Protein-glycosphingolipid interactions revealed using catch-and-release mass spectrometry

Area of Science:

• Biochemistry
• Cell Biology
• Analytical Chemistry

Background:

• Glycosphingolipids (GSLs) are crucial cell surface receptors involved in biological recognition and adhesion.
• Functional characterization of protein-glycosphingolipid interactions remains a significant challenge in biological research.

Purpose of the Study:

• To develop a novel assay for identifying specific interactions between water-soluble proteins and GSLs.
• To enable the functional characterization of protein-GSL interactions using a sensitive and specific method.

Main Methods:

• Development of a catch-and-release electrospray ionization mass spectrometry (CaR-ESI-MS) assay.
• Incorporation of GSLs into nanodiscs for assay compatibility.
• Testing assay specificity and sensitivity with known toxin-receptor interactions.

Main Results:

• The CaR-ESI-MS assay successfully identified specific binding between cholera toxin and its GSL receptor, ganglioside GM1.
• The assay also detected the interaction between Shiga toxin and its GSL receptor, globotriaosylceramide (Gb3).
• Demonstrated detection of cholera toxin-GM1 binding within complex lipid mixtures from cell membranes.

Conclusions:

• The CaR-ESI-MS assay provides a sensitive and specific method for identifying protein-GSL interactions.
• This assay has potential for discovering novel biologically relevant protein-GSL interactions in complex biological samples.
• The developed assay facilitates the functional characterization of GSLs as receptors.