Redox Biology (Jan 2020)

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

  • Stefano Bestetti,
  • Mauro Galli,
  • Ilaria Sorrentino,
  • Paolo Pinton,
  • Alessandro Rimessi,
  • Roberto Sitia,
  • Iria Medraño-Fernandez

Journal volume & issue
Vol. 28

Abstract

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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. Keywords: Aquaporins, Peroxiporins, Hydrogen peroxide, Membrane permeability, Endoplasmic reticulum, Redox homeostasis