GSK3&bgr; Phosphorylates Newly Identified Site in the Proline-Alanine–Rich Region of Cardiac Myosin–Binding Protein C and Alters Cross-Bridge Cycling Kinetics in Human: Short Communication
GSK3&bgr; Phosphorylates Newly Identified Site in the Proline-Alanine–Rich Region of Cardiac Myosin–Binding Protein C and Alters Cross-Bridge Cycling Kinetics in Human: Short Communication
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GSK3&bgr; 磷酸化心脏肌球蛋白结合蛋白 C 富含脯氨酸丙氨酸的区域中新发现的位点并改变人类的跨桥循环动力学：短通讯
DOI：
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发表时间：
2012
影响因子：
20.1
通讯作者：
J. van der Velden
中科院分区：
文献类型：
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作者：
D. Kuster;V. Sequeira;A. Najafi;N. Boontje;P. Wijnker;E. R. Witjas;Steven B Marston;C. D. dos Remedios;L. Carrier;Jeroen A. A. Demmers;C. Redwood;S. Sadayappan;J. van der Velden
理由：心肌肌球蛋白结合蛋白 C (cMyBP-C) 调节跨桥循环动力学，从而微调心肌收缩和舒张的速率。它对心脏动力学的影响通过磷酸化而改变。体内已鉴定出三个磷酸化位点（Ser275、Ser284 和 Ser304），全部位于 cMyBP-C 的心脏特异性 M 结构域中。然而，最近的研究表明，人类 cMyBP-C 中存在多达 4 个磷酸基团。目的：鉴定并表征人 cMyBP-C 中的其他磷酸化位点。方法和结果：Cardiac MyBP-C 是从人心脏组织中半纯化的。串联质谱分析在 cMyBP-C 的 C0 和 C1 结构域之间富含脯氨酸-丙氨酸的接头序列中的丝氨酸 133 上发现了一个新的磷酸化位点。与已知位点不同，Ser133 不是蛋白激酶 A 的靶标。在硅片激酶预测中显示糖原合成酶激酶 3&bgr; (GSK3&bgr;) 是最有可能磷酸化 Ser133 的激酶。 cMyBP-C 的 C0C2 片段与 GSK3&bgr 的体外孵育Ser133 被磷酸化。此外，GSK3&bgr; Ser304 被磷酸化，尽管与蛋白激酶 A 诱导的 Ser304 磷酸化相比，磷酸化程度较低。葛兰素史克3&bgr;单膜透化的人心肌细胞的治疗显着提高了张力重建的最大速率。结论：GSK3&bgr;在一个新位点上磷酸化 cMyBP-C，该位点位于富含脯氨酸丙氨酸的区域并增加力发展的动力学，表明 GSK3&bgr 具有非典型作用。在肌节水平。 cMyBP-C 接头结构域中 Ser133 的磷酸化可能是调节肌节动力学的新机制。
Rationale: Cardiac myosin–binding protein C (cMyBP-C) regulates cross-bridge cycling kinetics and, thereby, fine-tunes the rate of cardiac muscle contraction and relaxation. Its effects on cardiac kinetics are modified by phosphorylation. Three phosphorylation sites (Ser275, Ser284, and Ser304) have been identified in vivo, all located in the cardiac-specific M-domain of cMyBP-C. However, recent work has shown that up to 4 phosphate groups are present in human cMyBP-C. Objective: To identify and characterize additional phosphorylation sites in human cMyBP-C. Methods and Results: Cardiac MyBP-C was semipurified from human heart tissue. Tandem mass spectrometry analysis identified a novel phosphorylation site on serine 133 in the proline-alanine–rich linker sequence between the C0 and C1 domains of cMyBP-C. Unlike the known sites, Ser133 was not a target of protein kinase A. In silico kinase prediction revealed glycogen synthase kinase 3&bgr; (GSK3&bgr;) as the most likely kinase to phosphorylate Ser133. In vitro incubation of the C0C2 fragment of cMyBP-C with GSK3&bgr; showed phosphorylation on Ser133. In addition, GSK3&bgr; phosphorylated Ser304, although the degree of phosphorylation was less compared with protein kinase A–induced phosphorylation at Ser304. GSK3&bgr; treatment of single membrane–permeabilized human cardiomyocytes significantly enhanced the maximal rate of tension redevelopment. Conclusions: GSK3&bgr; phosphorylates cMyBP-C on a novel site, which is positioned in the proline-alanine–rich region and increases kinetics of force development, suggesting a noncanonical role for GSK3&bgr; at the sarcomere level. Phosphorylation of Ser133 in the linker domain of cMyBP-C may be a novel mechanism to regulate sarcomere kinetics.
影响因子：
5
作者：
Copeland, O'Neal;Sadayappan, Sakthivel;Marston, Steven B.
通讯作者：
Marston, Steven B.
影响因子：
5
作者：
Govindan S;McElligott A;Muthusamy S;Nair N;Barefield D;Martin JL;Gongora E;Greis KD;Luther PK;Winegrad S;Henderson KK;Sadayappan S
通讯作者：
Sadayappan S