title: Peroxisomal membrane protein import does not require Pex17p.
abstract: Of the approximately 20 proteins required for peroxisome biogenesis, only four have been implicated in the process of peroxisomal membrane protein (PMP) import: Pex3p, Pex16p, Pex17p, and Pex19p. To improve our understanding of the role that Pex17p plays in PMP import, we examined the behavior of PMPs in a Pichia pastoris pex17 mutant. Relative to wild-type cells, pex17 cells appeared to have a mild reduction in PMP stability and slightly aberrant PMP behavior in subcellular fractionation experiments. However, we also found that the behavior of PMPs in the pex17 mutant was indistinguishable from PMP behavior in a pex5 mutant, which has no defect in PMP import, and was far different from PMP behavior in a pex3 mutant, which has a bona fide defect in PMP import. Furthermore, we found that a pex14 mutant, which has no defect in PMP import, lacks detectable levels of Pex17p. Based on these and other results, we propose that Pex17p acts primarily in the matrix protein import pathway and does not play an important role in PMP import.
authors.affiliation: Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
authors.forename: Courtney C
authors.initials: CC
authors.lastname: Harper
authors.forename: Sarah T
authors.initials: ST
authors.lastname: South
authors.forename: J Michael
authors.initials: JM
authors.lastname: McCaffery
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Gould
mesh_terms: D018528:ATP-Binding Cassette Transporters; D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D003593:Cytoplasm / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000502:physiology; D007425:Intracellular Membranes / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins; D008854:Microscopy, Electron; D009154:Mutation; D000074401:Peroxins; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000378:metabolism*; D010641:Phenotype; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D005656:Fungal Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C499195:PEX14 protein, S cerevisiae; C070895:PEX3 protein, S cerevisiae; C000614263:PEX5 protein, Pichia pastoris; D000074401:Peroxins; D000074435:Peroxisome-Targeting Signal 1 Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D012097:Repressor Proteins; C406793:SPF1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins