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Team:Warsaw/Stage2/Background
From 2010.igem.org
MinC
MinC is the component of MinCDE system. Together with nucleoid occlusion it ensures that cell division will occur in the middle of a cell. Three proteins – MinC, MinD and MinE play different role[s] in preventing formation of division complex too close to cell poles [1]. MinC is directly responsible for stopping the early stage of division by inhibiting the polymerization of FtsZ protein monomers into a structure known as the Z-ring [8].
FtsZ is a tubuline homologue capable of creating chains, lariats and rings independently of other cellular factors [3]. The stability and decay of these structures is dependent on GTPase activity of FtsZ proteins [7]. At the beginning of cell division FtsZ monomers form the Z-ring to which other proteins responsible for the division are recruited. The presence of N-terminal domain of MinC prevents establishing additional Z-rings [9] [additional Z-rings from forming/being established].
In bacterial cells MinC is recruited to membrane by the second protein of the system – MinD. This process involves C-terminal domain of MinC, which is also responsible for oligomerisation of MinC [its oligomerisation]. Recruitment to membrane is necessary for the inhibiting effect to occur at the physiological concentration of protein [4]. Finally the third protein – MinE [-] is responsible for keeping the MinCD complex from acting in the midcell region[,] thus enabling the formation of Z-ring in the proper location [5]. It was shown that mutants in either minC or minD divide at cell pole much more often than wild type, resulting in creation of nucleoid-free minicells. This mutations, however are not lethal because enough of the cells in population divide properly to sustain growth [6].
Although MinCDE is mostly analysed in E.coli, it’s elements were found in many different bacteria groups including Proteobacteria, Deinococcus-Thermus and Firmicutes phyla [1]. In B. subtilis the MinE protein is replaced by DivIVa which locates itself at the cell poles and with help of MinJ binds MinCD complex, decreasing it’s concentration at midcell [2].
When expressed at high level MinC is capable of preventing bacteria[l] cell from dividing. As a result, of this [the] cell become[s] filamentus. These [this] effect requires only high level of MinC, not MinD. It was [has been] proven that overexpression of C-terminal domain of MinC alone is sufficient to inhibit cell division [9].
