For about 20 years, researchers have known about the Z ring but have not understood precisely how it operated and why it always formed in the middle of rod-shaped cells. The main components of Z rings are filaments of a protein molecule called FtsZ
In the new journal article, the Johns Hopkins-led researchers were able to report for the first time that the changing of FtsZ threads from a liquid-like form to a more solid structure inside the cell is important for the formation of the Z ring. The team found that FtsZ threads weave themselves into a framework or scaffold that can hold all of the other molecules involved in the cell division process. The FtsZ filments are able to weave this tapestry, the researchers learned, because they tend to attract one another and interact along the length of each thread.
The team also discovered that MinC, another protein inside the bacterial cell, disrupts this process by liquefying the structure that is used to form a Z ring. MinC blocks the attraction between FtsZ filaments along their lengths, and it also makes the filaments more fragile, said Dajkovic. This has the effect of shearing the weavings in the tapestry of the Z ring, which causes the whole structure to fall apart.
MinC is most prevalent on the outer ends of the rod-shaped bacterial cell, the researchers said, and this explains why the Z ring always forms and splits the cell in the middle, where it is less likely to encounter its protein foe. The team members said this discovery also presents a promising opportunity: a new drug that mimics the effects of MinC could play havoc with the bacterial reproductive process and thereby put an end to an infection.
The findings resulted from a collaboration involving
|Contact: Phil Sneiderman|
Johns Hopkins University