Abstract
We identified a Saccharomyces cerevisiae peroxisomal membrane protein, Pex13p, that is essential for protein import. A point mutation in the COOH-terminal Src homology 3 (SH3) domain of Pex13p inactivated the protein but did not affect its membrane targeting. A two-hybrid screen with the SH3 domain of Pex13p identified Pex5p, a receptor for proteins with a type I peroxisomal targeting signal (PTS1), as its ligand. Pex13p SH3 interacted specifically with Pex5p in vitro. We determined, furthermore, that Pex5p was mainly present in the cytosol and only a small fraction was associated with peroxisomes. We therefore propose that Pex13p is a component of the peroxisomal protein import machinery onto which the mobile Pex5p receptor docks for the delivery of the selected PTS1 protein.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3-Hydroxyacyl CoA Dehydrogenases / metabolism
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Acetyl-CoA C-Acetyltransferase / analysis
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Amino Acid Sequence
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Base Sequence
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Biological Transport
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Catalase / metabolism
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Cloning, Molecular
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Cytosol / chemistry
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Fibroblasts
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Genes, Fungal / genetics
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Humans
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Intracellular Membranes / chemistry
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Ligands
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Membrane Proteins / analysis
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Microbodies / chemistry
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Microbodies / metabolism*
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Molecular Sequence Data
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Peroxisome-Targeting Signal 1 Receptor
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Point Mutation
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Receptors, Cytoplasmic and Nuclear / analysis
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Receptors, Cytoplasmic and Nuclear / genetics
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Receptors, Cytoplasmic and Nuclear / metabolism*
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae Proteins*
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Sequence Deletion
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src Homology Domains* / genetics
Substances
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Ligands
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Membrane Proteins
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PEX13 protein, S cerevisiae
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PEX13 protein, human
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Peroxisome-Targeting Signal 1 Receptor
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Receptors, Cytoplasmic and Nuclear
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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3-Hydroxyacyl CoA Dehydrogenases
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Catalase
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Acetyl-CoA C-Acetyltransferase