Insights into adenosine A receptor activation through cooperative modulation of agonist and allosteric lipid interactions
Bruzzese, Agustín (Universitat Autònoma de Barcelona. Institut de Neurociències)
Dalton, James A. R.. (Universitat Autònoma de Barcelona. Institut de Neurociències)
Giraldo, Jesús (Universitat Autònoma de Barcelona. Institut de Neurociències)

Data:	2020
Resum:	UDTAULÍ.
Resum:	The activation process of G protein-coupled receptors (GPCRs) has been extensively studied, both experimentally and computationally. In particular, Molecular Dynamics (MD) simulations have proven useful in exploring GPCR conformational space. The typical behaviour of class A GPCRs, when subjected to unbiased MD simulations from their crystallized inactive state, is to fluctuate between inactive and intermediate(s) conformations, even with bound agonist. Fully active conformation(s) are rarely stabilized unless a G protein is also bound. Despite several crystal structures of the adenosine A2a receptor (A2aR) having been resolved in complex with co-crystallized agonists and G protein, its agonist-mediated activation process is still not completely understood. In order to thoroughly examine the conformational landscape of A2aR activation, we performed unbiased microsecond-length MD simulations in quadruplicate, starting from the inactive conformation either in apo or with bound agonists: endogenous adenosine or synthetic NECA, embedded in two homogeneous phospholipid membranes: 1,2-dioleoyl-sn-glycerol-3-phosphoglycerol (DOPG) or 1,2-dioleoyl-sn-glycerol-3-phosphocholine (DOPC). In DOPC with bound adenosine or NECA, we observe transition to an intermediate receptor conformation consistent with the known adenosine-bound crystal state. In apo state in DOPG, two different intermediate conformations are obtained. One is similar to that observed with bound adenosine in DOPC, while the other is closer to the active state but not yet fully active. Exclusively, in DOPG with bound adenosine or NECA, we reproducibly identify receptor conformations with fully active features, which are able to dock G protein. These different receptor conformations can be attributed to the action/absence of agonist and phospholipid-mediated allosteric effects on the intracellular side of the receptor. Unbiased microsecond-length MD simulations of the adenosine A2a receptor (A2aR) were performed in quadruplicate, starting from the inactive conformation either in apo or with bound agonists: adenosine or NECA, each of them embedded in two different homogeneous phospholipid membranes. Different intermediate or active receptor conformations were found depending on the presence/absence of bound agonist and type of lipid environment. Exclusively, in DOPG with bound agonist, we reproducibly identify receptor conformations with fully active features, which are able to dock G protein. These different receptor conformations can be attributed to the action/absence of agonist and phospholipid-mediated allosteric effects on the intracellular side of the receptor. Dynamic structural data are key for the understanding of agonist-mediated GPCR activation simulated in realistic membrane environments.
Ajuts:	Ministerio de Ciencia e Innovación SAF2017-87199-R
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Publicat a:	PLoS computational biology, Vol. 16 (april 2020) , ISSN 1553-7358

DOI: 10.1371/journal.pcbi.1007818
PMID: 32298258

39 p, 7.8 MB

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