NTSR1 (neurotensin receptor 1) is a G protein-coupled receptor that binds the neuropeptide neurotensin and mediates diverse physiological functions through biased signaling pathways 1. The receptor signals through both canonical G protein activation, which triggers phosphatidylinositol-calcium second messenger systems and downstream MAP kinase pathways, and β-arrestin recruitment, which produces distinct cellular responses 12. NTSR1 exhibits significant disease relevance, being overexpressed in various cancers where it regulates tumor initiation, proliferation, apoptosis, and metastasis through IP3/Ca2+/PKC/MAPKs, MMPs/EGFR/MAPKs, and Rho-GTPases pathways 34. The receptor also modulates neurological functions, with genetic variants affecting working memory performance through interactions with hippocampal structure 5. Clinically, NTSR1 represents a promising therapeutic target. β-arrestin-biased modulators like SBI-553 and SBI-810 show efficacy in treating addiction and chr20 pain without typical GPCR side effects 16. The receptor's cancer overexpression makes it valuable for tumor imaging and targeted therapy development 4. Understanding NTSR1's complex protein biology, including its glycosylation and MMP-dependent cleavage into distinct functional forms, is crucial for developing effective NTSR1-targeting therapeutics 7.