G-protein-coupled receptors (GPCRs) represent the largest protein superfamily with more than 1000 members and play a key role in the treatment of various diseases. In addition to the classical signaling via different G-protein subclasses, new G-protein-independent signaling pathways have also been found over the years. The detailed examination of individual signaling pathways has an increasingly important role in modern GPCR drug discovery to develop novel drugs with improved side effect profiles. Although great progress has been made for many GPCRs, some questions remain open, such as receptor selectivity, biased signaling, or drug-like properties of potential drug candidates.

This Special Collection intends to help broaden our understanding of these important questions. In addition to the synthesis and characterization of novel GPCR ligands, comprehensive work on GPCR signaling or assay development in the field of molecular biology is also desired. Guest edited by Steffen Pockes (University of Regensburg, Germany).