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Yeast Oxa1 interacts with mitochondrial ribosomes: the importance of the C‐terminal region of Oxa1
Author(s) -
Jia Lixia,
Dienhart Mary,
Schramp Mark,
McCauley Matthew,
Hell Kai,
Stuart Rosemary A.
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg624
Subject(s) - biology , ribosome , mitochondrial ribosome , ribosomal protein , ribosomal rna , microbiology and biotechnology , mitochondrion , membrane transport protein , translocase of the outer membrane , translocase of the inner membrane , membrane protein , translation (biology) , inner mitochondrial membrane , genetics , biochemistry , mitochondrial membrane transport protein , rna , gene , membrane , messenger rna
The yeast mitochondrial Oxa1 protein is a member of the conserved Oxa1/YidC/Alb3 protein family involved in the membrane insertion of proteins. Oxa1 mediates the insertion of proteins (nuclearly and mitochondrially encoded) into the inner membrane. The mitochondrially encoded substrates interact directly with Oxa1 during their synthesis as nascent chains and in a manner that is supported by the associated ribosome. We have investigated if the Oxa1 complex interacts with the mitochondrial ribosome. Evidence to support a physical association between Oxa1 and the large ribosomal subunit is presented. Our data indicate that the matrix‐exposed C‐terminal region of Oxa1 plays an important role supporting the ribosomal–Oxa1 interaction. Truncation of this C‐terminal segment compromises the ability of Oxa1 to support insertion of substrate proteins into the inner membrane. Oxa1 can be cross‐linked to Mrp20, a component of the large ribosomal subunit. Mrp20 is homologous to L23, a subunit located next to the peptide exit tunnel of the ribosome. We propose that the interaction of Oxa1 with the ribosome serves to enhance a coupling of translation and membrane insertion events.