### TEAD4 Gene Overview

**Gene Symbol:** TEAD4  
**Function:** TEAD4 encodes a member of the transcriptional enhancer factor (TEF) family, acting as a transcription factor crucial for muscle-specific gene expression and playing a pivotal role in the Hippo signaling pathway, which regulates organ size, cell proliferation, and apoptosis.

---

### 1. Associated Genes
While the summaries focus mainly on the TEAD4's relationship with YAP1 and WWTR1/TAZ in relation to the Hippo pathway, TEAD4 is associated with several other genes, including:

- **MST1/2 (Mammalian Ste20-like protein kinases)**: They are upstream regulators in the Hippo signaling pathway that phosphorylate LATS1/2.
- **LATS1/2 (Large Tumor Suppressor kinases 1 and 2)**: They are downstream of MST1/2 and inactivate YAP1/TAZ.
- **SAV1 (Salvador homolog 1)**: A regulatory protein that helps activate MST1/2.
- **MOB1 (MOB kinase activator 1)**: Also part of the LATS activation cascade.
- **CTGF (Connective Tissue Growth Factor)** and **CYR61 (Cysteine-rich angiogenic inducer 61)**: These are YAP1 target genes that are involved in cellular proliferation and cellular responses.

---

### 2. Aging and Age-Related Diseases
TEAD4 is implicated in several aspects related to aging and age-related diseases:

- **Tumorigenesis**: Due to its role in the Hippo pathway, dysregulation of TEAD4 can lead to unchecked cell proliferation and plays a role in cancer progression.
- **Muscle Degeneration**: Altered expression of TEAD4 may contribute to muscle wasting associated with aging, particularly in conditions like sarcopenia.
- **Stem Cell Regulation**: TEAD4 is involved in regulating stem cell differentiation and maintaining stemness, which can decline with age, influencing tissue regeneration capacities.
- **Cellular Senescence**: The involvement of TEAD4 in apoptosis and proliferation ties it to cellular senescence, which is a hallmark of aging.

---

### 3. Drug and Drug Classes
While specific drugs that directly target the TEAD4 protein are limited, several drug classes may indirectly interact with the pathways involving TEAD4:

- **Hippo Pathway Inhibitors**: Experimental compounds or small molecules that inhibit components of the Hippo pathway (e.g., MST1/2 inhibitors) could potentially affect TEAD4 activity.
- **Anticancer Drugs**: Since TEAD4 is associated with tumor suppression, drugs targeting YAP1 or the broader Hippo signaling pathway (such as verteporfin) may influence TEAD4 activity.

---

### 4. Pathways and Biological Processes
TEAD4 is involved in numerous pathways and biological processes:

- **Hippo Signaling Pathway**: Central to regulating organ size and tumor suppression by controlling cell proliferation and apoptosis.
- **Muscle Development and Differentiation**: TEAD4 binds to M-CAT elements in promoters of muscle-specific genes, essential for skeletal muscle development.
- **Epithelial-Mesenchymal Transition (EMT)**: TEAD4 regulates gene expression in processes involving EMT, which is crucial in development and tumor metastasis.
- **Cell Proliferation and Survival**: TEAD4's interaction with YAP1/TAZ influences various cellular survival pathways.

In summary, TEAD4 plays a significant role in the regulation of gene expression, organ development, and cellular processes crucial to both healthy development and disease states, particularly cancer and age-related conditions.