cAMP-dependent protein kinase phosphorylation produces interdomain movement in SUR2B leading to activation of the vascular KATP channel
cAMP-dependent protein kinase phosphorylation produces interdomain movement in SUR2B leading to activation of the vascular KATP channel
复制标题
DOI：
10.1074/jbc.m709941200
复制
发表时间：
2008-03-21
影响因子：
4.8
通讯作者：
Harrison, Robert W.
中科院分区：
文献类型：
--
作者：
Shi, Yun;Chen, Xianfeng;Harrison, Robert W.
血管atp敏感的K+通道通过PKA被多种血管舒张激素和神经递质激活。在SUR2B亚基的第二个核苷酸结合域（NBD2）中发现了一个关键的PKA磷酸化位点（Ser-1387）。为了了解Ser-1387的磷酸化如何导致通道活性的变化，我们使用新结晶的ABC蛋白SAV1866对SUR2B进行了建模。模型显示Ser-1387位于NBD2与TMD1的交界面上，并与TMD1中的tyr506发生物理相互作用。在Ser-1387附近的NBD2中发现了一个带正电的残基Arg-1462。这三种残基中的任何一种的突变都会消除pka依赖的通道激活。分子动力学模拟表明，Ser-1387、tyrr -506和Arg-1462在Ser-1387磷酸化后形成紧密的三联体，导致NBD2界面重塑和NBD2和TMD1的移动。通过设计TMD1和NBD2之间的二硫键来限制结构域间的运动，以氧化还原依赖的方式阻止通道激活。因此，通过提高Ser-1387磷酸化后NBD-TMD偶联效率，提出了一种通道门控机制，该机制由多种血管扩张剂共享。
Vascular ATP-sensitive K+ channels are activated by multiple vasodilating hormones and neurotransmitters via PKA. A critical PKA phosphorylation site (Ser-1387) is found in the second nucleotide-binding domain (NBD2) of the SUR2B subunit. To understand how phosphorylation at Ser-1387 leads to changes in channel activity, we modeled the SUR2B using a newly crystallized ABC protein SAV1866. The model showed that Ser-1387 was located on the interface of NBD2 with TMD1 and physically interacted with Tyr-506 in TMD1. A positively charged residue (Arg-1462) in NBD2 was revealed in the close vicinity of Ser-1387. Mutation of either of these three residues abolished PKA-dependent channel activation. Molecular dynamics simulations suggested that Ser-1387, Tyr-506, and Arg-1462 formed a compact triad upon Ser-1387 phosphorylation, leading to reshaping of the NBD2 interface and movements of NBD2 and TMD1. Restriction of the interdomain movements by engineering a disulfide bond between TMD1 and NBD2 prevented the channel activation in a redox-dependent manner. Thus, a channel-gating mechanism is suggested through enhancing the NBD-TMD coupling efficiency following Ser-1387 phosphorylation, which is shared by multiple vasodilators.