Facilitation of murine cardiac L-type Cav1.2 channel is modulated by Calmodulin kinase II-dependent phosphorylation of S1512 and S1570
Facilitation of murine cardiac L-type Cav1.2 channel is modulated by Calmodulin kinase II-dependent phosphorylation of S1512 and S1570
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DOI：
10.1073/pnas.0914287107
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发表时间：
2010-06-01
影响因子：
11.1
通讯作者：
Moosmang, Sven
中科院分区：
文献类型：
--
作者：
Blaich, Anne;Welling, Andrea;Moosmang, Sven
改变钙(Ca~(2+))内流的活性依赖方式被认为具有重大的生理后果，尽管De。对这一假设的零星测试才刚刚开始。易化和失活提供了两种相反的、依赖于活性的方式来改变通过心脏Cav1.2钙通道的钙内流。据报道，Cav1.2的电压和频率依赖于钙调蛋白(CaM)和/或钙调蛋白激酶II(CaMKII)的活性。心脏L型钙通道复合体中的几个部位被认为是CaMKII的靶点。在这里，我们产生了α(1)1.2 S1512和S1570磷酸化位点敲门突变的小鼠[正弦促进(SF)小鼠]。同卵母细胞SF小鼠是存活的，并以孟德尔比例繁殖。携带SF突变的心室肌细胞的电压依赖易化性从1.58倍下降到1.18倍。CaMKII抑制剂KN-93使对照心肌细胞的易化性降低到1.28。SF突变负性改变了电压依赖性失活，减缓了失活的恢复，从而使可用于激活的通道更少。不同心率下的遥测心电记录显示，在更高的心率下，SF组的QT时间比对照组小鼠显著减少。我们的结果有力地支持了这一观点，即CaMKII依赖的S1512和S1570上的Cav1.2磷酸化介导了小鼠心脏的钙电流易化。
Activity-dependent means of altering calcium (Ca2+) influx are assumed to be of great physiological consequence, although de. nitive tests of this assumption have only begun to emerge. Facilitation and inactivation offer two opposing, activity-dependent means of altering Ca2+ influx via cardiac Cav1.2 calcium channels. Voltage-and frequency-dependent facilitation of Cav1.2 has been reported to depend on Calmodulin (CaM) and/or the activity of Calmodulin kinase II (CaMKII). Several sites within the cardiac Ltype calcium channel complex have been proposed as the targets of CaMKII. Here, we generated mice with knockin mutations of alpha(1)1.2 S1512 and S1570 phosphorylation sites [sine facilitation (SF) mice]. Homocygote SF mice were viable and reproduced in a Mendelian ratio. Voltage-dependent facilitation in ventricular cardiomyocytes carrying the SF mutation was decreased from 1.58- to 1.18-fold. The CaMKII inhibitor KN-93 reduced facilitation to 1.28 in control cardiomyocytes. SF mutation negatively shifted the voltage-dependent inactivation and slowed recovery from inactivation, thereby making fewer channels available for activation. Telemetric ECG recordings at different heart rates showed that QT time decreased significantly more in SF than in control mice at higher rates. Our results strongly support the notion that CaMKII-dependent phosphorylation of Cav1.2 at S1512 and S1570 mediates Ca2+ current facilitation in the murine heart.