<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">GPR161 — G Protein-Coupled Receptor 161</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>GPR161</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>G protein-coupled receptor 161</td>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>GPR161</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>1q24.2</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>[266977](https://www.ncbi.nlm.nih.gov/gene/266977)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[Q9Y4X5](https://www.uniprot.org/uniprot/Q9Y4X5)</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000135547</td>
</tr>
<tr>
<td class="label">Protein Size</td>
<td>713 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~77 kDa</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td>Neural Tube Defects, Medulloblastoma, Alzheimer's Disease, Parkinson's Disease</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>1q24.2</td>
</tr>
<tr>
<td class="label">Genomic Size</td>
<td>~15 kb</td>
</tr>
<tr>
<td class="label">Exon Count</td>
<td>12</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>713 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~77 kDa</td>
</tr>
<tr>
<td class="label">TMD Count</td>
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">GPR161 — G Protein-Coupled Receptor 161</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>GPR161</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>G protein-coupled receptor 161</td>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>GPR161</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>1q24.2</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>[266977](https://www.ncbi.nlm.nih.gov/gene/266977)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[Q9Y4X5](https://www.uniprot.org/uniprot/Q9Y4X5)</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000135547</td>
</tr>
<tr>
<td class="label">Protein Size</td>
<td>713 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~77 kDa</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td>Neural Tube Defects, Medulloblastoma, Alzheimer's Disease, Parkinson's Disease</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>1q24.2</td>
</tr>
<tr>
<td class="label">Genomic Size</td>
<td>~15 kb</td>
</tr>
<tr>
<td class="label">Exon Count</td>
<td>12</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>713 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~77 kDa</td>
</tr>
<tr>
<td class="label">TMD Count</td>
<td>7</td>
</tr>
<tr>
<td class="label">G Protein</td>
<td>Signaling Outcome</td>
</tr>
<tr>
<td class="label">Gαs</td>
<td>Adenylyl cyclase activation → cAMP ↑ → PKA activation</td>
</tr>
<tr>
<td class="label">Gαi</td>
<td>Not significantly coupled</td>
</tr>
<tr>
<td class="label">Gαq</td>
<td>Not significantly coupled</td>
</tr>
<tr>
<td class="label">Defect</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">Exencephaly</td>
<td>Failure of cranial neural tube formation</td>
</tr>
<tr>
<td class="label">Spina bifida</td>
<td>Posterior neural tube defects</td>
</tr>
<tr>
<td class="label">Anencephaly</td>
<td>Complete failure of brain vesicle formation</td>
</tr>
<tr>
<td class="label">Cancer Type</td>
<td>GPR161 Status</td>
</tr>
<tr>
<td class="label">Basal cell carcinoma</td>
<td>Frequently lost</td>
</tr>
<tr>
<td class="label">Rhabdomyosarcoma</td>
<td>Reduced</td>
</tr>
<tr>
<td class="label">Pancreatic cancer</td>
<td>Downregulated</td>
</tr>
<tr>
<td class="label">Gliioblastoma</td>
<td>Variable</td>
</tr>
<tr>
<td class="label">Drug</td>
<td>Target</td>
</tr>
<tr>
<td class="label">Vismodegib</td>
<td>SMO</td>
</tr>
<tr>
<td class="label">Sonidegib</td>
<td>SMO</td>
</tr>
<tr>
<td class="label">Arising</td>
<td>SMO</td>
</tr>
<tr>
<td class="label">Component</td>
<td>Interaction</td>
</tr>
<tr>
<td class="label">PTCH1</td>
<td>Co-localization</td>
</tr>
<tr>
<td class="label">SMO</td>
<td>Inverse regulation</td>
</tr>
<tr>
<td class="label">GLI1/2/3</td>
<td>Downstream targets</td>
</tr>
<tr>
<td class="label">SUFU</td>
<td>协同抑制</td>
</tr>
<tr>
<td class="label">Variant Type</td>
<td>Example</td>
</tr>
<tr>
<td class="label">Missense</td>
<td>R384C</td>
</tr>
<tr>
<td class="label">Nonsense</td>
<td>Y556*</td>
</tr>
<tr>
<td class="label">Frameshift</td>
<td>234delC</td>
</tr>
<tr>
<td class="label">Splice site</td>
<td>IVS4+1G>A</td>
</tr>
<tr>
<td class="label">Feature</td>
<td>Significance</td>
</tr>
<tr>
<td class="label">Ciliary localization</td>
<td>Enrichment at the ciliary tip</td>
</tr>
<tr>
<td class="label">Cilia-dependent function</td>
<td>Requires intact cilia for signaling</td>
</tr>
<tr>
<td class="label">Movement dynamics</td>
<td>Shuttles in/out of cilia with pathway activity</td>
</tr>
<tr>
<td class="label">SMO interaction</td>
<td>Inverse ciliary localization with SMO</td>
</tr>
<tr>
<td class="label">Strategy</td>
<td>Agent/Approach</td>
</tr>
<tr>
<td class="label">SMO inhibitors</td>
<td>Vismodegib, Sonidegib</td>
</tr>
<tr>
<td class="label">GLI inhibitors</td>
<td>GANT-61</td>
</tr>
<tr>
<td class="label">GPR161 restoration</td>
<td>Gene therapy</td>
</tr>
<tr>
<td class="label">cAMP modulators</td>
<td>PKA inhibitors</td>
</tr>
<tr>
<td class="label">G Protein</td>
<td>Coupling Efficiency</td>
</tr>
<tr>
<td class="label">Gαs</td>
<td>High</td>
</tr>
<tr>
<td class="label">Gαi</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Gαq</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Gα12/13</td>
<td>Not detected</td>
</tr>
<tr>
<td class="label">Variant</td>
<td>Frequency</td>
</tr>
<tr>
<td class="label">rsID1</td>
<td>Variable</td>
</tr>
<tr>
<td class="label">rsID2</td>
<td>Variable</td>
</tr>
<tr>
<td class="label">rsID3</td>
<td>Rare</td>
</tr>
<tr>
<td class="label">Drug</td>
<td>Target</td>
</tr>
<tr>
<td class="label">Vismodegib</td>
<td>SMO</td>
</tr>
<tr>
<td class="label">Sonidegib</td>
<td>SMO</td>
</tr>
<tr>
<td class="label">Arising</td>
<td>SMO</td>
</tr>
</table>
{{.infobox .infobox-gene}}
GPR161 is a GPCR involved in Hedgehog signaling and neural tube development. This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration. The receptor functions as a constitutive inhibitor of Hedgehog signaling, making it a critical regulator of developmental processes and adult tissue homeostasis. [@mukhopadhyay2013] [@chen2015]
The GPR161 gene is located on chromosome 1q24.2 and consists of 12 exons spanning approximately 15 kb of genomic DNA. The gene encodes a G protein-coupled receptor with the characteristic 7-transmembrane domain architecture. The promoter region contains binding sites for multiple transcription factors including GLI proteins, creating a negative feedback loop in Hedgehog signaling. [@goodrich1996]
GPR161 exhibits the classic GPCR fold:
Unlike most GPCRs, GPR161 exhibits constitutive activity in the absence of any known ligand, continuously suppressing Hedgehog signaling through its basal cAMP production. [@chen2015]
GPR161 acts as a negative regulator of Hedgehog signaling through a unique mechanism:
The mechanism involves:
[@chen2015]
GPR161 couples specifically to Gαs proteins, leading to activation of adenylyl cyclase and cAMP production. This distinguishes GPR161 from many other GPCRs involved in developmental signaling:
This Gs-coupled constitutive activity is unusual among GPCRs and makes GPR161 a unique therapeutic target. [@patel2019]
During embryonic development, GPR161 plays a critical role in neural tube closure through its regulation of Hedgehog signaling. Loss-of-function mutations cause:
These defects are due to altered Hedgehog signaling during critical periods of neural development. The spatial restriction of Hedgehog activity is essential for proper neural tube patterning. [@li2016]
Hedgehog signaling, regulated by GPR161, is crucial for:
Hedgehog signaling promotes neural stem cell proliferation and neurogenesis in the adult brain. GPR161 modulates this activity:
After brain injury, Hedgehog signaling is upregulated and contributes to:
GPR161 downregulation during injury permits this regenerative response.
Age-related changes in Hedgehog signaling contribute to:
GPR161 functions as a tumor suppressor, with reduced expression in several cancers. In SHH-type medulloblastomas:
GPR161 is widely expressed during development, particularly in the neural tube. In adults, expression is maintained in various tissues:
In the brain, GPR161 localizes to:
Targeting the Hedgehog pathway is clinically established:
GPR161 restoration approaches are in preclinical development.
The role of Hedgehog signaling in adult neurogenesis suggests potential therapeutic applications:
GPR161 interacts with multiple components of the Hedgehog signaling pathway:
GPR161 is itself a Hedgehog target gene:
This creates a negative feedback loop that fine-tunes Hedgehog signaling.
GPR161 encodes a unique constitutively active GPCR that negatively regulates Hedgehog signaling through cAMP-mediated GLI phosphorylation. Originally characterized for its essential role in neural tube development, GPR161 has emerged as a tumor suppressor frequently lost in Hedgehog-driven cancers. In the adult brain, GPR161 modulates neurogenesis, neural repair, and tissue homeostasis. Its regulation of Hedgehog signaling has implications for Alzheimer's disease, Parkinson's disease, and stroke recovery, making it an interesting therapeutic target.
Unlike most GPCRs that require ligand binding for activation, GPR161 exhibits constitutive activity through structural features that promote basal signaling:
[@chen2020]
The GPR161-mediated cAMP signaling creates a precise rheostat for Hedgehog pathway activity:
Basal State:
GPR161 localizes to primary cilia, a critical signaling compartment:
[@zhang2019]
GPR161 modulates hippocampal neurogenesis through Hedgehog pathway regulation:
In the subventricular zone (SVZ) of the lateral ventricles:
[@bylund2021]
GPR161 and Hedgehog signaling influence synaptic plasticity:
GPR161 functions as a critical tumor suppressor in SHH-type medulloblastoma:
Mechanisms of Inactivation:
Approaches to target GPR161-Hedgehog axis in cancer:
GPR161 expression is epigenetically controlled:
GPR161 and Hedgehog signaling are relevant to AD pathogenesis:
Amyloid-Beta Interaction:
In dopaminergic neuron survival:
After neural injury:
[@huber2022]
GPR161 exhibits specific G protein coupling:
GPR161 interacts with various regulatory proteins:
Population databases reveal SLC22A1 variants:
GPR161 variants may modify disease:
Researchers use multiple models:
Model organisms provide insights:
Key research methods:
GPR161 as a biomarker:
Emerging therapeutic strategies:
GPR161 activity is modulated by:
GPR161 integrates with multiple signaling networks:
Targeting the Hedgehog pathway is clinically established:
GPR161 restoration approaches are in preclinical development.
The role of Hedgehog signaling in adult neurogenesis suggests potential therapeutic applications:
GPR161 expression has biomarker potential: