The Bgs1 ring and CR proteins exhibit a differential persistence in the septum edge during the two consecutive septation phases in cells deprived of F-actin. (A) Persistence of Bgs1 localization as a ring in cells after 5 min of LatA treatment (arrow). The percentage of open septa containing RFP-Bgs1 as a ring with respect to the septum length (measured by CW staining) was quantified. Bgs1 ring was found to be absent (Bgs1 spread) in phase 1 rudiments (≤0.30 µm) and still present (arrow) in phase 2 ingressing septa (>0.30 µm; n = 281 septa). (B) Myo2 and Cdc12 also display a dual persistence in cells treated with LatA. The persistence of Bgs1 (n = 728 septa), Myo2 (n = 152 septa), and Cdc12 (n = 83 septa) localizations as rings in either phase 1 rudiments or phase 2 ingressing septa was quantified as in A. (C) Scheme of the two successive septation phases in cells lacking F-actin: non-ingressing septum rudiment (≤0.30 µm, septum of phase 1) and ingressing longer septum (>0.30 µm, septum of phase 2). Error bars show SD.