Membrane potential enhances the rate of entry of cell-penetrating peptides (CPPs) into the GUV lumen

What is it about?

In this paper, we have developed a novel method to examine the effect of membrane potential (φm) on the translocation of cell-penetrating peptides (CPPs) across lipid bilayers and their entry into the lumen of single giant unilamellar vesicles (GUVs).

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Why is it important?

Membrane potential in single GUVs were determined by measuring the fluorescence intensity of the GUV membrane due to a φm-sensitive fluorescent probe using confocal laser scanning microscopy (CLSM). To detect the entry of fluorescent probe-labeled CPPs into the single GUV lumen, we used the single GUV method with CLSM developed by our lab. Using this method, we examined the effect of membrane potential on the entry of a fluorescent probe-labeled CPP, transportan 10 (CF-TP10) into single GUV lumen. We found that the rate of the translocation of CF-TP10 across the GUV bilayer and the rate of the entry into single GUV lumen without pore formation increased with an increase in negative φm. These data indicate that the φm-enhancement of the translocation of CPPs across lipid bilayer is one of the main causes for the φm-enhanced rate of entry of CPPs into single GUV lumen.