SHP2 Protein

SHP2 Protein

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">SHP2 Protein</th>
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<td class="label">Symbol</td>
<td><strong>SHP2</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>SHP2</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=SHP2" target="_blank">Search UniProt</a></td>
</tr>
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<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">2 edges</a></td>
</tr>
</table>

SHP2 Protein

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">SHP2 Protein</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>SHP2</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>SHP2</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=SHP2" target="_blank">Search UniProt</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">2 edges</a></td>
</tr>
</table>

SHP2 (Src Homology 2 Domain-Containing Phosphatase 2) is a widely expressed protein tyrosine phosphatase encoded by the [PTPN11](/genes/ptpn11) gene. Originally identified as a positive regulator of RAS-RAF-MEK-ERK signaling downstream of growth factor receptors, SHP2 has emerged as a critical regulator of neuronal function, synaptic plasticity, and cell survival in the nervous system. Germline gain-of-function mutations in PTPN11 cause Noonan syndrome, a developmental disorder, while somatic mutations drive oncogenesis in various cancers. In the context of neurodegeneration, SHP2 plays complex and context-dependent roles—it's been implicated in both protective and pathogenic signaling in Alzheimer's disease (AD), Parkinson's disease (PD), and other neurological conditions. The protein's enzymatic activity, adaptor functions, and subcellular localization are tightly regulated, with dysregulation contributing to neuronal dysfunction and death.

Gene and Protein Overview

The [PTPN11](/genes/ptpn11) gene (located on chromosome 12q24.13 in humans) encodes a protein of 593 amino acids with a molecular weight of approximately 68 kDa. SHP2 belongs to the protein tyrosine phosphatase (PTP) family and is one of two SH2 domain-containing phosphatases in mammals (the other being SHP1/PTPN6). Unlike SHP1, which is primarily expressed in hematopoietic cells, SHP2 is ubiquitously expressed with particularly high levels in the brain.

Structural Features

SHP2 possesses a characteristic multi-domain architecture:

The crystal structure reveals that in the inactive conformation, the NSH2 domain blocks access to the catalytic site. Activation requires binding to phosphotyrosine-containing peptides, which induces a conformational change that opens the active site. [@shp2_structure]

Tissue Distribution

SHP2 is ubiquitously expressed with high levels in:

• Brain: Particularly in the cortex, hippocampus, and basal ganglia
• Neurons: Both excitatory glutamatergic and inhibitory GABAergic neurons
• Astrocytes: Supporting neuronal function
• Microglia: Immune cells of the CNS
• Peripheral tissues: Heart, lung, kidney, and others

Normal Physiological Function

RAS-RAF-MEK-ERK Signaling

SHP2 is a well-established positive regulator of the RAS-RAF-MEK-ERK mitogen-activated protein kinase (MAPK) pathway:

Mechanism:

This function makes SHP2 essential for normal development and tissue homeostasis. [@shp2_ras_mapk]

Synaptic Plasticity

In neurons, SHP2 plays critical roles in synaptic function:

Postsynaptic signaling:

• Recruited to NMDA receptors and other postsynaptic density proteins
• Regulates AMPA receptor trafficking
• Modulates long-term potentiation (LTP) and long-term depression (LTD)
• Required for learning and memory in mouse models

• Regulates vesicle release probability
• Modulates neurotransmitter release

• Neuron-specific SHP2 knockout impairs spatial learning
• Alters hippocampal synaptic plasticity
• Affects memory consolidation

Cell Survival and Death

SHP2 regulates both pro-survival and pro-death signaling:

Pro-survival functions:

• Activation of PI3K-AKT pathway through RAS
• Regulation of STAT3 signaling
• Modulation of p53 function

• Can protect neurons from apoptotic stimuli
• May also contribute to pathological signaling in some conditions
• The balance depends on cell type, stimulus, and subcellular localization

Role in Disease

Noonan Syndrome

Germline gain-of-function mutations in PTPN11 cause Noonan syndrome:

Clinical features:

• Characteristic facial dysmorphism
• Short stature
• Cardiac defects (pulmonary valve stenosis, hypertrophic cardiomyopathy)
• Chest deformities
• Developmental delay
• Increased cancer risk

• Constitutively active SHP2 hyperactivates RAS-RAF-MEK-ERK signaling
• Disrupts normal developmental programs
• Affects cell migration, proliferation, and differentiation

Cancer

Somatic PTPN11 mutations are found in various cancers:

• Leukemia: ~35% of juvenile myelomonocytic leukemia (JMML) cases
• Solid tumors: Lung, breast, colorectal, and other cancers
• Mechanism: Hyperactive SHP2 promotes oncogenic RAS-ERK signaling

Alzheimer's Disease

SHP2 has complex roles in AD pathogenesis:

Pathological changes:

• Increased SHP2 expression in AD brain
• Colocalization with amyloid plaques and neurofibrillary tangles
• Association with cognitive decline

• SHP2 regulates amyloid precursor protein (APP) processing
• Modulates tau phosphorylation via ERK pathways
• Affects synaptic dysfunction in AD models
• May contribute to excitotoxicity

• SHP2 inhibitors may reduce pathological signaling
• Modulating SHP2 could protect synapses

Parkinson's Disease

In PD, SHP2 shows both protective and pathogenic roles:

Neuroprotection:

• SHP2 activity protects dopaminergic neurons from oxidative stress
• Required for proper mitochondrial function
• Supports neurotrophic factor signaling

• LRRK2 G2019S mutation may hyperactivate SHP2-dependent pathways
• Contributes to neuroinflammation in PD models
• Altered SHP2 expression in PD brain

• Context-dependent effects complicate targeting
• Need to understand specific molecular contexts

Autism Spectrum Disorder

PTPN11 variants have been associated with ASD:

Genetic evidence:

• De novo PTPN11 variants identified in ASD patients
• Affected individuals often have macrocephaly
• Overlap with Noonan syndrome phenotypes

• Altered synaptic function
• Impaired neuronal connectivity
• Affected social and communication behaviors

Signaling Pathways

SHP2 Substrates and Interactors

SHP2 interacts with numerous signaling proteins:

Receptors:

• EGFR and other RTKs
• cytokine receptors (IFNAR, IL-2R)
• Notch receptors
• glutamate receptors (NMDA, AMPA)

• GRB2-SOS complex
• SHC family proteins
• Gab family proteins

• RASGAPs (p120GAP, NF1)
• STAT3
• PTEN

Cross-Talk with Other Pathways

SHP2 interacts with multiple signaling cascades:

PI3K-AKT pathway:

• SHP2 promotes PI3K activation downstream of RTKs
• AKT promotes cell survival
• Cross-talk with RAS-MAPK pathway

• SHP2 regulates STAT3 phosphorylation
• Affects cytokine signaling
• Important for neuroinflammation

• SHP2 indirectly activates mTORC1
• Affects protein synthesis
• Relevant for synaptic plasticity

Therapeutic Implications

SHP2 Inhibitors in Cancer

Allosteric SHP2 inhibitors are in clinical development:

TNO155: First-in-class allosteric SHP2 inhibitor

• Binds to the NSH2-PTP interface
• Locks SHP2 in inactive conformation
• Being tested in solid tumors

• Showing promise in KRAS-mutant cancers
• Being evaluated in combination with other agents

Neurodegeneration Applications

SHP2 modulators may be useful in:

Challenges

• Achieving brain penetration
• Achieving subtype selectivity
• Understanding context-dependent effects
• Balancing efficacy and toxicity

Relationship to Other Neurodegeneration Proteins

LRRK2 and SHP2

In PD:

• LRRK2 G2019S may interact with SHP2 pathways
• Both affect RAS-MAPK signaling
• Therapeutic targeting must consider interaction

Tau and SHP2

In AD:

• SHP2 regulates tau phosphorylation via ERK
• Pathological tau affects SHP2 signaling
• Bidirectional relationship

PTEN and SHP2

• Cross-talk between SHP2 and PTEN
• Both regulate PI3K-AKT signaling
• Balance affects cell survival

Cross-Links to Related Pages

• [PTPN11 gene](/genes/ptpn11) - Gene-level details
• [Alzheimer's disease](/diseases/alzheimers-disease) - SHP2 in AD
• [Parkinson's disease](/diseases/parkinsons-disease) - SHP2 in PD
• [Autism spectrum disorder](/diseases/autism-spectrum-disorder) - SHP2 in ASD
• [RAS-RAF-MEK-ERK pathway](/mechanisms/ras-raf-mek-erk) - SHP2 in MAPK signaling
• [Synaptic plasticity](/mechanisms/synaptic-plasticity) - SHP2 in synaptic function
• [Noonan syndrome](/diseases/noonan-syndrome) - SHP2 in development

Current Research Directions

See Also

• [Mechanisms: RAS-RAF-MEK-ERK Signaling](/mechanisms/ras-raf-mek-erk)
• [Mechanisms: Synaptic Plasticity](/mechanisms/synaptic-plasticity)
• [Mechanisms: Neuroprotection](/treatments/neuroprotection)
• [Cell Types: Neuron](/cell-types/neuron)
• [Cell Types: Microglia](/cell-types/microglia)

References

External Links

• [UniProt: Q16178](https://www.uniprot.org/uniprot/Q16178)
• [Gene: PTPN11 (12q24.13)](https://www.ncbi.nlm.nih.gov/gene/5781)
• [PDB: 2SBA, 4DGP](https://www.rcsb.org/)
• [OMIM: 163950 - Noonan syndrome](https://www.omim.org/entry/163950)
• [ClinicalTrials.gov: SHP2 inhibitor trials](https://clinicaltrials.gov/search?cond=SHP2+inhibitor)