Metabolic Labeling-Based Chemoproteomics Establishes Choline Metabolites as Protein Function Modulators

Area of Science:

• Biochemistry
• Cell Biology
• Cancer Biology

Background:

• Choline is an essential nutrient with incompletely understood cellular functions beyond lipid metabolism.
• Elevated choline metabolite levels are a known hallmark of various cancers.
• Understanding these roles is critical for both fundamental physiology and cancer research.

Purpose of the Study:

• To identify proteins that interact with choline metabolites in mammalian cells.
• To elucidate novel functions of choline metabolites in cellular physiology.
• To explore the implications of these findings for cancer biology and therapeutic targeting.

Main Methods:

• Development and utilization of a photocrosslinkable choline probe for identifying interacting proteins.
• Metabolic labeling experiments with diverse choline analogues.
• Biochemical assays to assess protein-ligand interactions and inhibition by phosphocholine.

Main Results:

• Established a mammalian choline metabolite-interacting proteome.
• Discovered a novel choline lipid headgroup remodeling mechanism involving dealkylation and methylation.
• Demonstrated that phosphocholine inhibits the binding of the anticancer target p32 to its ligands and the Lyp-1 agent.

Conclusions:

• Choline metabolites act as critical modulators of protein function.
• These findings reveal new roles for choline metabolites in cellular physiology.
• The identified interactions and mechanisms have potential implications for developing novel cancer therapies targeting p32.