The protein import motor of mitochondria: Unfolding and trapping of preproteins ave distinct and separable functions of matrix Hsp70

被引：206

作者：

Voisine, C

Craig, EA ^{[1
]}

Zufall, N

von Ahsen, O

Pfanner, N

Voos, W

机构：

[1] Univ Wisconsin, Dept Biomol Chem, Madison, WI 53706 USA

[2] Univ Freiburg, Inst Biochem & Mol Biol, D-79104 Freiburg, Germany

来源：

CELL | 1999年 / 97卷 / 05期

关键词：

D O I：

10.1016/S0092-8674(00)80768-0

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Mitochondrial heat shock protein 70 (mtHsp70) functions in unfolding, translocation, and folding of imported proteins. Controversial models of mtHsp70 action have been discussed: (1) physical trapping of preproteins is sufficient to explain the various mtHsp70 functions, and (2) unfolding of preproteins requires an active motor function of mtHsp70 ("pulling"). Intragenic suppressors of a mutant mtHsp70 separate two functions: a nonlethal folding defect caused by enhanced trapping of preproteins, and a conditionally lethal unfolding defect caused by an impaired interaction of mtHsp70 with the membrane anchor Tim44. Even enhanced trapping in wild-type mitochondria does not generate a pulling force. The motor function of mtHsp70 cannot be explained by passive trapping alone but includes an essential ATP-dependent interaction with Tim44 to generate a pulling force and unfold preproteins.

引用

收藏

页码：565 / 574

页数：10

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