title: The signal peptide NPFSD fused to ricin A chain enhances cell uptake and cytotoxicity in Candida albicans.
abstract: Microorganisms possess stringent cell membranes which limit the cellular uptake of antimicrobials. One strategy to overcome these barriers is to attach drugs or research reagents to carrier peptides that enter cells by passive permeation or active uptake. Here the short endocytosis signal peptide NPFSD was found to efficiently deliver both FITC and GFP into Saccharomyces cerevisiae and Candida albicans with uptake into the majority of cells in a population. The NPFSD signal is itself non-toxic, but when fused to the ricin A chain toxin (RTA) the peptide enhanced both cell uptake and toxicity against C. albicans, which like other yeasts is resistant to naked RTA. Cell entry required at least 1 h incubation, temperatures above 4 degrees C, and an energy source, and uptake was out-competed with free peptide. Therefore, the NPFSD peptide can carry a range of compounds into yeasts and this delivery route holds promise to enhance the activity of antifungals.
authors.affiliation: Center for Genomics and Bioinformatics, Karolinska Institute, Berzelius väg 35, 17177 Stockholm, Sweden.
authors.forename: Gunaratna Kuttuva
authors.initials: GK
authors.lastname: Rajarao
authors.forename: Natalia
authors.initials: N
authors.lastname: Nekhotiaeva
authors.forename: Liam
authors.initials: L
authors.lastname: Good
mesh_terms: D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000378:metabolism / Q000633:toxicity; D002176:Candida albicans / Q000187:drug effects / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism / Q000633:toxicity; D012276:Ricin / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D012276:Ricin; D016650:Fluorescein-5-isothiocyanate