Efficient cellular transformation via protein delivery through the protrusion-derived extracellular vesicles.

Extracellular vesicles (EVs) mediate the transfer of intracellular proteins from producer to recipient cells. EVs originate either from plasma membrane protrusions or endosomes, with endosome-derived EVs being extensively studied and engineered. However, the efficiency and functionality of protein transfer via both types of EVs remain poorly understood. Here, we demonstrate that natural EVs derived from cell protrusions dependent on the I-BAR protein MIM, rather than from endosomes, deliver the functional small GTPase Rac1 protein at levels similar to microinjection. Rac1-containing EVs are internalized via endocytosis, trafficked through endosomal compartments, and subsequently released into the cytosol, where they enhance cell motility. To evaluate broader applicability, the genome-editing protein Cas12f is packaged into protrusion-derived EVs by MIM and endosome-derived EVs by endosomal tetraspanin CD63. Notably, protrusion-derived EVs deliver Cas12f with significantly higher efficiency than endosome-derived EVs, highlighting their superior capability for functional protein transfer. Our findings establish the protrusion-derived EVs as a powerful platform for the efficient and bioactive delivery of both native and engineered proteins, expanding the EV-based therapeutic strategies.