Abstract
We have isolated the Penicillium chrysogenum pex5 gene encoding the receptor for microbody matrix proteins containing a type 1 peroxisomal targeting signal (PTS1). Pc-pex5 contains 2 introns and encodes a protein of approximately 75 kDa. P. chrysogenum pex5 disruptants appear to be highly unstable, show poor growth, and are unable to sporulate asexually. Furthermore, pex5 cells mislocalize a fluorescent PTS1 reporter protein to the cytosol. Pc-pex5 was expressed in a PEX5 null mutant of the yeast Hansenula polymorpha. Detailed analysis demonstrated that the PTS1 proteins dihydroxyacetone synthase and catalase were almost fully imported into microbodies. Surprisingly, alcohol oxidase, which also depends on Pex5p for import into microbodies, remained mainly in the cytosol. Thus, P. chrysogenum Pex5p has a different specificity of cargo recognition than its H. polymorpha counterpart. This was also suggested by the observation that Pc-Pex5p sorted a reporter protein fused to various functional PTS1 signals with different efficiencies.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Alcohol Oxidoreductases / metabolism
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Aldehyde-Ketone Transferases / metabolism
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Amino Acid Sequence
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Catalase / metabolism
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Conserved Sequence
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Cytoplasm / chemistry
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DNA, Complementary
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DNA, Fungal / chemistry
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DNA, Fungal / isolation & purification
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Fungal Proteins / genetics
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Fungal Proteins / metabolism*
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Gene Deletion
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Genes, Fungal
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Introns
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Microbodies / metabolism*
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Molecular Sequence Data
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Molecular Weight
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Mutagenesis, Insertional
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Penicillium chrysogenum / genetics*
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Penicillium chrysogenum / growth & development
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Penicillium chrysogenum / metabolism*
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Peroxisome-Targeting Signal 1 Receptor
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Pichia / metabolism*
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Pichia / ultrastructure
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Protein Transport
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Receptors, Cytoplasmic and Nuclear / genetics
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Receptors, Cytoplasmic and Nuclear / metabolism*
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Recombinant Proteins / metabolism
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Sequence Alignment
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Spores, Fungal / growth & development
Substances
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DNA, Complementary
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DNA, Fungal
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Fungal Proteins
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PEX5 protein, Pichia pastoris
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Peroxisome-Targeting Signal 1 Receptor
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Receptors, Cytoplasmic and Nuclear
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Recombinant Proteins
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Alcohol Oxidoreductases
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alcohol oxidase
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Catalase
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Aldehyde-Ketone Transferases
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formaldehyde transketolase