MINC

MinC is a bacterial cell division regulator, best known as a component of the Min system that also includes MinD and MinE. It is found in many bacteria, notably Escherichia coli, where it functions to prevent the assembly of the division machinery near the cell poles and thereby promote midcell placement of the division site.

MinC acts as an inhibitor of FtsZ polymerization. In the E. coli system, MinD binds ATP and associates with the inner membrane, recruiting MinC to form a MinCD complex on the membrane. This complex locally inhibits FtsZ, preventing the Z-ring from forming at the poles. MinE forms a counteracting gradient by stimulating MinD’s ATPase activity, causing the MinCD complex to disassemble and rebind elsewhere. The result is an oscillation of MinCD from pole to pole with a periodicity of tens of seconds. Because MinC activity is lowest at midcell on average, the Z-ring is most likely to assemble there, guiding cytokinesis to the cell center.

Biochemically, MinC is a dimer with distinct N- and C-terminal domains; the C-terminal portion enhances interaction with FtsZ, contributing to its inhibitory effect. Genetically, minC mutants often produce minicells due to polar septation, underscoring its role in accurate division site selection. While best characterized in E. coli, MinC homologs exist across bacteria, though some lineages use variations or additional factors (for example, DivIVA/MinJ in certain Gram-positive bacteria) to achieve proper MinCD localization. Overall, MinC functions as a spatial regulator that prevents polar division and promotes midcell cytokinesis.