7eb2
Cryo-EM structure of human GABA(B) receptor-Gi protein complex
Structural highlights
FunctionGNAI1_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 PubMedG-protein-coupled receptors (GPCRs) have central roles in intercellular communication(1,2). Structural studies have revealed how GPCRs can activate G proteins. However, whether this mechanism is conserved among all classes of GPCR remains unknown. Here we report the structure of the class-C heterodimeric GABA(B) receptor, which is activated by the inhibitory transmitter GABA, in its active form complexed with G(i1) protein. We found that a single G protein interacts with the GB2 subunit of the GABA(B) receptor at a site that mainly involves intracellular loop 2 on the side of the transmembrane domain. This is in contrast to the G protein binding in a central cavity, as has been observed with other classes of GPCR. This binding mode results from the active form of the transmembrane domain of this GABA(B) receptor being different from that of other GPCRs, as it shows no outside movement of transmembrane helix 6. Our work also provides details of the inter- and intra-subunit changes that link agonist binding to G-protein activation in this heterodimeric complex. Structural basis of GABA(B) receptor-G(i) protein coupling.,Shen C, Mao C, Xu C, Jin N, Zhang H, Shen DD, Shen Q, Wang X, Hou T, Chen Z, Rondard P, Pin JP, Zhang Y, Liu J Nature. 2021 Jun;594(7864):594-598. doi: 10.1038/s41586-021-03507-1. Epub 2021 , Apr 28. PMID:33911284[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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