**PSMA3 Gene Overview:**
The PSMA3 gene encodes a subunit of the 20S proteasome core, which is integral to the proteasomal degradation pathway in cells. The proteasome plays a critical role in protein homeostasis and regulation, processing ubiquitinated proteins and maintaining cellular functions by degrading misfolded, damaged, or unneeded proteins.

### 1. Associated Genes:
While the summaries provided focus primarily on the PSMA3 gene itself, it is important to recognize that the proteasome system is heavily interconnected. Here are some genes that are closely associated with PSMA3:

- **PSMB** family genes (such as PSB1, PSB2, PSB3, PSB4, etc.): These encode different beta subunits of the proteasome that together with PSMA3 form the 20S core complex.
- **PSMA1, PSMA2**: Other alpha subunits that comprise the proteasome core.
- **UBQLN** (ubiquilin): Involved in the recognition and delivery of ubiquitinated substrates to the proteasome.
- **MPEG1** (macrophage expressed gene 1): Associated with the immune response and protein degradation.

### 2. Aging and Age-related Diseases:
The PSMA3 gene, via its role in the proteasome complex, has implications in aging and several age-related diseases. Key points include:

- **Cellular Senescence**: Impaired proteasome function is correlated with increased cellular senescence. The accumulation of damaged and misfolded proteins due to decreased proteasome activity has been observed in aging cells.
- **Neurodegenerative Diseases**: PSMA3 has been associated with conditions like Alzheimer’s disease and Parkinson’s disease, where protein aggregation occurs due to diminished proteasomal activity.
- **Cancer**: Dysregulation of proteasomal processing can influence processes like apoptosis and cell proliferation, leading to cancer progression. Notably, certain cancers have been linked with overexpressed proteasome components, including PSMA3.

### 3. Drug Interactions:
While direct drug interactions specific to PSMA3 may not be well-documented, the following classes of drugs may have effects indirectly related to the function of the proteasome:

- **Proteasome Inhibitors**: Medications such as bortezomib (Velcade) and carfilzomib (Kyprolis) are used to target the proteasome’s function in treating multiple myeloma and some other hematological malignancies. These inhibitors affect the degradation of proteins, including those regulated by PSMA3.
- **Histone Deacetylase Inhibitors**: Some drugs in this category may interact with the degradation pathways involving the proteasome and could indirectly modulate the activity of components like PSMA3.

### 4. Pathways and Biological Processes:
PSMA3 is implicated in several key biological processes and pathways, including:

- **Proteasomal Protein Catabolic Process**: The primary function of PSMA3 is as part of the proteasome, facilitating the degradation of ubiquitinated proteins.
- **Antigen Processing and Presentation**: It plays a critical role in generating peptides for MHC class I presentation, especially in the context of immune responses via the immunoproteasome.
- **Regulation of Transcription**: PSMA3 is involved in the degradation of specific transcription factors and modulators, affecting gene expression.
- **Signal Transduction Pathways**: Through the degradation of signaling proteins such as CDKN1A (p21), PSMA3 influences various signaling pathways, including those related to the cell cycle.

In summary, PSMA3 is an essential component of the proteasome with critical roles in protein degradation, cellular homeostasis, and immune responses. Its implications in aging, diseases, and potential interactions with therapeutics reflect its importance in biology and medicine.