### Overview of ATP2B3 Gene

**Gene Symbol:** ATP2B3

**Description:** The ATP2B3 gene encodes the plasma membrane calcium ATPase isoform 3, which is part of the P-type ion transport ATPase family. This enzyme primarily functions to extrude bivalent calcium ions (Ca²⁺) from eukaryotic cells against steep concentration gradients. The ATP-driven Ca²⁺ pump plays a crucial role in maintaining intracellular calcium homeostasis and is especially important at presynaptic nerve terminals. Like other members of this family, ATP2B3 acts by forming a phosphoenzyme intermediate during the transport process.

### 1. Associated Genes
ATP2B3 may be associated with several genes involved in calcium signaling, transport, and muscle contraction regulations. Relevant associated genes include:
- **ATP2B1:** Another isoform of the calcium ATPase, implicated in calcium homeostasis.
- **ATP2B2:** Similar to ATP2B3, also involved in calcium transport.
- **SLC8A1 (NCX1):** A sodium/calcium exchanger that works in concert with calcium pumps.
- **CALM1:** Calmodulin 1, a calcium-binding messenger protein that mediates various calcium signal transductions.

### 2. Aging and Age-Related Diseases
- **Calcium Dysregulation:** ATP2B3's role in maintaining calcium homeostasis implicates it in processes related to aging since dysregulation of calcium levels can lead to neurodegenerative diseases such as Alzheimer's disease. 
- **Cardiovascular Health:** Altered ATP2B3 expression has been linked to cardiovascular diseases, as proper calcium signaling in cardiac myocytes is essential for heart function; thus, its dysfunction may contribute to heart aging or heart failure.
- **Skeletal Muscle Aging:** Research suggests that with age, calcium handling in muscle cells becomes less efficient, which could be related to decreased expression or function of ATP2B3.

### 3. Interacting Drugs or Drug Classes
While specific drugs directly targeting ATP2B3 are not well established, calcium ATPases have been shown to have clinical relevance, with calcium channel blockers and certain diuretics acting modulating calcium transport indirectly:
- **Calcium Channel Blockers:** Such as amlodipine, which may influence calcium homeostasis in a broader sense, potentially impacting ATP2B3 function.
- **Thiazide Diuretics:** These may indirectly affect calcium levels and, thus, potentially ATP2B3 activity due to their role in renal calcium handling.

### 4. Pathways and Biological Processes
ATP2B3 is involved in several biological processes and signaling pathways, including:
- **Calcium Ion Homeostasis:** A principal function focusing on maintaining low intracellular calcium levels.
- **Regulation of Presynaptic and Postsynaptic Function:** Specifically involved in neurotransmitter release at synapses.
- **Muscle Contraction:** Plays a role in cardiac and skeletal muscle cell function through calcium signaling.
- **Apoptosis Signaling Pathway:** Dysregulation of calcium can impact processes like apoptosis.
- **Neurotransmitter Release:** Essential for synaptic signaling and proper neuronal function.

In summary, the ATP2B3 gene is crucial for maintaining calcium homeostasis across various cell types, and its regulation has implications for aging and age-related health conditions, as well as interactions with drugs affecting calcium signaling.