Isolation and characterization of topological specificity mutants of minD in Bacillus subtilis.
In rod-shaped bacteria such as Bacillus subtilis, division site selection is mediated by MinC and MinD, which together function as a division inhibitor. Topological specificity is imposed by DivIVA, which ensures that MinCD specifically inhibits division close to the cell poles, while allowing division 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 division 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.
Karoui
M E
ME
Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
Errington
J
J
D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division; D029968:Escherichia coli Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010957:Plasmids; D011485:Protein Binding; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; C104636:DivIVA protein, bacteria; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; D000251:Adenosine Triphosphatases; C072069:MinD protein, E coli