Protein kinase D increases maximal Ca2+-activated tension of cardiomyocyte contraction by phosphorylation of cMyBP-C-Ser315
Protein kinase D increases maximal Ca2+-activated tension of cardiomyocyte contraction by phosphorylation of cMyBP-C-Ser315
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DOI：
10.1152/ajpheart.00749.2011
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发表时间：
2012-08-01
影响因子：
4.8
通讯作者：
Luiken, Joost J. F. P.
中科院分区：
文献类型：
--
作者：
Dirkx, Ellen;Cazorla, Olivier;Luiken, Joost J. F. P.
Dirkx E，卡佐拉O，Schwenk RW，Lorenzen-Schmidt I，Sadayappan S，货车Lint J，Carrier L，货车Eys GJ，Glatz JF，Luiken JJ.蛋白激酶D通过cMyBP-C-Ser的磷酸化增加心肌细胞收缩的最大Ca 2+激活张力（315）。Am J Physiol Heart Circ Physiol 303：H323-H331，2012。首次出版于2012年5月25日; doi：10.1152/ajpheart. 00749.2011.-心肌肌球蛋白结合蛋白C（cMyBP-C）参与心肌肌丝收缩的调节。最近的证据表明，蛋白激酶D（PKD）是磷酸化cMyBP-C的激酶之一。然而，PKD诱导的cMyBP-C磷酸化影响心脏收缩反应的机制尚不清楚。使用免疫沉淀，我们发现，在收缩心肌细胞中，PKD与cMyBP-C结合并在Ser（315）处磷酸化。在从野生型（WT）和cMyBP-C敲除（KO）小鼠分离的透化心室肌细胞中研究PKD介导的cMyBP-C磷酸化对心肌肌丝功能的影响，在全长活性PKD存在下孵育。在WT心肌细胞中，PKD增加肌丝Ca 2+敏感性（pCa（50））和最大Ca 2+激活收缩张力（Tmax）。在cMyBP-C KO皮肤的肌细胞中，PKD增加pCa（50），但不改变Tmax。这表明cMyBP-C不参与PKD介导的肌丝对Ca 2+的敏化，但对于PKD诱导的Tmax增加是必需的。此外，PKD-Ser（916）和cMyBP-C-Ser（315）的磷酸化都是收缩频率依赖性的，表明PKD介导的cMyBP-C磷酸化主要在收缩活动增加期间起作用。因此，在高收缩频率期间，PKD通过增加Ca 2+敏感性和通过cMyBP-C的磷酸化增加Tmax来促进心肌细胞的收缩。
Dirkx E, Cazorla O, Schwenk RW, Lorenzen-Schmidt I, Sadayappan S, Van Lint J, Carrier L, van Eys GJ, Glatz JF, Luiken JJ. Protein kinase D increases maximal Ca2+-activated tension of cardiomyocyte contraction by phosphorylation of cMyBP-C-Ser(315). Am J Physiol Heart Circ Physiol 303: H323-H331, 2012. First published May 25, 2012; doi:10.1152/ajpheart. 00749.2011.-Cardiac myosin-binding protein C (cMyBP-C) is involved in the regulation of cardiac myofilament contraction. Recent evidence showed that protein kinase D (PKD) is one of the kinases that phosphorylate cMyBP-C. However, the mechanism by which PKD-induced cMyBP-C phosphorylation affects cardiac contractile responses is not known. Using immunoprecipitation, we showed that, in contracting cardiomyocytes, PKD binds to cMyBP-C and phosphorylates it at Ser(315). The effect of PKD-mediated phosphorylation of cMyBP-C on cardiac myofilament function was investigated in permeabilized ventricular myocytes, isolated from wild-type (WT) and from cMyBP-C knockout (KO) mice, incubated in the presence of full-length active PKD. In WT myocytes, PKD increased both myofilament Ca2+ sensitivity (pCa(50)) and maximal Ca2+-activated tension of contraction (Tmax). In cMyBP-C KO skinned myocytes, PKD increased pCa(50) but did not alter T-max. This suggests that cMyBP-C is not involved in PKD-mediated sensitization of myofilaments to Ca2+ but is essential for PKD-induced increase in T-max. Furthermore, the phosphorylation of both PKD-Ser(916) and cMyBP-C-Ser(315) was contraction frequency-dependent, suggesting that PKD-mediated cMyBP-C phosphorylation is operational primarily during periods of increased contractile activity. Thus, during high contraction frequency, PKD facilitates contraction of cardiomyocytes by increasing Ca2+ sensitivity and by an increased Tmax through phosphorylation of cMyBP-C.