Functional association of the AAA complex and the peroxisomal importomer.
The AAA peroxins, Pex1p and Pex6p, are components of the peroxisomal protein import machinery required for the relocation of the import receptor Pex5p from the peroxisomal membrane to the cytosol. We demonstrate that Pex1p and Pex6p form a stable complex in the cytosol, which associates at the peroxisomal membrane with their membrane anchor Pex15p and the peroxisomal importomer. The interconnection of Pex15p with the components of the importomer was independent of Pex1p and Pex6p, indicating that Pex15p is an incorporated component of the assembly. Further evidence suggests that the AAA peroxins shuttle between cytosol and peroxisome with proper binding of the Pex15p-AAA complex to the importomer and release of the AAA peroxins from the peroxisomal membrane depending on an operative peroxisomal protein import mechanism. Pex4p-deficient cells exhibit a wild-type-like assembly of the importomer, which differs in that it is associated with increased amounts of Pex1p and Pex6p, in agreement with a function for Pex4p in the release of AAA peroxins from the peroxisomal membrane.
Rosenkranz
Katja
K
Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Germany.
Birschmann
Ingvild
I
Grunau
Silke
S
Girzalsky
Wolfgang
W
Kunau
Wolf-H
WH
Erdmann
Ralf
R
D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002478:Cells, Cultured; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000378:metabolism; D020675:Peroxisomes / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D015003:Yeasts / Q000145:classification / Q000378:metabolism
D005656:Fungal Proteins; D008565:Membrane Proteins; D046912:Multiprotein Complexes; C110177:PEX15 protein, S cerevisiae; D010750:Phosphoproteins; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; D000074183:ATPases Associated with Diverse Cellular Activities; C511586:PEX1 protein, S cerevisiae; C490760:PEX6 protein, S cerevisiae