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Saccharomyces cerevisiae Pex3p and Pex19p are required for proper localization and stability of peroxisomal membrane proteins
Author(s) -
Hettema Ewald H.,
Girzalsky Wolfgang,
van den Berg Marlene,
Erdmann Ralf,
Distel Ben
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.2.223
Subject(s) - biology , saccharomyces cerevisiae , peroxisome , membrane protein , microbiology and biotechnology , membrane , protein stability , fungal protein , peroxisomal targeting signal , biochemistry , yeast , gene
The mechanisms by which peroxisomal membrane proteins (PMPs) are targeted to and inserted into membranes are unknown, as are the required components. We show that among a collection of 16 Saccharomyces cerevisiae peroxisome biogenesis ( pex ) mutants, two mutants, pex3Δ and pex19Δ , completely lack detectable peroxisomal membrane structures and mislocalize their PMPs to the cytosol where they are rapidly degraded. The other pexΔ mutants contain membrane structures that are properly inherited during vegetative growth and that house multiple PMPs. Even Pex15p requires Pex3p and Pex19p for localization to peroxisomal membranes. This PMP was previously hypothesized to travel via the endoplasmic reticulum (ER) to peroxisomes. We provide evidence that ER‐accumulated Pex15p is not a sorting intermediate on its way to peroxisomes. Our results show that Pex3p and Pex19p are required for the proper localization of all PMPs tested, including Pex15p, whereas the other Pex proteins might only be required for targeting/import of matrix proteins.