title: Ubp15p, a ubiquitin hydrolase associated with the peroxisomal export machinery.
abstract: Peroxisomal matrix protein import is facilitated by cycling receptors shuttling between the cytosol and the peroxisomal membrane. One crucial step in this cycle is the ATP-dependent release of the receptors from the peroxisomal membrane. This step is facilitated by the peroxisomal AAA (ATPases associated with various cellular activities) proteins Pex1p and Pex6p with ubiquitination of the receptor being the main signal for its export. Here we report that the AAA complex contains dislocase as well as deubiquitinating activity. Ubp15p, a ubiquitin hydrolase, was identified as a novel constituent of the complex. Ubp15p partially localizes to peroxisomes and is capable of cleaving off ubiquitin moieties from the type I peroxisomal targeting sequence (PTS1) receptor Pex5p. Furthermore, Ubp15p-deficient cells are characterized by a stress-related PTS1 import defect. The results merge into a picture in which removal of ubiquitin from the PTS1 receptor Pex5p is a specific event and might represent a vital step in receptor recycling.
authors.affiliation: Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Bochum, Germany.
authors.forename: Mykhaylo O
authors.initials: MO
authors.lastname: Debelyy
authors.forename: Harald W
authors.initials: HW
authors.lastname: Platta
authors.forename: Delia
authors.initials: D
authors.lastname: Saffian
authors.forename: Astrid
authors.initials: A
authors.lastname: Hensel
authors.forename: Sven
authors.initials: S
authors.lastname: Thoms
authors.forename: Helmut E
authors.initials: HE
authors.lastname: Meyer
authors.forename: Bettina
authors.initials: B
authors.lastname: Warscheid
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Girzalsky
authors.forename: Ralf
authors.initials: R
authors.lastname: Erdmann
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D020675:Peroxisomes / Q000201:enzymology* / Q000235:genetics; D021381:Protein Transport / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin; D010450:Endopeptidases; C561120:Ubp15 protein, S cerevisiae; D000251:Adenosine Triphosphatases; D000074183:ATPases Associated with Diverse Cellular Activities; C511586:PEX1 protein, S cerevisiae; C490760:PEX6 protein, S cerevisiae