Lamellipodin

Lamellipodin is an actin-regulatory adaptor protein encoded by the RAPH1 gene in humans. It localizes to lamellipodia at the leading edge of migrating cells and contributes to the control of actin filament polymerization and cell motility.

Lamellipodin contains multiple proline-rich regions that recruit Ena/VASP family proteins via their EVH1 domains, promoting actin filament elongation at the leading edge. It also interacts with small GTPases and membrane signaling lipids, linking extracellular cues to cytoskeletal remodeling. The presence of these motifs enables lamellipodin to function as a platform for assembling actin-regulatory complexes.

By coordinating Ena/VASP-mediated elongation with Rac1- and PI3K-driven signaling, lamellipodin supports lamellipodium formation and sustained protrusions, contributing to directional cell migration, wound healing processes, and possibly neuronal development.

Lamellipodin is conserved in vertebrates and is studied for its role in cell motility across various cell types. Disruptions in lamellipodin function can alter leading-edge dynamics and migration, reflecting its importance in the regulation of the actin cytoskeleton.