Figure 9.TIF (641.7 kB)

Models for the arrangement of FtsZ protofilaments inside the Z ring.

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posted on 11.09.2012, 11:11 by Michael P. Strauss, Andrew T. F. Liew, Lynne Turnbull, Cynthia B. Whitchurch, Leigh G. Monahan, Elizabeth J. Harry

(A) We propose two models to describe the architecture of the Z ring. The overlapping model predicts that short FtsZ protofilaments begin to bundle in both lateral (circumferential) and radial directions of the cell. Alternatively, FtsZ protofilaments could be arranged into a single layer in the radial direction and only bundle in the lateral direction. (B) The amount of FtsZ inside the Z ring is constant throughout constriction, but the distribution of FtsZ inside the rings fluctuates over time. As constriction begins the Z ring exerts a localized pinching force on the membrane where increased levels of FtsZ are found. Gaps (indicated by red brackets) in the Z ring allow constriction to occur continuously as the circumference of this structure becomes reduced (indicated by the decrease in height of the blue rectangle).