Targeting the gamma-Aminobutyric Acid Type B (GABAB) Receptor Complex: Development of Inhibitors Targeting the K+Channel Tetramerization Domain (KCTD) Containing Proteins/GABABReceptor Protein-Protein Interaction.
Sereikaite, V., Fritzius, T., Kasaragod, V.B., Bader, N., Maric, H.M., Schindelin, H., Bettler, B., Stromgaard, K.(2019) J Med Chem 62: 8819-8830
- PubMed: 31509708 
- DOI: https://doi.org/10.1021/acs.jmedchem.9b01087
- Primary Citation of Related Structures:  
6I0Q - PubMed Abstract: 
Targeting multiprotein receptor complexes, rather than receptors directly, is a promising concept in drug discovery. This is particularly relevant to the GABA B receptor complex, which plays a prominent role in many brain functions and diseases. Here, we provide the first studies targeting a key protein-protein interaction of the GABA B receptor complex-the interaction with KCTD proteins. By employing the μSPOT technology, we first defined the GABA B receptor-binding epitope mediating the KCTD interaction. Subsequently, we developed a highly potent peptide-based inhibitor that interferes with the KCTD/GABA B receptor complex and efficiently isolates endogenous KCTD proteins from mouse brain lysates. X-ray crystallography and SEC-MALS revealed inhibitor induced oligomerization of KCTD16 into a distinct hexameric structure. Thus, we provide a template for modulating the GABA B receptor complex, revealing a fundamentally novel approach for targeting GABA B receptor-associated neuropsychiatric disorders.
Organizational Affiliation: 
Center for Biopharmaceuticals, Department of Drug Design and Pharmacology , University of Copenhagen , 2100 Copenhagen , Denmark.