Phosphatidylinositol-4,5-Biphosphate (PI(4,5)P₂) Is Required for Rapid Endocytosis in Chromaffin Cells

Objective. Phosphoinositides play a regulatory role in clathrin-mediated endocytosis. However, their involvement in clathrin-independent endocytosis termed rapid endocytosis (RE), which is the mode of vesicle recycling during neurotransmitter release by transient fusion (known as kiss-and-run), has not been investigated. Here, we used patch-clamp recording of whole-cell membrane capacitance in adrenal chromaffin cells (ACC) to monitor changes of RE kinetics in response to pharmacological alteration of phosphatidylinositol-4,5-biphosphate (PI(4,5)P₂) level by phenylarsine oxide (PAO) or antibody against phosphatidylinositol 4-kinase (Ab_PI4K). Results. We found that PAO and Ab_PI4K significantly abrogated RE kinetics. Infusion of PI(4,5)P₂ through the patch pipette potentiated RE kinetics and reversed PAO- and Ab_PI4K-induced blockade of RE. Similarly, the application of the bifunctional thiol dithiothreitol (DTT) to PAO-treated cells completely prevented the inhibitory effect of PAO on RE. These findings indicate that PI(4,5)P₂ is implicated in the signaling (mechanistic) process of RE in ACC.

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Published in: BioMed Research International
License: http://creativecommons.org/licenses/by/4.0
See article on publisher's website: http://dx.doi.org/10.1155/2020/9692503