Melatonin receptor 1B

Melatonin receptor 1B, also known as MTNR1B, is a protein that in humans is encoded by the MTNR1B gene.^[5][6]

MTNR1B
Identifiers
Aliases	MTNR1B, FGQTL2, MEL-1B-R, MT2, Melatonin receptor 1B
External IDs	OMIM: 600804; MGI: 2181726; HomoloGene: 4350; GeneCards: MTNR1B; OMA:MTNR1B - orthologs
Gene location (Human) Chr. Chromosome 11 (human)[1] Band 11q14.3 Start 92,969,651 bp[1] End 92,985,066 bp[1]
Gene location (Mouse) Chr. Chromosome 9 (mouse)[2] Band 9|9 A2 Start 15,735,824 bp[2] End 15,785,852 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in gonad islet of Langerhans nucleus accumbens placenta caudate nucleus renal cortex endometrium left testis right testis Hypothalamus Top expressed in lip More reference expression data BioGPS More reference expression data
Gene ontology Molecular function signal transducer activity melatonin receptor activity protein binding G protein-coupled receptor activity Cellular component integral component of membrane membrane integral component of plasma membrane plasma membrane Biological process glucose homeostasis regulation of insulin secretion G protein-coupled receptor signaling pathway, coupled to cyclic nucleotide second messenger circadian rhythm signal transduction chemical synaptic transmission G protein-coupled receptor signaling pathway negative regulation of cGMP-mediated signaling positive regulation of circadian rhythm camera-type eye development negative regulation of neuron apoptotic process positive regulation of circadian sleep/wake cycle, non-REM sleep negative regulation of insulin secretion negative regulation of cytosolic calcium ion concentration negative regulation of transmission of nerve impulse positive regulation of transmission of nerve impulse regulation of neuronal action potential negative regulation of delayed rectifier potassium channel activity Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 4544 244701 Ensembl ENSG00000134640 ENSMUSG00000050901 UniProt P49286 Q8CIQ6 Q3SXF8 RefSeq (mRNA) NM_005959 NM_145712 RefSeq (protein) NP_005950 NP_663758 Location (UCSC) Chr 11: 92.97 – 92.99 Mb Chr 9: 15.74 – 15.79 Mb PubMed search [3] [4]
Wikidata
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Function

This gene encodes the MT₂ protein, one of two high-affinity forms of a receptor for melatonin, the primary hormone secreted by the pineal gland. This gene product is an integral membrane protein that is a G-protein coupled, 7-transmembrane receptor. It is found primarily in the retina and brain; however, this detection requires RT-PCR. It is thought to participate in light-dependent functions in the retina and may be involved in the neurobiological effects of melatonin.^[5] Besides the brain and retina this receptor is expressed on the bone forming cells where it regulates their function in depositing bone.^[7]

Clinical significance

Several studies have identified MTNR1B receptor mutations that are associated with increased average blood sugar level and around a 20 percent elevated risk of developing type 2 diabetes.^[8][9][10] MTNR1B mRNA is expressed in human islets, and immunocytochemistry confirms that it is primarily localized in beta cells in islets.^[9]

Ligands

The following MT2R ligands have selectivity over MT1R:

• Compound 3d: antagonist with sub-nM affinity^[11]
• Compound 18f: antagonist and compound 18g partial agonist: sub-nM affinity, >100-fold selectivity over MT1^[12]
• Compound 14: antagonist^[13]
• Compound 13: agonist^[14]

See also

• Melatonin receptor
• Discovery and development of melatonin receptor agonists