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).
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.
| Property | Value |
|---|---|
| Gene Symbol | RAMP2 |
| Full Name | Receptor Activity Modifying Protein 2 |
| Chromosomal Location | 17p12 |
| NCBI Gene ID | 10267 |
| Ensembl ID | ENSG00000132139 |
| UniProt ID | O60884 |
| Protein Length | 175 amino acids |
| Molecular Weight | ~18 kDa |
| Structure | Type I single-pass membrane protein |
| Subcellular Localization | Plasma membrane, endoplasmic reticulum |
RAMP2 has a characteristic RAMP structure:
RAMP2 associates with CALCRL to form two functional receptors:
Adrenomedullin Receptor 1 (AM1): CALCRL + RAMP2
CGRP Receptor 2: CALCRL + RAMP2
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.
RAMP2 is widely expressed:
RAMP2 plays a crucial role in maintaining the neurovascular unit, which consists of:
Adrenomedullin signaling through RAMP2-containing receptors regulates:
RAMP2 is essential for blood-brain barrier (BBB) function. Studies show that:
Adrenomedullin signaling via RAMP2 has neuroprotective 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)
Angiogenesis: Promotes formation of new blood vessels in the recovery phase
Anti-apoptotic: Reduces neuronal death in the penumbra
Anti-inflammatory: Modulates post-ischemic neuroinflammation
Adrenomedullin and RAMP2-targeted therapies are being developed for stroke treatment (Tominaga et al., 2019).
In Alzheimer's disease, RAMP2 function is impaired, contributing to neurovascular dysfunction:
RAMP2 interacts with amyloid-beta pathology in AD:
Adrenomedullin signaling through RAMP2 has anti-inflammatory effects:
Enhancing RAMP2-mediated signaling represents a potential therapeutic strategy for AD:
RAMP2 expression is altered in Parkinson's disease models. Adrenomedullin signaling may provide neuroprotection to dopaminergic neurons, though this area requires more research.
| Interactor | Relationship |
|---|---|
| CALCRL | Receptor partner |
| Adrenomedullin (ADM) | Ligand |
| CGRP (CALCA) | Ligand |
| RAMP1 | Family member |
| RAMP3 | Family member |
| β-arrestin | Signaling partner |
| G proteins (Gs, Gq) | Signaling coupling |