TY  - JOUR
A1  - Ulrich, Thomas
A1  - Groß, Lucia Evita
A1  - Sommer, Maik Sascha
A1  - Schleiff, Enrico
A1  - Rapaport, Doron
T1  - Chloroplast β-barrel proteins are assembled into the mitochondrial outer membrane in a process that depends on the TOM and TOB complexes
T2  - Journal of biological chemistry
N2  - 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.
KW  - Chloroplast
KW  - Membrane Proteins
KW  - Mitochondria
KW  - Mitochondrial Transport
KW  - Protein Sorting
KW  - β-Barrel Proteins
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/76658
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-766580
SN  - 0021-9258
VL  - 287.2012
IS  - 33
SP  - 27467
EP  - 27479
PB  - American Society for Biochemistry and Molecular Biology Publications
CY  - Bethesda, Md
ER  -