Synergistic interplay of Gβγ and phosphatidylinositol 4,5-bisphosphate dictates Kv7.4 channel activity

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• 作者：Oleksandr V. Povstyan ; Vincenzo Barrese…
• 关键词：Potassium channel ; KCNQ ; PIP2 ; G ; protein βγ ; Ion channel regulation
• 刊名：Pflügers Archiv - European Journal of Physiology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：469
• 期：2
• 页码：213-223
• 全文大小：3119KB
• 刊物主题：Human Physiology; Molecular Medicine; Neurosciences; Cell Biology; Receptors;
• 出版者：Springer Berlin Heidelberg
• ISSN：1432-2013
• 卷排序：469

文摘

Kv7.4 channels are key determinants of arterial contractility and cochlear mechanosensation that, like all Kv7 channels, have an obligatory requirement for phosphatidylinositol 4,5-bisphosphate (PIP₂). βγ G proteins (Gβγ) have been identified as novel positive regulators of Kv7.4. The present study ascertained whether Gβγ increased Kv7.4 open probability through an increased sensitivity to PIP₂. In HEK cells stably expressing Kv7.4, PIP₂ or Gβγ increased open probability in a concentration dependent manner. Depleting PIP₂ prevented any Gβγ-mediated stimulation whilst an array of Gβγ inhibitors prohibited any PIP₂-induced current enhancement. A combination of PIP₂ and Gβγ at sub-efficacious concentrations increased channel open probability considerably. The stimulatory effects of three Kv7.2-7.5 channel activators were also lost by PIP₂ depletion or Gβγ inhibitors. This study alters substantially our understanding of the fundamental processes that dictate Kv7.4 activity, revealing a more complex and subtle paradigm where the reliance on local phosphoinositide is dictated by interaction with Gβγ.