Publication
Isolation and characterization of topological specificity mutants of minD in Bacillus subtilis
Publisher:
Wiley
Date:
12-2001
DOI:
10.1046/J.1365-2958.2001.02710.X
Abstract: In rod-shaped bacteria such as Bacillus subtilis, ision site selection is mediated by MinC and MinD, which together function as a ision inhibitor. Topological specificity is imposed by DivIVA, which ensures that MinCD specifically inhibits ision close to the cell poles, while allowing ision at mid-cell. MinD plays a central role in this process, as it positions and activates MinC and is dependent on DivIVA for its own positioning at the poles. To investigate MinD activities further, we have constructed and analysed a collection of minD mutants. Mutations in the conserved ATPase motifs lead to an inactive protein, possibly unable to oligomerize, but which nevertheless retains some affinity for the cell membrane. Several mutations affecting the mid- to C-terminal parts of MinD led to a protein probably unable to interact with DivIVA, but that could still stimulate ision inhibition by MinC. These findings suggest that the ATPase activity of MinD is necessary for all its functions (possibly in part by controlling the oligomerization state of the protein). The other mutations may identify a surface of MinD involved in its interactions with DivIVA and a possible mechanism for control of MinD by DivIVA.