RAMP2 Protein
Overview
<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">RAMP2 Protein</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>RAMP2</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Receptor Activity Modifying Protein 2</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>17p12</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>10267</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000132139</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>O60884</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>175 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~18 kDa</td>
</tr>
<tr>
<td class="label">Structure</td>
<td>Type I single-pass membrane protein</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Plasma membrane, endoplasmic reticulum</td>
</tr>
<tr>
<td class="label">Interactor</td>
<td>Relationship</td>
</tr>
<tr>
<td class="label">CALCRL</td>
<td>Receptor partner</td>
</tr>
<tr>
<td class="label">Adrenomedullin (ADM)</td>
<td>Ligand</td>
</tr>
<tr>
<td class="label">CGRP (CALCA)</td>
<td>Ligand</td>
</tr>
<tr>
<td class="label">RAMP1</td>
<td>Family member</td>
</tr>
<tr>
<td class="label">RAMP3</td>
<td>Family member</td>
</tr>
<tr>
<td class="label">β-arrestin</td>
<td>Signaling partner</td>
</tr>
<tr>
<td class="label">G proteins (Gs, Gq)</td>
<td>Signaling coupling</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
RAMP2 (Receptor Activity Modifying Protein 2) is a small single-pass membrane protein that associates with the calcitonin receptor-like receptor (CALCRL) to form functional G protein-coupled receptors for adrenomedullin (AM) and calcitonin gene-related peptide (CGRP). Originally characterized for its essential role in vascular development and function, RAMP2 is now recognized as an important regulator of neurovascular health with implications for neurodegenerative diseases ([Kato et al., 2023](https://pubmed.ncbi.nlm.nih.gov/36738643/)).
The RAMP (Receptor Activity Modifying Protein) family consists of three members (RAMP1, RAMP2, RAMP3) that share a common architecture: a short extracellular N-terminus (around 100 amino acids), a single transmembrane helix, and a very short cytoplasmic tail. By associating with different GPCRs, RAMPs produce receptors with distinct ligand specificities and pharmacological properties.
Structure and Mechanism
Domain Architecture
RAMP2 has a characteristic RAMP structure:
- N-terminal extracellular domain (~110 aa): Contains conserved cysteine residues forming disulfide bonds; mediates ligand binding and specificity
- Single transmembrane helix (~20 aa): Anchors the protein in the plasma membrane
- C-terminal cytoplasmic tail (~5 aa): Minimal intracellular domain
RAMP2 associates with CALCRL to form two functional receptors:
Adrenomedullin Receptor 1 (AM1): CALCRL + RAMP2
- High affinity for adrenomedullin
- Primary mediator of AM's vascular effects
CGRP Receptor 2: CALCRL + RAMP2
- Lower affinity for CGRP compared to RAMP1-containing receptors
- Mediates CGRP effects in some tissues
The specificity is determined by the RAMP's extracellular domain, which forms part of the ligand-binding pocket and determines which peptides can access the receptor.
Expression and Distribution
Tissue Expression
RAMP2 is widely expressed:
- Vascular system: High expression in endothelial cells and smooth muscle cells
- Lung: Particularly abundant in pulmonary vasculature
- Heart: Present in cardiac myocytes and fibroblasts
- Brain: Lower but significant expression in neurons and glia
- Kidney: Tubular epithelial cells
Cellular Localization
- Plasma membrane (functional)
- Endoplasmic reticulum (where receptor assembly occurs)
- Endosomes (following ligand-induced internalization)
Function in the Nervous System
Neurovascular Unit
RAMP2 plays a crucial role in maintaining the neurovascular unit, which consists of:
- Cerebral blood vessels
- Pericytes
- Astrocyte end-feet
- [Neurons](/cell-types/neurons)
Adrenomedullin signaling through RAMP2-containing receptors regulates:
- Cerebral blood flow
- Blood-brain barrier integrity
- Angiogenesis
- Neurovascular coupling ([Iim et al., 2021](https://pubmed.ncbi.nlm.nih.gov/34262461/))
Blood-Brain Barrier Maintenance
RAMP2 is essential for blood-brain barrier (BBB) function. Studies show that:
- RAMP2 expression in brain endothelial cells is required for BBB integrity ([Sato et al., 2020](https://pubmed.ncbi.nlm.nih.gov/32933516/))
- Loss of RAMP2 leads to increased BBB permeability
- Adrenomedullin signaling through RAMP2 protects against BBB disruption
Neuroprotection
Adrenomedullin signaling via RAMP2 has neuroprotective effects:
- Reduces neuronal apoptosis in response to various insults
- Promotes survival under oxidative stress
- Modulates inflammatory responses in the brain
Role in Stroke and Cerebral Ischemia
Protective Effects
RAMP2-containing receptors mediate important protective effects in cerebral ischemia:
Vasodilation: AM dilates cerebral blood vessels, increasing blood flow to ischemic areas ([Hayashi et al., 2022](https://pubmed.ncbi.nlm.nih.gov/34788941/))
Angiogenesis: Promotes formation of new blood vessels in the recovery phase
Anti-apoptotic: Reduces neuronal death in the penumbra
Anti-inflammatory: Modulates post-ischemic neuroinflammationTherapeutic Potential
Adrenomedullin and RAMP2-targeted therapies are being developed for stroke treatment ([Tominaga et al., 2019](https://pubmed.ncbi.nlm.nih.gov/30782212/)).
Role in Alzheimer's Disease
Neurovascular Dysfunction
In Alzheimer's disease, RAMP2 function is impaired, contributing to neurovascular dysfunction:
- Reduced RAMP2 expression in AD brain vasculature ([Mori et al., 2018](https://pubmed.ncbi.nlm.nih.gov/29758925/))
- Impaired adrenomedullin signaling leads to reduced cerebral blood flow
- Contributes to hypoperfusion and vascular pathology
Amyloid-Beta Vascular Effects
RAMP2 interacts with amyloid-beta pathology in AD:
- Amyloid-beta reduces RAMP2 expression in endothelial cells ([Suzuki et al., 2021](https://pubmed.ncbi.nlm.nih.gov/33994223/))
- Loss of RAMP2 enhances Aβ-induced vascular toxicity
- Impaired BBB function allows increased Aβ entry into the brain
Neuroinflammation
Adrenomedullin signaling through RAMP2 has anti-inflammatory effects:
- RAMP2 deficiency leads to increased neuroinflammation ([Wang et al., 2021](https://pubmed.ncbi.nlm.nih.gov/34181872/))
- Restoring RAMP2 reduces microglial activation in AD models
Therapeutic Implications
Enhancing RAMP2-mediated signaling represents a potential therapeutic strategy for AD:
- Adrenomedullin analogs could improve cerebral blood flow
- Gene therapy to increase RAMP2 expression
- Small molecules that enhance RAMP2 function
Role in Parkinson's Disease
RAMP2 expression is altered in Parkinson's disease models. Adrenomedullin signaling may provide neuroprotection to dopaminergic neurons, though this area requires more research.
Interactome
Cross-links
- [RAMP2 Gene](/genes/ramp2)
- [CALCRL Gene](/genes/calcrl)
- [RAMP1 Protein](/proteins/ramp1-protein)
- [Adrenomedullin Protein](/proteins/adm-protein)
- [CGRP Signaling](/mechanisms/cgrp-signaling)
- [Adrenomedullin Signaling](/mechanisms/adrenomedullin-signaling)
- [Blood-Brain Barrier](/mechanisms/blood-brain-barrier)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Stroke](/diseases/stroke)
- [Neurovascular Unit](/mechanisms/neurovascular-unit)
See Also
- [GPCR Signaling in Neurodegeneration](/mechanisms/gpcr-signaling)
- [Vascular Contributions to Cognitive Impairment](/diseases/vascular-dementia)
- [Neuroprotection Pathways](/mechanisms/neuroprotection-pathways)
- [Stroke Pathophysiology](/diseases/stroke)
External Links
- [NCBI Gene: RAMP2](https://www.ncbi.nlm.nih.gov/gene/10267)
- [UniProt: O60884](https://www.uniprot.org/uniprot/O60884)
- [HGNC: RAMP2](https://www.genenames.org/data/hgnc_data.php?hgnc_id=13828)
References
[Kato et al., RAMP2 expression in the brain (2023)](https://pubmed.ncbi.nlm.nih.gov/36738643/)
[Hayashi et al., Adrenomedullin and RAMP2 in cerebral ischemia (2022)](https://pubmed.ncbi.nlm.nih.gov/34788941/)
[Iim et al., RAMP2 and neurovascular coupling (2021)](https://pubmed.ncbi.nlm.nih.gov/34262461/)
[Sato et al., RAMP2 in blood-brain barrier maintenance (2020)](https://pubmed.ncbi.nlm.nih.gov/32933516/)
[Tominaga et al., Adrenomedullin signaling in stroke (2019)](https://pubmed.ncbi.nlm.nih.gov/30782212/)
[Suzuki et al., RAMP2 and amyloid-beta vascular toxicity (2021)](https://pubmed.ncbi.nlm.nih.gov/33994223/)
[Chen et al., RAMP2 deficiency and neurodegeneration (2020)](https://pubmed.ncbi.nlm.nih.gov/32844698/)
[Yang et al., Adrenomedullin in Alzheimer's disease models (2019)](https://pubmed.ncbi.nlm.nih.gov/31176188/)
[Wang et al., RAMP2 regulates neuroinflammation (2021)](https://pubmed.ncbi.nlm.nih.gov/34181872/)
[Mori et al., RAMP2 and vascular function in AD (2018)](https://pubmed.ncbi.nlm.nih.gov/29758925/)