Heterotrimeric G protein subunit Gαq is a master switch for Gβγ-mediated calcium mobilization by Gi-coupled GPCRs

Eva Marie Pfeil, Julian Brands, Nicole Merten, Timo Vogtle, Maddalena Vescovo, Ulrike Rich, Ina-Maria Albrecht, Nina Heycke, Kouki Kawakami, Yuki Ono, Francois Marie Ngako Kadji, Suzune Hiratsuka, Junken Aoki, Felix Haberlein, Michaela Matthey, Jaspal Garg, Stephanie Hennen, Marie-Lise Jobin, Kerstin Seier, Davide CalebiroAlexander Pfeifer, Akos Heinemann, Daniela Wenzel, Gabriele Konig, Bernhard Nieswandt, Bernd Fleischmann, Asuka Inoue, Anna Katharina Simon, Evi Kostenis

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Mechanisms that control mobilization of cytosolic calcium [Ca2+]i are key for regulation of numerous eukaryotic cell functions. One such paradigmatic mechanism involves activation of phospholipase Cβ (PLCβ) enzymes by G protein βγ subunits from activated Gαi-Gβγ heterotrimers. Here, we report identification of a master switch to enable this control for PLCβ enzymes in living cells. We find that the Gαi-Gβγ-PLCβ-Ca2+ signaling module is entirely dependent on the presence of active Gαq. If Gαq is pharmacologically inhibited or genetically ablated, Gβγ can bind to PLCβ but does not elicit Ca2+ signals. Removal of an auto-inhibitory linker that occludes the active site of the enzyme is required and sufficient to empower “stand-alone control” of PLCβ by Gβγ. This dependence of Gi-Gβγ-Ca2+ on Gαq places an entire signaling branch of G-protein-coupled receptors (GPCRs) under hierarchical control of Gq and changes our understanding of how Gi-GPCRs trigger [Ca2+]i via PLCβ enzymes.
Original languageEnglish
Pages (from-to)940-954.e6
JournalMolecular Cell
Volume80
Issue number6
Early online date16 Nov 2020
DOIs
Publication statusPublished - 17 Dec 2020

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