Affinage

RAMP3

Receptor activity-modifying protein 3 · UniProt O60896

Length
148 aa
Mass
16.5 kDa
Annotated
2026-06-10
24 papers in source corpus 19 papers cited in narrative 19 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 5/6 claims corpus-supported (83%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

RAMP3 is a single-transmembrane accessory protein that determines the pharmacology, trafficking, and signaling output of multiple G protein-coupled receptors by heterodimerizing with them at the cell surface (PMID:11591721, PMID:12970090, PMID:31712427). Its extracellular N-terminal domain forms the ligand interface of the CLR/RAMP3 (AM2) adrenomedullin receptor: residues 59-65 and Glu74 are critical for high-affinity adrenomedullin binding and AM-evoked cAMP production, and N-glycosylation together with six cysteine-stabilized disulfide bonds are required for functional receptor expression (PMID:11591721, PMID:12939163, PMID:21402116). RAMP3 identity dictates the antagonist selectivity of the receptor complex, distinguishing CLR/RAMP3 from CLR/RAMP2 pharmacologically (PMID:12970090), and helix 1 and helix 2 residues govern CLR association and trafficking versus ligand-pocket formation (PMID:20017504). Beyond CLR, RAMP3 partners with the calcitonin receptor (CTR) to form the AMY3 amylin receptor, where it reshapes the contribution of CTR extracellular loops 2 and 3 to signal propagation and stabilizes a transmembrane-domain heterodimer interface whose agonist-driven dissociation tunes cAMP output [PMID:32219220, PMID:bio_10.1101_2024.10.09.617487]. RAMP3 also acts as a recycling chaperone for the atypical chemokine receptors ACKR3 and ACKR2, promoting their Rab4-dependent return to the plasma membrane to sustain chemokine scavenging and chemotactic gradient formation (PMID:31712427, PMID:39437486), and biases GLP-1R signaling away from Gαs/cAMP toward Gαq/Gαi and Ca2+ mobilization to enhance glucose-stimulated insulin secretion [PMID:bio_10.1101_2025.01.24.634724]. In vivo, RAMP3 is dispensable for baseline vascular development but is specifically required for lymphatic vessel drainage, directed retinal angiogenesis, later cardiac adaptation to pressure overload through cardiac lymphatics, and the anorectic and glucose-homeostatic effects of amylin (PMID:31712427, PMID:25264174, PMID:33545715, PMID:31881259).

Mechanistic history

Synthesis pass · year-by-year structured walk · 13 steps
  1. 2001 High

    Established which part of RAMP3 contacts ligand, answering how an accessory protein contributes to adrenomedullin pharmacology rather than merely escorting the receptor.

    Evidence Deletion mutagenesis with 125I-AM binding and cAMP readouts in HEK293 cells co-expressing CRLR

    PMID:11591721

    Open questions at the time
    • Does not resolve the structural fold of the bound complex
    • No information on RAMP3 partners beyond CLR
  2. 2003 High

    Defined the structural requirements (N-glycosylation, disulfide bonds) for a functional CLR/RAMP3 receptor and showed RAMP identity dictates antagonist pharmacology.

    Evidence Oocyte and COS7 reconstitution with cysteine/glycosylation mutagenesis and cross-species pharmacological antagonism

    PMID:12939163 PMID:12970090

    Open questions at the time
    • Disulfide connectivity not directly mapped
    • Species-dependence of antagonist selectivity not mechanistically explained
  3. 2005 Medium

    Showed RAMP3 expression is regulated, identifying it as a cAMP-PKA-driven primary response gene downstream of PTH in osteoblasts.

    Evidence RT-PCR with cycloheximide, forskolin, and H89 pharmacological dissection in primary mouse osteoblasts

    PMID:16075364

    Open questions at the time
    • Transcription factors mediating induction not identified
    • Functional consequence of RAMP3 induction in bone not tested
  4. 2010 Medium

    Separated the RAMP determinants of receptor association/trafficking from those shaping the ligand-binding pocket, refining how RAMP3-type proteins remodel CLR.

    Evidence RAMP1/RAMP3 chimera analysis with CLR trafficking and agonist potency assays plus molecular modeling

    PMID:20017504

    Open questions at the time
    • Modeling-based, no experimental structure
    • Single lab
  5. 2011 Medium

    Pinpointed a single residue (Glu74) contributing charge/geometry to adrenomedullin specificity at the AM2 receptor.

    Evidence Site-directed mutagenesis of RAMP3 with cAMP and surface-ELISA readouts in COS7 cells

    PMID:21402116

    Open questions at the time
    • Single residue context only
    • No structural confirmation of the contact
  6. 2014 High

    Moved RAMP3 from in vitro pharmacology to physiology, showing it is selectively required for lymphatic vessel function rather than general vascular development.

    Evidence RAMP3 knockout mice with ICG lymphangiography, tail lymphedema model, and lymphatic endothelial scratch-wound assays

    PMID:25264174

    Open questions at the time
    • Receptor partner mediating the lymphatic phenotype not isolated in vivo
    • Cell-autonomous versus systemic contributions not separated
  7. 2019 High

    Revealed a chaperone/recycling function for RAMP3 distinct from G-protein modulation, explaining how it controls chemokine receptor surface levels and gradient formation.

    Evidence BRET interaction, Rab4-vesicle trafficking analysis, and RAMP3 KO mouse retinal angiogenesis

    PMID:31712427

    Open questions at the time
    • Recruitment mechanism of RAMP3 to Rab4 vesicles unknown
    • Generality of the recycling role across other GPCRs untested at the time
  8. 2019 Medium

    Extended RAMP3 function to AMY3 (CTR/RAMP3) signaling and to tumor-stromal biology, showing peptide-specific reshaping of CTR extracellular-loop signaling and a metastasis-promoting role via CAFs.

    Evidence Alanine scanning of CTR ECL2/ECL3 with cAMP and ERK readouts; RAMP3 KO mouse metastasis model with Src/Cas/PDPN signaling analysis

    PMID:31754214 PMID:32219220

    Open questions at the time
    • Direct structural basis of ECL remodeling not resolved
    • Mechanistic link between RAMP3 GPCR activity and Src/Cas/PDPN in CAFs not fully traced
  9. 2021 High

    Linked RAMP3 to organ-level stress adaptation, showing its loss impairs late cardiac compensation to pressure overload via reduced cardiac lymphatics.

    Evidence Global and cardiomyocyte-specific RAMP3 KO mice with transverse aortic constriction, echocardiography, fibrosis histology, and lymphatic vessel analysis

    PMID:33545715

    Open questions at the time
    • Temporal divergence from RAMP2 pathway mechanistically unexplained
    • Direct ligand-receptor axis in cardiac lymphatics not defined
  10. 2019 Medium

    Established RAMP3 as physiologically required for amylin's anorectic and glucose-homeostatic actions through the AMY3 receptor.

    Evidence RAMP3 global KO mice on high-fat diet with glucose tolerance tests, amylin/salmon calcitonin food-intake pharmacology, and area postrema c-Fos staining

    PMID:31881259

    Open questions at the time
    • Central versus peripheral site of action not fully resolved
    • Single lab
  11. 2024 Medium

    Generalized the Rab4-recycling chaperone mechanism to ACKR2, connecting RAMP3 to CCL2 scavenging and an anti-tumor immune/vascular phenotype.

    Evidence Co-IP, RAB4 trafficking, syngeneic HCC tumor model, CCL2 measurement, and STAT3/AKT phosphorylation assays

    PMID:39437486

    Open questions at the time
    • Direct binding interface with ACKR2 not mapped
    • Reconciliation with metastasis-promoting role in other models unresolved
  12. 2025 Medium

    Showed RAMP3 acts as a signaling-bias modulator of GLP-1R, redirecting it from Gαs/cAMP toward Gαq/Gαi and Ca2+ to enhance insulin secretion.

    Evidence BRET interaction, G protein coupling and Ca2+/cAMP assays, glucose-stimulated insulin secretion, and RAMP3 KO mouse tolerance tests (preprint)

    PMID:bio_10.1101_2025.01.24.634724

    Open questions at the time
    • Preprint, not yet peer-reviewed
    • Structural basis of biased coupling not determined
  13. 2024 Medium

    Provided a biophysical basis for AMY3 receptor behavior, showing a stronger TM interface and agonist-dependent subunit equilibrium that tunes signaling.

    Evidence Novel heterodimer-resolving biochemical assay with live-cell membrane and G protein/cAMP readouts (preprint)

    PMID:bio_10.1101_2024.10.09.617487

    Open questions at the time
    • Preprint, not yet peer-reviewed
    • In vivo relevance of the dissociation equilibrium untested

Open questions

Synthesis pass · forward-looking unresolved questions
  • How RAMP3 selects among its many GPCR partners in a given cell, and whether its recycling-chaperone versus pharmacology-modulating roles are coordinated, remains unresolved.
  • No structure of RAMP3 in complex with non-CLR partners reported in the corpus
  • Determinants of partner choice in native tissues unknown
  • Mechanism coupling RAMP3 expression regulation to its receptor functions undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0098772 molecular function regulator activity 4 GO:0060089 molecular transducer activity 3 GO:0005198 structural molecule activity 2
Localization
GO:0005886 plasma membrane 3 GO:0031410 cytoplasmic vesicle 2
Pathway
R-HSA-162582 Signal Transduction 4 R-HSA-5653656 Vesicle-mediated transport 2
Partners
ACKR2ACKR3CALCRCALCRLGLP1R
Complex memberships
CLR/RAMP3 (AM2) receptorCTR/RAMP3 (AMY3) amylin receptor

Evidence

Reading pass · 19 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2001 Seven amino acid sequences in the extracellular N-terminal domain of RAMP3 (residues 59-65) are critical for high-affinity adrenomedullin binding and AM-evoked cAMP production when co-expressed with CRLR in HEK293 cells; deletion of these residues significantly attenuated 125I-AM binding and AM-evoked cAMP production despite full cell surface expression of the receptor heterodimer. Deletion mutagenesis, 125I-AM binding assay, cAMP production assay in HEK293 cells The Journal of biological chemistry High 11591721
2003 N-glycosylation and conserved cysteine residues in RAMP3 are critical for functional expression of the CRLR/RAMP3 adrenomedullin receptor: elimination of all N-glycans significantly inhibited 125I-AM binding and increased EC50 for AM; mutation of all six cysteines to serines abolished AM binding and receptor function, indicating each cysteine participates in disulfide bond formation. Xenopus oocyte expression system, 125I-AM binding assay, site-directed mutagenesis of N-glycosylation sites and cysteines Biochemistry High 12939163
2003 CL/RAMP3 and CL/RAMP2 form pharmacologically distinct adrenomedullin receptors: AM22-52 selectively antagonizes CL/RAMP2 over CL/RAMP3 in a species-dependent manner, while CGRP8-37 shows opposite selectivity, demonstrating that RAMP identity determines antagonist pharmacology of the receptor complex. Radioligand binding and functional antagonism assays in COS7 cells (transient expression) and endogenously expressing cell lines (Rat2, L6) British journal of pharmacology High 12970090
2010 RAMP1-RAMP3 chimera analysis revealed that helix 1 and residues 62-69 in helix 2 of RAMP1 are critical for CLR trafficking (a marker of CLR association), and modeling indicates these exchanges alter the CLR recognition site; residues 86-89 at the helix 2-3 junction affect peptide potency but not CLR trafficking, suggesting a role in ligand binding pocket formation. RAMP1/RAMP3 chimera expression in cells, CLR trafficking assay, agonist potency assay, molecular modeling Biochemistry Medium 20017504
2011 Glu74 of RAMP3 contributes to AM binding and potency at the CLR/RAMP3 (AM2) receptor; substitution with Phe reduced AM potency, while Trp, Tyr, Ala, Ser, Thr, Arg, and Asn substitutions had mostly small effects, indicating the geometry and charge at position 74 contribute to AM interaction specificity. Site-directed mutagenesis of RAMP3, co-expression with CLR in COS7 cells, cAMP assay, cell surface ELISA Peptides Medium 21402116
2004 CRLR/RAMP2 and CRLR/RAMP3 receptors mediate adrenomedullin-induced HUVEC migration, invasion, and differentiation into cord-like structures on Matrigel; blocking these receptors inhibited AM-promoted angiogenic effects on endothelial cells in vitro. Migration/invasion assays with receptor-blocking approaches in HUVECs, Matrigel tube formation assay International journal of cancer Medium 14712479
2019 RAMP3 associates with atypical chemokine receptor 3 (ACKR3) and is required for rapid recycling of ACKR3 to the plasma membrane through Rab4-positive vesicles following AM or SDF-1/CXCL12 binding, without changing G-protein coupling; this recycling enables formation of dynamic spatiotemporal chemotactic gradients, and genetic deletion of RAMP3 in mice abolishes directed cell migration during retinal angiogenesis. BRET-based interaction assay, cell-surface expression assay, Rab4-vesicle trafficking analysis, RAMP3 knockout mouse retinal angiogenesis model Proceedings of the National Academy of Sciences of the United States of America High 31712427
2014 RAMP3 knockout mice develop normally without major vascular abnormalities, but display delayed drainage of subcutaneous lymphatic vessels (shown by ICG lymphangiography), delayed intestinal chyle transport, more severe interstitial edema in a tail lymphedema model, and impaired migration of isolated lymphatic endothelial cells in scratch-wound assays; AM administration failed to rescue re-endothelialization in RAMP3-/- cells. RAMP3 knockout mouse generation, ICG lymphangiography, tail lymphedema model, scratch-wound assay with isolated lymphatic endothelial cells Journal of molecular and cellular cardiology High 25264174
2021 In a pressure-overload (TAC) model, RAMP3 knockout mice show reduced systolic function and enhanced fibrosis appearing after 4 weeks (later than RAMP2-deficient mice), with a characteristic reduction in cardiac lymphatic vessels, indicating the AM-RAMP3 system is required for later cardiac adaptation to stress through regulation of lymphatic vessels. Cardiomyocyte-specific and global RAMP3 knockout mice subjected to transverse aortic constriction, echocardiography, histological fibrosis assessment, cardiac lymphatic vessel analysis Endocrinology High 33545715
2019 RAMP3 deficiency in mice suppresses tumor metastasis by reducing podoplanin (PDPN)-positive cancer-associated fibroblasts (CAFs) at metastatic sites; RAMP3 was shown to mediate Src/Cas/PDPN signaling, and RAMP3-deficient CAFs displayed suppressed migration, proliferation, and metastasis in co-culture with tumor cells. RAMP3 knockout mice with splenic injection pancreatic cancer model, immunostaining for PDPN+ CAFs, in vitro co-culture assays, signaling pathway analysis (Src/Cas/PDPN) Oncogene Medium 31754214
2005 PTH induces RAMP3 mRNA expression as a primary response gene in primary mouse osteoblasts primarily through the cAMP-PKA signaling pathway; this was demonstrated by showing that cycloheximide does not block PTH-induced RAMP3 expression (primary response), forskolin mimics the effect, and the PKA inhibitor H89 blocks both PTH- and forskolin-induced RAMP3 upregulation. RT-PCR in primary mouse osteoblasts, pharmacological dissection with PKA inhibitor (H89), PKC activator (PMA), calcium ionophore (ionomycin), and protein synthesis inhibitor (cycloheximide) Calcified tissue international Medium 16075364
2015 RAMP3 associates with CALCRL (CRLR) in vascular smooth muscle cells to mediate ADM-induced cAMP production; knockdown of RAMP3 (but not RAMP2) inhibited ADM-induced cAMP production, and proximity ligation assay showed ADM increases CALCRL-RAMP3 association; RAMP3 knockdown inhibited ADM interaction with CALCRL. siRNA knockdown of RAMP2 or RAMP3 in mesenteric artery VSMCs, cAMP assay, proximity ligation assay Biology of reproduction Medium 26423127
2019 In AMY3 receptors (CTR/RAMP3 heterodimers), RAMP3 fundamentally alters the dynamic role of CTR extracellular loops 2 and 3 in signal propagation compared to CTR alone; alanine scanning mutagenesis of ECL2 and ECL3 showed distinct peptide-specific effects on cAMP accumulation and ERK phosphorylation, demonstrating RAMP3 changes the signaling landscape of CTR in a peptide-dependent manner. Alanine scanning mutagenesis of CTR ECL2 and ECL3 in the context of RAMP3 co-expression, cAMP accumulation assay, ERK phosphorylation assay ACS pharmacology & translational science Medium 32219220
2009 RAMP3 is an early transcriptional target gene of the canonical Wnt pathway; stimulation of C57MG cells with Wnt-3a induced RAMP3 mRNA expression between 1 and 6 hours post-stimulation. Wnt-3a stimulation of C57MG cells, temporal mRNA expression analysis Cell biology international Low 19353769
2019 RAMP3 knockout mice on high-fat diet show glucose intolerance and altered amylin anorectic responses; RAMP3 KO mice respond to salmon calcitonin (CTR agonist) but not amylin for food intake suppression, establishing RAMP3 as necessary for amylin's anorectic effect and glucose homeostasis mediated through the CTR/RAMP3 (AMY3) receptor. RAMP3 global KO mice, high-fat diet feeding, glucose tolerance tests, food intake pharmacology with amylin and salmon calcitonin, c-Fos immunostaining in area postrema Neuroscience Medium 31881259
2018 RAMP3 deficiency in ovariectomized (postmenopausal) mice exacerbates obesity, adipose tissue weight gain, insulin resistance, and hepatic steatosis; GPR30 (membrane estrogen receptor) expression was downregulated in periuterine WAT from RAMP3-/- OVX mice, suggesting a GPR30-RAMP3 interaction in metabolic regulation. RAMP3 KO mice subjected to ovariectomy plus high-fat diet, metabolic phenotyping, adipose gene expression analysis Peptides Low 30385288
2024 RAMP3 binds to atypical chemokine receptor 2 (ACKR2) in HCC tumor cells and promotes membrane distribution of ACKR2 through RAB4-positive vesicles, thereby facilitating CCL2 scavenging by ACKR2 and inhibiting STAT3 and AKT phosphorylation; RAMP3 also suppressed CD11b+/Gr-1+ myeloid cell infiltration and neovascularization in tumors through ACKR2. Co-IP/protein-protein interaction assays in HCC cell lines (Huh7, HepG2, Hepa1-6), RAB4 vesicle trafficking assay, syngeneic mouse tumor model, CCL2 measurement, STAT3/AKT phosphorylation assay International immunopharmacology Medium 39437486
2025 RAMP3 interacts with GLP-1R and biases its signaling toward Ca2+ mobilization away from canonical cAMP-driven signaling; RAMP3 reduces Gαs activation but increases secondary coupling to Gαq and Gαi, leading to enhanced glucose-stimulated insulin secretion in cells overexpressing RAMP3; RAMP3 KO mice show reduced sensitivity to GLP-1 in glucose and insulin tolerance tests. BRET interaction assay, G protein coupling assays, Ca2+ mobilization assay, cAMP assay, glucose-stimulated insulin secretion in cells, RAMP3 KO mouse glucose/insulin tolerance tests bioRxivpreprint Medium bio_10.1101_2025.01.24.634724
2024 The AMY3R (CTR/RAMP3) has a stronger transmembrane domain interface than AMY1R/AMY2R, yielding a more stable heterodimer; human and salmon calcitonin agonists promote AMY3R dissociation whereas amylin promotes AMY1/2R subunit association; these distinct subunit equilibriums modulated by agonists determine cAMP signaling output. Novel biochemical assay resolving AMYR heterodimers and free subunits, live cell membrane assays, G protein coupling assays, cAMP signaling assays bioRxivpreprint Medium bio_10.1101_2024.10.09.617487

Source papers

Stage 0 corpus · 24 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2003 CL/RAMP2 and CL/RAMP3 produce pharmacologically distinct adrenomedullin receptors: a comparison of effects of adrenomedullin22-52, CGRP8-37 and BIBN4096BS. British journal of pharmacology 117 12970090
2004 Effects of adrenomedullin on endothelial cells in the multistep process of angiogenesis: involvement of CRLR/RAMP2 and CRLR/RAMP3 receptors. International journal of cancer 111 14712479
2002 Increased myocardial expression of RAMP1 and RAMP3 in rats with chronic heart failure. Biochemical and biophysical research communications 55 12051717
2001 The seven amino acids of human RAMP2 (86) and RAMP3 (59) are critical for agonist binding to human adrenomedullin receptors. The Journal of biological chemistry 53 11591721
2009 Chronological expression of Wnt target genes Ccnd1, Myc, Cdkn1a, Tfrc, Plf1 and Ramp3. Cell biology international 46 19353769
2019 RAMP3 determines rapid recycling of atypical chemokine receptor-3 for guided angiogenesis. Proceedings of the National Academy of Sciences of the United States of America 44 31712427
2003 Changes in the expression of calcitonin receptor-like receptor, receptor activity-modifying protein (RAMP) 1, RAMP2, and RAMP3 in rat uterus during pregnancy, labor, and by steroid hormone treatments. Biology of reproduction 41 12801991
2019 RAMP1 and RAMP3 Differentially Control Amylin's Effects on Food Intake, Glucose and Energy Balance in Male and Female Mice. Neuroscience 36 31881259
2014 Functional differentiation of RAMP2 and RAMP3 in their regulation of the vascular system. Journal of molecular and cellular cardiology 34 25264174
2003 N-Glycosylation and conserved cysteine residues in RAMP3 play a critical role for the functional expression of CRLR/RAMP3 adrenomedullin receptor. Biochemistry 23 12939163
2019 Deficiency of the adrenomedullin-RAMP3 system suppresses metastasis through the modification of cancer-associated fibroblasts. Oncogene 22 31754214
2011 Structure-function analysis of amino acid 74 of human RAMP1 and RAMP3 and its role in peptide interactions with adrenomedullin and calcitonin gene-related peptide receptors. Peptides 22 21402116
2005 Parathyroid hormone induces receptor activity modifying protein-3 (RAMP3) expression primarily via 3',5'-cyclic adenosine monophosphate signaling in osteoblasts. Calcified tissue international 19 16075364
2004 RAMP2 and RAMP3 mRNA levels are increased in failing rat cardiomyocytes and associated with increased responsiveness to adrenomedullin. Journal of molecular and cellular cardiology 19 15623431
2019 Deconvoluting the Molecular Control of Binding and Signaling at the Amylin 3 Receptor: RAMP3 Alters Signal Propagation through Extracellular Loops of the Calcitonin Receptor. ACS pharmacology & translational science 11 32219220
2018 RAMP3 deficiency enhances postmenopausal obesity and metabolic disorders. Peptides 10 30385288
2021 Adrenomedullin-RAMP2 and -RAMP3 Systems Regulate Cardiac Homeostasis during Cardiovascular Stress. Endocrinology 9 33545715
2015 Involvement of Receptor Activity-Modifying Protein 3 (RAMP3) in the Vascular Actions of Adrenomedullin in Rat Mesenteric Artery Smooth Muscle Cells. Biology of reproduction 8 26423127
2010 Structure-function analysis of RAMP1-RAMP3 chimeras. Biochemistry 6 20017504
2005 Induction of BAALC and down regulation of RAMP3 in astrocytes treated with differentiation inducers. Cell biology international 6 16376586
2019 Analysis of RAMP3 gene polymorphism with body composition and bone density in young and elderly women. Gene: X 5 32550545
2021 Adrenomedullin 2 and 5 activate the calcitonin receptor-like receptor (clr) - Receptor activity-modifying protein 3 (ramp3) receptor complex in Xenopus tropicalis. General and comparative endocrinology 3 33711314
2019 Analysis of RAMP3 gene polymorphism with body composition and bone density in young and elderly women. Gene 2 34530989
2024 -RAMP3 promotes hepatocellular carcinoma tumor cell-mediated CCL2 degradation by supporting membrane distribution of ACKR2. International immunopharmacology 1 39437486

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