7xjl

From Proteopedia

Cryo-EM structure of the spexin-bound GALR2-miniGq complex

Structural highlights

7xjl is a 6 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 3.5Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

GBG2_HUMAN Guanine nucleotide-binding proteins (G proteins) are involved as a modulator or transducer in various transmembrane signaling systems. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction (By similarity).

Publication Abstract from PubMed

Galanin is a biologically active neuropeptide, and functions through three distinct G protein-coupled receptors (GPCRs), namely GALR1, GALR2, and GALR3. GALR signaling plays important roles in regulating various physiological processes such as energy metabolism, neuropathic pain, epileptic activity, and sleep homeostasis. GALR1 and GALR3 signal through the Gi/o pathway, whereas GALR2 signals mainly through the Gq/11 pathway. However, the molecular basis for galanin recognition and G protein selectivity of GALRs remains poorly understood. Here, we report the cryoelectron microscopy structures of the GALR1-Go and the GALR2-Gq complexes bound to the endogenous ligand galanin or spexin. The galanin peptide mainly adopts an alpha helical structure, which binds at the extracellular vestibule of the receptors, nearly parallel to the membrane plane without penetrating deeply into the receptor core. Structural analysis combined with functional studies reveals important structural determinants for the G protein selectivity of GALRs as well as other class A GPCRs. In addition, we show that the zinc ion is a negative allosteric regulator of GALR1 but not GALR2. Our studies provide insight into the mechanisms of G protein selectivity of GPCRs and highlight a potential function of the neuromodulator zinc ion as a modulator of GPCR signaling in the central nervous system.

Structural insights into galanin receptor signaling.,Jiang W, Zheng S Proc Natl Acad Sci U S A. 2022 May 24;119(21):e2121465119. doi: , 10.1073/pnas.2121465119. Epub 2022 May 20. PMID:35594396^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Jiang W, Zheng S. Structural insights into galanin receptor signaling. Proc Natl Acad Sci U S A. 2022 May 24;119(21):e2121465119. PMID:35594396 doi:10.1073/pnas.2121465119