Detection of PIP₂ distributions in biological membranes using a peptide-based sensor

Area of Science:

• Cell Biology
• Biochemistry
• Molecular Biology

Background:

• Plasma membrane organization influences cellular functions.
• Phosphatidylinositol phosphate (PIP) lipids regulate signaling pathways.
• Accurate detection of PIP lipids is crucial for understanding cellular processes.

Purpose of the Study:

• To develop a novel peptide-based sensor for quantifying PI(4,5)P2 lipids.
• To investigate the impact of Ras mutations on PI(4,5)P2 distribution in living cells.
• To assess the effect of Sotorasib treatment on PI(4,5)P2 dynamics in Ras mutant cells.

Main Methods:

• Implementation of a peptide-based, ratiometric sensor for PI(4,5)P2 detection.
• Quantification of PI(4,5)P2 densities in reconstituted membrane systems and living cells.
• Application of the sensor to cells expressing Ras mutations and treated with Sotorasib.

Main Results:

• The sensor accurately quantifies PI(4,5)P2 levels down to physiological concentrations.
• Ras mutations induce mutation-specific alterations in surface PI(4,5)P2 levels and distributions.
• Sotorasib treatment of G12C mutant Ras cells restores PI(4,5)P2 arrangements similar to wild-type.

Conclusions:

• The study highlights the dynamic coupling between membrane lipid composition and cellular signaling.
• The developed sensor provides a valuable tool for studying membrane lipid organization and its role in cellular programs.
• Understanding protein-lipid interactions is key to characterizing therapeutics and cellular mechanisms.