Peroxisome biogenesis and human peroxisome biogenesis disorders

1)利用过氧化物酶体膜组装缺陷CHO突变体ZPG208克隆了编码42-kDa膜过氧化物的PEX3。PEX3功能障碍导致过氧化物酶体生物发生障碍（PBDs），如补体组g . Zellweger综合征。2)在3种环过氧化物酶中，包括Pex2p、Pex10p和Pex12p， Pex12p环指对于过氧化物酶体恢复活性是必需的，但对于过氧化物酶体靶向不是必需的。Pex12p环指结合Pex10p和过氧化物酶体靶向信号1 （PTS1）受体Pex5p。3)我们发现，CG4致病基因PEX6可以恢复CG6 PBD成纤维细胞中过氧化物酶体的组装。该患者为PEX6等位基因复合杂合。因此，通过将CG6与CG4.4合并，将人pbd划分为12个cggs。)Pex5p的两种同工异构体，Pex5pS和37个氨基酸长的Pex5pL在哺乳动物中表达。我们发现Pex5pL与细胞质中PTS2受体pex7p -PTS2蛋白复合物相互作用，并将其易位到Pex14p上。我们定义了更多与Pex7p、Pex13p和Pex14p相互作用的Pex5p结构域。包含1-243位氨基酸残基的n端一半Pex5pL与Pex7p、Pex13p和Pex14p结合，足以恢复pex5细胞突变体受损的PTS2输入，而c端四肽重复基序则需要与pts1结合。位于n端区域的7个（Pex5pS中6个）五肽WxxxF/ y基序对于peex5p与peex14p和peex13p相互作用是必不可少的。Pex14p和Pex13p与负载pts1的Pex5p形成复合体，但在无负载的Pex5p存在下解离，这意味着Pex5p的PTS产物在Pex14p的下游和Pex13p的上游被释放。我们报道了Pex7p在CHO和人类细胞的细胞质和过氧化物酶体之间呈现双峰分布，这意味着Pex7p像Pex5p一样穿梭于过氧化物酶体和细胞质之间。Pex7p需要几乎完整的长度，包括所有的WD基序，才能发挥其功能。5)我们最近利用CHO细胞突变体ZP167分离了人类PEX26编码一种新的34 kda型II型过氧化物酶体膜蛋白。PEX26的表达仅在CG8 PBD患者的成纤维细胞中恢复过氧化物酶体蛋白的输入。该患者具有纯合子灭活致病性点突变R98W。因此，我们可以声明，导致12个CGs - pbd的所有致病基因都已被克隆。此外，AAA atp酶家族的Pex6p和Pex1p与Pex26p共同免疫沉淀。结合几条形态学证据，我们得出结论，Pex26p将Pex6p-Pex1p复合物招募到过氧化物酶体上。少

1) PEX3 encoding 42-kDa membrane peroxin was cloned by using a peroxisome membrane assembly-defective CHO mutant, ZPG208. Dysfunction of PEX3 was responsible for peroxisome biogenesis disorders (PBDs) such as Zellweger syndrome of complementation group G.2) Of 3 RING peroxins, including Pex2p, Pex10p, and Pex12p, Pex12p RING finger was essential for peroxisome restoring activity but not necessary for targeting to peroxisomes. Pex12p RING finger binds to Pex10p and peroxisome targeting signal 1 (PTS1)-receptor Pex5p.3) We showed that PEX6, the CG4 pathogenic gene, restored peroxisome assembly in CG6 PBD fibroblasts. This patient was compound heterozygous for PEX6 alleles. Accordingly, human PBDs are classified into 12 CGs by merging CG6 with CG4.4) Two isoforms of Pex5p, Pex5pS and 37-amino acid-longer Pex5pL, are expressed in mammals. We found that Pex5pL interacts with the PTS2 receptor Pex7p-PTS2-protein complexes in the cytosol and translocates them to Pex14p. We defined the functio … More nal Pex5p domains interacting with Pex7p, Pex13p, and Pex14p. An N-terminal half Pex5pL comprising amino acid residues at 1-243 bound to Pex7p, Pex13p and Pex14p and was sufficient for restoring the impaired PTS2 import of pex5 cell mutants, whilst the C-terminal tetratricopeptide repeat motifs were required for PTS1-binding. Seven (six in Pex5pS) pentapeptide WxxxF/Y-motifs residing at the N-terminal region were essential for Pex5p interaction with Pex14p and Pex13p. Pex14p and Pex13p formed a complex with PTS1-loaded Pex5p but dissociated in the presence of cargo-unloaded Pex5p, hence implying that PTS cargoes are released from Pex5p at the step downstream of Pex14p and upstream of Pex13p. We reported that Pex7p shows a bimodal distribution between the cytoplasm and peroxisomes in CHO and human cells, implying that Pex7p shuttles between peroxisomes and the cytosol, like Pex5p. Pex7p requires nearly the full length, including all WD motifs, for its function.5) We recently isolated human PEX26 encoding a novel, 34-kDa type II peroxisomal membrane protein, using a CHO cell mutant ZP167. PEX26 expression restored peroxisomal protein import in only the CG8 PBD patient's fibroblasts. This patient possessed a homozygous, inactivating pathogenic point mutation, R98W. Accordingly, we can state that all of pathogenic genes responsible for 12 CGs PBDs have been cloned. Moreover, Pex6p and Pex1p of the AAA ATPase family were co-immunoprecipitated with Pex26p. Together with several lines of morphological evidence, we concluded that Pex26p recruits Pex6p-Pex1p complexes to peroxisomes. Less