Fluorescence Correlation Spectroscopy Reveals Efficient Cytosolic Delivery of Protein Cargo by Cell-Permeant Miniature Proteins.

ABSTRACT: New methods for delivering proteins into the cytosol of mammalian cells are being reported at a rapid pace. Differentiating between these methods in a quantitative manner is difficult, however, as most assays for evaluating cytosolic protein delivery are qualitative and indirect and thus often misleading. Here we make use of fluorescence correlation spectroscopy (FCS) to determine with precision and accuracy the relative efficiencies with which seven different previously reported "cell-penetrating peptides" (CPPs) transport a model protein cargo-the self-labeling enzyme SNAP-tag-beyond endosomal membranes and into the cytosol. Using FCS, we discovered that the miniature protein ZF5.3 is an exceptional vehicle for delivering SNAP-tag to the cytosol. When delivered by ZF5.3, SNAP-tag can ach

SUBMITTER: Wissner RF 

PROVIDER: S-EPMC6202653 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature