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PsychedeliaDokholyan Laboratory
TargetGlutamate receptors

Metabotropic glutamate receptor 4

NMDA, AMPA, kainate and metabotropic receptors.

Measurements
2
Compounds
1
Binding constants
1
Median pX
—

I · Identity

What this target is

Its function as UniProt states it, where in a cell the protein is found, and which cell types and tissues transcribe its gene.

Protein

GRM4_HUMANGRM4Homo sapiens

Metabotropic glutamate receptor 4

G protein-coupled receptor for glutamate. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors. Signaling inhibits adenylate cyclase activity

Quoted from UniProt’s FUNCTION annotation for Q14833 (reviewed).

What it acts with

STRING’s highest-confidence human functional partners. The combined score mixes several kinds of evidence, so each channel is shown separately — a partner supported by experiment is a different claim from one supported only by text mining, and for a receptor this is where its coupling appears as evidence rather than as assertion.

PartnerCombinedExperimentDatabaseText mining
GRM20.9520.0000.4000.917
GRM60.9520.0000.9000.534
GRM80.9410.0000.9000.416
GRM10.9200.0000.9000.142
GNAI30.9040.9000.0000.070
GRM70.8700.3800.4000.663
GNG20.8170.8000.0000.112
GNB10.8120.8000.0000.102
GRIK10.7740.0000.0000.767
HTR1A0.7600.0000.0000.733

Where it sits in the cell

UniProt, curated Cell membrane

Expression by cell type

Single cell type RNA, the 6 highest of those the Human Protein Atlas reports for this gene. Transcript, not protein, and a cell type rather than a tissue.

  • Brain excitatory neurons163.6 nCPM
  • Retinal amacrine cells74.2 nCPM
  • Pancreatic islet cells47.9 nCPM
  • Brain inhibitory neurons44.3 nCPM
  • Retinal ganglion cells38.6 nCPM
  • Somatotrophs19.4 nCPM

Expression by tissue

The tissues this gene is enriched in, by consensus RNA. A tissue absent from this list is one the Atlas does not call specific for this gene, which is not the same as absent from it.

  • brain254 nTPM

II · Anatomy

Where the gene is transcribed

The same two atlases the compound plates use, asked about this gene alone. Brain on the left, peripheral and autonomic tissues on the right.

Brain

cerebral cortex — 2.8 nTPM, from GRM4cerebellum — 254.0 nTPM, from GRM4hippocampal formation — 1.9 nTPM, from GRM4amygdala — 1.5 nTPM, from GRM4hypothalamus — 3.3 nTPM, from GRM4thalamus — no resolved target expressed herebasal ganglia — 16.6 nTPM, from GRM4medulla oblongata — no resolved target expressed here

basal ganglia: drawn as the caudate nucleus, putamen and globus pallidus.

Measured but not drawn — this anatomogram has no outline for them: spinal cord 4.1, midbrain 1.4, retina 0.7, pituitary gland 0.4.

Body

heart — no resolved target expressed heresmooth muscle — 0.1 nTPM, from GRM4lung — no resolved target expressed hereliver — no resolved target expressed herekidney — no resolved target expressed herestomach — no resolved target expressed hereduodenum — no resolved target expressed heresmall intestine — 0.1 nTPM, from GRM4colon — no resolved target expressed hereadrenal gland — 0.1 nTPM, from GRM4thyroid gland — no resolved target expressed herepancreas — 0.7 nTPM, from GRM4urinary bladder — no resolved target expressed hereskeletal muscle — no resolved target expressed herespleen — no resolved target expressed heresalivary gland — no resolved target expressed here
0254 nTPM

Square-root ramp · shared scale across both plates

Shading is transcript level — not affinity, and not affinity combined with expression. Outlined but unshaded organs hold none of GRM4 transcript above the atlas’s detection threshold. Anatomy from EMBL-EBI Anatomogram (Apache License 2.0); regions identified by Uberon (uberon.org), CC BY 3.0.

Brain · 10

  • cerebellum254.0 nTPM
  • basal ganglia16.6 nTPM
  • spinal cord4.1 nTPM
  • hypothalamus3.3 nTPM
  • cerebral cortex2.8 nTPM
  • hippocampal formation1.9 nTPM
  • amygdala1.5 nTPM
  • midbrain1.4 nTPM
  • retina0.7 nTPM
  • pituitary gland0.4 nTPM

Peripheral and autonomic · 4

  • pancreas0.7 nTPM
  • smooth muscle0.1 nTPM
  • small intestine0.1 nTPM
  • adrenal gland0.1 nTPM

Transcript is not protein. These are RNA levels for GRM4, shaded on √nTPM so that a three-order range stays legible — on a linear ramp every region but the strongest would read as blank, which looks like absence rather than less. A region carrying no shading is one the atlas reports no consensus value for, not one where the gene is silent. And a gene being transcribed somewhere is not evidence that any compound reaches it. Human Protein Atlas, RNA expression, nTPM (normalized transcripts per million), consensus tissue dataset.

IV · Evidence

Every measurement at this target

Each row links to the ChEMBL assay it came from.

Equilibrium binding constants 1

Ki and Kd — a concentration at equilibrium. Directly comparable across rows at the same target.

TargetClassTypeValue (nM)pXOrganismAssay
Metabotropic glutamate receptor 4Glutamate receptorsKi— no normalized value— value does not convert to pXHomo sapiensCHEMBL716502

Functional readouts 1

IC₅₀, EC₅₀, AC₅₀ and potency. Assay-dependent, and not interchangeable with a binding constant.

TargetClassTypeValue (nM)pXOrganismAssay
Metabotropic glutamate receptor 4Glutamate receptorsEC50— no normalized value— value does not convert to pXHomo sapiensCHEMBL818788
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