CALMODULIN-DEPENDENT PROTEIN KINASE II IN HEART CALCIUM CHANNEL REGULATION

流经心肌细胞肌膜钙通道的钙电流 是细胞钙稳态的重要决定因素，因此是一个重要的 多种细胞功能的决定因素。而钙离子和膜 钙离子通道的电压依赖性正调节 最近的报道，对这种机制知之甚少。我们的研究 提供了令人信服的证据，证明在成年大鼠的心肌细胞中 钙离子/钙调素依赖性激酶II介导L型钙电流 促进，即电流大小的增大和/或减慢 在重复去极化过程中它的失活，由单一的强 去极化预脉冲或通过去极化保持电位。所有的 这些对海流的影响被纳入完全消除了 钙/钙调蛋白激酶II的特异性多肽抑制物在 移液器充液或用Ba2取代Ca2 浴液。钙离子/钙调蛋白激酶II对钙离子的影响 当前的监管进一步得到了本地化分配的支持 在细胞肌膜附近发现一种针对该激酶的特异性抗体 通过数字共聚焦荧光成像。此外， 抗体的免疫荧光显著增强。 高[K]O去极化，并通过去除CaO或 钙调素抑制剂W7。因此，钙/钙调蛋白激酶II 依赖蛋白的磷酸化是一种重要的机制 可变因素，如钙离子、重复刺激和强 去极化能正向调节心肌细胞内钙电流，并且 膜电位在调节细胞周期中起着至关重要的作用 激活剂的活性。这些发现为我们提供了新的见解 了解心肌细胞内钙通道的调节可能是在 其他细胞类型也是如此。

Ca2+ current flowing via sarcolemmal Ca2+ channels of heart cells is an important determinant of cell Ca2+ homeostasis and thus an important determinant of a variety of cell functions. While Ca2+- and membrane voltage-dependent positive regulation of Ca2+ channels have been recently reported, little is known of the mechanism. Our studies provide compelling evidence that in adult rat cardiac ventricular cells Ca2+/calmodulin dependent kinase II mediates L-type Ca2+ current facilitation, i.e., an augmentation in current magnitude and or slowing of its inactivation during repetitive depolarizations, by single strong depolarizing prepulse or by depolarizing holding potentials. All of these effects on the current were completely abolished by a inclusion of specific peptide inhibitor of Ca2+/calmodulin kinase II within the pipette filling solution or by the replacement of Ca2+ with Ba2+ in bath solution. The involvement of Ca2+/calmodulin kinase II on Ca2+ current regulation is further supported by the localized distribution of a specific antibody to the kinase near cell sarcolemma as revealed by digital confocal fluorescent imaging. Furthermore, the immunofluorescence of the antibody was significantly enhanced by depolarization with high [K+]o and attenuated by removal of Ca2+o or by W7, a calmodulin inhibitor. Thus, Ca2+/calmodulin kinase II dependent protein phosphorylation is an important mechanism by which variable factors, such as Ca2+, repetitive stimulation and strong depolarization can positively regulate Ca2+ current in heart cells, and that membrane potential plays an essential role in the modulation of the kinase activity. These findings provide new insights toward understanding Ca2+ channel regulation in cardiac cells as possibly in other cell types as well.