A practical approach for intracellular protein delivery

Proteindelivery represents a powerful tool for experiments in live cells including studies of protein-protein interactions, proteininterference with blocking antibodies, intracellular trafficking and proteinor peptide biological functions. Most available reagents dedicated to the proteindelivery allow efficient crossing of the plasma membrane. Nevertheless, the major disadvantage for these reagents is a weak release of the delivered proteininto the cytoplasm. In this publication we demonstrate efficient proteindelivery with a non-peptide based reagent, in human epithelial carcinoma HeLa cells and primary human skin fibroblasts. Using a fluorescent proteinin combination with fluorescence microscopy and fluorescence-assisted cell sortinganalysis, we show that the delivered proteinis indeed released effectively in the cytoplasm, as expected for a dedicated carrier. Furthermore, we present a step-by-step method to optimize conditions for successful intracellular proteindelivery.