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bioRxiv · 10.1101/2022.08.30.505925

PIP2 and Ca2+ regulation of TMEM16A currents in excised inside-out patches

Tembo, M.·Lara-Santos, C.·Rosenbaum, J. C.·Carlson, A. E.
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Abstract

The Ca2+ activated Cl- channel formed by transmembrane member 16A (TMEM16A) is broadly expressed and regulates diverse processes. In addition to Ca2+, TMEM16A channels require the acidic phospholipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) to open. Like other channels regulated by PI(4,5)P2, TMEM16A-conducted currents recorded in excised patches slowly decay overtime. Here we assessed how intracellular Ca2+ alters the rate of this current rundown, using the channels endogenously expressed in oocytes from the African clawed frog, Xenopus laevis. We found that in excised, inside-out patches, the concentration of applied Ca2+ alters the rate of rundown, with high Ca2+ concentrations speeding rundown by activating membrane associated phospholipase C (PLC). Together, these results clarify our understanding of how Ca2+ regulates both TMEM16A directly, and targets PLC to regulate the membrane PI(4,5)P2 content.

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Tembo, M., Lara-Santos, C., Rosenbaum, J. C., Carlson, A. E.. 2022-09-02. PIP2 and Ca2+ regulation of TMEM16A currents in excised inside-out patches. https://doi.org/10.1101/2022.08.30.505925

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