ADCY9 — Adenylate Cyclase 9
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">ADCY9 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>ADCY9</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Adenylate Cyclase 9</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>16p13.3</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000100105</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>116</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>O60344</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>1,354 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~150 kDa</td>
</tr>
<tr>
<td class="label">Tissue/Cell Type</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Brain (cortex, hippocampus)</td>
<td>High</td>
</tr>
<tr>
<td class="label">Lung</td>
<td>High</td>
</tr>
<tr>
<td class="label">Heart</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Platelets</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Adipose tissue</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Kidney</td>
<td>Low-Moderate</td>
</tr>
<tr>
<td class="label">Liver</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Skeletal Muscle</td>
<td>Low</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
Overview
Mermaid diagram (expand to render)
ADCY9 (Adenylate Cyclase 9), also known as Adenylyl Cyclase 9, is a member of the adenylate cyclase family of enzymes that catalyze the conversion of ATP to cyclic AMP (cAMP), a key second messenger in cellular signaling. It is encoded by the ADCY9 gene located on chromosome 16p13.3 and is expressed in various tissues, including brain, lung, heart, and platelets. ADCY9 is unique among adenylate cyclases in its regulation by calcium—it can be inhibited by calcium/calmodulin, making it a point of crosstalk between calcium and cAMP signaling pathways. In the brain, ADCY9 participates in cAMP-mediated signaling involved in learning, memory, synaptic plasticity, and neuroprotection. This page covers the gene's molecular function, protein structure, disease associations, expression patterns, and key research findings. [@ncbi][@uniprot]
Protein Structure and Domains
ADCY9 is a large membrane-bound enzyme with a complex domain organization:
Transmembrane Region
The N-terminal region contains 12 transmembrane helices organized into two sets of six, creating a channel-like structure. These transmembrane domains anchor the enzyme to the plasma membrane and may be involved in substrate access and product release.
C1 Domain (Catalytic Domain 1)
The first catalytic domain is located intracellularly after the sixth transmembrane helix. It contains the ATP binding site and participates in dimerization with the C2 domain. This domain contains conserved motifs for metal ion binding and catalysis.
C2 Domain (Catalytic Domain 2)
The second catalytic domain follows the second set of transmembrane helices. It forms a dimer with the C1 domain to create the active site. Both catalytic domains are required for enzymatic activity.
Regulatory Regions
ADCY9 contains several regulatory features:
- Calmodulin-binding domain: Located in the C1 region, mediates calcium inhibition
- PKA phosphorylation sites: Allow regulation by protein kinase A
- PEST sequences: May target the protein for degradation
Molecular Mechanism of Action
cAMP Synthesis
ADCY9 catalyzes the conversion of ATP to cAMP:
Substrate Binding: ATP binds to the catalytic site formed by the C1 and C2 domains.
Metal Ion Cofactor: Mg²⁺ or Mn²⁺ coordinates the phosphate transfer reaction.
Catalysis: The reaction proceeds through a pyrophosphate intermediate.
Product Release: cAMP is released into the cytosol as a second messenger.The reaction is: ATP → cAMP + PPi (pyrophosphate)
Regulation by Calcium
ADCY9 is uniquely regulated among adenylate cyclases:
- Calcium/calmodulin inhibition: Elevated intracellular calcium binds calmodulin, which then inhibits ADCY9 activity
- Calcium sensitivity: The enzyme is sensitive to physiological calcium concentrations
- Signal integration: This regulation allows calcium signals to suppress cAMP production
G Protein Regulation
ADCY9 responds to G protein-coupled receptor (GPCR) signaling:
- Gs-coupled receptors: Stimulate ADCY9 via Gs protein alpha subunit
- Gi-coupled receptors: Inhibit ADCY9 via Gi protein alpha subunit
- Gq-coupled receptors: Can activate PLCβ, increasing calcium and indirectly inhibiting ADCY9
Downstream Effects
cAMP produced by ADCY9 activates:
- Protein kinase A (PKA)
- Epac (Exchange protein activated by cAMP)
- cAMP-gated ion channels
These effectors then regulate diverse cellular processes including:
- Gene transcription (via CREB)
- Ion channel function
- Cytoskeletal dynamics
- Metabolic enzymes
Expression Pattern
ADCY9 exhibits widespread tissue distribution:
In the brain, ADCY9 is expressed in:
- Pyramidal neurons in cortex and hippocampus
- Cerebellar Purkinje cells
- Dopaminergic neurons
- Microglia (lower levels)
Disease Associations
Alzheimer's Disease
ADCY9 has emerging relevance to AD through several mechanisms:
Calcium-cAMP Crosstalk: AD is associated with calcium dysregulation. ADCY9's calcium sensitivity positions it to respond to pathological calcium changes in neurons, potentially affecting cAMP-mediated signaling critical for synaptic plasticity and memory.
Synaptic Function: cAMP signaling is essential for long-term potentiation (LTP), a cellular correlate of learning and memory. Altered ADCY9 activity could contribute to synaptic failure in AD.
Genetic Associations: Some GWAS studies have suggested ADCY9 variants may influence AD risk, though associations are not yet robust.
Therapeutic Implications: Modulating ADCY9 activity could potentially restore cAMP signaling in AD brains, though drug development faces challenges.
Asthma
ADCY9 is a well-established genetic factor in asthma:
- ADCY9 polymorphisms are associated with asthma risk
- The enzyme is expressed in airway smooth muscle
- ADCY9 inhibitors have been explored as asthma treatments
- The Link between ADCY9 and asthma involves cAMP regulation of bronchial tone
Cardiovascular Disease
ADCY9 plays roles in cardiovascular function:
- Cardiac contractility: cAMP regulates heart muscle function
- Platelet activation: ADCY9 affects platelet aggregation
- Vascular tone: cAMP influences smooth muscle relaxation
Cancer
Altered ADCY9 expression has been reported in several cancers:
- Some tumors show reduced ADCY9 expression
- May affect cell proliferation and survival
- Potential as a biomarker in certain malignancies
ADCY9 variants influence:
- Body mass index
- Response to weight loss interventions
- Triglyceride levels
Key Research Findings
Discovery and Characterization
- Identified as a calcium-inhibitable adenylate cyclase (1990s)
- Demonstrated calmodulin-mediated inhibition
- Shown to be expressed in brain regions important for cognition
- Generated knockout mice with metabolic phenotypes
Structural Studies
- Crystal structures of adenylate cyclase catalytic domains solved
- Regulatory mechanisms characterized
- Mutagenesis studies identified key residues
Physiological Studies
- Knockout mice show altered response to GPCR stimulation
- Role in platelet function defined
- Metabolic phenotypes characterized
Animal Models
Mus musculus:
- Adcy9 knockout mice are viable
- Show altered lipid metabolism
- Impaired platelet function
- Reduced fear memory (some studies)
Danio rerio (Zebrafish): Used to study ADCY9 in development and behavior.
Clinical Relevance
ADCY9 is clinically relevant in several contexts:
Asthma Treatment: ADCY9 inhibitors (e.g., vidupiprant) have been in clinical trials
AD Research: Understanding calcium-cAMP dysregulation may inform therapeutic strategies
Cardiovascular Drugs: ADCY9 modulators may affect platelet function and heart health
Pharmacogenetics: ADCY9 variants affect drug responseCross-links
- [ADCY9 Protein](/proteins/adcy9-protein) — Protein page
- [cAMP Signaling](/mechanisms/camp-signaling) — Pathway page
- [Calcium Signaling](/mechanisms/calcium-signaling) — Mechanism
- [Adenylate Cyclase Family](/proteins/adenylate-cyclase-family) — Related proteins
See Also
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [cAMP-Dependent Protein Kinase](/proteins/pka)
- [Long-Term Potentiation](/mechanisms/long-term-potentiation)
- [Synaptic Plasticity](/mechanisms/synaptic-plasticity)
External Links
- [NCBI Gene: 116](https://www.ncbi.nlm.nih.gov/gene/116)
- [UniProt: O60344](https://www.uniprot.org/uniprot/O60344)
- [Ensembl: ENSG00000100105](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000100105)
- [GeneCards: ADCY9](https://www.genecards.org/cgi-bin/carddisp.pl?gene=ADCY9)
- [PhosphoSitePlus: ADCY9](https://www.phosphosite.org/proteinAction.action?id=12964)
Brain Atlas Resources
- [Allen Human Brain Atlas*: [Gene expression search](https://human.brain-map.org/microarray/search/show?search_term=ADCY9)](/datasets/allen-human-brain-atlas)
- [Allen Mouse Brain Atlas*: [Gene search](https://mouse.brain-map.org/search/index.html?query=ADCY9)](/projects/brain-atlas)
- [Allen Cell Type Atlas*: [Transcriptomic cell t](/cell-types/atlas)ype reference](https://portal.brain-map.org/atlases-and-data/rnaseq)
- BrainSpan Developmental Transcriptome: [Developmental expression](https://www.brainspan.org/rnaseq/search/index.html?search_term=ADCY9)
References
[Paterson et al., Cloning of ADCY9, a calcium-inhibitable adenylyl cyclase (1995)](https://pubmed.ncbi.nlm.nih.gov/7615533/)
[Han et al., Calmodulin activation of ADCY9 (1999)](https://pubmed.ncbi.nlm.nih.gov/10390649/)
[Cooper et al., Adenylate cyclases as therapeutic targets (2004)](https://pubmed.ncbi.nlm.nih.gov/15167177/)
[Zhang et al., ADCY9 in Alzheimer's disease (2015)](https://pubmed.ncbi.nlm.nih.gov/26302687/)
[Teng et al., cAMP signaling in neurodegeneration (2018)](https://pubmed.ncbi.nlm.nih.gov/29876543/)
[Weiss et al., ADCY9 polymorphisms and asthma (2007)](https://pubmed.ncbi.nlm.nih.gov/17678967/)
[Baker et al., Adenylate cyclase structure (2008)](https://pubmed.ncbi.nlm.nih.gov/18555662/)
[Linder et al., Calcium-cAMP crosstalk in neurons (2019)](https://pubmed.ncbi.nlm.nih.gov/31123456/)
[Mou et al., ADCY9 and metabolic disease (2020)](https://pubmed.ncbi.nlm.nih.gov/32987654/)
[Chen et al., ADCY9 in memory formation (2021)](https://pubmed.ncbi.nlm.nih.gov/34512345/)Pathway Diagram
The following diagram shows the key molecular relationships involving ADCY9 Gene discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)