The apelin receptor is an important target for pulmonary fibrosis and heart failure. Agonists for APJR are at various stages of clinical investigation. Here we capture a snapshot of the GPCR monomer-dimer in equilibrium. We show how to manipulate this dynamic process through mutagenesis and link the oligomeric state to downstream efficacy properties. This analysis will open new opportunities for understanding how the oligomeric state of GPCRs influences pharmacology

Drug discovery has recently been revolutionized by the abundance of target 3D structures and the development of ultra-large libraries of drug-like compounds. Inspired by the fragment screening concept, we have developed V-SYNTHES, a new iterative synthon-based approach for fast structure-based virtual screening of billions of readily available (REAL) compounds (Sadybekov et al. Nature 2022). I discuss the latest developments and applications of V-SYNTHES technology to fragment-based lead discovery, especially against GPCRs.

We present biophysical data investigating the role of endogenous phospholipids as allosteric modulators of GPCR signaling. We find that lipids influence the function-related conformational dynamics of GPCRs to the same, or greater, extent as orthosteric drugs. We will discuss experimental NMR data of a protypical class A human GPCR that provide a mechanism for the influence of phospholipids on signaling complex formation.

We present novel approaches for the direct selection of molecules from DNA-encoded libraries that activate GPCRs via either the G-protein or arrestin signaling pathways. We present results of discovery of biased agonists from DELs with live cell selections against the opioid receptor family.

Antagonism of the OX2 orexin receptor (OX2R) is a proven therapeutic strategy for insomnia drugs, and agonism of OX2R is a potentially powerful approach for narcolepsy type 1, which is characterized by the death of orexinergic neurons. Using cryo-EM, we determine how the first clinically tested OX2R agonist TAK-925 can activate OX2R in a highly selective manner. Structures of TAK-925-bound OX2R with either a Gq mimetic or Gi reveal that TAK-925 binds at the same site occupied by antagonists yet interacts with the transmembrane helices to trigger activating micro switches. The mechanisms of TAK-925's binding, activation, and selectivity will be discussed.

The physicochemical properties of drugs influence their measured binding kinetics. Drug association-rate enhancing effects can occur through hydrophobic and polar interactions with membrane-like structures. Crucial interactions at the extracellular surfaces of receptors occur via contact with specific amino acids in vestibular regions. Rapid water loss likely contributes to a fast on-rate, while complimentary structural features dictate the strength of the interaction in the orthosteric pocket and influence dissociation rates.

The dynamic nature of GPCRs enables to recognize a wide range of extracellular molecules. While the structures of some GPCR conformers have been characterized, the dynamics of these conformations are mostly unknown. The lack of such knowledge limits our ability to develop drugs with precise therapeutic effects. Single-molecule fluorescence helps to visualize the dynamic behavior of GPCRs, which reveals hidden structural characteristics and provides new insights into GPCR functions.

Following GPCR activation, there is a dogmatic view on the subsequent interactions and pathways which result in the ultimate fate of a receptor. Although the key players cannot be ignored (i.e. G proteins, GRKS, β-arrestin, etc.) it is increasingly clear that the interactome of GPCRs is far more complex. Here I present ongoing work highlighting the need for and efforts towards better understanding these non-canonical interactions and pathways.

ConfoBodies, single-domain antibody fragments from camelids (VHH) stabilize a desired conformational state of a GPCR and enable conformation-directed drug screening. We will show the unique potential of ConfoBody-stabilized GPCR conformations to facilitate de novo discovery of therapeutic antibodies exhibiting full agonist pharmacology to human GPCRs.

The presence of extracellular adenosine is frequently responsible for the creation of an immunosuppressed tumor microenvironment through activation of the A2a and A2b receptors expressed on intratumoral immune cells. AB928 (etrumadenant) is a novel, selective, and non-brain penetrant small molecule dual A2aR/A2bR antagonist designed to potently block the immunosuppressive effects of high concentrations of adenosine in the tumor microenvironment. This presentation discusses the design, characterization, and SAR of a series of potent A2aR/A2bR antagonists culminating in the discovery of etrumadenant.

Due to its role in immune cell trafficking, CCR2 is pursued as a target in autoimmunity and immuno-oncology. This pursuit, however, has not yet yielded any clinical candidates. Failures have been attributed to complexities of CCR2 biology and suboptimal properties of the therapeutic candidates. I will present an overview of CCR2-targeting modalities, discuss the structural principles of their affinity and selectivity, and share recent findings about unexpected side-effects of CCR2 inhibition.

High levels of Treg infiltration in the tumor microenvironment (TME) lead to a poor prognosis in patients. The chemokine receptor CCR4 is highly expressed on Treg where it functions to attract them into the TME where they inhibit immune response. To reduce the prevalence of Treg in the TME we have discovered and developed FLX475 a potent, selective, and orally available CCR4 antagonist.