Metabotropic glutamate receptor 4

Metabotropic glutamate receptor 4 is a protein that in humans is encoded by the GRM4 gene.

Together with GRM6, GRM7 and GRM8 it belongs to group III of the metabotropic glutamate receptor family. Group III receptors are linked to the inhibition of the cyclic AMP cascade. Activation of GRM4 has potential therapeutic benefits in the treatment of parkinson's disease. Splice variant "taste-GRM4" is involved in the perception of umami taste.

Orthosteric

 * Cinnabarinic acid, a tryptophan metabolite
 * LSP1-2111: agonist
 * LSP4-2022: agonist
 * LSP2-9166: mixed agonist at mGluR4 and mGluR7

Positive allosteric modulators (PAMs)

 * Foliglurax (PXT-002331, DT-1687)
 * Tricyclic thiazolopyrazole derivative 22a: EC50 = 9 nM, Emax = 120%
 * ML-128: EC50 = 240 nM, Emax = 182%
 * VU0652957 (AP-472) (Valiglurax)
 * VU-0418506
 * VU-001171: EC50 = 650 nM, Emax = 141%, 36-fold shift
 * VU-0155041: subtype-selective PAM, intrinsic allosteric agonist activity, robust in-vivo activity
 * PHCCC: PAM of mGluR4, negative allosteric modulator of mGluR1, direct agonist at mGluR6