Import into mitochondria of phospholipid hydroperoxide glutathione peroxidase requires a leader sequence.
An in vitro import system was used to characterize the mechanism of import of phospholipid hydroperoxide glutathione peroxidase (PHGPx) into mitochondria. Mitochondria were isolated from rat liver and incubated at 25 degrees C with [35S]methionine-labeled products of the in vitro translation of mRNA that encoded 23-kDa and 20-kDa PHGPx. 23-kDa PHGPx was imported into mitochondria in a time-dependent manner and was processed to yield the 20-kDa form of PHGPx. The 20-kDa form of PHGPx, without a leader sequence, associated weakly with mitochondria but was not imported. An analysis with an uncoupler of oxidative phosphorylation showed that a membrane potential in the mitochondria was also required for the import of PHGPx. It appears, therefore, that the leader sequence in the precursor to PHGPx is the signal for import into the mitochondria. This is the first report to indicate that the precursor to PHGPx is imported into the mitochondria via the action of a leader sequence.
Arai
M
M
School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
Imai
H
H
Sumi
D
D
Imanaka
T
T
Takano
T
T
Chiba
N
N
Nakagawa
Y
Y
D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D005979:Glutathione Peroxidase / Q000096:biosynthesis / Q000378:metabolism*; D007700:Kinetics; D008715:Methionine / Q000378:metabolism; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D013462:Sulfur Radioisotopes
D009838:Oligodeoxyribonucleotides; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D013462:Sulfur Radioisotopes; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D008715:Methionine; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D005979:Glutathione Peroxidase