Figure 1.
Actin cytoskeleton reorganization upon entry into quiescence. (A) Wild-type yeast cells were grown in YPDA at 30°C. Cell density was monitored by measuring OD600 nm (gray line). At various stage of growth, samples were taken, glucose concentration in the medium was measured (gray triangles), and cells were stained with Alexa-phalloidin. For each time point, cells with polarized actin cytoskeleton (black dashed curve), depolarized actin cytoskeleton (open squares), or actin bodies (black curve) were counted (n > 200 for each time point). The budding index (percentage of budding cells) is shown as black circles (n > 200 for each time point). (B) Left, examples of polarized cells in exponential phase of growth (time point 3 h in A). Middle, examples of depolarized cells upon diauxic shift (time point 6.5 h in A). Right, examples of quiescent cells bearing actin bodies (time point 72 h in A). Images are two-dimensional (2D) maximal projection of three-dimensional (3D) image stacks. Bar, 2 μm. (C) Western blot analysis of the steady-state levels of Abp1p, Act1p, and Cap1/2p upon entry into quiescence. Time points and OD correspond to time points in A.