Myofibril growth during cardiac hypertrophy is regulated through dual phosphorylation and acetylation of the actin capping protein CapZ.
Myofibril growth during cardiac hypertrophy is regulated through dual phosphorylation and acetylation of the actin capping protein CapZ.
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DOI：
10.1016/j.cellsig.2016.05.011
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发表时间：
2016-08
影响因子：
4.8
通讯作者：
Russell B
中科院分区：
文献类型：
--
作者：
Lin YH;Warren CM;Li J;McKinsey TA;Russell B
由机械负荷增加而在心肌中启动的机械转导信号通路被认为会导致长期的转录变化和肥大，但在肌节水平上的快速适应事件还不完全清楚。本研究的目的是验证心肌细胞生长过程中肌动蛋白细丝组装受CAPZβ1翻译后修饰(PTM)调控的假说。在苯肾上腺素(PE)刺激的快速肥大的新生大鼠心室肌细胞中，CAPZβ1的双向凝胶电泳(2DGE)显示其向更多的负电荷转变。与此一致的是，质谱仪检测到CAPZβ1在丝氨酸-2 0 4和赖氨酸-199上的磷酸化和乙酰化，这两个残基位于CAPZβ1的肌动蛋白结合面附近。在NRVM中异位表达显性负的ε(dnPKCε)可以钝化PE诱导的CAPZ动力学增加，光漂白后荧光恢复的动力学常数(KFRAP)证实了这一点，同时减少了CAPZβ1的磷酸化和乙酰化。此外，抑制I类组蛋白去乙酰基酶(HDAC)增加了CAPZβ1上的赖氨酸-199乙酰化，从而增加了CAPZ的KFRAP并刺激了肌动蛋白动力学。最后，我们发现PE处理NRVMs导致了HDAC3与肌原纤维结合的减少，提示了一种信号依赖的调节肌节相关的CAPZβ1乙酰化的机制。综上所述，这种通过CAPZβ1的磷酸化和乙酰化的双重调节为心肌肥厚过程中肌原纤维的生长调控提供了一种新的模型。
The mechanotransduction signaling pathways initiated in heart muscle by increased mechanical loading are known to lead to long-term transcriptional changes and hypertrophy, but the rapid events for adaptation at the sarcomeric level are not fully understood. The goal of this study was to test the hypothesis that actin filament assembly during cardiomyocyte growth is regulated by post-translational modifications (PTMs) of CapZβ1. In rapidly hypertrophying neonatal rat ventricular myocytes (NRVMs) stimulated by phenylephrine (PE), two-dimensional gel electrophoresis (2DGE) of CapZβ1 revealed a shift toward more negative charge. Consistent with this, mass spectrometry identified CapZβ1 phosphorylation on serine-204 and acetylation on lysine-199, two residues which are near the actin binding surface of CapZβ1. Ectopic expression of dominant negative PKCε (dnPKCε) in NRVMs blunted the PE-induced increase in CapZ dynamics, as evidenced by the kinetic constant (Kfrap) of fluorescence recovery after photobleaching (FRAP), and concomitantly reduced phosphorylation and acetylation of CapZβ1. Furthermore, inhibition of class I histone deacetylases (HDACs) increased lysine-199 acetylation on CapZβ1, which increased Kfrap of CapZ and stimulated actin dynamics. Finally, we show that PE treatment of NRVMs results in decreased binding of HDAC3 to myofibrils, suggesting a signal-dependent mechanism for the regulation of sarcomere-associated CapZβ1 acetylation. Taken together, this dual regulation through phosphorylation and acetylation of CapZβ1 provides a novel model for the regulation of myofibril growth during cardiac hypertrophy.