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Updated: Jul 8, 2025

Assessing Lysosomal Alkalinization in the Intestine of Live Caenorhabditis elegans
Published on: April 13, 2018
Loss of Dja2 accompanies pH deviation in lysosomes and lysosome-related organelles
Kazutoyo Terada1, Motoyoshi Endo1, Hiroshi Kiyonari2
1Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Abstract:
The Dja2 knockout (Dja2-/- ) mice had respiratory distress, and >60% died within 2 days after birth. The surviving adult Dja2-/- mice were infertile and the lungs of Dja2-/- mice showed several abnormalities, including the processing defect of prosurfactant protein C in the alveolar epithelial type II cells and the accumulation of glycolipids in enlarged alveolar macrophages. The luminal pH of acidic organelles in Dja2-/- cells was shifted to pH 5.37-5.45. This deviated pH was immediately restored to control levels (pH 4.56-4.65) by the addition of a diuretic, ethyl isopropyl amiloride (EIPA). Although the role of DJA2 in maintaining the pH homeostasis of lysosome-related organelles is currently obscure, this rapid and remarkable pH resilience is best explained by an EIPA-sensitive proton efflux machinery that is disorganized and overactivated due to the loss of Dja2.
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