Abstract
Almost proteins in peroxisomes are synthesized in the cytosol and transported via PTS1 or PTS2 pathways. Whereas PTS1 proteins are synthesized as mature sizes, PTS2 proteins are done as large precursors with N-terminal presequences. We focused on AtDeg15 that is a homologue of E.coli DegQ protease, which is a candidate for processing protease of presequences. We analyzed an Arabidopsis mutant of T-DNA insertion in AtDeg15. Peroxisomes of deg15 had normal import machinery for PTS1 and PTS2 proteins, but accumulated precursors for PTS2 proteins. Complementation studies of the mutant showed that AtDeg15 is essential for PTS2 processing. β-oxidation activity of deg15 was lower than that of WT and an enzyme activity of recombinant precursor for PMDH was also lower than that of mature PMDH. These results indicated that AtDeg15 is involved in maturation of PTS2 proteins and the processing seems to be necessary for assembly of peroxisomal functions.
