Degradation of Rat Sarcoma Proteins Targeting the Post-Translational Prenyl Modifications via Cascade Azidation/Fluorination and Click Reaction

Abstract

Protein degradation is emerging as a powerful strategy to modulate protein functions and alter cellular signaling pathways. Proteolysis-targeting chimeras (PROTACs) have been used to degrade a range of “undruggable” proteins in cells. Here, we present a type of chemically catalyzed PROTAC to induce rat sarcoma (RAS) degradation based on the chemistry of post-translational prenyl modification. Trimethylsilyl azide and Selectfluor were used to chemically tag the prenyl modification on Caax motif of RAS protein, and a sequential click reaction was applied using the propargyl pomalidomide probe to degrade the prenylated RAS in several cells. Thus, this approach was successfully applied to degrade RAS in multiple cancer cell lines including HeLa, HEK 293T, A549, MCF-7, and HT-29. This novel approach targeting RAS’s post-translational prenyl modification to induce RAS degradation by employing the sequential azidation/fluorination and click reaction has been demonstrated efficiently and highly selectively, expanding PROTAC toolsets in the study of disease-relevant protein targets.

Sequential Azidation/Azolation of Prenylated Derivatives and a Click Reaction Enable Selective Labeling and Degradation of RAS Protein

“…To increase the prenyl’s tool visibility, we aim to develop more practical and versatile methods based on the findings reported previously. ,, We noticed that manipulations of the prenyl group in organic solvents in various conditions have been disclosed, although its usage in living cells remains elusive. Thus, we report here our trials to unlock the selective functionalization of the prenyl group on RAS, and subsequently, by employing the well-designed probes via the click reaction, we realize the labeling, chemical pulldown, enrichment, and degradation of prenylated RAS in an efficient and selective approach.…”

“…Our group has been interested in revealing prenyl’s biological roles in living systems; a series of chemical tools targeting prenyl functionalities on proteins and nucleic acids have been explored and utilized. ,,− To develop more reliable and readily available tools, we report here the chemically selective and efficient approach targeting prenyl functionality. Interestingly, proteolysis-targeting chimera (PROTAC) techniques have also been comprehensively explored for precise degradation of targeted proteins in the past decade, although specific ligand identifications are needed. − The cereblon (CRBN) and von Hippel-Lindau (VHL) proteins are substrate recognition subunits of two ubiquitously expressed and biologically important Cullin RING E3 ubiquitin ligase complexes.…”