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

TY - JOUR

T1 - Regulated exocytosis: Renal Aquaporin-2 3D Vesicular Network Organization and Association with F-actin

AU - Holst, Mikkel Roland

AU - Jensen, Louis Gammelgaard

AU - Aaron, Jesse

AU - Login, Frédéric H.

AU - Rajkumar, Sampavi

AU - Hahn, Ute

AU - Nejsum, Lene Niemann

PY - 2021/12

Y1 - 2021/12

N2 - 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.

AB - 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.

KW - AQP2

KW - Aquaporin-2

KW - IPALM

KW - MDCK

KW - Superresolution

UR - http://www.scopus.com/inward/record.url?scp=85120066267&partnerID=8YFLogxK

U2 - 10.1152/ajpcell.00255.2021

DO - 10.1152/ajpcell.00255.2021

M3 - Journal article

C2 - 34432538

SN - 0363-6143

VL - 321

SP - 1060

EP - 1069

JO - American Journal of Physiology: Cell Physiology

JF - American Journal of Physiology: Cell Physiology

IS - 6

ER -