title: Tetratricopeptide repeat domain of Yarrowia lipolytica Pex5p is essential for recognition of the type 1 peroxisomal targeting signal but does not confer full biological activity on Pex5p.
abstract: Peroxins are proteins required for peroxisome assembly and are encoded by the PEX genes. The Yarrowia lipolytica pex5-1 mutant fails to import a subset of peroxisomal matrix proteins, including those with a type 1 peroxisomal targeting signal (PTS1). Pex5p family members interact with a PTS1 through their characteristic tetratricopeptide repeat (TPR) domain. We used binding assays in vitro to investigate the nature of the association of Y. lipolytica Pex5p (YlPex5p) with the PTS1 signal. A purified recombinant YlPex5p fusion protein interacted specifically, directly and autonomously with a protein terminating in a PTS1. Wild-type YlPex5p translated in vitro recognized functional PTS1s specifically. This activity is abrogated by the substitution of an aspartic residue for a conserved glycine residue in the TPR domain (G455D) of YlPex5p encoded by the pex5-1 allele. Deletion analysis demonstrated that an intact TPR domain of YlPex5p is necessary but not sufficient for both interaction with a PTS1 and functional complementation of a strain lacking YlPex5p.
authors.affiliation: Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: R K
authors.initials: RK
authors.lastname: Szilard
authors.forename: R A
authors.initials: RA
authors.lastname: Rachubinski
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000483:Alleles; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D001665:Binding Sites; D001692:Biological Transport; D002455:Cell Division; D017124:Conserved Sequence / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D019301:Oleic Acid / Q000378:metabolism; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000737:chemistry / Q000378:metabolism*; D010641:Phenotype; D011485:Protein Binding; D021382:Protein Sorting Signals / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics / Q000502:physiology*; D004718:Saccharomycetales / Q000737:chemistry / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D005656:Fungal Proteins; D000074435:Peroxisome-Targeting Signal 1 Receptor; D021382:Protein Sorting Signals; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; D019301:Oleic Acid; D019342:Acetic Acid