NPY Protein

Neuropeptide Y (NPY) — Protein

Introduction

Neuropeptide Y (NPY) is a 36-amino acid peptide neurotransmitter and hormone that plays diverse roles in the central and peripheral nervous systems. It is one of the most abundant neuropeptides in the mammalian brain and is critically involved in stress response, appetite regulation, energy homeostasis, and circadian rhythms. Emerging evidence links NPY signaling to neuroprotection and modulation of neurodegenerative processes in Alzheimer's Disease (AD), Parkinson's Disease (PD), and related conditions [1][2].

Neuropeptide Y (NPY) — Protein

Introduction

Neuropeptide Y (NPY) is a 36-amino acid peptide neurotransmitter and hormone that plays diverse roles in the central and peripheral nervous systems. It is one of the most abundant neuropeptides in the mammalian brain and is critically involved in stress response, appetite regulation, energy homeostasis, and circadian rhythms. Emerging evidence links NPY signaling to neuroprotection and modulation of neurodegenerative processes in Alzheimer's Disease (AD), Parkinson's Disease (PD), and related conditions [1][2].

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">Neuropeptide Y (NPY)</th></tr>
<tr><td><strong>Protein Name</strong></td><td>Neuropeptide Y</td></tr>
<tr><td><strong>Gene</strong></td><td>[NPY](/genes/npy)</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[P01308](https://www.uniprot.org/uniprot/P01308)</td></tr>
<tr><td><strong>PDB Structures</strong></td><td>[1RON](https://www.rcsb.org/structure/1RON), [1QFA](https://www.rcsb.org/structure/1QFA)</td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>~10,271 Da (mature peptide)</td></tr>
<tr><td><strong>Subcellular Localization</strong></td><td>Secreted peptide (dense-core vesicles)</td></tr>
<tr><td><strong>Protein Family</strong></td><td>Neuropeptide Y family (PP-fold)</td></tr>
<tr><td><strong>Brain Regions</strong></td><td>Hypothalamus, amygdala, [hippocampus](/brain-regions/hippocampus), [cortex](/brain-regions/cortex), striatum</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/asthma" style="color:#ef9a9a">Asthma</a>, <a href="/wiki/cardiac" style="color:#ef9a9a">Cardiac</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">78 edges</a></td>
</tr>
</table>
</div>

Structure

NPY is synthesized as a 97-amino acid precursor (pre-pro-NPY) that undergoes proteolytic processing:

Structural Features

• PP-fold motif: NPY shares the pancreatic polypeptide fold with peptide YY (PYY) and pancreatic polypeptide (PP)
• N-terminal coil: Important for receptor binding specificity
• C-terminal tail: Essential for receptor activation
• Amidation: C-terminal Tyr36 is amidated, crucial for biological activity

Normal Function

Neurophysiological Roles

NPY is expressed in various brain regions and performs multiple functions:

Receptor Signaling

NPY acts through five G protein-coupled receptors (GPCRs):

| Receptor | Distribution | Primary Effects |
|----------|-------------|-----------------|
| Y1R (NPY1R) | Brain, periphery | Anxiolysis, appetite, vasoconstriction |
| Y2R (NPY2R) | Brain (presynaptic) | Inhibits neurotransmitter release |
| Y4R (NPY4R) | Peripheral tissues | Energy homeostasis |
| Y5R (NPY5R) | Hypothalamus | Appetite regulation |
| Y6R (NPY6R) | Limited (pseudogene in humans) | N/A |

Role in Alzheimer's Disease

NPY alterations are implicated in AD pathophysiology:

Changes in AD Brain

• NPY levels: Variable reports—some studies show increased NPY in AD brains, others show decreased
• Y1R expression: Reduced Y1R binding in AD hippocampus
• Y2R alterations: Changes in Y2R in AD cortex

Neuroprotective Mechanisms

• Anti-excitotoxic effects: NPY protects against glutamate-induced neurotoxicity via Y2R
• Anti-amyloid effects: NPY may reduce [amyloid-beta](/proteins/amyloid-beta) (Aβ) toxicity
• Memory enhancement: Y1R and Y5R activation improves memory consolidation
• Neurogenesis: NPY promotes hippocampal neurogenesis

Therapeutic Implications

• NPY receptor agonists as cognitive enhancers
• Y1R/Y5R-targeted AD therapeutics
• Gene therapy approaches using NPY overexpression

Role in Parkinson's Disease

NPY interactions in PD include:

• Dopaminergic system: NPY modulates dopaminergic neuron survival
• Motor control: NPY in basal ganglia influences movement
• Levodopa-induced dyskinesia: Y1R antagonism may reduce dyskinesias
• Neuroinflammation: NPY exerts anti-inflammatory effects in microglial models

Role in Other Neurodegenerative Diseases

Huntington's Disease

• NPY interneurons are relatively spared in HD
• NPY overexpression may provide neuroprotection
• Y2R agonists under investigation

Epilepsy

• NPY is a potent endogenous anticonvulsant
• NPY gene therapy in clinical trials for epilepsy
• Seizures upregulate NPY expression

Stroke and Ischemia

• NPY is neuroprotective in cerebral ischemia
• Y1R and Y5R mediate ischemic preconditioning

Therapeutic Potential

Drug Development

| Target | Approach | Status |
|--------|----------|--------|
| Y1R agonists | Cognitive enhancement | Preclinical |
| Y2R agonists | Anti-excitotoxic | Preclinical |
| Y5R antagonists | Appetite suppression | Clinical (obesity) |
| NPY gene therapy | Epilepsy treatment | Phase I/II trials |

Challenges

• [Blood-brain barrier](/entities/blood-brain-barrier) penetration
• Receptor subtype selectivity
• Balancing anxiogenic vs anxiolytic effects
• Dose-dependent effects

Key Publications

See Also

• [NPY Gene](/genes/npy)
• [NPY1R Gene](/genes/npy1r)
• [NPY2R Gene](/genes/npy2r)
• [NPY5R Gene](/genes/npy5r)
• [Neuropeptide Signaling](/mechanisms/neuropeptide-signaling)
• [Hypothalamic NPY Neurons](/cell-types/hypothalamic-npy-neurons)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Huntington's Disease](/diseases/huntingtons)

References