curvaturesensing

Curvature sensing is the ability of molecules, particles, or assemblies to preferentially interact with surfaces or interfaces that have a particular curvature. In biology and soft matter, the term is often used to describe how proteins bind to curved membranes, but it also applies to synthetic systems that recognize or respond to curvature on micro- to nanometer scales.

In membranes, curvature sensing arises from shape complementarity, structural asymmetry, or the insertion of amphipathic elements into one leaflet of a lipid bilayer. Proteins with intrinsic curvature, such as elongated or conical shapes, can lower the energetic cost of binding to curved regions. Some proteins also polymerize or scaffold on membranes, stabilizing and amplifying curvature. Conversely, crowding of proteins on relatively flat areas can drive bending elsewhere.

A canonical class of curvature-sensing proteins is the BAR family, including N-BAR and F-BAR domains, which preferentially bind and stabilize curved membranes and can actively induce vesicle formation. Other examples involve amphipathic helices that insert into the outer leaflet. In many systems, sensing and induction of curvature are coupled, guiding vesicle trafficking, organelle shaping, and cytokinetic or endocytic processes.

Experimentally, curvature sensing is studied with liposomes or giant unilamellar vesicles of different sizes, fluorescence assays, electron microscopy, and biophysical models based on bending energy like the Helfrich framework, which relates curvature to surface energy. Applications span cell biology and the design of curvature-responsive materials in soft matter and nanotechnology.