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Updated: Jun 13, 2026

Reconstitution of Msp1 Extraction Activity with Fully Purified Components
Published on: August 10, 2021
Peroxisomal membrane proteins insert into the endoplasmic reticulum
Adabella van der Zand1, Ineke Braakman, Henk F Tabak
1Cellular Protein Chemistry, Faculty of Science, Utrecht University, NL-3584 CH Utrecht, The Netherlands.
Abstract:
We show that a comprehensive set of 16 peroxisomal membrane proteins (PMPs) encompassing all types of membrane topologies first target to the endoplasmic reticulum (ER) in Saccharomyces cerevisiae. These PMPs insert into the ER membrane via the protein import complexes Sec61p and Get3p (for tail-anchored proteins). This trafficking pathway is representative for multiplying wild-type cells in which the peroxisome population needs to be maintained, as well as for mutant cells lacking peroxisomes in which new peroxisomes form after complementation with the wild-type version of the mutant gene. PMPs leave the ER in a Pex3p-Pex19p-dependent manner to end up in metabolically active peroxisomes. These results further extend the new concept that peroxisomes derive their basic framework (membrane and membrane proteins) from the ER and imply a new functional role for Pex3p and Pex19p.
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