title: AWP1/ZFAND6 functions in Pex5 export by interacting with cys-monoubiquitinated Pex5 and Pex6 AAA ATPase.
abstract: During biogenesis of the peroxisome, a subcellular organelle, the peroxisomal-targeting signal 1 (PTS1) receptor Pex5 functions as a shuttling receptor for PTS1-containing peroxisomal matrix proteins. However, the precise mechanism of receptor shuttling between peroxisomes and cytosol remains elusive despite the identification of numerous peroxins involved in this process. Herein, a new factor was isolated by a combination of biochemical fractionation and an in vitro Pex5 export assay, and was identified as AWP1/ZFAND6, a ubiquitin-binding NF-κB modulator. In the in vitro Pex5 export assay, recombinant AWP1 stimulated Pex5 export and an anti-AWP1 antibody interfered with Pex5 export. AWP1 interacted with Pex6 AAA ATPase, but not with Pex1-Pex6 complexes. Preferential binding of AWP1 to the cysteine-ubiquitinated form of Pex5 rather than to unmodified Pex5 was mediated by the AWP1 A20 zinc-finger domain. Inhibition of AWP1 by RNA interference had a significant effect on PTS1-protein import into peroxisomes. Furthermore, in AWP1 knock-down cells, Pex5 stability was decreased, similar to fibroblasts from patients defective in Pex1, Pex6 and Pex26, all of which are required for Pex5 export. Taken together, these results identify AWP1 as a novel cofactor of Pex6 involved in the regulation of Pex5 export during peroxisome biogenesis.
authors: Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan.
authors: Non
authors: N
authors: Miyata
authors: Kanji
authors: K
authors: Okumoto
authors: Satoru
authors: S
authors: Mukai
authors: Masafumi
authors: M
authors: Noguchi
authors: Yukio
authors: Y
authors: Fujiki
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D002458:Cell Fractionation; D006224:Cricetinae; D003412:Cricetulus; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D008099:Liver / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D008969:Molecular Sequence Data; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000378:metabolism*; D055550:Protein Stability; D021381:Protein Transport; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D054875:Ubiquitination; D016335:Zinc Fingers
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C000614264:PEX5 protein, human; D000074435:Peroxisome-Targeting Signal 1 Receptor; C000614265:Pex5 protein, mouse; D018160:Receptors, Cytoplasmic and Nuclear; C417945:ZFAND6 protein, human; C485956:Zfand6 protein, mouse; D000251:Adenosine Triphosphatases; D000074183:ATPases Associated with Diverse Cellular Activities; C490759:PEX6 protein, human