Optical Control of Adenosine A Receptor Using Istradefylline Photosensitivity.

In recent years, there has been growing interest in the potential therapeutic use of inhibitors of adenosine A receptors (AR) for the treatment of neurodegenerative diseases and cancer. Nevertheless, the widespread expression of AR throughout the body emphasizes the importance of temporally and spatially selective ligands. Photopharmacology is an emerging strategy that utilizes photosensitive ligands to attain high spatiotemporal precision and regulate the function of biomolecules using light.

Agonists and allosteric modulators promote signaling from different metabotropic glutamate receptor 5 conformations.

Metabotropic glutamate receptors (mGluRs) are dimeric G-protein-coupled receptors activated by the main excitatory neurotransmitter, L-glutamate. mGluR activation by agonists binding in the venus flytrap domain is regulated by positive (PAM) or negative (NAM) allosteric modulators binding to the 7-transmembrane domain (7TM). We report the cryo-electron microscopy structures of fully inactive and intermediate-active conformations of mGlu receptor bound to an antagonist and a NAM or an agonist and a PAM, respectively, as well as the crystal structure of the 7TM bound to a photoswitchable NAM.

[Recent advances in the structural biology of the class C G protein-coupled receptors: The metabotropic Glutamate receptor 5].

Class C GPCRs, that include metabotropic glutamate receptors (mGlu), taste receptors, GABA receptor and Calcium-sensing receptor, are unusual in terms of their molecular architecture and allosteric regulation. They all form obligatory dimers, dimerization being fundamental for their function. More specifically, the mGlu are activated by the main excitatory neurotransmitter, L-glutamate.