title: Molecular requirements for peroxisomal targeting of alanine-glyoxylate aminotransferase as an essential determinant in primary hyperoxaluria type 1.
abstract: Alanine-glyoxylate aminotransferase is a peroxisomal enzyme, of which various missense mutations lead to irreversible kidney damage via primary hyperoxaluria type 1, in part caused by improper peroxisomal targeting. To unravel the molecular mechanism of its recognition by the peroxisomal receptor Pex5p, we have determined the crystal structure of the respective cargo-receptor complex. It shows an extensive protein/protein interface, with contributions from residues of the peroxisomal targeting signal 1 and additional loops of the C-terminal domain of the cargo. Sequence segments that are crucial for receptor recognition and hydrophobic core interactions within alanine-glyoxylate aminotransferase are overlapping, explaining why receptor recognition highly depends on a properly folded protein. We subsequently characterized several enzyme variants in vitro and in vivo and show that even minor protein fold perturbations are sufficient to impair Pex5p receptor recognition. We discuss how the knowledge of the molecular parameters for alanine-glyoxylate aminotransferase required for peroxisomal translocation could become useful for improved hyperoxaluria type 1 treatment.
authors.affiliation: European Molecular Biology Laboratory Hamburg, Hamburg, Germany.
authors.forename: Krisztián
authors.initials: K
authors.lastname: Fodor
authors.forename: Janina
authors.initials: J
authors.lastname: Wolf
authors.forename: Ralf
authors.initials: R
authors.lastname: Erdmann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schliebs
authors.forename: Matthias
authors.initials: M
authors.lastname: Wilmanns
mesh_terms: D001665:Binding Sites; D002478:Cells, Cultured; D018360:Crystallography, X-Ray; D006801:Humans; D006960:Hyperoxaluria, Primary / Q000201:enzymology* / Q000235:genetics; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense; D020675:Peroxisomes / Q000201:enzymology*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D021381:Protein Transport; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry*; D000637:Transaminases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: C529762:PEX5L protein, human; D018160:Receptors, Cytoplasmic and Nuclear; D000637:Transaminases; C019635:Alanine-glyoxylate transaminase