FUNCTIONAL COOPERATION OF MITOCHONDRIAL PROTEIN IMPORT RECEPTORS IN YEAST
FUNCTIONAL COOPERATION OF MITOCHONDRIAL PROTEIN IMPORT RECEPTORS IN YEAST
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DOI：
10.1002/j.1460-2075.1993.tb06095.x
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发表时间：
1993-11-01
期刊：
影响因子：
11.4
通讯作者：
SCHATZ, G
中科院分区：
文献类型：
--
作者：
RAMAGE, L;JUNNE, T;SCHATZ, G
我们已经确定了一个20 kDa的酵母线粒体外膜蛋白（称为MAS 20），它似乎作为一个蛋白质输入受体的功能。我们克隆了MAS 20基因，测序和物理定位，发现该蛋白质与粗糙脉孢菌的MOM 19输入受体同源。MAS 20和MOM 19含有序列基序F-X-K-A-L-X-V/L，其在MAS 70/MOM 72受体中重复数次，具有微小变化。为了确定MAS 20如何与先前鉴定的酵母受体MAS 70一起起作用，我们构建了缺乏一种或两种受体的酵母突变体。单独缺失任一受体对发酵生长的影响很小或没有影响，并且仅部分抑制体内线粒体蛋白的输入。两种受体的缺失都是致命的。仅缺失MAS 70不影响呼吸;仅缺失MAS 20导致呼吸丧失，但呼吸可通过过表达MAS 70恢复。进口的F1-ATP酶β-亚基到分离的线粒体中，只有部分抑制IgG对MAS 20或MAS 70，但这两个IgG完全抑制进口。我们的结论是，这两种受体有重叠的特异性线粒体前体蛋白，没有受体本身是必不可少的。
We have identified a 20 kDa yeast mitochondrial outer membrane protein (termed MAS20) which appears to function as a protein import receptor. We cloned, sequenced and physically mapped the MAS20 gene and found that the protein is homologous to the MOM19 import receptor from Neurospora crassa. MAS20 and MOM19 contain the sequence motif F-X-K-A-L-X-V/L, which is repeated several times with minor variations in the MAS70/MOM72 receptors. To determine how MAS20 functions together with the previously identified yeast receptor MAS70, we constructed yeast mutants lacking either one or both of the receptors. Deletion of either receptor alone had little or no effect on fermentative growth and only partially inhibited mitochondrial protein import in vivo. Deletion of both receptors was lethal. Deleting only MAS70 did not affect respiration; deleting only MAS20 caused loss of respiration, but respiration could be restored by overexpressing MAS70. Import of the F1-ATPase beta-subunit into isolated mitochondria was only partly inhibited by IgGs against either MAS20 or MAS70, but both IgGs inhibited import completely. We conclude that the two receptors have overlapping specificities for mitochondrial precursor proteins and that neither receptor is by itself essential.