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

Biomed Res Int. 2020 Sep 9:2020:9692503. doi: 10.1155/2020/9692503. eCollection 2020.

Abstract

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 (AbPI4K).

Results: We found that PAO and AbPI4K significantly abrogated RE kinetics. Infusion of PI(4,5)P2 through the patch pipette potentiated RE kinetics and reversed PAO- and AbPI4K-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.

MeSH terms

  • Arsenicals / metabolism
  • Calcium / metabolism
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Chromaffin Cells / drug effects
  • Chromaffin Cells / metabolism*
  • Chromaffin Cells / physiology*
  • Clathrin / metabolism
  • Dithiothreitol / pharmacology
  • Endocytosis / drug effects
  • Endocytosis / physiology*
  • Kinetics
  • Phosphatidylinositol 4,5-Diphosphate / metabolism*
  • Phosphatidylinositols / metabolism
  • Signal Transduction / drug effects
  • Signal Transduction / physiology

Substances

  • Arsenicals
  • Clathrin
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphatidylinositols
  • oxophenylarsine
  • Calcium
  • Dithiothreitol