TY  - JOUR
A1  - Dugar, Gaurav
A1  - Svensson, Sarah L.
A1  - Bischler, Thorsten
A1  - Waldchen, Sina
A1  - Reinhardt, Richard
A1  - Sauer, Markus
A1  - Sharma, Cynthia M.
T1  - The CsrA-FliW network controls polar localization of the dual-function flagellin mRNA in Campylobacter jejuni
JF  - Nature Communications
N2  - The widespread CsrA/RsmA protein regulators repress translation by binding GGA motifs in bacterial mRNAs. CsrA activity is primarily controlled through sequestration by multiple small regulatory RNAs. Here we investigate CsrA activity control in the absence of antagonizing small RNAs by examining the CsrA regulon in the human pathogen Campylobacter jejuni. We use genome-wide co-immunoprecipitation combined with RNA sequencing to show that CsrA primarily binds flagellar mRNAs and identify the major flagellin mRNA (flaA) as the main CsrA target. The flaA mRNA is translationally repressed by CsrA, but it can also titrate CsrA activity. Together with the main C. jejuni CsrA antagonist, the FliW protein, flaA mRNA controls CsrA-mediated post-transcriptional regulation of other flagellar genes. RNA-FISH reveals that flaA mRNA is expressed and localized at the poles of elongating cells. Polar flaA mRNA localization is translation dependent and is post-transcriptionally regulated by the CsrA-FliW network. Overall, our results suggest a role for CsrA-FliW in spatiotemporal control of flagella assembly and localization of a dual-function mRNA.
KW  - bacterial genetics
KW  - cell signalling
KW  - translation
KW  - Campylobacter jejuni
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-173201
VL  - 7
ER  - 
TY  - JOUR
A1  - Schneider, Johannes
A1  - Klein, Teresa
A1  - Mielich-Süss, Benjamin
A1  - Koch, Gudrun
A1  - Franke, Christian
A1  - Kuipers, Oskar P.
A1  - Kovács, Ákos T.
A1  - Sauer, Markus
A1  - Lopez, Daniel
T1  - Spatio-temporal Remodeling of Functional Membrane Microdomains Organizes the Signaling Networks of a Bacterium
JF  - PLoS Genetics
N2  - Lipid rafts are membrane microdomains specialized in the regulation of numerous cellular processes related to membrane organization, as diverse as signal transduction, protein sorting, membrane trafficking or pathogen invasion. It has been proposed that this functional diversity would require a heterogeneous population of raft domains with varying compositions. However, a mechanism for such diversification is not known. We recently discovered that bacterial membranes organize their signal transduction pathways in functional membrane microdomains (FMMs) that are structurally and functionally similar to the eukaryotic lipid rafts. In this report, we took advantage of the tractability of the prokaryotic model Bacillus subtilis to provide evidence for the coexistence of two distinct families of FMMs in bacterial membranes, displaying a distinctive distribution of proteins specialized in different biological processes. One family of microdomains harbors the scaffolding flotillin protein FloA that selectively tethers proteins specialized in regulating cell envelope turnover and primary metabolism. A second population of microdomains containing the two scaffolding flotillins, FloA and FloT, arises exclusively at later stages of cell growth and specializes in adaptation of cells to stationary phase. Importantly, the diversification of membrane microdomains does not occur arbitrarily. We discovered that bacterial cells control the spatio-temporal remodeling of microdomains by restricting the activation of FloT expression to stationary phase. This regulation ensures a sequential assembly of functionally specialized membrane microdomains to strategically organize signaling networks at the right time during the lifespan of a bacterium.
KW  - membrane proteins
KW  - gene expression
KW  - bacillus subtilis
KW  - fluorescence microscopy
KW  - cell fusion
KW  - signal transduction
KW  - gene regulation
KW  - lipids
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125577
VL  - 11
IS  - 4
ER  -