Chloroplast β-barrel proteins are assembled into the mitochondrial outer membrane in a process that depends on the TOM and TOB complexes

  • Membrane-embedded β-barrel proteins are found in the outer membranes (OM) of Gram-negative bacteria, mitochondria and chloroplasts. In eukaryotic cells, precursors of these proteins are synthesized in the cytosol and have to be sorted to their corresponding organelle. Currently, the signal that ensures their specific targeting to either mitochondria or chloroplasts is ill-defined. To address this issue, we studied targeting of the chloroplast β-barrel proteins Oep37 and Oep24. We found that both proteins can be integrated in vitro into isolated plant mitochondria. Furthermore, upon their expression in yeast cells Oep37 and Oep24 were exclusively located in the mitochondrial OM. Oep37 partially complemented the growth phenotype of yeast cells lacking Porin, the general metabolite transporter of this membrane. Similarly to mitochondrial β-barrel proteins, Oep37 and Oep24 expressed in yeast cells were assembled into the mitochondrial OM in a pathway dependent on the TOM and TOB complexes. Taken together, this study demonstrates that the central mitochondrial components that mediate the import of yeast β-barrel proteins can deal with precursors of chloroplast β-barrel proteins. This implies that the mitochondrial import machinery does not recognize signals that are unique to mitochondrial β-barrel proteins. Our results further suggest that dedicated targeting factors had to evolve in plant cells to prevent mis-sorting of chloroplast β-barrel proteins to mitochondria.

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Metadaten
Author:Thomas Ulrich, Lucia Evita GroßGND, Maik Sascha SommerGND, Enrico SchleiffORCiDGND, Doron RapaportORCiDGND
URN:urn:nbn:de:hebis:30:3-766580
DOI:https://doi.org/10.1074/jbc.M112.382093
ISSN:0021-9258
Pubmed Id:https://pubmed.ncbi.nlm.nih.gov/22745120
Parent Title (English):Journal of biological chemistry
Publisher:American Society for Biochemistry and Molecular Biology Publications
Place of publication:Bethesda, Md
Document Type:Article
Language:English
Date of Publication (online):2021/01/04
Year of first Publication:2012
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2024/02/06
Tag:Chloroplast; Membrane Proteins; Mitochondria; Mitochondrial Transport; Protein Sorting; β-Barrel Proteins
Volume:287.2012
Issue:33
Page Number:13
First Page:27467
Last Page:27479
Institutes:Biowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - CC BY - Namensnennung 4.0 International