flotillin => membrane fluidity control protein

In order to implement these properties, different types of proteins are active in cells, including the so-called flotillins. These proteins are present in cells from bacteria to humans. Until now, scientists assumed that these flotillins mainly help in the formation of other functional protein complexes and confine highly ordered areas of the cell membrane.

researchers were able to show that flotillin proteins apparently have a direct influence on the structure of the cell membrane and can make it more fluid under certain conditions.

Apparently, they regulate the fluidity of bacterial membranes, making them more fluid to a certain extent and thus, changing their properties," 

This assumption might also explain the effect that flotillins have on the synthesis of the cell wall: building blocks for the cell wall are produced inside the cells and must subsequently be "flipped" outwards, which is easier to do in a more fluid membrane. In addition, the protein machinery that synthesizes the cell wall moves dynamically through the cell membrane and this movement is significantly reduced in the absence of the flotillins. 

These experiments showed that fast-growing cells are unable to develop their typical shape in the absence of flotillins. However, if the researchers added a chemical substance to fluidize the membranes, the bacteria could maintain their shape even without flotillin proteins. "We therefore assume that they take over a physical role in the bacterial membrane,"

In further research, the researchers hope to find out what is the exact molecular mechanism between the flotillin proteins and membrane fluidity.

 

Flotillins have been implicated in myriad processes that include endocytosis, signal transduction and regulation of the cortical cytoskeleton, (Journal of Cell Science 2011 124: 3933-3940; doi: 10.1242/jcs.092015)

 

 

reference

 Aleksandra Zielińska et al. Flotillin-mediated membrane fluidity controls peptidoglycan synthesis and MreB movement, eLife (2020). DOI: 10.7554/eLife.57179