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Probing the 14-3-3 Isoform-Specificity Profile of Interactions Stabilized by Fusicoccin A

revised on 03.04.2020, 15:42 and posted on 06.04.2020, 09:15 by James Frederich, Ananya Sengupta, Josue Liriano, Ewa A. Bienkiewicz, Brian G. Miller
Fusicoccin A (FC) is a fungal phytotoxin that stabilizes protein–protein interactions (PPIs) between 14-3-3 adapter proteins and their phosphoprotein interaction partners. In recent years, FC has emerged as an important chemical probe of human 14-3-3 PPIs implicated in cancer and neurological diseases. These previous studies have established the structural requirements for FC-induced stabilization of 14-3-3·client phosphoprotein complexes; however, the effect of different 14-3-3 isoforms on FC activity has not been systematically explored. This is a relevant question for the continued development of FC variants because there are seven distinct isoforms of 14-3-3 in humans. Despite their remarkable sequence and structural similarities, a growing body of experimental evidence supports both tissue-specific expression of 14-3-3 isoforms and isoform-specific functions in vivo. Herein, we report the isoform-specificity profile of FC in vitrousing recombinant human 14-3-3 isoforms and a focused library of fluorescein-labeled hexaphosphopeptides mimicking the C-terminal 14-3-3 recognition domains of client phosphoproteins targeted by FC in cell culture. Our results reveal modest isoform preferences for individual client phospholigands and demonstrate that FC differentially stabilizes PPIs involving 14-3-3s. Together, these data provide strong motivation for the development of non-natural FC variants with enhanced selectivity for individual 14-3-3 isoforms.


R01-GM125926, R01-GM133843, R01-GM115388


Email Address of Submitting Author


Florida State University


United States

ORCID For Submitting Author


Declaration of Conflict of Interest

authors declare no conflict of interest

Version Notes

updated on 04/03/2020 to reflect a typo in the structure of FC