Molecular interplay of surface topography-guided actin assembly through nanoscale protein and lipid compartmentalization

Abstract

Membrane curvature is crucial in regulating various biological processes like endocytosis and signal transduction, yet the mechanisms by which it influences protein assembly and function are not fully understood. This study investigates the relationship between membrane morphology and cellular activities, using minimal in vitro reconstitution systems and nanoscale patterning. We demonstrate that membrane curvature dynamically regulates actin nucleation complex assembly and activation. Specifically, curvature-sensitive protein, FBP17 and its binding partner N-WASP, form nanoclusters at membrane deformation sites, which leading to localized actin polymerization. Additionally, we explore the role of membrane curvature and lipid composition in the distribution and clustering of palmitoylated proteins using a chemical mimic of S-palmitoylation—PAPM (Palmitic acid-PEG-Maleimide), across 2D, 2.5D, and 3D membrane systems. Our findings indicate that curvature-induced clustering of proteins plays a critical role in the spatiotemporal regulation of actin cytoskeleton assembly and the functional recognition of nanodomains by lipid-modified proteins.