1. The peroxisome counteracts oxidative stresses by suppressing catalase import via Pex14 phosphorylation
- Author
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Kanji Okumoto, Mahmoud El Shermely, Masanao Natsui, Hidetaka Kosako, Ryuichi Natsuyama, Toshihiro Marutani, and Yukio Fujiki
- Subjects
catalase ,Pex14 ,peroxisomal protein import ,phosphorylation ,hydrogen peroxide ,oxidative stress ,Medicine ,Science ,Biology (General) ,QH301-705.5 - Abstract
Most of peroxisomal matrix proteins including a hydrogen peroxide (H2O2)-decomposing enzyme, catalase, are imported in a peroxisome-targeting signal type-1 (PTS1)-dependent manner. However, little is known about regulation of the membrane-bound protein import machinery. Here, we report that Pex14, a central component of the protein translocation complex in peroxisomal membrane, is phosphorylated in response to oxidative stresses such as H2O2 in mammalian cells. The H2O2-induced phosphorylation of Pex14 at Ser232 suppresses peroxisomal import of catalase in vivo and selectively impairs in vitro the interaction of catalase with the Pex14-Pex5 complex. A phosphomimetic mutant Pex14-S232D elevates the level of cytosolic catalase, but not canonical PTS1-proteins, conferring higher cell resistance to H2O2. We thus suggest that the H2O2-induced phosphorylation of Pex14 spatiotemporally regulates peroxisomal import of catalase, functioning in counteracting action against oxidative stress by the increase of cytosolic catalase.
- Published
- 2020
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