Conserved mechanism of Oxa1 insertion into the mitochondrial inner membrane
| Autor: | Grazyna Domanska, Elke A Dian, Christian Motz, Joachim Rassow, Olga Randelj, Thomas Krimmer, Sebastian Reif |
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| Rok vydání: | 2005 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Translocase of the outer membrane Saccharomyces cerevisiae Biology Electron Transport Complex IV Mitochondrial Proteins Mitochondrial membrane transport protein Structural Biology Mitochondrial Precursor Protein Import Complex Proteins HSP70 Heat-Shock Proteins Molecular Biology Integral membrane protein Peripheral membrane protein Membrane Transport Proteins Nuclear Proteins Intracellular Membranes Cell biology Mitochondria Molecular Weight Membrane protein Translocase of the inner membrane Mutation biology.protein ATP–ADP translocase Intermembrane space Protein Binding |
| Zdroj: | Journal of molecular biology. 354(3) |
| ISSN: | 0022-2836 |
| Popis: | Oxa1 is the mitochondrial representative of a family of related proteins that mediate the insertion of substrate proteins into the membranes of bacteria, chloroplasts, and mitochondria. Several studies have demonstrated that the bacterial homologue YidC participates both in the direct uptake of proteins from the bacterial cytosol, and in the uptake of nascent proteins from the Sec translocase. Studies on the biogenesis of membrane proteins in mitochondria established that Oxa1 has the capability to receive substrates at the inner surface of the inner membrane. In this study, we asked if Oxa1 may similarly cooperate with a protein translocase within the membrane. Since Oxa1 is involved in its own biogenesis, we used the precursor of Oxa1 as a model protein and investigated its import pathway. We found that immediately after import into mitochondria, Oxa1 initially accumulates at Tim23 that forms the inner membrane protein translocase. Cleavage of the Oxa1 presequence is dependent on mtHsp70, a heat shock protein of the mitochondrial matrix. However, mutant mtHsp70 showing a defect in the release of bound substrate proteins does not interfere with subsequent membrane insertion, indicating that membrane insertion of the mature protein is essentially mtHsp70-independent. We conclude that Oxa1 has the ability to accept preproteins within the membrane. |
| Databáze: | OpenAIRE |
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