Quinolimide-based peptide biosensor for probing p25 in vitro and in living cells

Fueyo-Gonzalez, Francisco; Herranz, Rosario; Plesselova, Simona; Giron, Maria D.; Salto, Rafael; Manuel Paredes, Jose; Orte, Angel; Morris, May C.; Gonzalez-Vera, Juan A.

VL / 339 - BP / - EP /
CDK5 kinase is activated through interactions with different partners including the p35/p25 regulators. Active CDK5 plays a key role in several neuronal functions and its hyperactivity contributes to a variety of neurodegenerative processes and several human cancers, in particular glioblastomas and neuroblastomas. In order to probe partners that interact with CDK5, we designed and synthesized fluorescent quinolimide-labelled peptides derived from the C-helix of CDK5, which were implemented to probe CDK5 partners in vitro and by in cellulo imaging in U87 glioblastoma and N2a neuroblastoma cells. Ectopic expression of a NIR fluorescent protein miRFP670 fusion with p25 (p25-miRFP670) in N2a cells induced FRET between a quinolimide-labelled peptide biosensor and p25-miRFP670, and fluorescence intensity was proportional to the expression level of p25, thereby demonstrating the potential of the quinolimide-labelled peptide biosensor to report on p25 relative abundance.

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