调蛋白依赖性蛋白激酶 II 在心脏钙通道调节中的作用

• 批准号: 3745559
• 负责人: R P XIAO
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3745559
• 关键词: calcium channel; calcium flux; calmodulin; calmodulin dependent protein kinase; confocal scanning microscopy; enzyme activity; enzyme inhibitors; genetic regulation; heart cell; homeostasis; inhibitor /antagonist; laboratory rat; membrane potentials; potassium; sarcolemma

Ca2+ entry through voltage-dependent Ca2+ channels is important in cardiac and vascular muscle excitation-contraction coupling. The Ca2+ regulated multifunctional protein kinase, Ca2+/calmodulin-dependent protein kinase II (CaMKII), has a very important role in signal transduction in nervous system, such as long-term potentiation (LTP) and memory. However, little i known as to whether this protein kinase also modulates the function of cardiac cells. Our studies demonstrate both spatially resolved and temporally distinct novel effects of CaMKII on L-type Ca2+ channel current (ICa) in cardiac cells. Either depolarization alone or calcium influx can increase the amplitude and slow the inactivation of ICa. The distinct volt e- and Ca2+-dependent effects persist with time constants of about 1.7 s and 9 s, respectively. Both effects are completely abolished by a specific peptide inhibitor of CaMKII. This CaMKII inhibitor also suppresses the prolongation of ICa induced by depolarizing holding potentials. An antibod specific for the autophosphorylated (activated) CaMKII, PY-66, is localized close to sarcolemmal membranes and the profile of CaMKII activation is qualitatively correlated with the changes in ICa under various conditions. Thus, the action of CaMKII on ICa is dually regulated by membrane depolarization and by calcium influx: the latter directly activates CaMKII while the former likely promotes the interaction between constitutive CaMKI and the membrane channel proteins. In contrast to the active CaMKII distribution, the intracellular distribution of the total CaMKII enzyme (visualized by using an antibody which specifically reacts with CaMKII k isoform) but does not sense its activation state is uniform with a higher nuclear distribution. This suggests that CaMKII is translocated to the cel sarcolemma following activation in cardiac myocytes. These findings provid new insights toward understanding the physiological function of the ubiquitous protein kinase, CaMKII in cardiac muscle cells as possibly in other type of cells as well.

通过电压依赖性钙通道的钙内流在心脏中是重要的 和血管肌肉兴奋-收缩偶联。 Ca 2+调节 多功能蛋白激酶，钙/钙调蛋白依赖性蛋白激酶II 钙调素激酶Ⅱ（CaMKII）在神经细胞的信号转导中起着非常重要的作用。 长时程增强（LTP）和记忆。 然而，小i 已知这种蛋白激酶是否也调节 心肌细胞 我们的研究表明，空间分辨率和 CaMKII对L-型钙通道电流时间特异性作用 (ICa)在心脏细胞中。 去极化或钙离子内流均可 增加ICa的振幅，减慢ICa的失活。 独特的伏特 电子，电子 和Ca 2+依赖性效应持续存在，时间常数约为1.7 s， 9、分别。 这两种效应都被一种特定的 CaMKII的肽抑制剂。 这种CaMKII抑制剂还抑制了 去极化保持电位引起的伊卡延长。 抗体 特异于自磷酸化（活化）CaMKII，PY-66，被定位 接近肌膜，CaMKII激活的特征是 在各种条件下，与伊卡的变化定性相关。 因此，CaMKII对伊卡的作用受到膜的双重调节 去极化和钙内流：后者直接激活CaMKII 而前者可能促进了组成型CaMKI与 和膜通道蛋白。 与活性CaMKII相比， 分布，总CaMKII酶的细胞内分布 （通过使用与CaMK II k特异性反应的抗体可视化 同种型），但不感测其活化状态是均匀的， 核分布 这表明CaMKII易位到细胞中， 心肌细胞激活后的肌膜 这些发现提供了 新的见解对理解的生理功能， 心肌细胞中普遍存在的蛋白激酶CaMKII， 其他类型的细胞也是如此。