Alexander Tyler D, Tymanskyj Stephen, Kennedy Kyle J, Kaczmarek Leonard K, Covarrubias Manuel
Department of Neuroscience, Farber Institute for Neuroscience and Jefferson Synaptic Biology Center, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA 19107.
Department of Pharmacology, Yale School of Medicine, Yale University, New Haven, CT 06510.
Proc Natl Acad Sci U S A. 2025 Jan 7;122(1):e2411033121. doi: 10.1073/pnas.2411033121. Epub 2024 Dec 31.
Use-dependent spike broadening (UDSB) results from inactivation of the voltage-gated K (Kv) channels that regulate the repolarization of the action potential. However, the specific signaling and molecular processes that modulate UDSB have remained elusive. Here, we applied an adeno-associated viral vector approach and dynamic clamping to conclusively demonstrate how multisite phosphorylation of the N-terminal inactivation domain (NTID) of the Kv3.4 channel modulates UDSB in rat dorsal root ganglion (DRG) neurons. The Kv3.4 phosphonull variant promotes slow recovery from inactivation, cumulative inactivation, and UDSB. In contrast, the Kv3.4 phosphomimic variant promotes fast recovery from inactivation and robust resistance to cumulative inactivation and UDSB. Furthermore, knocking down Kv3.4 maximizes AP width and eliminates UDSB modulation. Together with the evidence from previous work, the results concretely suggest how dynamic UDSB modulation governed by multisite phosphorylation of the NTID of Kv3.4 in DRG neurons may play a significant role in mechanosensory transduction and pain modulation.
使用依赖性峰电位展宽（UDSB）源于调节动作电位复极化的电压门控钾（Kv）通道的失活。然而，调节UDSB的具体信号传导和分子过程仍不清楚。在这里，我们应用腺相关病毒载体方法和动态钳制来最终证明Kv3.4通道N端失活结构域（NTID）的多位点磷酸化如何调节大鼠背根神经节（DRG）神经元中的UDSB。Kv3.4磷酸化缺失变体促进失活后的缓慢恢复、累积失活和UDSB。相反，Kv3.4磷酸化模拟变体促进失活后的快速恢复以及对累积失活和UDSB的强大抗性。此外，敲低Kv3.4可使动作电位宽度最大化并消除UDSB调节。结合先前工作的证据，这些结果具体表明DRG神经元中由Kv3.4的NTID多位点磷酸化控制的动态UDSB调节如何在机械感觉转导和疼痛调节中发挥重要作用。
