Details

Autor(en) / Beteiligte

• Shibata, Michitaro
• Oikawa, Kazusato
• Yoshimoto, Kohki
• Kondo, Maki
• Mano, Shoji
• Yamada, Kenji
• Hayashi, Makoto
• Sakamoto, Wataru
• Ohsumi, Yoshinori
• Nishimura, Mikio

Titel

Highly Oxidized Peroxisomes Are Selectively Degraded via Autophagy in Arabidopsis

Ist Teil von

• The Plant cell, 2013-12, Vol.25 (12), p.4967-4983

Ort / Verlag

United States: American Society of Plant Biologists

Erscheinungsjahr

2013

Quelle

MEDLINE

Beschreibungen/Notizen

• The positioning of peroxisomes in a cell is a regulated process that is closely associated with their functions. Using this feature of the peroxisomal positioning as a criterion, we identified three Arabidopsis thaliana mutants (peroxisome unusual positioning1 [peup1], peup2, and peup4) that contain aggregated peroxisomes. We found that the PEUP1, PEUP2, and PEUP4 were identical to Autophagy-related2 (A7G2), ATG18a, and ATG7, respectively, which are involved in the autophagic system. The number of peroxisomes was increased and the peroxisomal proteins were highly accumulated in the peupi mutant, suggesting that peroxisome degradation by autophagy (pexophagy) is deficient in the peup1 mutant. These aggregated peroxisomes contained high levels of inactive catalase and were more oxidative than those of the wild type, indicating that peroxisome aggregates comprise damaged peroxisomes. In addition, peroxisome aggregation was induced in wild-type plants by exogenous application of hydrogen peroxide. The cat2 mutant also contained peroxisome aggregates. These findings demonstrate that hydrogen peroxide as a result of catalase inactivation is the inducer of peroxisome aggregation. Furthermore, an autophagosome marker, ATG8, frequently colocalized with peroxisome aggregates, indicating that peroxisomes damaged by hydrogen peroxide are selectively degraded by autophagy in the wild type. Our data provide evidence that autophagy is crucial for quality control mechanisms for peroxisomes in Arabidopsis.