Fig. 5: FtsZ-YFP-mts rings inside deflated GUVs cause membrane deformations that depend on GTPase activity.
From: FtsZ induces membrane deformations via torsional stress upon GTP hydrolysis
a Representative image of GUVs encapsulating FtsZ (N > 10, each condition) (scale bar = 5 µm). b TIRF microscopy imaging of FtsZ-YFP-mts and FtsZ-YFP-mts*[T108A] rings at the bottom-inside GUVs (N > 10, each condition) (scale bar = 2 µm). c Intensity profile of structures indicated in b showed that FtsZ-YFP-mts (green line) rings exhibit smaller diameter than FtsZ-YFP-mts*[T108A] (magenta line). d Size distribution of (N = 112) FtsZ-YFP-mts*[T108A] (gray bars and magenta line) and (N = 102) FtsZ-YFP-mts showed a drastic reduction in ring diameter due to GTP hydrolysis. e After deflation, both mutants yielded outwards deformations. For the case of FtsZ-YFP-mts, N = 21/26 (80%) vesicles showed outwards deformations and constriction necks compared to N = 4/15 (26%) for FtsZ-YFP-mts*[T108A]. This suggests that GTPase activity promotes constriction and neck formation (scale bar = 5 µm). f We suggest that intrinsic torsion can create out-of-plane forces; however, g GTP hydrolysis triggered a super-constricted state favoring higher curvatures. These higher curvatures and membrane deformations cause a mechanical strain on the polymer that promotes fragmentation and then the emergence of clockwise and anticlockwise FtsZ treadmilling filaments.
