Details

Autor(en) / Beteiligte

• Omi, Sizue
• Nakata, Rie
• Okamura-Ikeda, Kazuko
• Konishi, Hiroaki
• Taniguchi, Hisaaki

Titel

Contribution of Peroxisome-specific Isoform of Lon Protease in Sorting PTS1 Proteins to Peroxisomes

Ist Teil von

• Journal of biochemistry (Tokyo), 2008-05, Vol.143 (5), p.649-660

Ort / Verlag

England: Japanese Biochemical Society

Erscheinungsjahr

2008

Quelle

MEDLINE

Beschreibungen/Notizen

• Using an organelle proteomics approach, we previously studied the rat peroxisome in order to characterize the proteins participating in its biogenesis. A peroxisome-specific isoform of Lon (pLon) protein was accordingly identified. However, the precise role of pLon in peroxisomes remains to be elucidated. Here, we demonstrate that pLon plays a role in processing and activating a specific regulatory protein belonging to the peroxisome targeting signal (PTS) 1-containing proteins. Proteomic analysis of proteins co-immunoprecipitated with Lon suggested that Lon interacts with PMP70 and several enzymes involved in β-oxidation, including acyl-CoA oxidase (AOX). The processing of AOX for its activation in peroxisomes was strongly inhibited in cells expressing a dominant negative form of pLon. Furthermore, a catalase possessing a modified PTS1 sequence was misdistributed in this cell line. pLon exhibits little, if any, in vitro AOX processing activity, and does not process PTS2-containing 3-ketoacyl-coenzyme A thiolase (PTL). Therefore, pLon may specifically control, sort and process PTS1 proteins. Based on the relationship between pLon and the β-oxidation enzymes that regulate peroxisomal morphology, the observation of enlarged peroxisomes in cells expressing recombinant pLon suggests that pLon is a critical factor determining peroxisome morphology.