McCollum D, Monosov E, Subramani S
Department of Biology, University of California, San Diego, La Jolla 92093-0322.
J Cell Biol. 1993 May;121(4):761-74. doi: 10.1083/jcb.121.4.761.
We previously described the isolation of mutants of the yeast Pichia pastoris that are deficient in peroxisome assembly (pas mutants). We describe the characterization of one of these mutants, pas8, and the cloning of the PAS8 gene. The pas8 mutant is deficient for growth, but not for division or segregation of peroxisomes, or for induction of peroxisomal proteins. Two distinct peroxisomal targeting signals, PTS1 and PTS2, have been identified that are sufficient to direct proteins to the peroxisomal matrix. We show that the pas8 mutant is deficient in the import of proteins with the PTS1, but not the PTS2, targeting signal. This is the same import deficiency as that found in cells from patients with the lethal human peroxisomal disorder Zellweger syndrome. Cloning and sequencing of the PAS8 gene reveals that it is a novel member of the tetratricopeptide repeat gene family. Antibodies raised against bacterially expressed PAS8 are used to show that PAS8 is a peroxisomal, membrane-associated protein. Also, we have found that in vitro translated PAS8 protein is capable of binding the PTS1 targeting signal specifically, raising the possibility that PAS8 is a PTS1 receptor.
我们之前描述过酵母毕赤酵母中过氧化物酶体组装缺陷的突变体（pas突变体）的分离。我们描述了其中一个突变体pas8的特征以及PAS8基因的克隆。pas8突变体生长存在缺陷，但过氧化物酶体的分裂、分离以及过氧化物酶体蛋白的诱导均无缺陷。已鉴定出两种不同的过氧化物酶体靶向信号，PTS1和PTS2，它们足以将蛋白质导向过氧化物酶体基质。我们发现pas8突变体对带有PTS1靶向信号的蛋白质的导入存在缺陷，但对带有PTS2靶向信号的蛋白质的导入无缺陷。这与患有致死性人类过氧化物酶体疾病泽尔韦格综合征患者细胞中的导入缺陷相同。PAS8基因的克隆和测序表明它是四肽重复基因家族的一个新成员。针对细菌表达的PAS8产生的抗体用于证明PAS8是一种与过氧化物酶体膜相关的蛋白质。此外，我们发现体外翻译的PAS8蛋白能够特异性结合PTS1靶向信号，这增加了PAS8是一种PTS1受体的可能性。
