Human small G proteins, ObgH1, and ObgH2, participate in the maintenance of mitochondria and nucleolar architectures
Human small G proteins, ObgH1, and ObgH2, participate in the maintenance of mitochondria and nucleolar architectures
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DOI：
10.1111/j.1365-2443.2006.01017.x
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发表时间：
2006-11-01
期刊：
影响因子：
2.1
通讯作者：
Takeyasu, Kunio
中科院分区：
文献类型：
--
作者：
Hirano, Yasuhiro;Ohniwa, Ryosuke L.;Takeyasu, Kunio
Obg亚家族蛋白是一种P-loop小G蛋白，在从细菌到人类的许多生物中都高度保守。两个obg基因obgH1和obgH2存在于人类基因组中。ObgH1和ObgH2具有与细菌Obg蛋白相似的GTPase活性(分别为0.014+/-0.005和0.010+/-0.002/分)，并在大肠杆菌核糖体成熟过程中补充了Obg的功能，表明Obg蛋白的功能在进化过程中被很好地保守。HeLa细胞的免疫荧光显微镜显示，ObgH1定位于线粒体，ObgH2位于核仁的致密纤维室区域。RNAi敲除ObgH1导致线粒体伸长，而敲除ObgH2导致核仁结构解体。综上所述，这两种人OBG蛋白具有相似的补充细菌OBG功能的酶活性，但因细胞内定位不同而表现出不同的细胞功能(S)。
The Obg subfamily protein is one of the P-loop small G proteins and is highly conserved in many organisms from bacteria to human. Two obg genes, obgH1 and obgH2, exist in the human genome. Both ObgH1 and ObgH2 showed similar GTPase activities (0.014 +/- 0.005 and 0.010 +/- 0.002/min for ObgH1 and ObgH2, respectively) to those of the bacterial Obg proteins and complemented the Obg function in Escherichia coli ribosome maturation, suggesting that the functions of Obg proteins are well conserved through evolution. Immunofluorescence microscopy of HeLa cells revealed that ObgH1 localizes in mitochondria, and ObgH2 in the dense fibrillar compartment region of the nucleolus. Knock-down of ObgH1 by RNAi induced mitochondria elongation, whereas knock-down of ObgH2 resulted in the disorganization of the nucleolar architecture. In conclusion, the two human Obg proteins have similar enzymatic activities that can complement bacterial Obg function, but show different cellular function(s) with different intracellular localizations.