Deciphering biased-agonism complexity reveals a new active AT1 receptor entity.
Functional selectivity of G protein-coupled receptor (GPCR) ligands toward different downstream signals has recently emerged as a general hallmark of this receptor class. However, pleiotropic and crosstalk signaling of GPCRs makes functional selectivity difficult to decode. To look from the initial active receptor point of view, we developed new, highly sensitive and direct bioluminescence resonance energy transfer-based G protein activation probes specific for all G protein isoforms, and we used them to evaluate the G protein-coupling activity of [(1)Sar(4)Ile(8)Ile]-angiotensin II (SII), previously described as an angiotensin II type 1 (AT(1)) receptor-biased agonist that is G protein independent but β-arrestin selective. By multiplexing assays sensing sequential signaling events, from receptor conformations to downstream signaling, we decoded SII as an agonist stabilizing a G protein-dependent AT(1A) receptor signaling module different from that of the physiological agonist angiotensin II, both in recombinant and primary cells. Thus, a biased agonist does not necessarily select effects from the physiological agonist but may instead stabilize and create a new distinct active pharmacological receptor entity.
Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, Toulouse, France.
Aude
A
Saulière
Morgane
M
Bellot
Hervé
H
Paris
Colette
C
Denis
Frédéric
F
Finana
Jonas T
JT
Hansen
Marie-Françoise
MF
Altié
Marie-Hélène
MH
Seguelas
Atul
A
Pathak
Jakob L
JL
Hansen
Jean-Michel
JM
Sénard
Céline
C
Galés
D015374:Biosensing Techniques; D002460:Cell Line; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D011487:Protein Conformation; D044140:Receptor, Angiotensin, Type 1 / Q000819:agonists / Q000737:chemistry / Q000378:metabolism*
D044140:Receptor, Angiotensin, Type 1; D019204:GTP-Binding Proteins