title: Mitochondria can recognize and assemble fragments of a beta-barrel structure.
abstract: β-barrel proteins are found in the outer membranes of eukaryotic organelles of endosymbiotic origin as well as in the outer membrane of Gram-negative bacteria. Precursors of mitochondrial β-barrel proteins are synthesized in the cytosol and have to be targeted to the organelle. Currently, the signal that assures their specific targeting to mitochondria is poorly defined. To characterize the structural features needed for specific mitochondrial targeting and to test whether a full β-barrel structure is required, we expressed in yeast cells the β-barrel domain of the trimeric autotransporter Yersinia adhesin A (YadA). Trimeric autotransporters are found only in prokaryotes, where they are anchored to the outer membrane by a single 12-stranded β-barrel structure to which each monomer is contributing four β-strands. Importantly, we found that YadA is solely localized to the mitochondrial outer membrane, where it exists in a native trimeric conformation. These findings demonstrate that, rather than a linear sequence or a complete β-barrel structure, four β-strands are sufficient for the mitochondria to recognize and assemble a β-barrel protein. Remarkably, the evolutionary origin of mitochondria from bacteria enables them to import and assemble even proteins belonging to a class that is absent in eukaryotes.
authors: Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany.
authors: Jonas E N
authors: JE
authors: Müller
authors: Drazen
authors: D
authors: Papic
authors: Thomas
authors: T
authors: Ulrich
authors: Iwan
authors: I
authors: Grin
authors: Monika
authors: M
authors: Schütz
authors: Philipp
authors: P
authors: Oberhettinger
authors: Jan
authors: J
authors: Tommassen
authors: Dirk
authors: D
authors: Linke
authors: Kai S
authors: KS
authors: Dimmer
authors: Ingo B
authors: IB
authors: Autenrieth
authors: Doron
authors: D
authors: Rapaport
mesh_terms: D018829:Adhesins, Bacterial / Q000096:biosynthesis* / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism*; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000378:metabolism; D010446:Peptide Fragments / Q000096:biosynthesis* / Q000378:metabolism; D017510:Protein Folding; D055503:Protein Multimerization; D021382:Protein Sorting Signals; D055550:Protein Stability; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000378:metabolism; D012441:Saccharomyces cerevisiae
chemical_list: D018829:Adhesins, Bacterial; D018832:Molecular Chaperones; D010446:Peptide Fragments; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; C064832:YadA protein, Yersinia