Htr2C Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| Property |
Value |
| Gene Symbol |
HTR2C |
| Full Name |
5-Hydroxytryptamine Receptor 2C |
| Chromosomal Location |
Xq24 |
| NCBI Gene ID |
3358 |
| Ensembl ID |
ENSG00000140048 |
| UniProt ID |
P28335 |
| OMIM ID |
312861 |
| Protein Class |
G Protein-Coupled Receptor (Class A) |
| Species |
Human |
| Associated Diseases |
Prader-Willi Syndrome, Depression, Schizophrenia, Obesity, Epilepsy, RLS |
The HTR2C gene encodes the 5-hydroxytryptamine 2C (5-HT2C) receptor, a Gq-coupled serotonin receptor widely expressed in the central nervous system. The 5-HT2C receptor plays crucial roles in mood regulation, appetite, sleep, cognition, and motor control. It is a major therapeutic target for depression, schizophrenia, obesity, and Prader-Willi syndrome. Unlike most serotonin receptors, HTR2C undergoes RNA editing (A-to-I editing) that produces multiple receptor isoforms with varying signaling efficiency.
The 5-HT2C receptor is a Gq-coupled receptor that activates phospholipase C (PLC) signaling:
- PLC activation: Generates IP3 and DAG second messengers
- Intracellular calcium release: IP3 triggers Ca2+ release from ER stores
- Protein kinase C activation: DAG activates PKC isoforms
- ERK/MAPK signaling: Can activate downstream kinase cascades
- β-arrestin recruitment: Triggers G protein-independent signaling
Key characteristics:
- Constitutive activity: High basal activity in the absence of ligand
- RNA editing: 5 editing sites produce 24+ receptor isoforms (INI, ADI, VSV, etc.)
- Alternative splicing: Produces multiple splice variants
- Ligand properties: Agonists cause downregulation; antagonists cause upregulation
- Highest expression: Choroid plexus (where it regulates CSF production)
- High expression: Cortex (layer V), hippocampus, amygdala, hypothalamus
- Moderate expression: Basal ganglia, nucleus accumbens, substantia nigra
- Low expression: Cerebellum, brainstem
- Intestine: Enterochromaffin cells
- Platelets: Low expression
- Immune cells: Monocytes, lymphocytes
- Hyperphagia: HTR2C mutations cause loss of satiety signaling
- PWS patients: Have increased appetite and food-seeking behavior
- Therapeutic target: Setmelanotide (MC4R agonist) approved for PWS obesity
¶ Depression and Anxiety
- SSRIs: Downregulate HTR2C (therapeutic mechanism)
- Antidepressants: Many act as HTR2C antagonists (e.g., mirtazapine)
- Therapeutic effects: HTR2C antagonism improves mood and anxiety
- Antipsychotics: Most atypical antipsychotics block HTR2C
- Weight gain: HTR2C antagonism contributes to antipsychotic-induced weight gain
- Negative symptoms: HTR2C agonists may improve negative symptoms
- Serotonergic dysfunction: Altered 5-HT2C signaling implicated
- Therapeutic effects: SSRIs worsen RLS (via 5-HT2C modulation)
- Treatment: HTR2C-targeted approaches under investigation
- Motor complications: 5-HT2C modulation affects levodopa-induced dyskinesias
- Non-motor symptoms: Depression, anxiety in PD linked to 5-HT2C
- Seizure susceptibility: HTR2C modulates neuronal excitability
- Therapeutic potential: HTR2C agonists may have anticonvulsant effects
| Drug |
Type |
Indications |
Notes |
| Lorcaserin |
Agonist |
Obesity (withdrawn) |
First selective HTR2C agonist |
| Vilazodone |
Partial agonist |
Depression |
5-HT1A partial agonist + SRI |
| Vortioxetine |
Antagonist |
Depression |
Multi-modal action |
| Mirtazapine |
Antagonist |
Depression, insomnia |
Also blocks H1, 5-HT3 |
| Trazodone |
Antagonist |
Depression, insomnia |
5-HT2A/2C antagonist |
- Obesity: Selective HTR2C agonists without cardiac valve effects
- Depression: Fast-acting antidepressants via 5-HT2C modulation
- RBD: HTR2C antagonists for REM sleep behavior disorder
- Neuroprotection: HTR2C agonists in PD models
- Obesity: Develop obesity even on normal diet
- Hyperphagia: Increased food intake
- Seizures: Increased susceptibility to seizures
- Emotional behavior: Anxious and depressive-like phenotypes
- Humanized HTR2C mice for drug testing
- Editing-deficient mice show enhanced canonical signaling
- Conditional knockout for region-specific studies
- RNA editing: Understanding editing in disease states
- Structure-based drug design: Develop selective agonists/antagonists
- Biomarkers: HTR2C expression as a biomarker
- Gene therapy: Viral vector delivery of HTR2C
The study of Htr2C Gene has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- PMID:1372603 - Cloning of the human 5-HT2C receptor
- PMID:7608714 - RNA editing of the 5-HT2C receptor
- PMID:10828789 - HTR2C and Prader-Willi syndrome
- PMID:11752352 - 5-HT2C receptor in depression
- PMID:15588916 - Antipsychotic weight gain and HTR2C
- PMID:20431768 - HTR2C and appetite regulation
- PMID:23450155 - HTR2C in Parkinson's disease
- PMID:28134917 - Serotonin 2C receptors in epilepsy