Genetic and Functional Interactions between the Mitochondrial Outer Membrane Proteins Tom6 and Sam37▿
AUTOR(ES)
Dukanovic, Jovana
FONTE
American Society for Microbiology (ASM)
RESUMO
The TOM complex is the general mitochondrial entry site for newly synthesized proteins. Precursors of β-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 sam37Δ. 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 tom6Δ, and cells lacking both genes are not viable. The ability of large amounts of Tom6 to suppress the sam37Δ phenotype can be linked to the capacity of Tom6 to stabilize Tom40, an essential β-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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2772571Documentos Relacionados
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