Tpp1 Protein (Tripeptidyl Peptidase 1) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
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| Attribute |
Value |
| Protein Name |
Tripeptidyl Peptidase 1 |
| Gene |
TPP1 |
| UniProt ID |
O14773 |
| PDB Structure |
3EDY, 4ATG |
| Molecular Weight |
59 kDa |
| Subcellular Localization |
Lysosomal lumen |
| Protein Family |
S9 family serine proteases |
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TPP1 (Tripeptidyl Peptidase 1) is a lysosomal serine protease that cleaves tripeptides from the N-terminus of proteins. It is the major exopeptidase in lysosomes and plays a critical role in protein degradation. Mutations in TPP1 cause Late Infantile Neuronal Ceroid Lipofuscinosis (LINCL)[1].
TPP1 is a 563-amino acid glycoprotein:
- Signal peptide: 25 aa
- Propeptide: 105 aa
- Mature enzyme: 433 aa
TPP1 structure (PDB: 3EDY):
- Fold: α/β hydrolase fold with additional β-propeller domain
- Active site: Ser228, Asp276, His331 (catalytic triad)
- Substrate binding: Large active site pocket
- N-linked glycosylation: Multiple sites for lysosomal targeting
- Signal peptide: Cleaved at position 25
- Propeptide: Cleaved in lysosome, activating the enzyme
TPP1 is a serine protease with unique tripeptidyl-peptidase activity:
- Primary activity: Cleaves N-terminal tripeptides from protein substrates
- Secondary activity: Endopeptidase activity
- pH optimum: Acidic (pH 4.5-5.5)
- Lysosomal Protein Degradation: Primary exopeptidase
- Protein Turnover: Essential for cellular homeostasis
- Autophagy: Participates in protein clearance
- Neuronal Function: Critical for neuronal health
TPP1 degrades:
- Lysosomal proteins
- Cytosolic proteins delivered via autophagy
- Storage materials in NCL
TPP1 mutations cause LINCL (also known as CLN2 disease)[1]:
- Inheritance: Autosomal recessive
- Onset: 2-4 years
- Features: Seizures, vision loss, cognitive decline, motor dysfunction
- Progression: Fatal by 6-15 years
TPP1 deficiency causes:
- Accumulation of lysosomal storage material (ceroid)
- Progressive neuronal loss
- Disrupted autophagy
- Synaptic dysfunction
Cerliponase alfa (Brineura) - First disease-modifying therapy for LINCL:
- Type: Recombinant human TPP1 (rhTPP1)
- Delivery: Intracerebroventricular infusion every 2 weeks
- Efficacy: Slows disease progression[2]
- Gene therapy: AAV-vector delivery in trials
- Stem cell therapy: Investigational
- Small molecule approaches: Being studied
The study of Tpp1 Protein (Tripeptidyl Peptidase 1) has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- Sleat DE, et al. "Mutations in the pepstatin A-insensitive aspartyl protease gene, TPSN1, are responsible for a variant form of late infantile neuronal ceroid lipofuscinosis." Am J Hum Genet. 2005;77(4):686-695.
- Markham A. "Cerliponase alfa: first global approval." Drugs. 2017;77(11):1247-1249.
- Kohan R, et al. "Late infantile neuronal ceroid lipofuscinosis: from genetics to treatment." Mol Genet Metab. 2015;116(1-2):35-43.
Last updated: March 2026