An anionic human protein mediates cationic liposome delivery of genome editing proteins into mammalian cells

Nat Commun. 2019 Jul 2;10(1):2905. doi: 10.1038/s41467-019-10828-3.


Delivery into mammalian cells remains a significant challenge for many applications of proteins as research tools and therapeutics. We recently reported that the fusion of cargo proteins to a supernegatively charged (-30)GFP enhances encapsulation by cationic lipids and delivery into mammalian cells. To discover polyanionic proteins with optimal delivery properties, we evaluate negatively charged natural human proteins for their ability to deliver proteins into cultured mammalian cells and human primary fibroblasts. Here we discover that ProTα, a small, widely expressed, intrinsically disordered human protein, enables up to ~10-fold more efficient cationic lipid-mediated protein delivery compared to (-30)GFP. ProTα enables efficient delivery at low- to mid-nM concentrations of two unrelated genome editing proteins, Cre recombinase and zinc-finger nucleases, under conditions in which (-30)GFP fusion or cationic lipid alone does not result in substantial activity. ProTα may enable mammalian cell protein delivery applications when delivery potency is limiting.

Publication types

  • Evaluation Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Gene Editing / instrumentation
  • Gene Editing / methods*
  • Green Fluorescent Proteins / chemistry
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • HeLa Cells
  • Humans
  • Integrases / chemistry
  • Integrases / genetics
  • Integrases / metabolism
  • Liposomes / chemistry*
  • Liposomes / metabolism
  • Protein Transport
  • Proteins / chemistry*
  • Proteins / genetics
  • Proteins / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Zinc Finger Nucleases / chemistry
  • Zinc Finger Nucleases / genetics
  • Zinc Finger Nucleases / metabolism


  • Liposomes
  • Proteins
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins
  • Cre recombinase
  • Integrases
  • Zinc Finger Nucleases