TY - JOUR
T1 - Conformational plasticity of the intracellular cavity of GPCR−G-protein complexes leads to G-protein promiscuity and selectivity
AU - Sandhu, Manbir
AU - Touma, Anja M.
AU - Dysthe, Matthew
AU - Sadler, Fredrik
AU - Sivaramakrishnan, Sivaraj
AU - Vaidehi, Nagarajan
PY - 2019/6/11
Y1 - 2019/6/11
N2 - While the dynamics of the intracellular surface in agonist-stimulated GPCRs is well studied, the impact of GPCR dynamics on G-protein selectivity remains unclear. Here, we combine molecular dynamics simulations with live-cell FRET and secondary messenger measurements, for 21 GPCR−G-protein combinations, to advance a dynamic model of the GPCR−G-protein interface. Our data show C terminus peptides of Gαs, Gαi, and Gαq proteins assume a small ensemble of unique orientations when coupled to their cognate GPCRs, similar to the variations observed in 3D structures of GPCR−G-protein complexes. The noncognate G proteins interface with latent intracellular GPCR cavities but dissociate due to weak and unstable interactions. Three predicted mutations in β2-adrenergic receptor stabilize binding of noncognate Gαq protein in its latent cavity, allowing promiscuous signaling through both Gαs and Gαq in a dose-dependent manner. This demonstrates that latent GPCR cavities can be evolved, by design or nature, to tune G-protein selectivity, giving insights to pluridimensional GPCR signaling.
AB - While the dynamics of the intracellular surface in agonist-stimulated GPCRs is well studied, the impact of GPCR dynamics on G-protein selectivity remains unclear. Here, we combine molecular dynamics simulations with live-cell FRET and secondary messenger measurements, for 21 GPCR−G-protein combinations, to advance a dynamic model of the GPCR−G-protein interface. Our data show C terminus peptides of Gαs, Gαi, and Gαq proteins assume a small ensemble of unique orientations when coupled to their cognate GPCRs, similar to the variations observed in 3D structures of GPCR−G-protein complexes. The noncognate G proteins interface with latent intracellular GPCR cavities but dissociate due to weak and unstable interactions. Three predicted mutations in β2-adrenergic receptor stabilize binding of noncognate Gαq protein in its latent cavity, allowing promiscuous signaling through both Gαs and Gαq in a dose-dependent manner. This demonstrates that latent GPCR cavities can be evolved, by design or nature, to tune G-protein selectivity, giving insights to pluridimensional GPCR signaling.
KW - G-protein−coupled receptor
KW - GPCR
KW - dynamics
KW - functional selectivity
KW - structural plasticity
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U2 - 10.1073/pnas.1820944116
DO - 10.1073/pnas.1820944116
M3 - Article
C2 - 31138704
AN - SCOPUS:85067052783
VL - 116
SP - 11956
EP - 11965
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 24
ER -