Lithgow T, Junne T, Suda K, Gratzer S, Schatz G
Biozentrum, Universität Basel, Switzerland.
Proc Natl Acad Sci U S A. 1994 Dec 6;91(25):11973-7. doi: 10.1073/pnas.91.25.11973.
We have cloned the gene encoding the protein Mas22p, which spans the outer membrane of yeast mitochondria. Cells that completely lack Mas22p are inviable. The plasmid-borne MAS22 gene suppresses several defects resulting from the deletion of one or more of the mitochondrial protein import receptors. Defects of Mas20p-deficient cells are explained by the reduced level of Mas22p in these mutants. Mas22p has one acidic domain in the cytosol and a second acidic domain in the mitochondrial intermembrane space. We suggest that these domains of Mas22p on either side of the outer membrane function as a relay system for transferring the basic targeting sequences of precursor proteins into the mitochondria.
我们已经克隆了编码蛋白质Mas22p的基因，该基因跨越酵母线粒体的外膜。完全缺乏Mas22p的细胞无法存活。质粒携带的MAS22基因可抑制因缺失一种或多种线粒体蛋白质导入受体而导致的几种缺陷。Mas20p缺陷细胞的缺陷可通过这些突变体中Mas22p水平的降低来解释。Mas22p在细胞质中有一个酸性结构域，在线粒体膜间隙中有第二个酸性结构域。我们认为，外膜两侧的这些Mas22p结构域作为一种中继系统，将前体蛋白的碱性靶向序列转移到线粒体中。
