Figure 1

Co-expression of native Tob55 and Tob55-BamA hybrids affects the detected levels of bacterial OMPs.

(a) Schematic representation of the Tob55/BamA hybrid proteins. Mitochondrial proteins/domains are in red whereas bacterial ones are in blue. (b) Yeast cells were transformed with an empty plasmid (Ø) or with a plasmid encoding the indicated hybrid protein. Growth was analyzed by drop-dilution assay at either 30 °C or 37 °C on rich medium containing either glucose (YPD) or glycerol (YPG), or on glucose-containing synthetic medium that lacks tryptophan (SD-Trp). (c–e) Crude mitochondria were isolated from cells co-expressing OmpA (c), OmpC (d) or PhoE (e) together with an empty plasmid (Ø) or the indicated hybrid protein. Proteins were analyzed by SDS-PAGE and immunodetection with antibodies against the indicated mitochondrial OM proteins Tob55, Porin (β-barrel protein) as well as Tom20 and Fis1 (single-span proteins). The Tob55/BamA variants are indicated with an asterisk (*) whereas a non-specific band of the Tob55 antibody is depicted with a hash (#). (f) The bands of at least three independent experiments as those described in (c–e) were quantified and their mean ± s.d. are presented. To allow comparison among the various samples, the levels of Tom20 were taken as internal reference. The intensities of the bands from cells transformed with an empty vector were set to 100%.