### SPPL3 Gene Overview

**Gene Symbol**: SPPL3  
**Enzyme Classification**: Aspartic endopeptidase (I-CLiP)  
**Function**: SPPL3 is known for its intramembrane-cleaving aspartic protease activity, which allows it to cleave type II membrane protein substrates. This activity is particularly significant for the regulation of glycosylation processes and modulating signaling pathways in T-cells.

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### Additional Gene Associations

1. **Associated Genes/Proteins**:
   - **STIM1**: Plays a critical role in calcium signaling and store-operated calcium entry (SOCE).
   - **ORAI1**: A calcium release-activated calcium (CRAC) channel pivotal for T-cell activation.
   - **MGAT5**: Involved in glycosylation and potentially related to cancer and immune responses.
   - **B4GAT1**, **B4GALT1**: Glycosyltransferases that may be affected by modifications mediated by SPPL3 activity.

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### Aging and Age-Related Diseases

- **Potential Associations with Aging**: Although direct links between SPPL3 and aging or specific age-related diseases are limited, its critical role in T-cell signaling and immune responses suggests that alterations in SPPL3 function could influence age-related immune decline (immunosenescence).
- **Research Context**: Studies have shown that changes in glycosylation and signaling pathways involving T-cells may contribute to chronic inflammation and other pathologies associated with aging.

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### Drug Interactions

1. **Known Interactions**:
   - There are no specific drugs or drug classes widely recognized to directly interact with SPPL3.
   - However, drugs that target calcium signaling or immune response may indirectly influence its activity, especially considering its role in T-cell signaling and calcium entry.

2. **Potentially Relevant Drug Classes**:
   - **Calcium Channel Blockers**: Since SPPL3 is involved in calcium signaling pathways, drugs that modulate calcium channels could affect its function in T-cell signaling.
   - **Immunomodulators**: As SPPL3 plays a role in T-cell receptor signaling, drugs affecting T-cell activity might indirectly relate.

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### Biological Pathways and Processes

1. **Pathways**:
   - **T-cell Receptor Signaling Pathway**: SPPL3 is essential for linking TCR signaling with downstream effects.
   - **Calcineurin-NFAT Signaling Cascade**: It positively regulates this pathway, crucial for T-cell activation.

2. **Biological Processes**:
   - **Positive Regulation of Protein Dephosphorylation**: Modulating the phosphorylation state of proteins, which is vital in signaling.
   - **Intramembrane Cleavage of Type II Membrane Proteins**: Involved in the proteolytic processing of various membrane proteins.
   - **Cellular Glycosylation Processes**: SPPL3 participates in regulating how proteins are glycosylated, affecting their function and stability.

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### Summary

The SPPL3 gene is an integral player in T-cell signaling and glycosylation processes, with significant implications for immune function and potential roles in age-related cellular processes. While direct associations with drugs are limited, its involvement in crucial signaling pathways offers avenues for research in pharmacology and immunology.