OPRM1 Gene: Opioid Receptor Mu 1
Key mediator of opioid analgesia and addiction; genetic variants influence pain sensitivity and opioid response.
Gene Information Card
| Symbol | OPRM1 |
|---|---|
| Full Name | Opioid Receptor Mu 1 |
| Gene Type | protein-coding |
| Chromosomal Location | 6q25.2 |
| NCBI Gene ID | 4988 ncbi.nlm.nih.gov/gene/4988 |
| Ensembl ID | ENSG00000112038 |
| UniProt ID | P35372 |
| OMIM ID | 600018 |
| HGNC ID | 8156 |
| Aliases | MOR1, OPRM, MOR, KIAA0403, M-OR-1 |
Description
The OPRM1 gene encodes the mu-opioid receptor, a G protein-coupled receptor that is the primary target for endogenous opioid peptides (e.g., beta-endorphin, enkephalins) and clinically used opioids (e.g., morphine, fentanyl). It mediates analgesia, reward, and addiction. Genetic variants, particularly the A118G (rs1799971) polymorphism, have been associated with altered receptor function, pain sensitivity, and differential responses to opioid therapy.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Opioid Dependence | Altered receptor signaling due to variants (e.g., A118G) affects reward pathways and addiction susceptibility. | ClinVar, PMID: 20034518 |
| Pain Sensitivity (Congenital insensitivity to pain, rare) | Loss-of-function mutations reduce receptor activity, impairing pain perception. | OMIM, PMID: 16916642 |
| Alcohol Dependence | OPRM1 variants influence alcohol reward and dependence risk. | ClinVar, PMID: 19012872 |
| Naltrexone Response in Alcoholism | A118G variant predicts better response to naltrexone treatment. | ClinVar, PMID: 19012872 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain (cortex) | 2.3 | Low |
| Brain (cerebellum) | 1.1 | Low |
| Spinal cord | 3.5 | Low |
| Adrenal gland | 0.8 | Low |
| Gastrointestinal tract | 0.5 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| SH-SY5Y (neuroblastoma) | 5.2 | Endogenous expression |
| U-87 MG (glioblastoma) | 1.4 | Low expression |
| HEK293 (embryonic kidney) | 0.0 | Not expressed (used for transfection) |
| HepG2 (hepatocellular carcinoma) | 0.0 | Not expressed |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| A118G (rs1799971) | SNP (missense, N40D) | Allele frequency: ~15-30% in various populations | Reduced receptor expression and signaling; altered pain sensitivity and opioid response. |
| C17T (rs1799972) | SNP (5' UTR) | ~5-10% | May affect mRNA stability and receptor expression. |
| R265H (rs540825) | Missense | Rare | Potential loss of function; associated with altered binding affinity. |
| S268P (rs17181000) | Missense | Rare | Impaired receptor trafficking and signaling. |
Mutation functional classification
Loss of Function (LOF)
A118G and S268P reduce receptor expression or signaling, leading to decreased opioid efficacy.
Gain of Function (GOF)
No common gain-of-function variants reported; some rare variants may increase signaling but not well characterized.
Dominant Negative (DN)
Not reported for OPRM1.
View complete mutation data：
Gene Ontology (GO)
| • G protein-coupled receptor activity | • opioid receptor activity |
| • signal transduction | • adenylate cyclase inhibition |
| • MAPK cascade | • response to morphine |
| • neurotransmitter receptor activity | • plasma membrane |
Pathways
• GPCR downstream signaling
• Opioid signaling pathway
• G alpha i signaling events
• cAMP signaling pathway
• MAPK signaling pathway
Protein Summary
The mu-opioid receptor (MOR) is a 7-transmembrane G protein-coupled receptor. Upon agonist binding, it activates G proteins (Gi/Go), inhibiting adenylate cyclase, reducing cAMP levels, and modulating ion channels (e.g., activating GIRK channels, inhibiting voltage-gated calcium channels). This leads to neuronal hyperpolarization and reduced neurotransmitter release, producing analgesia and reward. The receptor undergoes post-translational modifications including glycosylation and phosphorylation, which regulate trafficking and desensitization.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| OPRM1 Knockout HEK293 Cell Line | EDJ-KQ3041 | Human | 4988 | Details Get a Quote |
| OPRM1 Knockout HeLa Cell Line | EDJ-KQ54050 | Human | 4988 | Details Get a Quote |
| OPRM1 Knockout A-549 Cell Line | EDJ-KQ62538 | Human | 4988 | Details Get a Quote |
| OPRM1 Knockout HCT 116 Cell Line | EDJ-KQ71010 | Human | 4988 | Details Get a Quote |
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