L10: Division Site Selection

MinC and MinD

proteins that inhibit cell division. w/o minE, they will block division everywhere and cell will never divide.

Min C

protein that shortens and inhibits bundling of FtsZ filaments when bound to MinD.

MinD

protein that massively increases activity of MinC by binding to it

MinE

protein that prevents minCD from working at the midcell, so that minCD only blocks division at polar sites. Binds to minD and activates minD ATPase to make it release minC

YFD-MinD and MinE-CFP timelapse microscopy

showed that minE forms ring at medial edge of MinCD polar zone. E ring moves toward pole containing MinCD, causing it to release and set up a new polar zone at the opposite end

step 1 of min protein activities

MinC and minD-ATP bind to cytoplasmic membrane

step 2 of min protein activities

MinE binds to minD and IM, stimulates MinD ATPase and releases MinC, MinD-ATP, and MinE

step 3 of min protein activities

MinD-ADP undergoes nucleotide exchange. MinC and MinD-ATP rebind to membrane. If they are far away enough from MinE, a new MinCD zone is created

step 4 of min protein activities

when minE reaches the first pole and minD is gone, it diffuses until it contacts a new zone of MinCD

nucleoid occlusion

regulates placement of division site. Nucleoid signals prevent FtsZ ring formation nearby, and chromosomes packaged so that termini are located near middle of cell

SlmA

protein in e. coli that binds to SBS sequence at 30 different places in genome. bound complex inhibits FtsZ polymerization

SBS

20 bp sequence in e. coli genome where SlmA binds to

Noc

protein in b. sublitus analogous to SlmA in e. coli