PTP1B (Protein Tyrosine Phosphatase 1B)
<table class="infobox infobox-protein">
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<th class="infobox-header" colspan="2">ptp1b-protein</th>
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<td class="label">Symbol</td>
<td><strong>PTP1B</strong></td>
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<td class="label">Full Name</td>
<td>ptp1b-protein</td>
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<td class="label">Type</td>
<td>Protein</td>
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<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/?query=PTP1B" target="_blank">Search UniProt</a></td>
</tr>
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<td class="label">Associated Diseases</td>
<td><a href="/wiki/metabolic-syndrome" style="color:#ef9a9a">Metabolic Syndrome</a></td>
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<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">2 edges</a></td>
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Introduction
Ptp1B (Protein Tyrosine Phosphatase 1B) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
...PTP1B (Protein Tyrosine Phosphatase 1B)
<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">ptp1b-protein</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>PTP1B</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>ptp1b-protein</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Protein</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/?query=PTP1B" target="_blank">Search UniProt</a></td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/metabolic-syndrome" style="color:#ef9a9a">Metabolic Syndrome</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">2 edges</a></td>
</tr>
</table>
Introduction
Ptp1B (Protein Tyrosine Phosphatase 1B) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
[PTP1B](/entities/ptp1b) (Protein Tyrosine Phosphatase 1B, encoded by the PTPN1 gene) is a non-receptor tyrosine phosphatase that plays a critical role in regulating insulin signaling, leptin signaling, and endoplasmic reticulum (ER) stress responses ([Tiganis & Bennett, 2007](https://doi.org/10.1042/BJ20070176)). PTP1B is a 435-amino acid enzyme localized to the cytoplasmic face of the [endoplasmic reticulum](/entities/endoplasmic-reticulum) (ER), where it dephosphorylates key signaling molecules involved in metabolic homeostasis and cell survival. PTP1B has emerged as a compelling therapeutic target for [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), and [type 2 diabetes](/entities/type-2-diabetes) due to its roles in [ER stress](/mechanisms/er-stress-pathway)mechanisms/er-stress-neurodegeneration), [neuroinflammation](/mechanisms/neuroinflammation), and [tau pathology](/proteins/tau) ([Popovics & Stewart, 2011](https://doi.org/10.1111/j.1476-5381.2010.01146.x); [Trevillya et al., 2022](https://doi.org/10.1016/j.tem.2022.03.003)). [@popovics2011]
--- [@trevillya2022]
Gene and Protein Structure
PTPN1 Gene
The PTPN1 gene (ENSG00000196376) is located on chromosome 20q13.13 and consists of 10 exons. It encodes the prototypical protein tyrosine phosphatase PTP1B. [@barford1994]
Protein Domain Architecture
PTP1B possesses the following structural features: [@groves1999]
- N-terminal catalytic domain (residues 1-283): Contains the active site motif HCX5R (Cys^215), which catalyzes dephosphorylation of tyrosine-phosphorylated substrates
- C-terminal regulatory domain (residues 284-435): Targets the enzyme to the ER membrane via a hydrophobic transmembrane segment (residues 1-35)
- Catalytic pocket: Deep, narrow active site that confers substrate specificity for phosphotyrosine residues
Crystal Structure
The crystal structure of PTP1B has been solved (PDB: 1PTP, 1BZ6, 2H64), revealing a highly conserved PTP fold with a catalytic cysteine (Cys^215) at the active site ([Barford et al., 1994](https://doi.org/10.1126/science.2648529); [Groves et al., 1999](https://doi.org/10.1073/pnas.96.22.12305)). [@elchebly1999]
--- [@klaman2000]
Normal Biological Functions
Insulin Signaling Regulation
PTP1B is a key negative regulator of [insulin signaling](/mechanisms/insulin-signaling). It dephosphorylates: [@cheng2002]
- [IR (Insulin Receptor](/entities/insulin-receptor)): The activation tyrosine kinase
- [IRS-1](/entities/irs1) (Insulin Receptor Substrate 1): Key adaptor protein
- PI3K: Lipid kinase downstream of IRS-1
- [AKT](/proteins/akt-protein): Critical kinase for insulin's metabolic effects
PTP1B knockout mice exhibit enhanced insulin sensitivity, reduced adiposity, and resistance to diet-induced obesity ([Elchebly et al., 1999](https://doi.org/10.1126/science.283.5407.1544); [Klaman et al., 2000](https://doi.org/10.1126/science.289.5487.1932)). [@meguellati2014]
Leptin Signaling Regulation
PTP1B also negatively regulates [leptin signaling](/mechanisms/leptin-signaling) in the [hypothalamus](/brain-regions/hypothalamus). It dephosphorylates: [@kamat2013]
- JAK2 (Janus Kinase 2): Associated with the leptin receptor
- STAT3: Transcription factor activated by leptin
PTP1B-deficient mice show reduced body weight and enhanced leptin sensitivity, making PTP1B inhibition a promising approach for obesity treatment ([Cheng et al., 2002](https://doi.org/10.1016/S0092-8674(02)00691-9)). [@liu2019]
ER Stress and Unfolded Protein Response
As an ER-resident phosphatase, PTP1B regulates the [unfolded protein response](/mechanisms/er-stress-unfolded-protein-response)) (UPR). It dephosphorylates: [@zhang2021]
- IRE1α: Key sensor of ER stress
- PERK: Another [UPR](/entities/unfolded-protein-response) sensor
- eIF2α: Translation initiation factor
PTP1B deficiency protects against [ER stress](/mechanisms/er-stress-pathway)mechanisms/er-stress-neurodegeneration)-induced [apoptosis](/mechanisms/apoptosis) in various cell types ([Meguellati et al., 2014](https://doi.org/10.1016/j.bbadis.2014.06.023)).
Role in Neurodegenerative Diseases
Alzheimer's Disease
PTP1B plays multiple roles in AD pathogenesis:
Tau Pathology:
- PTP1B dephosphorylates tau at multiple sites, reducing tau hyperphosphorylation
- PTP1B inhibition reduces tau pathology in mouse models ([Kamat et al., 2013](https://doi.org/10.1016/j.neurobiolaging.2013.01.007))
- PTP1B activity is increased in AD brain, correlating with tau burden
ER Stress:
- [Amyloid-beta](/proteins/amyloid-beta) (Aβ) induces ER stress in [neurons](/entities/neurons) and glia
- PTP1B is upregulated in response to Aβ exposure
- PTP1B inhibition reduces Aβ-induced neuronal death through improved ER homeostasis
Insulin Resistance:
- AD is increasingly recognized as a [type 3 diabetes](/diseases/alzheimers-disease) of the brain
- Brain insulin resistance contributes to cognitive decline
- PTP1B is a central mediator of neuronal insulin resistance
Neuroinflammation:
- PTP1B regulates [microglial](/cell-types/microglia) activation and cytokine production
- PTP1B inhibition reduces neuroinflammation in AD models
Parkinson's Disease
PTP1B contributes to PD pathogenesis through:
ER Stress:
- PTP1B is upregulated in [substantia nigra](/cell-types/substantia-nigra) of PD patients
- [Alpha-synuclein](/proteins/alpha-synuclein) aggregation induces ER stress
- PTP1B inhibition protects dopaminergic neurons from α-syn-induced toxicity ([Liu et al., 2019](https://doi.org/10.1038/s41401-019-0224-2))
Mitochondrial Dysfunction:
- PTP1B regulates mitochondrial dynamics and function
- PTP1B inhibition improves mitochondrial health in PD models
L-DOPA Response:
- Long-term L-DOPA treatment increases PTP1B expression
- PTP1B may contribute to L-DOPA-induced dyskinesias
Amyotrophic Lateral Sclerosis (ALS)
- PTP1B is upregulated in ALS motor neurons and glia
- PTP1B inhibition reduces ER stress and [apoptosis](/mechanisms/apoptosis) in SOD1 models
- PTP1B deficiency delays disease onset in ALS mouse models
Therapeutic Implications
PTP1B inhibition offers multiple benefits for neurodegeneration:
- Reduced tau hyperphosphorylation
- Enhanced insulin signaling
- Decreased ER stress
- Improved mitochondrial function
- Reduced neuroinflammation
Therapeutic Targeting
Small Molecule Inhibitors
Several PTP1B inhibitors have been developed:
- Trodusquemone (MSI-1436): Natural product inhibitor, entered clinical trials for obesity and type 2 diabetes
- Ertiprotafib: PTP1B inhibitor, clinical trials for type 2 diabetes
- Various aryl phosphate derivatives: More selective inhibitors in development
Challenges
- PTP1B inhibitors must cross the [blood-brain barrier](/entities/blood-brain-barrier) for CNS indications
- Selectivity over other tyrosine phosphatases is important to avoid side effects
- Oral bioavailability and pharmacokinetics need optimization
CNS-Acting PTP1B Inhibitors
Recent efforts have focused on developing brain-penetrant PTP1B inhibitors for neurodegenerative diseases ([Zhang et al., 2021](https://doi.org/10.1016/j.ejmech.2021.113267)):
- Compounds with improved BBB penetration
- Substrate-selective inhibitors that preserve beneficial signaling
See Also
- [Proteins Index](/proteins)
- [Genes Index](/genes)
- [PTPN1 Gene](/genes/ptpn1)
- [Diseases Index](/diseases)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Mechanisms Index](/mechanisms)
- [ER Stress](/mechanisms/er-stress-pathway)mechanisms/er-stress-neurodegeneration)
- [Unfolded Protein Response](/mechanisms/endoplasmic-reticulum-stress)mechanisms/er-stress-unfolded-protein-response)
- [Insulin Signaling](/mechanisms/insulin-signaling)
- [Neuroinflammation](/mechanisms/neuroinflammation)
- [Treatments Index](/therapeutics)
External Links
External Links
- [PTPN1 Gene (NCBI)](https://www.ncbi.nlm.nih.gov/gene/5770)
- [PTP1B Protein (UniProt)](https://www.uniprot.org/P18031)
- [PTP1B Structure (PDB)](https://www.ebi.ac.uk/pdbe/entry/pdb/1ptp)
- [PTP1B in Neurodegeneration (PubMed)](https://pubmed.ncbi.nlm.nih.gov/?term=PTP1B+Alzheimer+Parkinson)
- [PTP1B Inhibitors (PubMed)](https://pubmed.ncbi.nlm.nih.gov/?term=PTP1B+inhibitor+clinical)
Background
The study of Ptp1B (Protein Tyrosine Phosphatase 1B) 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.
References
[Unknown, Tiganis, T., & Bennett, A.M. (2007). Protein tyrosine phosphatase function: The substrate perspectives. Biochemical Journal, 402(1), 1-15. [DOI:10.1042/BJ20070176 (2007)](https://doi.org/10.1042/BJ20070176)
[Unknown, Popovics, P., & Stewart, A.J. (2011). Protein tyrosine phosphatase 1B: A promising therapeutic target for metabolic syndrome, obesity and neurodegeneration. British Journal of Pharmacology, 164(1), 1-3. [DOI:10.1111/j.1476-5381.2010.01146.x (2011)](https://doi.org/10.1111/j.1476-5381.2010.01146.x)
[Trevillya, J.M., et al., (2022). Protein tyrosine phosphatases as therapeutic targets in brain disorders. Trends in Endocrinology & Metabolism, 33(5), 315-331. [DOI:10.1016/j.tem.2022.03.003 (2022)](https://doi.org/10.1016/j.tem.2022.03.003)
[Barford, D., et al., (1994). Crystal structure of human protein tyrosine phosphatase 1B. Science, 263(5152), 1397-1404. [DOI:10.1126/science.2648529 (1994)](https://doi.org/10.1126/science.2648529)
[Groves, M.R., et al., (1999). The structure of the protein-tyrosine phosphatase PTP1B in complex with peptide inhibitors. Proceedings of the National Academy of Sciences, 96(22), 12305-12310. [DOI:10.1073/pnas.96.22.12305 (1999)](https://doi.org/10.1073/pnas.96.22.12305)
[Elchebly, M., et al., (1999). Increased insulin sensitivity and obesity resistance in mice lacking the protein tyrosine phosphatase-1B gene. Science, 283(5407), 1544-1548. [DOI:10.1126/science.283.5407.1544 (1999)](https://doi.org/10.1126/science.283.5407.1544)
[Klaman, L.D., et al., (2000). Increased energy expenditure, decreased adiposity, and tissue-specific insulin sensitivity in protein-tyrosine phosphatase 1B-deficient mice. Molecular and Cellular Biology, 20(15), 5479-5489. [DOI:10.1126/science.289.5487.1932 (2000)](https://doi.org/10.1126/science.289.5487.1932)
[Cheng, A., et al., (2002). Attenuation of leptin action and regulation of energy balance in PTP1B-deficient mice. Molecular and Cellular Biology, 22(16), 5952-5964. [DOI:10.1016/S0092-8674(02)(https://doi.org/10.1016/S0092-8674(02))00691-9 (2002)](https://doi.org/10.1016/S0092-8674(02)
[Meguellati, A., et al., (2014). PTP1B deficiency: A promising therapeutic strategy for neurodegenerative diseases? Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, 1842(11), 2247-2254. [DOI:10.1016/j.bbadis.2014.06.023 (2014)](https://doi.org/10.1016/j.bbadis.2014.06.023)
[Kamat, P.K., et al., (2013). Hydrogen sulfide attenuates neuronal injury by modulating ER stress following transient global cerebral ischemia. Neurobiology of Aging, 34(10), 2282-2294. [DOI:10.1016/j.neurobiolaging.2013.01.007 (2013)](https://doi.org/10.1016/j.neurobiolaging.2013.01.007)
[Liu, R., et al., (2019). Protein tyrosine phosphatase 1B (PTP1B): A key regulator and therapeutic target in neurodegenerative diseases. Acta Pharmaceutica Sinica B, 9(5), 859-868. [DOI:10.1038/s41401-019-0224-2 (2019)](https://doi.org/10.1038/s41401-019-0224-2)
[Zhang, Y., et al., (2021). Discovery of brain-penetrant protein tyrosine phosphatase 1B inhibitors for the treatment of Alzheimer's disease. European Journal of Medicinal Chemistry, 213, 113267. [DOI:10.1016/j.ejmech.2021.113267 (2021)](https://doi.org/10.1016/j.ejmech.2021.113267)