title: Dynamic and functional assembly of the AAA peroxins, Pex1p and Pex6p, and their membrane receptor Pex26p.
abstract: Two AAA peroxins, Pex1p and Pex6p, are encoded by PEX1 and PEX6, the causal genes for peroxisome biogenesis disorders of complementation group 1 (CG1) and CG4, respectively. PEX26 responsible for peroxisome biogenesis disorders of CG8 encodes Pex26p, the recruiter of Pex1p.Pex6p complexes to peroxisomes. We herein assigned the binding regions between human Pex1p and Pex6p and elucidated pivotal roles of the AAA cassettes, called D1 and D2 domains, in Pex1p-Pex6p interaction and peroxisome biogenesis. ATP binding in both AAA cassettes but not ATP hydrolysis in D2 of both Pex1p and Pex6p was prerequisite for Pex1p-Pex6p interaction and their peroxisomal localization. The AAA cassettes, D1 and D2, were essential for peroxisome-restoring activity of Pex1p and Pex6p. In HEK293 cells, endogenous Pex1p was partly localized likely as a homo-oligomer in the cytoplasm, while Pex6p and Pex26p were predominantly localized on peroxisomes. Interaction of Pex1p with Pex6p conferred a conformational change and dissociation of the Pex1p oligomer. These results suggested that Pex1p possesses two distinct oligomeric forms, a homo-oligomer in the cytosol and a hetero-oligomer on peroxisome membranes, possibly playing distinct functions in peroxisome biogenesis.
authors.affiliation: Department of Biology, Faculty of Sciences, Kyushu University Graduate School, Fukuoka 812-8581, Japan.
authors.forename: Shigehiko
authors.initials: S
authors.lastname: Tamura
authors.forename: Shinobu
authors.initials: S
authors.lastname: Yasutake
authors.forename: Naomi
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Yukio
authors.initials: Y
authors.lastname: Fujiki
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000502:physiology; D000255:Adenosine Triphosphate / Q000378:metabolism; D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D006224:Cricetinae; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry* / Q000502:physiology; D020675:Peroxisomes / Q000737:chemistry / Q000502:physiology; D020798:Two-Hybrid System Techniques
chemical_list: D008565:Membrane Proteins; C474612:PEX26 protein, human; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D000074183:ATPases Associated with Diverse Cellular Activities; C111808:PEX1 protein, human; C490759:PEX6 protein, human