Structural basis of functional cooperation of Tim15/Zim17 with yeast mitochondrial Hsp70

• Published in: EMBO reports Vol. 8; no. 7; pp. 664 - 670
• Main Authors: Momose, Takaki, Ohshima, Chié, Maeda, Masahiro, Endo, Toshiya
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.07.2007; Blackwell Publishing Ltd; Nature Publishing Group
• Subjects: Cell growth; chaperone; Escherichia coli - genetics; Hsp70; HSP70 Heat-Shock Proteins - chemistry; HSP70 Heat-Shock Proteins - metabolism; Hydrogen Bonding; Intracellular Membranes - metabolism; mitochondria; Mitochondria - metabolism; Mitochondrial Proteins - chemistry; Mitochondrial Proteins - genetics; Mitochondrial Proteins - metabolism; Mitochondrial Proteins - physiology; Models, Molecular; Molecular biology; Mutagenesis; Mutation; NMR; Nuclear magnetic resonance; Nuclear Magnetic Resonance, Biomolecular; Protein Binding; protein import; Protein Structure, Secondary; Protein Structure, Tertiary; Proteins; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - chemistry; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Saccharomyces cerevisiae Proteins - physiology; Scientific Report; Static Electricity; Tim15; Yeast; Yeasts; Zinc Fingers
• ISSN: 1469-221X; 1469-3178; 1469-221X
• DOI: 10.1038/sj.embor.7400990

Mitochondrial heat‐shock protein 70 (mtHsp70) and its partner proteins drive protein import into the matrix. Tim15/Zim17/Hep1 is a mtHsp70 partner protein on the matrix side of the inner mitochondrial membrane. We determined the nuclear magnetic resonance (NMR) structure of the core domain of Tim15. On the basis of the NMR structure, we created Tim15 mutants and tested their ability to complement the functional defects of Tim15 depletion and to suppress self‐aggregation of mtHsp70 in vivo. A pair of basic residues, Arg 106 and His 107, conserved Asp 111 and flexible loop 133–137, and were important (Arg 106–His 107 pair and Asp 111) or partly important (the loop 133–137) for yeast cell growth, mitochondrial protein import and the suppression of mtHsp70 aggregation. Therefore, the function of Tim15 in yeast cell growth is well correlated with its ability to suppress mtHsp70 aggregation, although it is still unknown whether inhibition of mtHsp70 aggregation is the primary function of Tim15.