Abstract
Import of newly synthesized PTS1 proteins into the peroxisome requires the PTS1 receptor (Pex5p), a predominantly cytoplasmic protein that cycles between the cytoplasm and peroxisome. We have identified Pex13p, a novel integral peroxisomal membrane from both yeast and humans that binds the PTS1 receptor via a cytoplasmically oriented SH3 domain. Although only a small amount of Pex5p is bound to peroxisomes at steady state (< 5%), loss of Pex13p further reduces the amount of peroxisome-associated Pex5p by approximately 40-fold. Furthermore, loss of Pex13p eliminates import of peroxisomal matrix proteins that contain either the type-1 or type-2 peroxisomal targeting signal but does not affect targeting and insertion of integral peroxisomal membrane proteins. We conclude that Pex13p functions as a docking factor for the predominantly cytoplasmic PTS1 receptor.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Acetyl-CoA C-Acetyltransferase / metabolism
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Amino Acid Sequence
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Biological Transport
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Catalase / metabolism
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Cell Adhesion Molecules / metabolism
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Cell Line
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Cell Membrane / chemistry*
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Cloning, Molecular
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Cytoplasm / metabolism
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Fibroblasts
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Genes / genetics
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Genes, Fungal / genetics
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Humans
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Intracellular Membranes / chemistry
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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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Membrane Proteins / physiology
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Microbodies / chemistry
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Microbodies / metabolism*
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Molecular Sequence Data
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Peroxisomal Targeting Signal 2 Receptor
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Peroxisome-Targeting Signal 1 Receptor
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Pichia / genetics
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Receptors, Cytoplasmic and Nuclear / metabolism*
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Sequence Analysis, DNA
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src Homology Domains*
Substances
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Cell Adhesion Molecules
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Membrane Proteins
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PEX13 protein, human
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Peroxisomal Targeting Signal 2 Receptor
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Peroxisome-Targeting Signal 1 Receptor
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Receptors, Cytoplasmic and Nuclear
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Catalase
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Acetyl-CoA C-Acetyltransferase
Associated data
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GENBANK/U59222
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GENBANK/U71374