Polarization of yeast cells under different pheromone induction regimens

The yeast Saccharomyces cerevisiae undergoes polarized growth in two different contexts: budding and pheromone-induced mating. A key difference between the two processes is that mating polarization occurs in response to an external stimulus, which can be easily manipulated under laboratory conditions.  We exploited this property to test the hypothesis that the underlying polarity circuit is bistable.  To make this test we used microfluidics to precisely control the temporal profile of mating pheromone and live-cell imaging to monitor polarization in single living cells. Files posted here contain single cell polarity time course data under different pheromone regimens. These data clearly demonstrate that polarization as a function of pheromone concentration depends on the history of the system, a behavior that is a hallmark of bistability. The data also re­veal that polarity is rapidly lost following a sudden loss of phero­mone.

Methods
The accompanying "Data_Information" document explains how polarization was visualized in living cells, the metric used to quantify polarization and a Table summarizing the pheromone regimens under which the data were collected.