| Title: |
Defining proteoform-specific interactions for drug targeting in a native cell signalling environment |
| Authors: |
Lutomski, Corinne A., Bennett, Jack L., El-Baba, Tarick J., Wu, Di, Hinkle, Joshua D., Burnap, Sean A., Liko, Idlir, Mullen, Christopher, Syka, John E. P., Struwe, Weston B., Robinson, Carol V. |
| Source: |
Nature Chemistry; 20250101, Issue: Preprints p1-11, 11p |
| Abstract: |
Understanding the dynamics of membrane protein–ligand interactions within a native lipid bilayer is a major goal for drug discovery. Typically, cell-based assays are used, however, they are often blind to the effects of protein modifications. In this study, using the archetypal G protein-coupled receptor rhodopsin, we found that the receptor and its effectors can be released directly from retina rod disc membranes using infrared irradiation in a mass spectrometer. Subsequent isolation and dissociation by infrared multiphoton dissociation enabled the sequencing of individual retina proteoforms. Specifically, we categorized distinct proteoforms of rhodopsin, localized labile palmitoylations, discovered a Gβγ proteoform that abolishes membrane association and defined lipid modifications on G proteins that influence their assembly. Given reports of undesirable side-effects involving vision, we characterized the off-target drug binding of two phosphodiesterase 5 inhibitors, vardenafil and sildenafil, to the retina rod phosphodiesterase 6 (PDE6). The results demonstrate differential off-target reactivity with PDE6 and an interaction preference for lipidated proteoforms of G proteins. In summary, this study highlights the opportunities for probing proteoform–ligand interactions within natural membrane environments. |
| Database: |
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