{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n FFAR1 (also known as GPR40) is a G protein–coupled receptor predominantly expressed in pancreatic β‐cells that functions as a sensor for long‐chain free fatty acids, mediating their potentiation of glucose‐stimulated insulin secretion."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "3"}]}, {"type": "t", "text": " Upon activation by fatty acids, FFAR1 triggers intracellular signaling cascades—via phospholipase C stimulation, ensuing production of inositol phosphates, and Ca²⁺ mobilization—that amplify insulin release. Detailed structural studies, incorporating high‐resolution crystallography and site‐directed mutagenesis, have delineated a non‐canonical ligand entry route and identified key residues important for anchoring both endogenous fatty acids and synthetic agonists."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}, {"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": " In vivo models further support FFAR1’s role; deletion of FFAR1 largely attenuates the acute, fatty acid–mediated insulin secretory response, whereas receptor overexpression enhances glucose‐stimulated insulin secretion and improves glucose tolerance under dietary stress."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}, {"type": "fg_fs", "start_ref": "5", "end_ref": "7"}]}, {"type": "t", "text": " Moreover, emerging evidence indicates that FFAR1 is also expressed in pancreatic α‐cells, where it contributes to fatty acid–evoked glucagon secretion, suggesting a broader role in islet hormone regulation."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": " However, despite its critical involvement in acutely modulating hormone secretion, loss of FFAR1 does not protect against high‐fat diet–induced insulin resistance or hepatic steatosis, reflecting the receptor’s complex role in overall metabolic homeostasis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "9"}, {"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": " Collectively, these findings highlight FFAR1 as a promising therapeutic target for type 2 diabetes, where selective agonism could enhance glucose‐dependent insulin secretion, while also underscoring the need to further elucidate its broader metabolic consequences.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Ankita Srivastava, Jason Yano, Yoshihiko Hirozane, et al. 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