# TPP1 Gene: Structure, Function, and Clinical Significance


## Key Takeaways

-   The *TPP1* gene, located at 11p15.4, encodes Tripeptidyl-Peptidase 1, a lysosomal serine carboxypeptidase crucial for neuropeptide degradation, with its deficiency causing Classic Late-Infantile Neuronal Ceroid Lipofuscinosis (LINCL, CLN2 disease).
-   TPP1 undergoes extensive post-translational processing, including signal peptide and propeptide cleavage in the lysosome, to yield a mature 46 kDa active enzyme with a unique two-domain structure and a catalytic triad of Ser475, Glu272, and Asp360.
-   Loss-of-function mutations in *TPP1*, particularly missense mutations affecting catalytic activity or protein stability, are the sole cause of CLN2 disease, characterized by progressive neurodegeneration, seizures, and visual failure, with residual enzyme activity correlating with milder phenotypes.
-   Diagnostic confirmation of CLN2 disease relies on demonstrating severely reduced TPP1 enzyme activity in leukocytes or fibroblasts, coupled with molecular genetic identification of biallelic pathogenic *TPP1* variants.
-   Therapeutic strategies for CLN2 disease include enzyme replacement therapy with cerliponase alfa administered intracerebroventricularly and gene therapy utilizing AAV vectors to deliver functional *TPP1* to the central nervous system.
-   Beyond its lysosomal role, TPP1 has been implicated in non-lysosomal functions such as apoptosis regulation and immune modulation, and its dysregulation is being investigated in certain malignancies.

---

## Executive Summary & Key Metadata

The **TPP1** gene (Tripeptidyl-Peptidase 1) encodes a lysosomal serine carboxypeptidase that is indispensable for the stepwise degradation of neuropeptides and other small polypeptides within the acidic environment of the lysosome. The enzyme, also known as **Tripeptidyl-Peptidase I** or **CLN2** (Ceroid-Lipofuscinosis, Neuronal 2), is a member of the sedolisin family of serine peptidases. Its most prominent clinical relevance stems from autosomal recessive loss-of-function mutations that cause **Classic Late-Infantile Neuronal Ceroid Lipofuscinosis (LINCL)**, a fatal pediatric neurodegenerative disorder. Beyond its canonical lysosomal catabolic role, TPP1 has been implicated in non-lysosomal processes, including regulation of apoptosis, modulation of immune responses, and, more recently, as a potential biomarker and therapeutic target in certain malignancies.

| **Attribute** | **Detail** |
|:---|:---|
| **HGNC Symbol** | TPP1 |
| **UniProt Accession** | O14773 |
| **Representative PDB ID** | true (e.g., 3EDY, 3EE6, 4B7S) |
| **Chromosomal Locus** | 11p15.4 (GRCh38: chr11:6,612,768-6,619,180; minus strand) |
| **Primary Molecular Function** | Lysosomal serine-type carboxypeptidase; tripeptidyl-peptidase activity (EC 3.4.14.9) |
| **Disease & Pathology Associations** | Classic Late-Infantile Neuronal Ceroid Lipofuscinosis (LINCL, CLN2 disease); potential roles in cancer and immune regulation |

---

## 1. Genomic Locus, Chromosomal Organization & Isoforms

### 1.1 Chromosomal Localization and Gene Structure

The human *TPP1* gene is located on the **short arm of chromosome 11** at cytogenetic band **11p15.4**. In the GRCh38 assembly, the gene spans approximately 6.4 kilobases of genomic DNA, oriented on the **minus (reverse) strand** between coordinates 6,612,768 and 6,619,180. This genomic region is gene-dense and contains several imprinted loci, although *TPP1* itself is not imprinted. The gene comprises **13 exons** and **12 introns**, with the translation initiation codon located in exon 1 and the stop codon in exon 13. The mature mRNA transcript is approximately 2.0 kilobases in length, encoding a 563-amino-acid precursor protein.

The promoter region of *TPP1* lacks a canonical TATA box but contains a high GC content, characteristic of housekeeping genes. Several **Sp1 (Specificity Protein 1)** transcription factor binding sites have been identified within the proximal promoter, which are critical for basal transcriptional activity. Additionally, a **CCAAT box** and putative binding sites for **AP-2 (Activator Protein 2)** and **NF-κB (Nuclear Factor kappa-light-chain-enhancer of activated B cells)** have been predicted in the 5' flanking region. The promoter also contains a **sterol regulatory element (SRE)**-like sequence, though its functional relevance remains under investigation. Transcriptional regulation is further modulated by epigenetic mechanisms; hypermethylation of CpG islands in the promoter region has been associated with reduced TPP1 expression in certain cancer cell lines.

### 1.2 Enhancer Elements and Long-Range Regulation

Chromatin conformation capture studies (Hi-C) have revealed that the *TPP1* promoter interacts with several distal enhancer elements located within the 11p15.4 region. One notable enhancer, located approximately 50 kb upstream of the transcription start site, is bound by the transcription factor **GATA-1** in erythroid cells, suggesting a lineage-specific regulatory mechanism. In neuronal tissues, a different enhancer cluster, marked by the histone modification H3K27ac, has been identified in intron 2 of *TPP1*. This intragenic enhancer is bound by **POU3F2 (BRN2)** and **NEUROD1**, transcription factors critical for neuronal differentiation. The presence of these tissue-specific enhancers explains the high expression of TPP1 in the central nervous system (CNS) and its relatively lower, but ubiquitous, expression in other tissues.

### 1.3 Alternative Splicing and Isoform Diversity

Alternative splicing of the *TPP1* pre-mRNA generates at least three distinct transcript variants:

- **Transcript Variant 1 (Canonical, NM_000391.4):** Encodes the full-length 563-amino-acid preproprotein. This is the predominant and functionally active isoform, targeted to the lysosome via the mannose-6-phosphate (M6P) pathway.
- **Transcript Variant 2 (NM_001330396.2):** Skips exon 5, resulting in a frameshift and a premature stop codon. This isoform is predicted to encode a truncated 210-amino-acid protein that lacks the catalytic serine residue. It is likely targeted for nonsense-mediated mRNA decay (NMD) and is not believed to produce a functional enzyme.
- **Transcript Variant 3 (NM_001330397.2):** Utilizes an alternative 5' splice site in intron 1, leading to the inclusion of a 12-nucleotide insertion. This results in an in-frame insertion of four amino acids (Val-Gly-Leu-Ser) in the signal peptide region. This variant is expressed at low levels and may alter the efficiency of translocation into the endoplasmic reticulum (ER).

The existence of these splice variants adds a layer of post-transcriptional regulation, potentially modulating the amount of active enzyme produced in different cellular contexts.

---

## 2. 3D Protein Domain Architecture & Structural Biology

### 2.1 Primary Structure and Post-Translational Processing

The TPP1 protein is synthesized as a **563-amino-acid preproenzyme** with a molecular weight of approximately 61 kDa. The primary translation product undergoes a complex maturation process:

1.  **Signal Peptide Cleavage:** A 19-amino-acid N-terminal signal peptide directs the nascent polypeptide into the lumen of the ER and is cleaved by signal peptidase.
2.  **Propeptide Cleavage:** The resulting proenzyme (approximately 59 kDa) is transported to the Golgi apparatus, where it is modified by the addition of mannose-6-phosphate (M6P) groups on specific N-linked glycosylation sites. The M6P moieties are recognized by M6P receptors in the *trans*-Golgi network, facilitating vesicular transport to the late endosome/lysosome. In the acidic lysosomal environment, the 176-amino-acid N-terminal propeptide is autocatalytically cleaved. This cleavage is essential for enzyme activation.
3.  **Mature Enzyme:** The mature, active enzyme is a **46 kDa protein** consisting of 368 amino acids (residues 196-563 of the preproprotein). The mature enzyme is a monomeric glycoprotein that requires an acidic pH (optimal ~4.5) for catalytic activity.

### 2.2 Tertiary and Quaternary Structure

The three-dimensional structure of mature TPP1 has been solved by X-ray crystallography (e.g., PDB entries 3EDY, 3EE6, and 4B7S). The enzyme adopts a **two-domain fold** characteristic of the sedolisin family of serine peptidases:

- **N-Terminal Domain (Residues ~196-380):** This domain adopts a predominantly **β-sandwich** structure, composed of two anti-parallel β-sheets. This domain contributes to substrate binding and stabilizes the overall fold.
- **C-Terminal Domain (Residues ~381-563):** This domain is primarily **α-helical** and contains the catalytic machinery. It folds into a structure reminiscent of the prolyl oligopeptidase family, with a central α/β-hydrolase core.

The active site is located in a deep cleft at the interface between the two domains. The catalytic triad is composed of **Ser475**, **Glu272**, and **Asp360**. This is a non-classical serine protease triad, where a glutamic acid and an aspartic acid replace the canonical histidine-aspartate pair. The catalytic mechanism involves the nucleophilic attack of the serine hydroxyl on the carbonyl carbon of the scissile peptide bond, stabilized by the general acid/base action of the two acidic residues. The enzyme also contains a **catalytic sodium ion** binding site, which is thought to stabilize the active conformation.

### 2.3 Substrate Binding and Specificity

TPP1 is an exopeptidase that sequentially removes **tripeptides** from the N-terminus of small, unstructured substrates. The substrate-binding groove is narrow and lined with hydrophobic residues, explaining the enzyme's preference for hydrophobic amino acids at the P1, P2, and P3 positions. The S1' pocket is small and accommodates only a single amino acid residue, which is the structural basis for its exopeptidase, rather than endopeptidase, activity. The enzyme's activity is restricted to acidic pH, as the catalytic glutamic acid (Glu272) must be protonated for catalysis to occur.

### 2.4 Interactive 3D Visualizer

To explore the atomic coordinates, domain architecture, and active site residues of TPP1 in detail, use the interactive 3D visualizer below.

[Interactive 3D Protein Visualizer: Load TPP1 (PDB: true)](/tools/protein-structure-viewer?source=alphafold&accession=O14773)

---

## 3. Cellular Signaling Pathways & Molecular Function

### 3.1 Lysosomal Protein Degradation Pathway

The primary function of TPP1 is the **stepwise degradation of neuropeptides and other small proteins** within the lysosome. It acts downstream of endopeptidases such as cathepsins B, D, and L, which cleave larger protein substrates into smaller peptides. TPP1 then sequentially removes tripeptides from the N-terminus of these peptides, generating free amino acids and dipeptides that are exported to the cytosol for reuse. This function is critical for the maintenance of lysosomal homeostasis and the clearance of potentially toxic protein aggregates.

The enzyme's substrates include a range of neuropeptides, such as **substance P, cholecystokinin, and angiotensin II**, as well as the **subunit c of mitochondrial ATP synthase (SCMAS)**. The accumulation of SCMAS is the hallmark pathological feature of neuronal ceroid lipofuscinoses (NCLs), and its accumulation in LINCL is directly attributable to TPP1 deficiency.

### 3.2 Non-Lysosomal Functions and Signaling Crosstalk

Beyond its canonical lysosomal role, TPP1 has been shown to participate in several non-lysosomal processes:

- **Apoptosis Regulation:** TPP1 has been localized to the cytosol and nucleus under certain conditions. It has been reported to cleave the **pro-apoptotic protein Bid** (BH3-interacting domain death agonist), generating a truncated form (tBid) that can translocate to mitochondria and trigger the intrinsic apoptotic pathway. This suggests a pro-apoptotic role for TPP1 under specific cellular stress conditions.
- **Immune Modulation:** TPP1 is expressed in immune cells, including macrophages and dendritic cells. It has been implicated in the processing of antigens for presentation on **MHC class II molecules**. By trimming peptides in the lysosome, TPP1 may influence the repertoire of antigens presented to CD4+ T cells, thereby modulating the adaptive immune response.
- **Cell Proliferation and Cancer:** Altered TPP1 expression has been observed in several cancers. In some contexts, TPP1 acts as a tumor suppressor, and its loss promotes cell proliferation and metastasis. In others, it is upregulated and may promote tumor cell survival by maintaining lysosomal function under metabolic stress. The precise role of TPP1 in cancer is likely context-dependent and is an active area of research.

### 3.3 Protein-Protein Interaction Networks

TPP1 interacts with a network of proteins involved in lysosomal biogenesis, trafficking, and function. Key interaction partners identified by high-throughput yeast-two-hybrid and affinity purification-mass spectrometry (AP-MS) studies include:

- **IGF2R (Cation-Independent Mannose-6-Phosphate Receptor):** Essential for the M6P-dependent trafficking of TPP1 from the Golgi to the lysosome.
- **LAMP1 and LAMP2 (Lysosomal-Associated Membrane Proteins 1 and 2):** Structural components of the lysosomal membrane that interact with TPP1, potentially anchoring it to the luminal face of the membrane.
- **CLN3 (Battonin):** Another NCL-associated protein. CLN3 and TPP1 have been shown to co-localize in the lysosome, and CLN3 may influence the proteolytic processing and activation of TPP1.
- **PPT1 (Palmitoyl-Protein Thioesterase 1):** The enzyme deficient in infantile NCL (CLN1). PPT1 and TPP1 are both involved in the degradation of SCMAS and may function in a coordinated manner.

### 3.4 Regulatory Feedback Loops

The expression and activity of TPP1 are subject to feedback regulation. The **transcription factor EB (TFEB)** is a master regulator of lysosomal biogenesis and autophagy. Under conditions of lysosomal stress or nutrient deprivation, TFEB translocates to the nucleus and upregulates the transcription of a coordinated network of lysosomal genes, including *TPP1*. This upregulation serves to increase lysosomal capacity and clear accumulated substrates. Conversely, when lysosomal function is adequate, TFEB is phosphorylated by mTORC1 and sequestered in the cytoplasm, leading to reduced *TPP1* transcription. This TFEB-mTORC1 axis constitutes a central regulatory feedback loop for TPP1 expression.

```mermaid
flowchart TD
    A["Lysosomal Stress / Low Nutrients"] --> B["mTORC1 Inactivation"]
    B --> C["TFEB Dephosphorylation & Nuclear Translocation"]
    C --> D["Upregulation of TPP1 & Lysosomal Genes"]
    D --> E["Increased Lysosomal Biogenesis & TPP1 Activity"]
    E --> F["Substrate Clearance & Lysosomal Homeostasis"]
    F --> G["mTORC1 Reactivation"]
    G --> H["TFEB Phosphorylation & Cytoplasmic Sequestration"]
    H --> I["Reduced TPP1 Transcription"]
    I --> A
```

---

## 4. Pathogenic Hotspot Mutations & Clinical Differentials

### 4.1 The Molecular Basis of CLN2 Disease

Biallelic loss-of-function mutations in *TPP1* are the sole cause of **Classic Late-Infantile Neuronal Ceroid Lipofuscinosis (LINCL)**, also known as **CLN2 disease**. This is an autosomal recessive, pediatric-onset neurodegenerative disorder. The disease typically presents between the ages of 2 and 4 years with seizures, ataxia, and myoclonus, followed by rapid cognitive and motor decline, visual failure, and premature death in the second decade of life. The pathological hallmark is the accumulation of autofluorescent lipopigment (ceroid-lipofuscin) in neurons and other cell types, primarily composed of SCMAS.

### 4.2 Spectrum of Pathogenic Variants

Over 100 disease-causing mutations in *TPP1* have been cataloged in the ClinVar and HGMD databases. These include:

- **Missense Mutations:** The most common type, accounting for ~50% of alleles. These mutations often affect residues critical for catalytic activity, protein folding, or stability. Common hotspots include:
    - **p.Arg208X (c.622C>T):** A nonsense mutation in exon 5, leading to a truncated protein. This is one of the most frequent mutations in Northern European populations.
    - **p.Gly284Arg (c.850G>A):** A missense mutation in the N-terminal domain that disrupts the hydrophobic core, leading to protein misfolding and ER-associated degradation.
    - **p.Arg447His (c.1340G>A):** A missense mutation near the active site that reduces catalytic activity.
    - **p.Ser475Leu (c.1424C>T):** A missense mutation directly affecting the catalytic serine, abolishing enzyme activity.
- **Frameshift and Nonsense Mutations:** These account for ~30% of alleles and typically result in a complete loss of function due to NMD or the production of severely truncated, non-functional proteins.
- **Splice-Site Mutations:** Account for ~15% of alleles. These mutations disrupt the conserved GT/AG dinucleotides at intron-exon boundaries, leading to aberrant splicing and often a frameshift.
- **Large Deletions and Insertions:** Rare, but can involve one or more exons, resulting in a null allele.

### 4.3 Genotype-Phenotype Correlations

A clear genotype-phenotype correlation exists for CLN2 disease. Patients with two null alleles (nonsense, frameshift, or large deletions) typically have a severe, classic phenotype with onset around 2-3 years of age. In contrast, patients carrying at least one missense allele that retains residual enzymatic activity (e.g., p.Arg447His) may have a milder, later-onset phenotype, sometimes referred to as "atypical" LINCL, with slower disease progression and prolonged survival. The residual enzyme activity, often measured in patient fibroblasts or leukocytes, is a strong predictor of clinical severity.

### 4.4 Clinical Differentials and Diagnostic Approach

The clinical presentation of CLN2 disease overlaps with other NCLs and neurodegenerative disorders of childhood. The differential diagnosis includes:

- **Other NCLs:** CLN1 (PPT1 deficiency), CLN3 (Juvenile NCL), CLN5, CLN6, CLN7, CLN8.
- **Other Lysosomal Storage Disorders:** e.g., Gaucher disease type 3, Niemann-Pick disease type C.
- **Mitochondrial Encephalomyopathies:** e.g., Leigh syndrome, MELAS.
- **Inherited Ataxias and Epilepsies.**

The diagnostic workup for a suspected CLN2 disease involves:

1.  **Enzyme Assay:** Measurement of TPP1 enzyme activity in peripheral blood leukocytes, dried blood spots (DBS), or cultured fibroblasts using the synthetic fluorogenic substrate Ala-Ala-Phe-7-amido-4-methylcoumarin (AAF-AMC). Severely reduced or absent activity (<10% of normal) is diagnostic.
2.  **Molecular Genetic Testing:** Sanger sequencing or next-generation sequencing (NGS) of the *TPP1* gene to identify biallelic pathogenic variants.
3.  **Electron Microscopy:** Examination of a skin or conjunctival biopsy for the presence of characteristic "curvilinear bodies" or "fingerprint profiles" in lysosomes, which are pathognomonic for CLN2 disease.
4.  **Neuroimaging:** MRI of the brain may show cerebellar and cerebral atrophy, particularly affecting the cerebellum.

---

## 5. Host-Pathogen & Viral Interactions

### 5.1 TPP1 and Viral Infection

The role of TPP1 in host-pathogen interactions is an emerging area of research. Several viruses exploit the host endosomal/lysosomal system for entry, uncoating, and replication. TPP1, as a lysosomal protease, can influence these processes:

- **Flaviviruses (e.g., Dengue, Zika):** These viruses enter cells via receptor-mediated endocytosis and require low pH in the endosome for fusion. The viral envelope glycoprotein is cleaved by host proteases, including furin, in the *trans*-Golgi network. While TPP1 is not directly implicated in this cleavage, the acidic environment maintained by lysosomal enzymes is essential for the process. Alterations in lysosomal pH or protease activity due to TPP1 deficiency could theoretically impact viral entry, though direct evidence is lacking.
- **Coronaviruses (e.g., SARS-CoV-2):** SARS-CoV-2 entry requires the priming of its spike protein by the host protease TMPRSS2 at the cell surface or by cathepsin L in the endosome. TPP1's role in the endosomal degradation of viral components post-entry is plausible but not well-defined. It may contribute to the antigen processing of viral proteins for presentation to T cells.
- **Adeno-Associated Virus (AAV):** AAV vectors are used in gene therapy, including for CLN2 disease. The endosomal processing of AAV capsids is a critical step for efficient transduction. While TPP1 is not required for AAV uncoating, the lysosomal environment in target cells can affect the efficiency of transgene expression.

### 5.2 Bacterial Effectors and Immune Evasion

Certain bacterial pathogens, such as *Mycobacterium tuberculosis* and *Salmonella enterica*, survive within host macrophages by modulating the phagolysosomal environment. They can inhibit phagosome-lysosome fusion or neutralize the acidic pH, thereby inactivating lysosomal enzymes like TPP1. This is a form of immune evasion, as it prevents the complete degradation of bacterial antigens and the subsequent presentation to T cells. Conversely, the host may upregulate TPP1 expression as part of the innate immune response to enhance bacterial killing. The specific molecular interactions between bacterial effectors and TPP1 are not fully characterized, but the modulation of lysosomal protease activity is a recognized virulence strategy.

---

## 6. Pharmacogenomics, Drug Targets & Small-Molecule Inhibitors

### 6.1 Enzyme Replacement Therapy (ERT)

The most significant therapeutic advance for CLN2 disease is the development of **cerliponase alfa (Brineura™)**, a recombinant human TPP1 enzyme. This is the first and only FDA-approved ERT for a neuronal lysosomal storage disorder. Cerliponase alfa is administered directly into the cerebrospinal fluid (CSF) via an intracerebroventricular (ICV) infusion device, bypassing the blood-brain barrier. The enzyme is taken up by neurons and glial cells via the M6P receptor, trafficked to the lysosome, and cleaves accumulated substrates. Clinical trials have demonstrated that cerliponase alfa significantly slows the rate of decline in motor and language function in children with CLN2 disease. The treatment is administered bi-weekly and requires a surgical procedure for device implantation.

### 6.2 Gene Therapy

Gene therapy approaches for CLN2 disease are in active clinical development. The most advanced strategy involves the use of **Adeno-Associated Virus (AAV)** vectors to deliver a functional copy of the *TPP1* gene to the CNS.

- **AAVrh.10hCLN2:** This vector, delivered via intracerebral injection or ICV infusion, has shown promise in animal models and is being evaluated in clinical trials. The goal is to achieve sustained, long-term expression of TPP1 in the brain, potentially providing a one-time curative treatment.
- **AAV9-hCLN2:** AAV9 can cross the blood-brain barrier to some extent after systemic administration, making it an attractive vector for a less invasive intravenous delivery approach. Preclinical studies in large animal models have shown widespread CNS transduction and correction of the disease phenotype.

### 6.3 Small-Molecule Chaperones and Substrate Reduction Therapy

- **Pharmacological Chaperones:** For patients with missense mutations that lead to protein misfolding, small-molecule chaperones could stabilize the mutant enzyme and restore its trafficking and activity. High-throughput screening has identified several candidate compounds, including **bortezomib** (a proteasome inhibitor) and **suberoylanilide hydroxamic acid (SAHA)** (an HDAC inhibitor), which can increase TPP1 activity in patient-derived cells by upregulating the unfolded protein response or enhancing protein stability. However, these are not specific to TPP1 and are not yet in clinical use for this indication.
- **Substrate Reduction Therapy (SRT):** The goal of SRT is to reduce the synthesis of the storage material (SCMAS). While no specific SRT is approved for CLN2, inhibitors of mitochondrial ATP synthase, such as **oligomycin**, have been shown to reduce SCMAS accumulation in vitro. This approach is limited by the essential role of ATP synthase in cellular energy metabolism.

### 6.4 TPP1 as a Drug Target in Cancer

The dual role of TPP1 in cancer (both tumor-suppressive and oncogenic) makes it a complex therapeutic target. In cancers where TPP1 is overexpressed and promotes survival, specific small-molecule inhibitors could be used. However, no selective TPP1 inhibitors have been developed for clinical use. The development of such inhibitors is challenging due to the need for selectivity over other serine proteases. Conversely, in cancers where TPP1 acts as a tumor suppressor, strategies to upregulate its expression or activity could be explored.

---

## 7. Bioinformatic Resources & Database Accessions

The following table provides key database accessions and resources for the *TPP1* gene and protein.

| **Database** | **Identifier / Accession** | **URL** |
|:---|:---|:---|
| **NCBI Gene** | 7174 | [https://www.ncbi.nlm.nih.gov/gene/7174](https://www.ncbi.nlm.nih.gov/gene/7174) |
| **Ensembl** | ENSG00000166340 | [https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000166340](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000166340) |
| **UniProtKB** | O14773 | [https://www.uniprot.org/uniprotkb/O14773](https://www.uniprot.org/uniprotkb/O14773) |
| **RCSB PDB** | 3EDY, 3EE6, 4B7S | [https://www.rcsb.org/search?q=TPP1](https://www.rcsb.org/search?q=TPP1) |
| **OMIM** | 607998 (Gene), 204500 (CLN2) | [https://www.omim.org/entry/607998](https://www.omim.org/entry/607998) |
| **ClinVar** | Gene: TPP1 | [https://www.ncbi.nlm.nih.gov/clinvar/?term=TPP1%5Bgene%5D](https://www.ncbi.nlm.nih.gov/clinvar/?term=TPP1%5Bgene%5D) |
| **HGMD** | Gene: TPP1 | [http://www.hgmd.cf.ac.uk/ac/gene.php?gene=TPP1](http://www.hgmd.cf.ac.uk/ac/gene.php?gene=TPP1) |
| **Gene Ontology (GO)** | GO:0006508 (Proteolysis), GO:0005764 (Lysosome), GO:0008236 (Serine-type peptidase activity) | [https://www.ebi.ac.uk/QuickGO/](https://www.ebi.ac.uk/QuickGO/) |
| **STRING** | Protein-Protein Interaction Network | [https://string-db.org/network/9606.ENSP00000300047](https://string-db.org/network/9606.ENSP00000300047) |
| **BioGRID** | Interaction Data | [https://thebiogrid.org/](https://thebiogrid.org/) |
| **GTEx Portal** | Expression in Human Tissues | [https://gtexportal.org/home/gene/TPP1](https://gtexportal.org/home/gene/TPP1) |
| **Human Protein Atlas** | Protein Expression & Localization | [https://www.proteinatlas.org/ENSG00000166340-TPP1](https://www.proteinatlas.org/ENSG00000166340-TPP1) |

---

## Related Clinical & Scientific Guides

* [UTY Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/metabolic-pathways/uty-gene-structure-function-pathway)
* [ZBTB42 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/metabolic-pathways/zbtb42-gene-structure-function-pathway)
* [TTLL8 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/metabolic-pathways/ttll8-gene-structure-function-pathway)


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