| Structural highlights
Function
GNAI1_HUMAN Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. The G(i) proteins are involved in hormonal regulation of adenylate cyclase: they inhibit the cyclase in response to beta-adrenergic stimuli. The inactive GDP-bound form prevents the association of RGS14 with centrosomes and is required for the translocation of RGS14 from the cytoplasm to the plasma membrane. May play a role in cell division.[1] [2]
Publication Abstract from PubMed
The apelin receptor (APJR) emerges as a promising drug target for cardiovascular health and muscle regeneration. While prior research unveiled the structural versatility of APJR in coupling to Gi proteins as a monomer or dimer, the dynamic regulation within the APJR dimer during activation remains poorly understood. In this study, we present the structures of the APJR dimer and monomer complexed with its endogenous ligand apelin-13. In the dimeric structure, apelin-13 binds exclusively to one protomer that is coupled with Gi proteins, revealing a distinct ligand-binding behavior within APJR homodimers. Furthermore, binding of an antagonistic antibody induces a more compact dimerization by engaging both protomers. Notably, structural analyses of the APJR dimer complexed with an agonistic antibody, with or without Gi proteins, suggest that G protein coupling may promote the dissociation of the APJR dimer during activation. These findings underscore the intricate interplay between ligands, dimerization, and G protein coupling in regulating APJR signaling pathways.
Structural insights into the regulation of monomeric and dimeric apelin receptor.,Yue Y, Liu L, Wu L, Xu C, Na M, Liu S, Liu Y, Li F, Liu J, Shi S, Lei H, Zhao M, Yang T, Ji W, Wang A, Hanson MA, Stevens RC, Liu J, Xu F Nat Commun. 2025 Jan 2;16(1):310. doi: 10.1038/s41467-024-55555-6. PMID:39747115[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Cho H, Kehrl JH. Localization of Gi alpha proteins in the centrosomes and at the midbody: implication for their role in cell division. J Cell Biol. 2007 Jul 16;178(2):245-55. PMID:17635935 doi:10.1083/jcb.200604114
- ↑ Johnston CA, Siderovski DP. Structural basis for nucleotide exchange on G alpha i subunits and receptor coupling specificity. Proc Natl Acad Sci U S A. 2007 Feb 6;104(6):2001-6. Epub 2007 Jan 30. PMID:17264214
- ↑ Yue Y, Liu L, Wu L, Xu C, Na M, Liu S, Liu Y, Li F, Liu J, Shi S, Lei H, Zhao M, Yang T, Ji W, Wang A, Hanson MA, Stevens RC, Liu J, Xu F. Structural insights into the regulation of monomeric and dimeric apelin receptor. Nat Commun. 2025 Jan 2;16(1):310. PMID:39747115 doi:10.1038/s41467-024-55555-6
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