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. [1][2]
| Property | Value |
|---|---|
| Gene Symbol | ADCY9 |
| Full Name | Adenylate Cyclase 9 |
| Chromosomal Location | 16p13.3 |
| Ensembl ID | ENSG00000100105 |
| NCBI Gene ID | 116 |
| UniProt ID | O60344 |
| Protein Length | 1,354 amino acids |
| Molecular Weight | ~150 kDa |
ADCY9 is a large membrane-bound enzyme with a complex domain organization:
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.
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.
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.
ADCY9 contains several regulatory features:
ADCY9 catalyzes the conversion of ATP to cAMP:
The reaction is: ATP → cAMP + PPi (pyrophosphate)
ADCY9 is uniquely regulated among adenylate cyclases:
ADCY9 responds to G protein-coupled receptor (GPCR) signaling:
cAMP produced by ADCY9 activates:
These effectors then regulate diverse cellular processes including:
ADCY9 exhibits widespread tissue distribution:
| Tissue/Cell Type | Expression Level |
|---|---|
| Brain (cortex, hippocampus) | High |
| Lung | High |
| Heart | Moderate |
| Platelets | Moderate |
| Adipose tissue | Moderate |
| Kidney | Low-Moderate |
| Liver | Low |
| Skeletal Muscle | Low |
In the brain, ADCY9 is expressed in:
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.
ADCY9 is a well-established genetic factor in asthma:
ADCY9 plays roles in cardiovascular function:
Altered ADCY9 expression has been reported in several cancers:
ADCY9 variants influence:
Mus musculus:
Danio rerio (Zebrafish): Used to study ADCY9 in development and behavior.
ADCY9 is clinically relevant in several contexts: