PT  - JOURNAL ARTICLE
AU  - Matthias Kober
AU  - Silke Bergeler
AU  - Erwin Frey
TI  - Can a flux-based mechanism explain positioning of protein clusters in a three-dimensional cell geometry?
AID  - 10.1101/496364
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 496364
4099  - http://biorxiv.org/content/early/2018/12/13/496364.short
4100  - http://biorxiv.org/content/early/2018/12/13/496364.full
AB  - The plane of bacterial cell division must be precisely positioned. In the bacterium Myxococcus xanthus, the proteins PomX and PomY form a large cluster, which is tethered to the nucleoid by the ATPase PomZ and moves in a stochastic, but biased manner towards midcell, where it initiates cell division. Previously, a positioning mechanism based on the fluxes of PomZ on the nucleoid was proposed. However, the cluster dynamics was analyzed in a reduced, one-dimensional geometry. Here we introduce a mathematical model that accounts for the three-dimensional shape of the nucleoid, such that nucleoid-bound PomZ dimers can diffuse past the cluster without interacting with it. Using stochastic simulations, we find that the cluster still moves to and localizes at midcell. Redistribution of PomZ by diffusion in the cytosol is essential for this cluster dynamics. Our mechanism also positions two clusters equidistantly on the nucleoid. We conclude that a flux-based mechanism allows for cluster positioning in a biologically realistic three-dimensional cell geometry.