### FEM1C Gene Overview

**Gene Symbol:** FEM1C  
**Location:** Cytosol and nucleoplasm  
**Function:** Enables ubiquitin ligase-substrate adaptor activity; involved in ubiquitin-dependent protein catabolic processes via the C-end degron rule pathway.

**Role in Ubiquitination:**  
The FEM1C gene encodes a substrate-recognition component of a Cul2-RING E3 ubiquitin-protein ligase complex, known as CRL2. This complex plays a crucial role in the recognition and subsequent degradation of proteins containing specific C-terminal degradation motifs (C-degrons). Notably, it recognizes proteins with an arginine at the C-terminus and has been shown to mediate the ubiquitination of various substrates, including:

- SIL1
- OR51B2
- SLBP
- Truncated forms of MSRB1 and SEPX1 selenoproteins resulting from failed UGA/Sec decoding.

### 1. Associated Genes
While the summary provided highlights a few substrates, it may also indirectly associate with genes involved in the same signaling, regulatory, or functional pathways. Some frequently studied relationships include:

- **CUL2**: The gene encoding the cullin-2 protein, which is integral to the CRL2 E3 ligase complex.
- **RBX1**: This gene encodes a RING finger protein that is a critical component of E3 ligase complexes.
- **SEPX1 and MSRB1**: Genes encoding selenoproteins whose truncated forms are targeted for degradation via the FEM1C pathway.
- **SLBP**: Involved in histone mRNA metabolism.

### 2. Aging and Age-Related Diseases
FEM1C may have implications in various age-related diseases. Since the ubiquitination and proteolytic degradation processes are essential for maintaining cellular homeostasis, deregulated proteostasis affected by aberrations in ubiquitin ligase activities like those of FEM1C may contribute to:

- **Neurodegenerative diseases**: Dysregulated protein degradation mechanisms are known to contribute to the pathogenesis of diseases such as Alzheimer's and Parkinson's.
- **Cancer**: Given the role of the CRL2 complex in the regulation of various proteins, it may also play a role in tumorigenesis through the ubiquitination of oncogenic or tumor suppressor proteins.
- **Age-Related Sarcopenia**: Impaired protein turnover and degradation mechanisms could contribute to muscle wasting associated with aging.

### 3. Known Drug Interactions
There are currently no specific drugs directly targeting FEM1C itself reported in literature. However, certain classes of drugs that modulate protein degradation pathways may indirectly affect the action of FEM1C. These include:

- **Proteasome Inhibitors**: Such as bortezomib and carfilzomib, which may alter the overall ubiquitination landscape within cells.
- **E3 Ligase Modulators**: Novel compounds in research may target ubiquitin ligases, and there may be a pipeline for inhibitors or activators of the CRL2 complex that could interact with FEM1C indirectly.

### 4. Pathways and Biological Processes
FEM1C is involved in various biological processes and pathways including:

- **Ubiquitin-mediated proteolysis**: It plays a vital role in the degradation of proteins via ubiquitination.
- **C-end degron (DesCEND) pathway**: Specifically identifies and targets proteins with C-degrons for degradation.
- **Gene regulation**: The degradation of proteins such as SLBP influences the regulation of histone synthesis, thus impacting gene expression.
- **Stress response pathways**: As FEM1C is implicated in the degradation of misfolded or damaged proteins, it plays a role in cellular stress responses.

Overall, the FEM1C gene functions as a critical component in the complex regulatory framework governing protein stability and turnover, impacting numerous cellular processes and potentially influencing the pathology of age-related diseases.