### Overview of the PIK3R3 Gene

**Gene Symbol:** PIK3R3  
**Function:** The PIK3R3 gene encodes a regulatory subunit of phosphatidylinositol 3-kinase (PI3K), which plays a critical role in growth signaling pathways by phosphorylating phosphatidylinositol and similar compounds. The protein produced by PIK3R3 exhibits regulatory functions by binding to activated protein-tyrosine kinases through its two SH2 domains and modulating their activity. Notably, during insulin stimulation, it also interacts with insulin receptor substrate 1 (IRS-1), influencing insulin signaling.

### 1. Genes Associated with PIK3R3

While the PIK3R3 gene's direct associations include IRS-1 and various protein-tyrosine kinases, it is also connected with other genes in the PI3K signaling pathway, which may include:
- **PIK3CA** and **PIK3CB** (catalytic subunits of PI3K)
- **AKT1**, **AKT2**, **AKT3** (downstream effectors involved in cell proliferation and survival)
- **PTEN** (a tumor suppressor that antagonizes PI3K signaling)
- **mTOR** (mechanistic target of rapamycin, involved in cell growth regulation)

### 2. Aging and Age-Related Diseases Associated with PIK3R3

While there is not extensive direct evidence connecting PIK3R3 to aging, components of the PI3K/AKT/mTOR signaling pathway, in which PIK3R3 is involved, have been implicated in age-related processes and diseases such as:
- **Metabolic Disorders:** Altered PI3K signaling can contribute to insulin resistance, obesity, and type 2 diabetes, conditions that are commonly age-related.
- **Cancer:** Dysregulation of the PI3K pathway is often observed in various cancers, where PIK3R3 may play a role in tumorigenesis and cancer progression.
- **Neurodegenerative Diseases:** PI3K signaling has been implicated in neuroprotection and maintenance of neuronal health, with potential links to diseases like Alzheimer's.

### 3. Drugs or Drug Classes Known to Interact with PIK3R3

Drugs targeting the PI3K pathway are under investigation for therapeutic purposes, particularly in cancer treatment. These include:
- **PI3K Inhibitors:** Drugs such as Idelalisib and Copanlisib, which selectively inhibit the activity of PI3K, including the pathway influenced by PIK3R3.
- **mTOR Inhibitors:** Drugs like Everolimus and Temsirolimus that modulate downstream signaling in the PI3K pathway.
- **Dual Inhibitors:** Some experimental agents that target both PI3K and mTOR signaling.

### 4. Pathways and Biological Processes Involved

PIK3R3 is involved in several key biological pathways, including but not limited to:

- **Insulin signaling pathway:** Important for glucose uptake and metabolism.
- **PI3K/AKT pathway:** Plays a critical role in cell growth, proliferation, survival, and metabolism.
- **Regulation of metabolic processes:** Including those affecting lipid synthesis and the storage of energy.
- **Pathways regulating cellular growth and survival:** PI3K signaling is fundamental in both oncogenic and protective contexts.

### Conclusion

PIK3R3 is a pivotal gene in the context of cellular signaling, particularly relevant in metabolism and cancer biology. Its regulatory role in the PI3K pathway links it to numerous physiological processes, making it a significant focus for understanding various health conditions, aging, and therapeutic interventions. Further research investigating its specific roles in aging and disease pathology will be crucial to elucidating its complete function.