The structures of salt-inducible kinase 3 in complex with inhibitors reveal determinants for binding and selectivity

Advanced modeling of salt-inducible kinase (SIK) inhibitors incorporating protein flexibility through molecular dynamics and cross-docking

Salt-inducible kinases (SIK1, SIK2, and SIK3) regulate metabolism and immune responses, making them promising targets for inflammatory and autoimmune diseases. Understanding inhibitor selectivity among isoforms is crucial for therapeutic development. In this study, 44 compounds were investigated as SIK inhibitors using molecular modeling. A flexible treatment of the kinases via molecular dynamics (MD) simulations captured binding site conformational changes, followed by molecular docking to generate protein kinase (PK)-ligand complex models. Ligand orientations were validated against crystallographic data using LigRMSD and interaction fingerprints (IFPs). A genetic algorithm was applied to select conformations that maximize correlation between docking energies and biological activities, yielding R² values of 0.821, 0.646, and 0.620 for SIK1, SIK2, and SIK3, respectively. Our results highlight the importance of protein flexibility in achieving accurate correlations between docking energies and experimental pIC50 values, enhancing inhibitor selectivity predictions.

Macromolecular crystallography from an industrial perspective - the impact of synchrotron radiation on structure-based drug discovery

Structure-based drug design has been an integral part of drug discovery for over three decades, contributing to the development of numerous approved drugs. Here we discuss the evolution, as well as the current state, of structure-based drug design within the pharmaceutical industry, using data from AstraZeneca's internal repository for crystal structures to provide additional context. Over the past 20 years, the company has transitioned from a mixed in-house and synchrotron data collection model to a `synchrotron-only' approach, enabled by technological advancements at synchrotron facilities. We provide real-world examples of structure delivery to projects, including a high-throughput project and a case where a single structure was pivotal for discovering a candidate drug. We conclude that, despite recent developments in single-particle cryo-EM and deep-learning structure prediction methods, macromolecular crystallography remains a critical tool for drug discovery.

Central and Peripheral Roles of Salt-inducible Kinases in Metabolic Regulation

Salt-inducible kinases (SIKs), a member of the serine/threonine protein kinase family, have recently garnered considerable research interest as one of the emerging key regulators of metabolism. The 3 SIK isoforms-SIK1, SIK2, and SIK3-exhibit diverse roles both in central and peripheral physiological processes. While early studies focused on their role in inflammation, spurring the development of SIK inhibitors for chronic inflammatory diseases currently in clinical trials, emerging evidence highlights their broader functions in metabolism. In this review, we will summarize the current state of research on the central roles of SIKs in the brain, particularly in regulating energy balance and glucose homeostasis, alongside their peripheral functions in critical metabolic tissues such as the liver, adipose tissue, and pancreas. By integrating insights into their central and peripheral roles, this review underscores the importance of SIKs in maintaining metabolic homeostasis and highlights their therapeutic potential as novel targets for metabolic disease.