Oxidant-induced activation of type I protein kinase a is mediated by RI subunit interprotein disulfide bond formation
Oxidant-induced activation of type I protein kinase a is mediated by RI subunit interprotein disulfide bond formation
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DOI：
10.1074/jbc.m603952200
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发表时间：
2006-08-04
影响因子：
4.8
通讯作者：
Eaton, Philip
中科院分区：
文献类型：
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作者：
Brennan, Jonathan P.;Bardswell, Sonya C.;Eaton, Philip
在这里，我们证明 I 型蛋白激酶 A 具有氧化还原活性，响应细胞过氧化氢，在其两个调节 RI 亚基之间形成蛋白间二硫键。这种氧化二硫键的形成导致亚细胞易位和激酶激活，导致已建立的底物蛋白磷酸化。这种易位至少部分是由对 α-肌球蛋白重链具有增强亲和力的激酶的氧化形式介导的，该激酶充当蛋白激酶 A (PKA) 锚定蛋白，并将 PKA 定位于其肌丝底物肌钙蛋白 I 和肌球蛋白结合蛋白 C。这些事件在心肌细胞中的功能性结果是，过氧化氢独立于以下因素增加收缩性： β-肾上腺素能刺激和 cAMP 升高。氧化剂诱导的底物蛋白磷酸化和收缩性增加被激酶抑制剂 H89 阻断，表明这些事件涉及 PKA 激活。本质上，I 型 PKA 含有充当氧化还原传感器的蛋白质硫醇，它们被过氧化氢氧化直接激活激酶。
Here we demonstrate that type I protein kinase A is redoxactive, forming an interprotein disulfide bond between its two regulatory RI subunits in response to cellular hydrogen peroxide. This oxidative disulfide formation causes a subcellular translocation and activation of the kinase, resulting in phosphorylation of established substrate proteins. The translocation is mediated at least in part by the oxidized form of the kinase having an enhanced affinity for alpha-myosin heavy chain, which serves as a protein kinase A ( PKA) anchor protein and localizes the PKA to its myofilament substrates troponin I and myosin binding protein C. The functional consequence of these events in cardiac myocytes is that hydrogen peroxide increases contractility independently of beta-adrenergic stimulation and elevations of cAMP. The oxidant-induced phosphorylation of substrate proteins and increased contractility is blocked by the kinase inhibitor H89, indicating that these events involve PKA activation. In essence, type I PKA contains protein thiols that operate as redox sensors, and their oxidation by hydrogen peroxide directly activates the kinase.