PEX26: Probably required for protein import into peroxisomes. Anchors PEX1 and PEX6 to peroxisome membranes, possibly to form heteromeric AAA ATPase complexes required for the import of proteins into peroxisomes. Involved in the import of catalase and proteins containing a PTS2 target sequence, but not in import of proteins with a PTS1 target sequence. Defects in PEX26 are the cause of peroxisome biogenesis disorder complementation group 8 (PBD-CG8); also known as PBD-CGA. PBD refers to a group of peroxisomal disorders arising from a failure of protein import into the peroxisomal membrane or matrix. The PBD group is comprised of four disorders: Zellweger syndrome (ZWS), neonatal adrenoleukodystrophy (NALD), infantile Refsum disease (IRD), and classical rhizomelic chondrodysplasia punctata (RCDP). ZWS, NALD and IRD are distinct from RCDP and constitute a clinical continuum of overlapping phenotypes known as the Zellweger spectrum. The PBD group is genetically heterogeneous with at least 13 distinct genetic groups as concluded from complementation studies. Defects in PEX26 are a cause of Zellweger syndrome (ZWS). ZWS is a fatal peroxisome biogenesis disorder characterized by dysmorphic facial features, hepatomegaly, ocular abnormalities, renal cysts, hearing impairment, profound psychomotor retardation, severe hypotonia and neonatal seizures. Death occurs within the first year of life. Defects in PEX26 are a cause of adrenoleukodystrophy neonatal (NALD). NALD is a peroxisome biogenesis disorder characterized by the accumulation of very long-chain fatty acids, adrenal insufficiency and mental retardation. Defects in PEX26 are a cause of infantile Refsum disease (IRD). IRD is a mild peroxisome biogenesis disorder. Clinical features include early onset, mental retardation, minor facial dysmorphism, retinopathy, sensorineural hearing deficit, hepatomegaly, osteoporosis, failure to thrive, and hypocholesterolemia. The biochemical abnormalities include accumulation of phytanic acid, very long chain fatty acids (VLCFA), di- and trihydroxycholestanoic acid and pipecolic acid. Belongs to the peroxin-26 family.
Protein type: Membrane protein, integral
Chromosomal Location of Human Ortholog: 22q11.21
Cellular Component: integral to peroxisomal membrane; peroxisome
Molecular Function: protein C-terminus binding; protein binding; protein complex binding; ATPase binding
Biological Process: protein import into peroxisome matrix; protein import into peroxisome membrane
Disease: Peroxisome Biogenesis Disorder 7b; Peroxisome Biogenesis Disorder 7a (zellweger)
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