Biology subjects

Turlan, C.

Publications and source records attributed to Turlan, C..

2 recordsLinked to original sources

bioRxiv2020

Outer membrane lipoprotein DolP interacts with the BAM complex and promotes fitness during envelope stress response

In Gram-negative bacteria, coordinated remodelling of the outer membrane (OM) and the peptidoglycan is crucial for envelope integrity. Envelope stress caused by unfolded OM proteins (OMPs) activates sigmaE ({sigma}E) in Enterobacteria. {sigma}E upregulates OMP biogenesis factors, including the {beta}-barrel assembly machinery (BAM) that catalyzes OMP-folding. Elevated {sigma}E activity, however, can be detrimental for OM integrity. Here we report that DolP (YraP), a {sigma}E-upregulated OM lipoprotein important for envelope integrity, is a novel interactor of BAM and we demonstrate that OM-assembled BamA is a critical determinant of the BAM-DolP complex. Mid-cell recruitment of DolP had been previously associated to activation of septal peptidoglycan remodelling during cell division, but its role during envelope stress was unknown. We now show that DolP promotes cell fitness upon stress-induced activation of {sigma}E and opposes a detrimental effect caused by the overaccumulation of BAM in the OM. During envelope stress, DolP loses its association with the mid-cell, thus suggesting a possible link between envelope stress caused by impaired OMP biogenesis and the regulation of a late step of cell division.

microbiology↗

bioRxiv2019

Role of centromere sites in activation of ParB proteins for partition complex assembly

The ParB-parS partition complexes that bacterial replicons use to ensure their faithful inheritance also find employment in visualization of DNA loci, as less intrusive alternatives to fluorescent repressor-operator systems. The ability of ParB molecules to interact via their N-terminal domains and to bind to non-specific DNA enables expansion of the initial complex to a size both functional in partition and, via fusion to fluorescent peptides, visible by light microscopy. We have investigated whether it is possible to dispense with the need to insert parS in the genomic locus of interest, by determining whether ParB fused to proteins that bind specifically to natural DNA sequences can still assemble visible complexes. In yeast cells, coproduction of fusions of ParB to a fluorescent peptide and to a TALE protein targeting an endogenous sequence did not yield visible foci; nor did any of several variants of these components. In E.coli, coproduction of fusions of SopB (F plasmid ParB) to fluorescent peptide, and to dCas9 together with specific guide RNAs, likewise yielded no foci. The result of coproducing analogous fusions of SopB proteins with distinct binding specificities was also negative. We conclude that in order to assemble higher order partition complexes, ParB proteins need specific activation through binding to their cognate parS sites.

microbiology↗