Structural elucidation of the mesothelin-mucin-16/CA125 interaction.
Rupert, P.B., Buerger, M., Friend, D.J., Strong, R.K.(2024) Structure 32: 1049-1054.e2
- PubMed: 38703776 
- DOI: https://doi.org/10.1016/j.str.2024.04.011
- Primary Citation of Related Structures:  
8VM1 - PubMed Abstract: 
Mesothelin (MSLN) is a cell-surface glycoprotein expressed at low levels on normal mesothelium but overexpressed in many cancers. Mesothelin has been implicated to play role/s in cell adhesion and multiple signaling pathways. Mucin-16/CA125 is an enormous cell-surface glycoprotein, also normally expressed on mesothelium and implicated in the progression and metastasis of several cancers, and directly binds mesothelin. However, the precise biological function/s of mesothelin and mucin-16/CA125 remain mysterious. We report protein engineering and recombinant production, qualitative and quantitative binding studies, and a crystal structure determination elucidating the molecular-level details governing recognition of mesothelin by mucin-16/CA125. The interface is small, consistent with the ∼micromolar binding constant and is free of glycan-mediated interactions. Sequence comparisons and modeling suggest that multiple mucin-16/CA125 modules can interact with mesothelin through comparable interactions, potentially generating a high degree of avidity at the cell surface to overcome the weak affinity, with implications for functioning and therapeutic interventions.
Organizational Affiliation: 
Division of Basic Science, Fred Hutchinson Cancer Center, Seattle, WA, USA.