Small edits to SBI-553 tune NTSR1 signaling bias from an intracellular pocket
- Chemical variants of the β-arrestin-biased modulator SBI-553 shifted the balance between G-protein and β-arrestin signaling at neurotensin receptor 1.
- Cryo-EM structures of the receptor–effector complexes showed how the pocket reshapes the interface; phosphoproteomics gave each compound a partly distinct signaling fingerprint.
- One analog, N065, improved survival in a lethal mouse endotoxemia model.
💡 Points Based on the abstract
Having structures that explain why a small substituent changes bias is what turns biased signaling from a descriptive label into something you can design against. The open question for any pharmacologist is which arm actually drives the in vivo phenotype. A survival benefit in endotoxemia from one analog is a hint, not a validated link between bias profile and efficacy, and the non-obvious NTSR1 indication deserves skeptical follow-up.
Fine-tuning an intracellular allosteric pocket programs GPCR signaling bias ↗