Kv4.2 phosphorylation by PKA drives Kv4.2-KChIP2 dissociation, leading to Kv4.2 out of lipid rafts and internalization
Kv4.2 phosphorylation by PKA drives Kv4.2-KChIP2 dissociation, leading to Kv4.2 out of lipid rafts and internalization
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DOI：
10.1152/ajpcell.00307.2021
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发表时间：
2022-07-01
影响因子：
5.5
通讯作者：
Liu，Jie
中科院分区：
文献类型：
--
作者：
Li，Ying;Duan，Haixia;Liu，Jie
Kv4.2 瞬时外向钾电流 (Ito) 的交感神经调节对于生理和病理条件下心肌的急性电和收缩反应至关重要。先前的研究表明，Kv4 通道的关键辅助亚基 KChIP2 是 Kv4.2 电流密度的交感调节所必需的。有趣的是，Kv4.2 和 KChIP2 以及介导急性交感信号转导的关键成分存在于脂筏中，脂筏与大鼠心室肌细胞 Ito 密度的调节密切相关。然而，人们对 Kv4.2-raft 关联的机制及其与急性交感神经调节的联系知之甚少。借助高分辨率荧光显微镜，我们证明 KChIP2 协助 Kv4.2 在 HEK293 细胞的脂筏中定位。此外，PKA 介导的 Kv4.2 磷酸化（急性交感神经刺激的下游信号传导事件）诱导 Kv4.2 和 KChIP2 之间的解离，导致 Kv4.2 从 KChIP2 表达的 HEK293 中的脂筏中移出。通过 PKA 模拟 Kv4.2 磷酸化的突变 (K4.2-S552D) 类似地破坏了 Kv4.2 与 KChIP2 的相互作用，并且还降低了 Kv4.2 的表面稳定性。在用去氧肾上腺素 (PE) 急性肾上腺素刺激后，在天然新生大鼠心室肌细胞 (NRVM) 中也观察到减弱的 Kv4.2-KChIP2 相互作用。此外，PE 刺激减少了 Kv4.2 在脂筏上的位置，并诱导 Kv4.2 的内化以及脂筏破坏的效果。总之，KChIP2 有助于将 Kv4.2 靶向脂筏。急性肾上腺素能刺激诱导Kv4.2-KChIP2解离，导致Kv4.2脱离脂筏并内化，增强了Kv4.2-脂筏关联在Itoto急性交感神经调节的基本生理反应中的关键作用。
Sympathetic regulation of the Kv4.2 transient outward potassium current (Ito) is critical for the acute electrical and contractile response of the myocardium under physiological and pathological conditions. Previous studies have suggested that KChIP2, the key auxiliary subunit of Kv4 channels, is required for the sympathetic regulation of Kv4.2 current densities. Of interest, Kv4.2 and KChIP2, and key components mediating acute sympathetic signaling transduction are present in lipid rafts, which are profoundly involved in regulation ofItodensities in rat ventricular myocytes. However, little is known about the mechanisms of Kv4.2-raft association and its connection with acute sympathetic regulation. With the aid of high-resolution fluorescent microscope, we demonstrated that KChIP2 assisted Kv4.2 localization in lipid rafts in HEK293 cells. Moreover, PKA-mediated Kv4.2 phosphorylation, the downstream signaling event of acute sympathetic stimulation, induced dissociation between Kv4.2 and KChIP2, resulting in Kv4.2 shifting out of lipid rafts in KChIP2-expressed HEK293. The mutation that mimics Kv4.2 phosphorylation by PKA (K4.2-S552D) similarly disrupted Kv4.2 interaction with KChIP2 and also decreased the surface stability of Kv4.2. The attenuated Kv4.2-KChIP2 interaction was also observed in native neonatal rat ventricular myocytes (NRVMs) upon acute adrenergic stimulation with phenylephrine (PE). Furthermore, PE stimulation decreased Kv4.2 location at lipid rafts and induced internalization of Kv4.2 as well as the effect of lipid rafts disruption. In conclusion, KChIP2 contributes to targeting Kv4.2 to lipid rafts. Acute adrenergic stimulation induces Kv4.2-KChIP2 dissociation, leading to Kv4.2 out of lipid rafts and internalization, reinforcing the critical role of Kv4.2-lipid raft association in the essential physiological response ofItoto acute sympathetic regulation.