Paralog-specific intrabodies for PSD-93 and SAP102 expand the molecular toolkit to resolve excitatory synapse organization

Breillat, C.; Renou, E.; Darribere, M.; Rimbault, C.; Talenton, V.; Ecoutin, A.; Daburon, S.; Poujol, C.; Choquet, D.; Mackereth, C. D.; Sainlos, M.

doi:10.1101/2025.08.24.671450

bioRxiv · 10.1101/2025.08.24.671450

Paralog-specific intrabodies for PSD-93 and SAP102 expand the molecular toolkit to resolve excitatory synapse organization

Breillat, C.·Renou, E.·Darribere, M.·Rimbault, C.·Talenton, V.·Ecoutin, A.·Daburon, S.·Poujol, C.·Choquet, D.·Mackereth, C. D.·Sainlos, M.

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Abstract

A scarcity of live, paralog-specific tools has limited analysis of PSD-MAGUKs at excitatory synapses. To address this gap, we engineered small, 10FN3-derived binders that selectively recognize PSD-93 and SAP102 -alongside an enhanced PSD-95 reagent- and converted them into regulated, gene-encoded intrabodies for endogenous imaging. Through sequence-guided selection and targeted optimization, we obtained high-specificity reagents that label their native targets in neurons with minimal perturbation and support multiplexed live-cell and advanced imaging modalities. This toolkit enables differential visualization of MAGUK paralogs at native levels and provides a practical route to dissect their distinct contributions to synapse organization and plasticity.

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Breillat, C., Renou, E., Darribere, M., Rimbault, C., Talenton, V., Ecoutin, A., Daburon, S., Poujol, C., Choquet, D., Mackereth, C. D., Sainlos, M.. 2025-08-25. Paralog-specific intrabodies for PSD-93 and SAP102 expand the molecular toolkit to resolve excitatory synapse organization. https://doi.org/10.1101/2025.08.24.671450

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