### INPP4B Gene Overview

**Symbol:** INPP4B  
**Function:** Encodes inositol polyphosphate 4-phosphatase type II, involved in phosphatidylinositol signaling pathways.

#### 1. Associated Genes:
While the NCBI and UniProt summaries provide a primary focus on INPP4B, it is important to note that it interacts with various other signaling molecules and genes:

- **PIK3CA**: Phosphoinositide 3-kinase, a key player in the PI3K/AKT pathway, which INPP4B regulates by dephosphorylating phosphoinositides.
- **PTEN**: Phosphatase and tensin homolog, a tumor suppressor gene that also counteracts the PI3K/AKT signaling pathway.
- **AKT1/AKT2**: Proto-oncogenes involved in cell survival and proliferation, which are negatively regulated by INPP4B.
- **RAC1**: A member of the Rho family of GTPases involved in cell migration and cytoskeletal dynamics.

#### 2. Aging and Age-Related Diseases:
- **Cancer**: INPP4B exhibits tumor suppressor functions, and loss of its activity has been associated with various cancers. Mutations and down-regulation of INPP4B have been observed in breast cancer, prostate cancer, and more. Its role in regulating the PI3K/AKT signaling pathway is particularly relevant as this pathway is frequently dysregulated in cancer.
- **Metabolic Disorders**: Some studies suggest that INPP4B may influence metabolic effectiveness. Changes in its activity could potentially affect age-related metabolic syndromes and insulin signaling, although this area still requires extensive research.
- **Neurodegenerative Diseases**: There is emerging evidence that dysregulation of inositol phosphates can have implications in neurodegenerative conditions. However, specific links between INPP4B and age-related neurodegenerative diseases have not been fully established.

#### 3. Drug Interactions:
While specific drugs targeting INPP4B directly may not be well-characterized, the following classes of drugs may interact with its signaling pathway:

- **PI3K Inhibitors**: Drugs such as **Idelalisib** and **Copanlisib** aim to inhibit the PI3K signaling pathway, hence could indirectly influence the function or activity of INPP4B by altering the substrates available for dephosphorylation.
- **AKT Inhibitors**: Agents like **MK-2206** inhibit AKT, potentially enhancing the effects of INPP4B by lowering downstream signaling.
- **Hormone Therapies**: Since INPP4B is linked with cell growth and proliferation, agents used in cancer therapies may indirectly affect INPP4B function.

#### 4. Pathways and Biological Processes:
**Signaling Pathways**:
- **PI3K-AKT Signaling Pathway**: INPP4B plays a critical role by modulating this pathway through dephosphorylation processes.
- **Macropinocytosis**: INPP4B is involved in the late stages of macropinocytosis and regulates membrane ruffling by dephosphorylating phosphatidylinositol 3,4-bisphosphate.

**Biological Processes**:
- Lipid metabolism: INPP4B catalyzes reactions necessary for maintaining inositol phosphate levels.
- Regulation of phosphoinositide metabolism: Important for cellular signaling, apoptosis, and various other processes.
- Cell cycle regulation: Impacts cell survival, proliferation, and differentiation through its influence on the PI3K/AKT signaling cascade.

### Summary
INPP4B is an essential enzyme in the phosphatidylinositol signaling pathways with implications in cancer biology and cell survival mechanisms. It maintains cellular homeostasis and is an emerging target for therapeutic interventions in age-related diseases and cancers. The gene interacts with various other key signaling molecules and pathways, underlining its importance in multiple biological processes. Further studies are likely to unveil additional associations with aging and age-related diseases.