The TGFBR3 gene encodes the transforming growth factor-beta receptor type III (TGF-βRIII), which plays a critical role in the TGF-β signaling pathway. Here is a more detailed overview based on your requests:

### 1. Associated Genes
While the summaries mention TGF-β signaling, TGFBR3 is also associated with several other genes and proteins that are involved in similar pathways or have functional relevance, including:
- **TGFBR1** and **TGFBR2**: These are the type I and type II TGF-β receptors that work closely with TGFBR3 in mediating TGF-β signaling.
- **ACVR1**, **BMPR1A**, and **ACVR2A**: These genes encode receptors in the TGF-β superfamily, influencing similar cellular processes.
- **SMAD** family genes (like **SMAD2**, **SMAD3**, and **SMAD4**): These are downstream effectors that propagate the signal from TGF-β receptors to the nucleus.
- **INHBA** (Inhibin beta A): As mentioned, TGFBR3 acts as a co-receptor for inhibin A, implicating its connection to the regulation of FSH levels through interactions with this gene.

### 2. Aging and Age-Related Diseases
TGFBR3 has been implicated in various age-related processes, including:
- **Cancer**: Decreased expression of TGFBR3 is frequently observed in various tumors, suggesting its potential role as a tumor suppressor. The age-associated decline in its expression may enhance tumor progression.
- **Fibrosis**: Increased TGF-β signaling associated with aging can lead to fibrosis in many tissues; TGFBR3’s role in modulating this pathway may influence the development of age-associated fibrotic diseases.
- **Cardiovascular Diseases**: Dysregulation of TGF-β signaling has been associated with age-related cardiovascular conditions, such as hypertension and atherosclerosis.

### 3. Drug Interactions
While specific drug interactions with TGFBR3 are not widely documented, several classes of drugs and therapeutic agents target the TGF-β signaling pathway, where TGFBR3 is a significant player:
- **TGF-β inhibitors**: These drugs, such as: 
  - *Neutralizing antibodies against TGF-β* (e.g., fresolimumab)
  - *Small molecule inhibitors targeting TGF-β receptor signaling* are being researched for their roles in cancer treatment and fibrosis.
- **Immunomodulators**: Certain immunotherapy agents may influence TGF-β signaling, indirectly affecting TGFBR3 activity.

### 4. Pathways and Biological Processes
TGFBR3 is involved in numerous biological processes and signaling pathways, including:
- **TGF-β Signaling Pathway**: As a co-receptor, TGFBR3 captures and retains TGF-β for presentation to type I and II receptors, activating downstream signaling pathways (such as SMAD signaling).
- **Regulation of Cell Growth and Differentiation**: TGF-β signaling is crucial in regulating cellular growth, apoptosis, and differentiation, impacting processes such as wound healing and tissue repair.
- **Endocrine Regulation**: In gonadotrope cells, TGFBR3 functions in the modulation of FSH secretion, linking it with reproductive processes.

In summary, TGFBR3 is a crucial component of the TGF-β signaling network with significant implications in tumor biology, aging, and potential therapeutic interventions. The understanding of its interactions and function continues to evolve, highlighting its importance in both basic and clinical research.