Figure 2

Pvr, Ras1 and the MAPK pathway control cell size in a Drosophila hemocyte-like cell line. (a) Schematic of canonical Ras/MAPK signaling. (b) Control and RNAi-treated S2R+ cells fixed and stained for microtubules (20× magnification). Pvr and Ras1 RNAi cause a decrease in cell area, whereas Gap1 RNAi causes an increase in cell area compared to control. (c-e) Charts of the mean percentage change in volume of RNAi treated or Pvf transfected S2R+ cells relative to control cells, as measured using a CASY counter. (c) Silencing of positive regulators of the Ras/MAPK pathway causes a reduction in cell diameter, whereas silencing of Gap1, a negative regulator of Ras1 signaling, causes an increase in cell diameter. (d) Silencing of Pvf1, 2 or 3 individually has no effect on cell volume, but silencing of Pvf2 and Pvf3 in combination significantly reduces cell size. (e) Over-expression of Pvf2 or Pvf3, but not Pvf1 leads to an increase in cell volume. This affect is dependent on Pvr. Error bars indicate the standard error of the mean.