Regulated exocytosis: Renal Aquaporin-2 3D Vesicular Network Organization and Association with F-actin

Mikkel Roland Holst, Louis Gammelgaard Jensen, Jesse Aaron, Frédéric H. Login, Sampavi Rajkumar, Ute Hahn, Lene Niemann Nejsum

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Abstract

Regulated vesicle exocytosis is a key response to extracellular stimuli in diverse physiological processes, including hormone regulated short-term urine concentration. In the renal collecting duct, the water channel aquaporin-2 (AQP2) localizes to the apical plasma membrane as well as to small, subapical vesicles. In response to stimulation with the antidiuretic hormone, arginine vasopressin, aquaporin-2-containing vesicles fuse with the plasma membrane, which increases collecting duct water reabsorption and thus, urine concentration. The nanoscale size of these vesicles has limited analysis of their three-dimensional (3D) organization. Using a cell system combined with 3D superresolution microscopy, we provide the first direct analysis of the 3D network of aquaporin-2-containing exocytic vesicles in a cell culture system. We show that aquaporin-2 vesicles are 43 ± 3 nm in diameter, a size similar to synaptic vesicles, and that one fraction of AQP2 vesicles localized with the subcortical F-actin layer and the other localized in between the F-actin layer and the plasma membrane. Aquaporin-2 vesicles associated with F-actin and this association were enhanced in a serine 256 phospho-mimic of aquaporin-2, whose phosphorylation is a key event in antidiuretic hormone-mediated aquaporin-2 vesicle exocytosis.

Original languageEnglish
JournalAmerican Journal of Physiology: Cell Physiology
Volume321
Issue6
Pages (from-to)1060-1069
Number of pages10
ISSN0363-6143
DOIs
Publication statusPublished - Dec 2021

Keywords

  • AQP2
  • Aquaporin-2
  • IPALM
  • MDCK
  • Superresolution

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