title: Evolutionary conservation in biogenesis of β-barrel proteins allows mitochondria to assemble a functional bacterial trimeric autotransporter protein.
abstract: Yersinia adhesin A (YadA) belongs to a class of bacterial adhesins that form trimeric structures. Their mature form contains a passenger domain and a C-terminal β-domain that anchors the protein in the outer membrane (OM). Little is known about how precursors of such proteins cross the periplasm and assemble into the OM. In the present study we took advantage of the evolutionary conservation in the biogenesis of β-barrel proteins between bacteria and mitochondria. We previously observed that upon expression in yeast cells, bacterial β-barrel proteins including the transmembrane domain of YadA assemble into the mitochondrial OM. In the current study we found that when expressed in yeast cells both the monomeric and trimeric forms of full-length YadA were detected in mitochondria but only the trimeric species was fully integrated into the OM. The oligomeric form was exposed on the surface of the organelle in its native conformation and maintained its capacity to adhere to host cells. The co-expression of YadA with a mitochondria-targeted form of the bacterial periplasmic chaperone Skp, but not with SurA or SecB, resulted in enhanced levels of both forms of YadA. Taken together, these results indicate that the proper assembly of trimeric autotransporter can occur also in a system lacking the lipoproteins of the BAM machinery and is specifically enhanced by the chaperone Skp.
authors.affiliation: From the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ulrich
authors.affiliation: Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany, and.
authors.forename: Philipp
authors.initials: P
authors.lastname: Oberhettinger
authors.affiliation: Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany, and.
authors.forename: Monika
authors.initials: M
authors.lastname: Schütz
authors.affiliation: From the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Holzer
authors.affiliation: From the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Anne S
authors.initials: AS
authors.lastname: Ramms
authors.affiliation: Department of Protein Evolution, Max-Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Linke
authors.affiliation: Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076 Tübingen, Germany, and.
authors.forename: Ingo B
authors.initials: IB
authors.lastname: Autenrieth
authors.affiliation: From the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany, doron.rapaport@uni-tuebingen.de.
authors.forename: Doron
authors.initials: D
authors.lastname: Rapaport
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry / Q000378:metabolism*; D017124:Conserved Sequence; D019143:Evolution, Molecular; D006367:HeLa Cells; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D059748:Proteolysis; D012441:Saccharomyces cerevisiae / Q000378:metabolism
chemical_list: D018829:Adhesins, Bacterial; D024101:Mitochondrial Proteins; D018832:Molecular Chaperones; C064832:YadA protein, Yersinia
keywords: Autotransporters; BAM Complex; Bacterial Adhesion; Membrane Protein; Mitochondrial Transport; Molecular Evolution; Protein Stability; Protein Targeting; Skp; YadA