期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 278, 期 49, 页码 48997-49005出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M308436200
关键词
-
资金
- NCI NIH HHS [CA42014] Funding Source: Medline
- NIGMS NIH HHS [GM-53466] Funding Source: Medline
In the yeast Saccharomyces cerevisiae, the integral membrane protein Mmm1p is required for maintenance of mitochondrial morphology and retention of mitochondrial DNA ( mtDNA). Mmm1p localizes to discrete foci on mitochondria that are adjacent to mtDNA nucleoids in the matrix, raising the possibility that this protein plays a direct role in organizing, replicating, or segregating mtDNA. Although Mmm1p has been shown to cross the outer membrane with its C terminus facing the cytoplasm, the location of the N terminus has not been resolved. Here we show that Mmm1p spans both the outer and inner mitochondrial membranes, exposing its N terminus to the matrix. Surprisingly, deletion of the N-terminal extension decreased steady-state levels of the Mmm1 protein but did not affect mitochondrial morphology or mtDNA maintenance. Moreover, expression of Neurospora crassa MMM1, which naturally lacks a long N-terminal extension, substituted for loss of Mmm1p in budding yeast. These results indicate that the matrix-exposed portion of Mmm1p is not essential for mtDNA nucleoid maintenance. Additional studies revealed that the transmembrane segment and C-terminal domain of Mmm1p are required for foci formation and mitochondrial targeting, respectively. Our data suggest that the double membrane-spanning topology of Mmm1p at the membrane contact site is critical for formation of tubular mitochondria.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据