Robust Exocytosis Is Required for Stable Septin Ring Opening
(A) Septin ring (Cdc3-mCherry) progressively forms around the zone of focused exocytosis (Exo84-GFP) in wild-type cells. Top panels: side-view image sequences of entire cells; bottom panels: en face-view image sequences generated by 3D-reconstruction of selected regions (yellow rectangles). See also Figure S6 and Movie S5.
(B) An example of a failure to form a ring in sec4-8 secretion mutant. Top panels: side-view image sequences of entire cells; bottom panels: en face-view image sequences generated by 3D-reconstruction of selected regions (yellow rectangles). See also Movie S5.
(C) An example of a transient ring opening in sec4-8 mutant. The duration of ring opening is marked by magenta bar. Top panels: side-view image sequences of entire cells; bottom panels: en face-view image sequences generated by 3D-reconstruction of selected regions (yellow rectangles). See also Movie S5.
(D) Exocytic mutant sec4-8 largely fails to produce stable septin ring opening. See also Figure S6 showing chasing in sec4-8 cells.
(E) Overexpression of SEC4 rescues septin ring opening in latA-treated WT cells. See also Figure S6 and Movie S5.
Scale bars represent 3 μm.