The SH3 domain of the Saccharomyces cerevisiae peroxisomal membrane protein Pex13p functions as a docking site for Pex5p, a mobile receptor for the import PTS1-containing proteins.
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.
Elgersma
Y
Y
Department of Biochemistry, Academic Medical Centre, Amsterdam, The Netherlands.
Kwast
L
L
Klein
A
A
Voorn-Brouwer
T
T
van den Berg
M
M
Metzig
B
B
America
T
T
Tabak
H F
HF
Distel
B
B
D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000378:metabolism; D000101:Acetyl-CoA C-Acetyltransferase / Q000032:analysis; D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D002374:Catalase / Q000378:metabolism; D003001:Cloning, Molecular; D003600:Cytosol / Q000737:chemistry; D005347:Fibroblasts; D005800:Genes, Fungal / Q000235:genetics; D006801:Humans; D007425:Intracellular Membranes / Q000737:chemistry; D008024:Ligands; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D008830:Microbodies / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D000074435:Peroxisome-Targeting Signal 1 Receptor; D017354:Point Mutation; D018160:Receptors, Cytoplasmic and Nuclear / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D018909:src Homology Domains / Q000235:genetics
D008024:Ligands; D008565:Membrane Proteins; C491105:PEX13 protein, S cerevisiae; C101884:PEX13 protein, human; D000074435:Peroxisome-Targeting Signal 1 Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D015094:3-Hydroxyacyl CoA Dehydrogenases; D002374:Catalase; D000101:Acetyl-CoA C-Acetyltransferase