Activators of the glutamate-dependent acid resistance system alleviate deleterious effects of YidC depletion in Escherichia coli.

Zhong Yu (1) , Martijn Bekker (2) , Angela Tramonti (3) , Gregory M Cook (4) , Peter van Ulsen (1) , Dirk-Jan Scheffers (1, 5) , Joost Teixeira de Mattos (2) , Daniela de Biase (6) , Joen Luirink (1)

1 Department of Molecular Microbiology
2 Department of Molecular and Microbial Physiology
3 CNR, Dipartimento di Scienze Biochimiche
4 Department of Microbiology and Immunology
5 Department of Molecular Microbiology
6 Department of Medical-Surgical Sciences and Biotechnologies

The function of the essential inner membrane protein (IMP) YidC in Escherichia coli has been studied for a limited number of model IMPs and primarily using targeted approaches. These studies suggested that YidC acts at the level of insertion, folding, and quality control of IMPs, both in the context of the Sec translocon and as a separate entity. To further our understanding of YidC's role in IMP biogenesis, we screened a random overexpression library for factors that rescued the growth of cells upon YidC depletion. We found that the overexpression of the GadX and GadY regulators of the glutamate-dependent acid resistance system complemented the growth defect of YidC-depleted cells. Evidence is presented that GadXY overexpression counteracts the deleterious effects of YidC depletion on at least two fronts. First, GadXY prepares the cells for the decrease in respiratory capacity upon the depletion of YidC. Most likely, GadXY-regulated processes reduce the drop in proton-motive force that impairs the fitness of YidC-depleted cells. Second, in GadXY-overproducing cells increased levels of the general chaperone GroEL cofractionate with the inner membranes, which may help to keep newly synthesized inner membrane proteins in an insertion-competent state when YidC levels are limiting.

Domaines: Biochimie, Biologie Moléculaire

Zhong Yu, Martijn Bekker, Angela Tramonti, Gregory M Cook, Peter van Ulsen, et al.. Activators of the glutamate-dependent acid resistance system alleviate deleterious effects of YidC depletion in Escherichia coli.. Journal of Bacteriology, 2011, 193 (6), pp.1308-16. ⟨10.1128/JB.01209-10⟩. ⟨pasteur-00975347⟩