Genetic and functional interactions between the mitochondrial outer membrane proteins Tom6 and Sam37.
Mol Cell Biol
; 29(22): 5975-88, 2009 Nov.
Article
em En
| MEDLINE
| ID: mdl-19797086
ABSTRACT
The TOM complex is the general mitochondrial entry site for newly synthesized proteins. Precursors of beta-barrel proteins initially follow this common pathway and are then relayed to the SAM/TOB complex, which mediates their integration into the outer membrane. Three proteins, Sam50 (Tob55), Sam35 (Tob38/Tom38), and Sam37 (Mas37), have been identified as the core constituents of the latter complex. Sam37 is essential for growth at elevated temperatures, but the function of the protein is currently unresolved. To identify interacting partners of Sam37 and thus shed light on its function, we screened for multicopy suppressors of sam37Delta. We identified the small subunit of the TOM complex, Tom6, as such a suppressor and found a tight genetic interaction between the two proteins. Overexpression of SAM37 suppresses the growth phenotype of tom6Delta, and cells lacking both genes are not viable. The ability of large amounts of Tom6 to suppress the sam37Delta phenotype can be linked to the capacity of Tom6 to stabilize Tom40, an essential beta-barrel protein which is the central component of the TOM complex. Our results suggest that Sam37 is required for growth at higher temperatures, since it enhances the biogenesis of Tom40, and this requirement can be overruled by improved stability of newly synthesized Tom40 molecules.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
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Proteínas de Saccharomyces cerevisiae
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Proteínas Mitocondriais
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Proteínas de Transporte da Membrana Mitocondrial
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Membranas Mitocondriais
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Proteínas de Membrana
Idioma:
En
Revista:
Mol Cell Biol
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Alemanha