Phospholamban phosphorylation sites enhance the recovery of intracellular Ca2+ after perfusion arrest in isolated, perfused mouse heart
Phospholamban phosphorylation sites enhance the recovery of intracellular Ca2+ after perfusion arrest in isolated, perfused mouse heart
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DOI：
10.1016/j.cardiores.2006.01.018
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发表时间：
2006-05-01
影响因子：
10.8
通讯作者：
Mattiazzi, Alicia
中科院分区：
文献类型：
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作者：
Valverde, Carlos A.;Mundina-Wellenmann, Cecilia;Mattiazzi, Alicia
目的：探讨受磷蛋白（phospholamban，PLN）丝氨酸（16）和苏氨酸（17）位点磷酸化对顿抑心肌细胞内钙（Ca 2+）处理和收缩恢复的重要性。Ca ~（2+）（Rhod-2，脉冲局部场荧光显微镜）和收缩性（等容左心室发展压力，在Langendorff灌注的心脏中同时测量LVDP），所述心脏来自表达完整PLN（PLN-WT）或两个磷酸化位点突变为Ala（结果：两组缺血前Ca 2+和LvDP值相似。在PLN-WT中，再灌注早期Thr（17）磷酸化的瞬时增加先于Ca 2+瞬时振幅的恢复，实际上在再灌注结束时完成。再灌注30分钟时的LVDP为缺血前值的67.9 ± 7.6%，n =14。相反，在PLN-DM中，与PLN-WT心脏相比，Ca 2+瞬时振幅恢复较差，LVDP显著降低（28.3 +/-6.7%，n = 11，30 min再灌注）。尽管肌丝Ca 2+反应性和肌钙蛋白I（TnI）降解在组间没有差异，但在PLN-DM与PLN-WT心脏中，典型的Ca-i（2）+过载的机械交替事件显著延长。结论：PLN磷酸化似乎对顿抑期间的机械和Ca-i（2）+恢复至关重要，并对典型的Ca-i（2）+过载的机械异常具有保护作用。PLN磷酸化的重要性主要在于Thr（17）残基，其在再灌注的关键早期阶段被磷酸化。我们的研究结果强调，虽然消融PLN磷酸化不影响基础收缩性，但它确实改变了压力情况下的Ca 2+处理和机械性能。(c)2006年欧洲心脏病学会。Elsevier B. V.出版，保留所有权利。
Objective: To investigate the importance of the phosphorylation of Ser(16) and Thr(17) sites of phospholamban (PLN) on intracellular Ca2+ (Ca-i(2)+) handling and contractile recovery of the stunned myocardium.Methods: Ca-i(2)+ (Rhod-2, pulsed local-field fluorescence microscopy) and contractility (isovolumic left ventricular developed pressure, LVDP) were simultaneously measured in Langendorff perfused hearts from transgenic mice expressing either intact PLN (PLN-WT) or PLN with both phosphorylation sites mutated to Ala (PLN-DM), subjected to 12 min of global ischemia followed by a reperfusion period of 30 min.Results: Pre-ischemic values of Ca-i(2)+ and LvDP were similar in both groups. In PLN-WT, a transient increase in Thr(17) phosphorylation at early reperfusion preceded a recovery of Ca2+ transient amplitude, virtually completed by the end of reperfusion. LVDP at 30 min reperfusion was 67.9 +/- 7.6% of pre-ischemic values, n =14. In contrast, in PLN-DM, there was a poor recovery of Ca-i(2)+ transient amplitude and LVDP was significantly lower (28.3 +/- 6.7%, n = 11, 30 min reperfusion) than in PLN-WT hearts. Although myofilament Ca2+ responsiveness and troponin I (TnI) degradation did not differ between groups, the episodes of mechanical alternans, typical of Ca-i(2)+ overload, were significantly prolonged in PLN-DM vs. PLN-WT hearts.Conclusions: PLN phosphorylation appears to be crucial for the mechanical and Ca-i(2)+ recovery during stunning and protective against the mechanical abnormalities typical of Ca-i(2)+ overload. The importance of PLN phosphorylation would primarily reside in the Thr(17) residue, which is phosphorylated during the critical early phase of reperfusion. Our results emphasize that, although ablation of PLN phosphorylation does not affect basal contractility, it does alter Ca2+ handling and mechanical performance under stress situations. (c) 2006 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.