The multifunctional Ca(2+)/calmodulin-dependent protein kinase II delta (CaMKIIδ) phosphorylates cardiac titin's spring elements.
The multifunctional Ca(2+)/calmodulin-dependent protein kinase II delta (CaMKIIδ) phosphorylates cardiac titin's spring elements.
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DOI：
10.1016/j.yjmcc.2012.11.012
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发表时间：
2013-01
影响因子：
5
通讯作者：
Granzier, Henk L.
中科院分区：
文献类型：
--
作者：
Hidalgo, Carlos G.;Chung, Charles S.;Saripalli, Chandra;Methawasin, Mei;Hutchinson, Kirk R.;Tsaprailis, George;Labeit, Siegfried;Mattiazzi, Alicia;Granzier, Henk L.
基于肌联蛋白的被动刚度是由几种激酶磷酸化位于肌联蛋白的弹性I带区域内的特定弹簧元件后调节的。肌联蛋白是否被钙/钙调蛋白依赖性蛋白激酶II（CaMKII）磷酸化，CaMKII是心脏功能和疾病的重要调节因子，尚未得到解决。这项工作的目的是确定CaMKII δ（心脏中主要的CaMKII亚型）是否磷酸化肌联蛋白，并使用磷酸化测定和质谱法研究哪些肌联蛋白的弹簧元件可能被CaMKII δ靶向。发现CaMKII δ磷酸化小鼠LV皮肤纤维中的肌联蛋白，CaMKII δ位点可以被蛋白磷酸酶1（PP 1）去磷酸化，并且在基线条件下，在完整的离体心脏和皮肤心肌中，约一半的CaMKII δ位点被磷酸化。质谱分析显示，N2B和PEVK片段都被CaMKII δ靶向几个保守的丝氨酸残基。在几种条件下使用反向磷酸化测定和CaMKII δ位点的磷酸化特异性抗体测试CaMKII δ对肌联蛋白的磷酸化是否在体内发生。全脑缺血后再灌注增加肌联蛋白上CaMKII δ位点的磷酸化水平，这种作用可被CaMKII抑制剂KN-93消除。未发现PEVK元件的磷酸化水平的变化，表明IR中肌联蛋白磷酸化水平的增加可能是由于N2B元件的磷酸化。这些研究的结果首次表明，肌联蛋白可以在体外和体内被CaMK II δ磷酸化，并且肌联蛋白的决定舒张刚度的分子弹簧区域是CaMK II δ的靶点。
Titin-based passive stiffness is post-translationally regulated by several kinases that phosphorylate specific spring elements located within titin’s elastic I-band region. Whether titin is phosphorylated by calcium/calmodulin dependent protein kinase II (CaMKII), an important regulator of cardiac function and disease, has not been addressed. The aim of this work was to determine whether CaMKIIδ, the predominant CaMKII isoform in the heart, phosphorylates titin, and to use phosphorylation assays and mass spectrometry to study which of titin’s spring elements might be targeted by CaMKIIδ. It was found that CaMKIIδ phosphorylates titin in mouse LV skinned fibers, that the CaMKIIδ sites can be dephosphorylated by protein phosphatase 1 (PP1), and that under baseline conditions, in both intact isolated hearts and skinned myocardium, about half of the CaMKIIδ sites are phosphorylated. Mass spectrometry revealed that both the N2B and PEVK segments are targeted by CaMKIIδ at several conserved serine residues. Whether phosphorylation of titin by CaMKIIδ occurs in vivo, was tested in several conditions using back phosphorylation assays and phospho-specific antibodies to CaMKIIδ sites. Reperfusion following global ischemia increased the phosphorylation level of CaMKIIδ sites on titin and this effect was abolished by the CaMKII inhibitor KN-93. No changes in the phosphorylation level of the PEVK element were found suggesting that the increased phosphorylation level of titin in IR might be due to phosphorylation of the N2B element. The findings of these studies show for the first time that titin can be phosphoryalated by CaMKIIδ, both in vitro and in vivo, and that titin’s molecular spring region that determines diastolic stiffness is a target of CaMKIIδ.
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影响因子：
20.1
作者：
Hidalgo C;Hudson B;Bogomolovas J;Zhu Y;Anderson B;Greaser M;Labeit S;Granzier H
通讯作者：
Granzier H
影响因子：
5
作者：
Chung CS;Granzier HL
通讯作者：
Granzier HL
影响因子：
20.1
作者：
Granzier HL;Radke MH;Peng J;Westermann D;Nelson OL;Rost K;King NM;Yu Q;Tschöpe C;McNabb M;Larson DF;Labeit S;Gotthardt M
通讯作者：
Gotthardt M
影响因子：
--
作者：
Chung CS;Bogomolovas J;Gasch A;Hidalgo CG;Labeit S;Granzier HL
通讯作者：
Granzier HL
影响因子：
3.4
作者：
Granzier, H;Helmes, M;Trombitas, K
通讯作者：
Trombitas, K