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Early Events in β2AR Dimer Dynamics Mediated by Activation-Related Microswitches
Aneesh Kotipalli1, Shruti Koulgi1, Vinod Jani1
1HPC-Medical & Bioinformatics Applications Group, Centre for Development of Advanced Computing (C-DAC), Innovation Park, Panchawati, Pashan, Pune, India, 411008.
The Journal of Membrane Biology
|September 6, 2024
Summary
Molecular dynamics simulations reveal how G-Protein-Coupled Receptors (GPCRs), like beta-2 adrenergic receptor (β2AR), activate at the dimer level. Findings show activation can occur in one monomer, impacting dimer function and GPCR oligomerization mechanisms.
Area of Science:
- Biochemistry
- Structural Biology
- Pharmacology
Background:
- G-Protein-Coupled Receptors (GPCRs) are crucial drug targets, often existing as dimers.
- Beta-2 adrenergic receptor (β2AR) is vital for treating asthma and cardiovascular diseases.
- GPCR activation mechanisms at the dimer level are not fully understood.
Purpose of the Study:
- To investigate activation-related structural dynamics of β2AR dimers using molecular dynamics simulations.
- To explore how monomeric activation features translate to the dimeric state.
Main Methods:
- Performed ~21-μs molecular dynamics (MD) simulations on apo, agonist-bound, and inverse agonist-bound β2AR dimers (PDB IDs: 2RH1, 3P0G).
- Analyzed simulations using residue-based distances, Root Mean Square Deviation (RMSD), and Principal Component Analysis (PCA).
Main Results:
- Activation-related features were observed in at least one monomer of apo and agonist-bound β2AR dimers.
- Transmembrane helices TM5 and TM6 showed significant variations, with TM5 bulge and TM2-TM7 proximity potentially indicating early activation events.
- Dimeric interfaces (TM1-helix 8) remained stable in apo and agonist-bound states.
- Inverse agonists maintained inactive conformations in both monomers.
Conclusions:
- Monomeric activation features impact β2AR dimers, offering insights into GPCR oligomerization.
- Activation can be asymmetric within β2AR dimers.
- These findings contribute to understanding GPCR function and drug targeting.
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