Revealing GRK5 Activation Features by Interpretable Machine Learning and Molecular Dynamics Simulation.

G protein-coupled receptor kinase 5 (GRK5) is an important therapeutic target involving cardiovascular diseases, cancer, and inflammatory disorders. However, the features of its activation as an essential function regulation process have been poorly understood, limiting related drug development. The work utilizes a molecular dynamics simulation coupled with an interpretable machine learning model to identify key structure and dynamics determinants distinguishing the active and inactive states of GRK5. Benefiting from the unbiased and data-driven framework, the work reveals that the active site tether (AST) is a dominant activation-associated feature, acting as a conformational switch that regulates kinase domain movements. Beyond this canonical element, we also uncover two previously underappreciated structure modules contributing to GRK5 activation, such as the coupling interaction between the α10/α11 helix interface with the N-terminal lipid-binding domain (NLBD) in the active state, and the α5 helix region that facilitates large-scale RH domain reorientation. Conformation dynamics analyses further indicate that GRK5 activation involves disruption of the interdomain interactions and interaction coupling between AST, αN-helix, kinase domain N-lobe, NLBD, and α10/α11 hinge. These observations provide valuable insights into understanding the GPK5 activation mechanism and also highlight the power of machine learning in capturing functionally conformational changes, and in turn offering a methodological guideline for the studying of the protein function mechanism.