title: Targeting of the human adrenoleukodystrophy protein to the peroxisomal membrane by an internal region containing a highly conserved motif.
abstract: In this study we addressed the targeting requirements of peroxisomal ABC transporters, in particular the human adrenoleukodystrophy protein. This membrane protein is defective or missing in X-linked adrenoleukodystrophy, a neurodegenerative disorder predominantly presenting in childhood. Using adrenoleukodystrophy protein deletion constructs and green fluorescent protein fusion constructs we identified the amino acid regions 1-110 and 67-164 to be sufficient for peroxisomal targeting. However, the minimal region shared by these constructs (amino acids 67-110) is not sufficient for peroxisomal targeting by itself. Additionally, the NH2-terminal 66 amino acids enhance targeting efficiency. Green fluorescent protein-labeled fragments of human peroxisomal membrane protein 69 and Saccharomyces cerevisiae Pxa1 corresponding to the amino acid 67-164 adrenoleukodystrophy protein region were also directed to the mammalian peroxisome. The required region contains a 14-amino-acid motif (71-84) conserved between the adrenoleukodystrophy protein and human peroxisomal membrane protein 69 and yeast Pxa1. Omission or truncation of this motif in the adrenoleukodystrophy protein abolished peroxisomal targeting. The single amino acid substitution L78F resulted in a significant reduction of targeting efficiency. The in-frame deletion of three amino acids (del78-80LLR) within the proposed targeting motif in two patients suffering from X-linked adrenoleukodystrophy resulted in the mislocalization of a green fluorescent protein fusion protein to nucleus, cytosol and mitochondria. Our data define the targeting region of human adrenoleukodystrophy protein containing a highly conserved 14-amino-acid motif.
authors.affiliation: Dr. von Hauner Children's Hospital, Department of Clinical Chemistry, Laboratory of Molecular Biology, Ludwig-Maximilians-University Munich, Munich, Germany.
authors.forename: Pablo
authors.initials: P
authors.lastname: Landgraf
authors.forename: Peter U
authors.initials: PU
authors.lastname: Mayerhofer
authors.forename: Roman
authors.initials: R
authors.lastname: Polanetz
authors.forename: Adelbert A
authors.initials: AA
authors.lastname: Roscher
authors.forename: Andreas
authors.initials: A
authors.lastname: Holzinger
mesh_terms: D000074063:ATP Binding Cassette Transporter, Subfamily D, Member 1; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D000326:Adrenoleukodystrophy / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins; D008969:Molecular Sequence Data; D020675:Peroxisomes / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: C115572:ABCD1 protein, human; D000074063:ATP Binding Cassette Transporter, Subfamily D, Member 1; D018528:ATP-Binding Cassette Transporters; D008164:Luminescent Proteins; C098338:PXA1 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins