title: The Hansenula polymorpha PER3 gene is essential for the import of PTS1 proteins into the peroxisomal matrix.
abstract: PER genes are essential for the assembly of peroxisomes in Hansenula polymorpha. Here we describe the PER3 gene which was cloned by functional complementation of a H. polymorpha per3 mutant. The complementing PER3 gene encodes a protein of 569 amino acids (Per3p) with a calculated mass of 63.9 kDa; Per3p belongs to the tetratricopeptide repeat protein family and is located in both the cytosol and the peroxisomal matrix. Remarkably, Per3p does not contain a known targeting signal (PTS1 or PTS2). The PER3 gene product shows similarity to the Saccharomyces cerevisiae Pas10p (40% identity) and the Pichia pastoris Pas8p (55% identity). However, their function apparently cannot be interchanged since the P. pastoris PAS8 gene failed to functionally complement a H. polymorpha per3 disruption mutant. The per3 disruption mutant contained normal but small peroxisomes in which PTS2 proteins (both homologous and heterologous) were imported. Other matrix proteins (in particular PTS1 proteins) resided in the cytosol where they were normally assembled and active. We argue that Per3p is a component of the peroxisomal import machinery and most probably shuttles matrix proteins from the cytosol to the organellar matrix.
authors.affiliation: Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Haren, The Netherlands.
authors.forename: I J
authors.initials: IJ
authors.lastname: van der Klei
authors.forename: R E
authors.initials: RE
authors.lastname: Hilbrands
authors.forename: G J
authors.initials: GJ
authors.lastname: Swaving
authors.forename: H R
authors.initials: HR
authors.lastname: Waterham
authors.forename: E G
authors.initials: EG
authors.lastname: Vrieling
authors.forename: V I
authors.initials: VI
authors.lastname: Titorenko
authors.forename: J M
authors.initials: JM
authors.lastname: Cregg
authors.forename: W
authors.initials: W
authors.lastname: Harder
authors.forename: M
authors.initials: M
authors.lastname: Veenhuis
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology; D005656:Fungal Proteins / Q000378:metabolism*; D005800:Genes, Fungal; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology; D026901:Membrane Transport Proteins; D008830:Microbodies / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D010843:Pichia / Q000235:genetics*
chemical_list: D002352:Carrier Proteins; D005656:Fungal Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins