Entropic Coupling of the FtsZ Intrinsically Disordered Linker to Membrane Tension Regulates Z-ring Formation

FtsZ is a tubulin-like cytoskeletal protein that polymerizes into a ring at the future division site, recruiting other cell division proteins and generating the constrictive force required for cytokinesis. The intrinsically disordered C-terminal linker (CTL) of FtsZ mediates filament bundling and membrane interactions, but its role in sensing and overcoming membrane tension is not well understood. Motivated by Bacillus subtilis observations, we are reconstituting FtsZ assemblies on model membranes to quantify how CTL length affects filament condensation and membrane remodeling under defined tension. Native-length CTL is expected to enhance entropic filament condensation and curvature generation compared to shortened variants, particularly under elevated tension. These experiments aim to establish a mechanistic framework in which CTL-mediated, intrinsically disordered protein-driven condensation generates entropic forces sufficient to drive Z-ring formation and membrane deformation, linking cytoskeletal organization to membrane mechanics in bacterial division.