Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0162871 (abdominal aortic aneurysm)
 8,664 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In humans, defects in peroxisome assembly result in the peroxisome biogenesis disorders (PBDs), a group of genetically heterogeneous, lethal recessive diseases. We have identified the human gene PXAAA1 based upon its similarity to PpPAS5, a gene required for peroxisome assembly in the yeast Pichia pastoris. Expression of PXAAA1 restored peroxisomal protein import in fibroblasts from 16 unrelated members of complementation group 4 (CG4) of the PBD. Consistent with this observation, CG4 patients carry mutations in PXAAA1. The product of this gene, Pxaaa1p, belongs to the AAA family of ATPases and appears to be a predominantly cytoplasmic protein. Substitution of an arginine for the conserved lysine residue in the ATPase domain of Pxaaa1p abolished its biological activity, suggesting that Pxaaa1p is an ATPase. Furthermore, Pxaaa1p is required for stability of the predominantly cytoplasmic PTS1 receptor, Pxr1p. We conclude that Pxaaa1p plays a direct role in peroxisomal protein import and is required for PTS1 receptor activity.
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PMID:The peroxisome biogenesis disorder group 4 gene, PXAAA1, encodes a cytoplasmic ATPase required for stability of the PTS1 receptor. 867 Jul 92

Peroxisomal import receptors bind their cargo proteins in the cytosol and target them to docking and translocation machinery at the peroxisomal membrane (reviewed in ref. 1). The receptors release the cargo proteins into the peroxisomal lumen and, according to the model of cycling receptors, they are supposed to shuttle back to the cytosol. This shuttling of the receptors has been assigned to peroxins including the AAA peroxins Pex1p and Pex6p, as well as the ubiquitin-conjugating enzyme Pex4p (reviewed in ref. 2). One possible target for Pex4p is the PTS1 receptor Pex5p, which has recently been shown to be ubiquitinated. Pex1p and Pex6p are both cytosolic and membrane-associated AAA ATPases of the peroxisomal protein import machinery, the exact function of which is still unknown. Here we demonstrate that the AAA peroxins mediate the ATP-dependent dislocation of the peroxisomal targeting signal-1 (PTS1) receptor from the peroxisomal membrane to the cytosol.
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PMID:Functional role of the AAA peroxins in dislocation of the cycling PTS1 receptor back to the cytosol. 1600 78

Peroxisomal matrix protein import is facilitated by cycling receptors shuttling between the cytosol and the peroxisomal membrane. One crucial step in this cycle is the ATP-dependent release of the receptors from the peroxisomal membrane. This step is facilitated by the peroxisomal AAA (ATPases associated with various cellular activities) proteins Pex1p and Pex6p with ubiquitination of the receptor being the main signal for its export. Here we report that the AAA complex contains dislocase as well as deubiquitinating activity. Ubp15p, a ubiquitin hydrolase, was identified as a novel constituent of the complex. Ubp15p partially localizes to peroxisomes and is capable of cleaving off ubiquitin moieties from the type I peroxisomal targeting sequence (PTS1) receptor Pex5p. Furthermore, Ubp15p-deficient cells are characterized by a stress-related PTS1 import defect. The results merge into a picture in which removal of ubiquitin from the PTS1 receptor Pex5p is a specific event and might represent a vital step in receptor recycling.
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PMID:Ubp15p, a ubiquitin hydrolase associated with the peroxisomal export machinery. 2166 45