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X-ray crystal structure of Pex19pX-ray crystal structure of Pex19p
Structural highlights
DiseasePEX19_HUMAN Defects in PEX19 are the cause of peroxisome biogenesis disorder complementation group 14 (PBD-CG14) [MIM:614886; also known as PBD-CGJ. 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 14 distinct genetic groups as concluded from complementation studies.[1] Defects in PEX19 are the cause of peroxisome biogenesis disorder 12A (PBD12A) [MIM:614886. A fatal peroxisome biogenesis disorder belonging to the Zellweger disease spectrum and clinically characterized by severe neurologic dysfunction with profound psychomotor retardation, severe hypotonia and neonatal seizures, craniofacial abnormalities, liver dysfunction, and biochemically by the absence of peroxisomes. Additional features include cardiovascular and skeletal defects, renal cysts, ocular abnormalities, and hearing impairment. Most severely affected individuals with the classic form of the disease (classic Zellweger syndrome) die within the first year of life. FunctionPEX19_HUMAN Necessary for early peroxisomal biogenesis. Acts both as a cytosolic chaperone and as an import receptor for peroxisomal membrane proteins (PMPs). Binds and stabilizes newly synthesized PMPs in the cytoplasm by interacting with their hydrophobic membrane-spanning domains, and targets them to the peroxisome membrane by binding to the integral membrane protein PEX3. Excludes CDKN2A from the nucleus and prevents its interaction with MDM2, which results in active degradation of TP53.[2] [3] [4] [5] [6] [7] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe protein Pex19p functions as a receptor and chaperone of peroxisomal membrane proteins (PMPs). The crystal structure of the folded C-terminal part of the receptor reveals a globular domain that displays a bundle of three long helices in an antiparallel arrangement. Complementary functional experiments, using a range of truncated Pex19p constructs, show that the structured alpha-helical domain binds PMP-targeting signal (mPTS) sequences with about 10 muM affinity. Removal of a conserved N-terminal helical segment from the mPTS recognition domain impairs the ability for mPTS binding, indicating that it forms part of the mPTS-binding site. Pex19p variants with mutations in the same sequence segment abolish correct cargo import. Our data indicate a divided N-terminal and C-terminal structural arrangement in Pex19p, which is reminiscent of a similar division in the Pex5p receptor, to allow separation of cargo-targeting signal recognition and additional functions. The peroxisomal receptor Pex19p forms a helical mPTS recognition domain.,Schueller N, Holton SJ, Fodor K, Milewski M, Konarev P, Stanley WA, Wolf J, Erdmann R, Schliebs W, Song YH, Wilmanns M EMBO J. 2010 Aug 4;29(15):2491-500. Epub 2010 Jun 8. PMID:20531392[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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