Structural mechanism underlying G protein family-specific regulation of G protein-gated inwardly rectifying potassium channel

Hanaho Kano, Yuki Toyama, Shunsuke Imai, Yuta Iwahashi, Yoko Mase, Mariko Yokogawa, Masanori Osawa, Ichio Shimada

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Abstract

G protein-gated inwardly rectifying potassium channel (GIRK) plays a key role in regulating neurotransmission. GIRK is opened by the direct binding of the G protein βγ subunit (Gβγ), which is released from the heterotrimeric G protein (Gαβγ) upon the activation of G protein-coupled receptors (GPCRs). GIRK contributes to precise cellular responses by specifically and efficiently responding to the Gi/o-coupled GPCRs. However, the detailed mechanisms underlying this family-specific and efficient activation are largely unknown. Here, we investigate the structural mechanism underlying the Gi/o family-specific activation of GIRK, by combining cell-based BRET experiments and NMR analyses in a reconstituted membrane environment. We show that the interaction formed by the αA helix of Gαi/o mediates the formation of the Gαi/oβγ-GIRK complex, which is responsible for the family-specific activation of GIRK. We also present a model structure of the Gαi/oβγ-GIRK complex, which provides the molecular basis underlying the specific and efficient regulation of GIRK.

Original languageEnglish
Article number2008
JournalNature communications
Volume10
Issue number1
DOIs
Publication statusPublished - 2019 Dec 1

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ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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