1. G Protein-Coupling of Adhesion GPCRs ADGRE2/EMR2 and ADGRE5/CD97, and Activation of G Protein Signalling by an Anti-EMR2 Antibody.
- Author
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Bhudia N, Desai S, King N, Ancellin N, Grillot D, Barnes AA, and Dowell SJ
- Subjects
- Blotting, Western, HEK293 Cells metabolism, Humans, Immunoprecipitation, Receptors, G-Protein-Coupled antagonists & inhibitors, Receptors, G-Protein-Coupled immunology, Antibodies immunology, Antigens, CD metabolism, GTP-Binding Proteins metabolism, Receptors, G-Protein-Coupled metabolism, Signal Transduction drug effects
- Abstract
The experimental evidence that Adhesion G Protein-Coupled Receptors (aGPCRs) functionally couple to heterotrimeric G proteins has been emerging in incremental steps, but attributing biological significance to their G protein signalling function still presents a major challenge. Here, utilising activated truncated forms of the receptors, we show that ADGRE2/EMR2 and ADGRE5/CD97 are G protein-coupled in a variety of recombinant systems. In a yeast-based assay, where heterologous GPCRs are coupled to chimeric G proteins, EMR2 showed broad G protein-coupling, whereas CD97 coupled more specifically to G
α12 , Gα13 , Gα14 and Gαz chimeras. Both receptors induced pertussis-toxin (PTX) insensitive inhibition of cyclic AMP (cAMP) levels in mammalian cells, suggesting coupling to Gαz . EMR2 was shown to signal via Gα16 , and via a Gα16 /Gαz chimera, to stimulate IP1 accumulation. Finally, using an NFAT reporter assay, we identified a polyclonal antibody that activates EMR2 G protein signalling in vitro. Our results highlight the potential for the development of soluble agonists to understand further the biological effects and therapeutic opportunities for ADGRE receptor-mediated G protein signalling.- Published
- 2020
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