Gene

Cytoplasm

Cell biology

Biology

Regulator

Cytosol

STIM1

Biochemistry

Endoplasmic reticulum

Downregulation and upregulation

Organelle

Intracellular

Organic chemistry

Membrane

Aquaporin

Enzyme

Mitochondrion

Subcellular localization

Chemistry

Flux (metallurgy)

Redox Biology

Hydrogen peroxide (H2O2) is an essential second intracellular messenger. To reach its targets in the cytosol, H2O2 must cross a membrane, a feat that requires aquaporins (AQP) endowed with 'peroxiporin' activity (AQP3, AQP8, AQP9). Here, we exploit different organelle-targeted H2O2-sensitive probes to show that also AQP11 efficiently conduits H2O2. Unlike other peroxiporins, AQP11 is localized in the endoplasmic reticulum (ER), accumulating partly in mitochondrial-associated ER membranes (MAM). Its downregulation severely perturbs the flux of H2O2 through the ER, but not through the mitochondrial or plasma membranes. These properties make AQP11 a potential regulator of ER redox homeostasis and signaling.

Human aquaporin-11 guarantees efficient transport of H2O2 across the endoplasmic reticulum membrane