Four different mechanisms for switching cell polarity
Fig 1
Signal-induced polarity switching.
A Schematic representation of a rod-shaped cell with polarity marker A shown in yellow. Proteins can either be bound to the poles or diffuse in the cytoplasm. The abundances of the polarity marker at the two poles are denoted by A1 and A2. The release of a signal protein X in the cytoplasm, shown in purple, can lead to a polarity reversal, such that the polarity marker switches from pole 1 to pole 2. B Schematic representation of the molecular interactions of the polarity model. The polarity marker A and its antagonist B inhibit each others binding to the pole. B can cooperatively recruit itself to the pole and promotes binding of the recruitment factor R, which in turn recruits A. Dashed lines indicate exemplary hypothetical interactions of the signal protein X with the polarity proteins. C The switching signal is implemented as a pulse in the total amount of X, parameterized by the signal duration τ and signal amplitude Xmax.