alpha-Klotho is a non-enzymatic molecular scaffold for FGF23 hormone signalling.
Chen, G., Liu, Y., Goetz, R., Fu, L., Jayaraman, S., Hu, M.C., Moe, O.W., Liang, G., Li, X., Mohammadi, M.(2018) Nature 553: 461-466
- PubMed: 29342138
- DOI: https://doi.org/10.1038/nature25451
- Primary Citation of Related Structures:
5W21 - PubMed Abstract:
The ageing suppressor α-klotho binds to the fibroblast growth factor receptor (FGFR). This commits FGFR to respond to FGF23, a key hormone in the regulation of mineral ion and vitamin D homeostasis. The role and mechanism of this co-receptor are unknown. Here we present the atomic structure of a 1:1:1 ternary complex that consists of the shed extracellular domain of α-klotho, the FGFR1c ligand-binding domain, and FGF23. In this complex, α-klotho simultaneously tethers FGFR1c by its D3 domain and FGF23 by its C-terminal tail, thus implementing FGF23-FGFR1c proximity and conferring stability. Dimerization of the stabilized ternary complexes and receptor activation remain dependent on the binding of heparan sulfate, a mandatory cofactor of paracrine FGF signalling. The structure of α-klotho is incompatible with its purported glycosidase activity. Thus, shed α-klotho functions as an on-demand non-enzymatic scaffold protein that promotes FGF23 signalling.
Organizational Affiliation:
Chemical Biology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.