Metabotropic glutamate receptor 1; Metabotropic glutamate receptor 5 (mGluR1; mGluR5)

Metabotropic glutamate receptor 1 and metabotropic glutamate receptor 5 are members of the Group I metabotropic glutamate receptor subfamily, encoded by GRM1 and GRM5 genes, respectively. These family C G protein-coupled receptors (GPCRs) play a central role in modulating excitatory neurotransmission, synaptic plasticity, and neuronal signaling within the central nervous system. Structurally, both receptors function as obligate dimers, possess large N-terminal extracellular ligand-binding (Venus flytrap) domains, and couple primarily to Gq/11 proteins. Upon activation by glutamate, they stimulate phospholipase C, leading to intracellular calcium release and the initiation of diverse second messenger signaling cascades. Both receptors participate in the regulation of learning, memory, and neuronal excitability, and their dysfunction has been linked to neurological and psychiatric disorders including epilepsy, schizophrenia, autism spectrum disorders, Parkinson's disease, and various forms of addiction. Highly selective orthosteric and allosteric modulators have been developed for research and potential therapy.

Other names

mGlu-1 receptorGRM1Glutamate receptor, metabotropic 1mGlu-5 receptorGRM5Glutamate receptor, metabotropic 5

Orthosteric agonists bind the Venus flytrap domain (VFT) to activate receptor signaling - Positive allosteric modulators increase receptor responsiveness to glutamate by binding sites in the transmembrane domain - Negative allosteric modulators bind non-orthosteric sites, decrease activity - Antagonists block receptor activation - Signal transduction through Gq/11 proteins, leading to PLC activation and increased IP₃, DAG, and calcium signaling (Group I: mGluR1, mGluR5)