Membrane reshaping by micrometric curvature sensitive septin filaments

Area of Science:

• Cell biology
• Biophysics
• Cytoskeletal dynamics

Background:

• Septins are essential cytoskeletal filaments crucial for cell division.
• They assemble at the plasma membrane, influencing membrane remodeling and constriction.
• Understanding septin behavior on dynamic membrane structures is vital for cell biology.

Purpose of the Study:

• To investigate the in vitro behavior of yeast septins on curved and deformable membranes.
• To elucidate the relationship between septin filament organization and membrane curvature.
• To develop a theoretical model explaining septin-mediated membrane deformations.

Main Methods:

• Utilized in vitro assays with Giant Unilamellar Vesicles (GUVs).
• Employed custom-designed periodic wavy patterns to present controlled micrometric curvatures.
• Observed septin filament behavior using microscopy and developed a theoretical model.

Main Results:

• Septins induced membrane deformations, forming periodic spikes on GUVs and flattening smaller vesicles.
• Septin filaments exhibited preferential arrangements based on membrane curvature, remaining straight on convex and bending on concave surfaces.
• A theoretical model accurately described septin's curvature sensitivity and deformation patterns.

Conclusions:

• Septins actively remodel membranes in response to specific curvatures.
• The findings provide mechanistic insights into septin's role in cytokinesis and cell division.
• The developed model offers a framework for understanding septin-membrane interactions in vivo.