The Saga of Endocrine FGFs

• Published in: Cells (Basel, Switzerland) Switzerland), 2021-09, Vol.10 (9), p.2418
• Main Authors: Phan, Phuc, Saikia, Bibhuti Ballav, Sonnaila, Shivakumar, Agrawal, Shilpi, Alraawi, Zeina, Kumar, Thallapuranam Krishnaswamy Suresh, Iyer, Shilpa
• Format: Article
• Language: English
• Subjects: Autocrine signalling; BASIC BIOLOGICAL SCIENCES; Bile; Bile acids; Binding sites; biomedical applications; Biosynthesis; Brain research; Cell Biology; cell signaling; Cofactors; Diabetes; endocrine FGFs; FGF19; FGF21; FGF23; FGFR; Fibroblast growth factor 23; fibroblast growth factors; Glucose; Growth factors; Heparan sulfate; Homeostasis; Human subjects; Hypoglycemia; Insulin; Kinases; klotho; Klotho protein; Ligands; Lipid metabolism; Liver; metabolic disease; Metabolic disorders; Metabolism; Minerals; Paracrine signalling; Physiology; Proteins; Review; Structure-function relationships; Transgenic animals; Vitamin D
• ISSN: 2073-4409; 2073-4409
• DOI: 10.3390/cells10092418

Fibroblast growth factors (FGFs) are cell-signaling proteins with diverse functions in cell development, repair, and metabolism. The human FGF family consists of 22 structurally related members, which can be classified into three separate groups based on their action of mechanisms, namely: intracrine, paracrine/autocrine, and endocrine FGF subfamilies. FGF19, FGF21, and FGF23 belong to the hormone-like/endocrine FGF subfamily. These endocrine FGFs are mainly associated with the regulation of cell metabolic activities such as homeostasis of lipids, glucose, energy, bile acids, and minerals (phosphate/active vitamin D). Endocrine FGFs function through a unique protein family called klotho. Two members of this family, α-klotho, or β-klotho, act as main cofactors which can scaffold to tether FGF19/21/23 to their receptor(s) (FGFRs) to form an active complex. There are ongoing studies pertaining to the structure and mechanism of these individual ternary complexes. These studies aim to provide potential insights into the physiological and pathophysiological roles and therapeutic strategies for metabolic diseases. Herein, we provide a comprehensive review of the history, structure–function relationship(s), downstream signaling, physiological roles, and future perspectives on endocrine FGFs.