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エンドウ トシヤ
ENDO TOSHIYA
遠藤 斗志也 所属 京都産業大学 生命科学部 先端生命科学科 職種 客員教授 |
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| 言語種別 | 英語 |
| 発行・発表の年月 | 2001/10 |
| 形態種別 | 研究論文 |
| 査読 | 査読あり |
| 標題 | Loss of the mitochondrial Hsp70 functions causes aggregation of mitochondria in yeast cells |
| 執筆形態 | その他 |
| 掲載誌名 | JOURNAL OF CELL SCIENCE |
| 出版社・発行元 | COMPANY OF BIOLOGISTS LTD |
| 巻・号・頁 | 114(19),pp.3565-3574 |
| 著者・共著者 | A Kawai,S Nishikawa,A Hirata,T Endo |
| 概要 | Ssc1p, a member of the Hsp70 family in the mitochondrial matrix of budding yeast, mediates protein import into mitochondria and prevents irreversible aggregation of proteins in the mitochondrial matrix during folding/ assembly or at elevated temperature. Here, we show that functional inactivation of the mitochondrial Hsp70 system causes aggregation of mitochondria. When temperature-sensitive mitochondrial Hsp70 mutant cells were incubated at restrictive temperature, a tubular network of mitochondria was collapsed to form aggregates. Inhibition of protein synthesis in the cytosol did not suppress the mitochondrial aggregation and functional impairment of Tim23, a subunit of mitochondrial protein translocator in the inner membrane, did not cause mitochondrial aggregation. Therefore defects of the Hsp70 function in protein import into mitochondria or resulting accumulation of precursor forms of mitochondrial proteins outside the mitochondria are not the causal reason for the aberrant mitochondrial morphology. By contrast, deletion of Mdj1p, a functional partner for mitochondrial Hsp70 in prevention of irreversible protein aggregation in the matrix, but not in protein import into mitochondria, caused aggregation of mitochondria, which was enhanced at elevated temperature (37 degreesC). The aggregation of mitochondria at 37 degreesC was reversed when the temperature was lowered to 23 degreesC unless protein synthesis was blocked. On the basis of these results, we propose that the mitochondrial matrix contains a protein that is responsible for the maintenance of mitochondrial morphology and requires mitochondrial Hsp70 for its function. |
| ISSN | 0021-9533/1477-9137 |