overproduction of flotillin influences cell differentiation and shape in bacillus subtilis unlabelled bacteria organize many membranerelated signaling processes in functional microdomains that are structurally and functionally similar to the lipid rafts of eukaryotic cells an important structural component of these microdomains is the protein flotillin which seems to act as a chaperone in recruiting other proteins to lipid rafts to facilitate their interaction in eukaryotic cells the occurrence of severe diseases is often observed in combination with an overproduction of flotillin but a functional link between these two phenomena is yet to be demonstrated in this work we used the bacterial model bacillus subtilis as a tractable system to study the physiological alterations that occur in cells that overproduce flotillin we discovered that an excess of flotillin altered specific signal transduction pathways that are associated with the membrane microdomains of bacteria as a consequence of this we detected significant defects in cell division and cell differentiation these physiological alterations were in part caused by an unusual stabilization of the raftassociated protease ftsh this report opens the possibility of using bacteria as a working model to better understand fundamental questions related to the functionality of lipid raftsimportance the identification of signaling platforms in the membrane of bacteria that are functionally and structurally equivalent to eukaryotic lipid rafts reveals a level of sophistication in signal transduction and membrane organization unexpected in bacteria it opens new and promising venues to address intricate questions related to the functionality of lipid rafts by using bacteria as a more tractable system this is the first report that uses bacteria as a working model to investigate a fundamental question that was previously raised while studying the role of eukaryotic lipid rafts it also provides evidence of the critical role of these signaling platforms in orchestrating diverse physiological processes in prokaryotic cells