Wylin T, Baes M, Brees C, Mannaerts G P, Fransen M, Van Veldhoven P P
Katholieke Universiteit Leuven, Faculteit Geneeskunde, Departement Moleculaire Celbiologie, Afdeling Farmacologie, Belgium.
Eur J Biochem. 1998 Dec 1;258(2):332-8. doi: 10.1046/j.1432-1327.1998.2580332.x.
The cDNA of a human protein displaying 33% identity to the peroxisomal integral membrane protein PMP47 of Candida boidinii (CbPMP47) was cloned. It encodes a protein of 307 amino acids, with a calculated molecular mass of 34,566 Da. The protein, which we name HsPMP34, contains six membrane spans and belongs, like PMP47, to the family of mitochondrial solute carriers. Based on overlapping available expressed sequence tags (ESTs) combined with the sequencing of one EST, the amino acid sequence of the mouse counterpart (molecular mass of 34,422 Da) could also be deduced. By means of reverse-transcription PCR, the presence of PMP34 mRNA was revealed in liver of man and in liver and other tissues of mouse and rat. The human gene is localized to chromosome 22q13. Given the similarity of HsPMP34 not only to CbPMP47 but also to known or putative mitochondrial transporters, its subcellular localization was investigated. Fluorescence microscopy of HepG2 cells or mouse fibroblasts transfected with a plasmid encoding a HsPMP34/green fluorescent fusion protein revealed a punctate pattern, reminiscent of a peroxisomal distribution. By indirect immunofluorescence, the HsPMP34/green fluorescent fusion protein clearly colocalized with the dimeric peroxisomal thiolase. Upon transfection of mouse fibroblasts lacking functional peroxisomes due the knock-out of PEX5 [Baes, M., Gressens, P., Baumgart, E., Carmeliet, P., Casteels, M., Fransen, M., Evrard, P., Fahimi, D., Declercq, P. E., Collen, D., Van Veldhoven, P. P. & Mannaerts, G. P. (1997) Nat. Genet. 17, 49-53], fluorescence was associated with larger and less-abundant structures. Taken together, the data indicate that HsPMP34 is a peroxisomal membrane protein and is either the human counterpart of CbPMP47 or closely related to it. According to its structure, the protein is most probably involved in transport.
克隆了一种与博伊丁假丝酵母（CbPMP47）的过氧化物酶体整合膜蛋白PMP47具有33%同源性的人类蛋白质的cDNA。它编码一个由307个氨基酸组成的蛋白质，计算分子量为34566道尔顿。我们将该蛋白质命名为HsPMP34，它含有六个跨膜结构域，与PMP47一样，属于线粒体溶质载体家族。基于重叠的可用表达序列标签（EST）并结合一个EST的测序，也可以推断出小鼠对应物（分子量为34422道尔顿）的氨基酸序列。通过逆转录PCR，发现在人的肝脏以及小鼠和大鼠的肝脏及其他组织中存在PMP34 mRNA。人类基因定位于22号染色体q13区。鉴于HsPMP34不仅与CbPMP47相似，而且与已知或推定的线粒体转运蛋白相似，因此对其亚细胞定位进行了研究。对用编码HsPMP34/绿色荧光融合蛋白的质粒转染的HepG2细胞或小鼠成纤维细胞进行荧光显微镜观察，发现呈现点状模式，让人联想到过氧化物酶体的分布。通过间接免疫荧光法，HsPMP34/绿色荧光融合蛋白与二聚体过氧化物酶体硫解酶明显共定位。在用PEX5基因敲除而缺乏功能性过氧化物酶体的小鼠成纤维细胞中转染后[Baes, M., Gressens, P., Baumgart, E., Carmeliet, P., Casteels, M., Fransen, M., Evrard, P., Fahimi, D., Declercq, P. E., Collen, D., Van Veldhoven, P. P. & Mannaerts, G. P. (1997) Nat. Genet. 17, 49 - 53]，荧光与更大且数量更少的结构相关。综上所述，数据表明HsPMP34是一种过氧化物酶体膜蛋白，要么是CbPMP47的人类对应物，要么与之密切相关。根据其结构，该蛋白很可能参与转运。
