Figure 4.

Inhibition of Sty1 Leads to Repolarization of Quiescent Cells

(A) Cartoon of cell divisions after nitrogen starvation (N starvation) in heterothallic cells. Upon N starvation, cells divide twice en route to quiescence, with relatively little elongation during interphase. This produces a chain of four small granddaughter cells that lack any overall polarization. Cell-polarity machinery (e.g., CRIB-3xmCitrine) is shown in orange.

(B) Still images from movies of CRIB-3xmCitrine (CRIB-3mCit) in N-starved wild-type and sty1-T97A cells before and after addition of 3-BrB-PP1 (3BrB). Chains of four granddaughter cells are shown. Red arrowheads indicate ectopic patches of CRIB-3mCit. Yellow arrowheads indicate repolarization of CRIB-3mCit. Note the elongation of sty1-T97A cells after 3BrB-induced repolarization, and the absence of repolarization/elongation in wild-type cells. Times shown are relative to 3BrB addition; at 0 min, cells have already been N starved for 11 hr, including 1 hr of imaging.

Scale bar, 5 μm. See also Movie S4, in which ectopic CRIB patches are more apparent.