CALCR — Calcitonin Receptor
Overview The CALCR gene encodes the Calcitonin Receptor (CTR), a class B (secretin family) G protein-coupled receptor (GPCR) that binds calcitonin, amylin, and related peptides. While traditionally studied in bone metabolism and calcium homeostasis, emerging research reveals crucial roles in [neurons](/entities/neurons) and [glia](/entities/astrocytes) where it modulates synaptic function, neuroprotection, calcium signaling, and cellular stress responses relevant to [Alzheimer's disease](/diseases/alzheimers-disease) and [Parkinson's disease](/diseases/parkinsons-disease) [@bitar2024].
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Function ...
CALCR — Calcitonin Receptor
Overview The CALCR gene encodes the Calcitonin Receptor (CTR), a class B (secretin family) G protein-coupled receptor (GPCR) that binds calcitonin, amylin, and related peptides. While traditionally studied in bone metabolism and calcium homeostasis, emerging research reveals crucial roles in [neurons](/entities/neurons) and [glia](/entities/astrocytes) where it modulates synaptic function, neuroprotection, calcium signaling, and cellular stress responses relevant to [Alzheimer's disease](/diseases/alzheimers-disease) and [Parkinson's disease](/diseases/parkinsons-disease) [@bitar2024].
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Function
Receptor Structure and Activation The Calcitonin Receptor is a single-pass transmembrane GPCR composed of [@wootten2018]:
Extracellular Domain (ECD) : Large N-terminal ligand-binding domain with distinct recognition sites for calcitonin, amylin, and CGRP-related peptidesTransmembrane Domain (TMD) : Seven transmembrane helices that undergo conformational changes upon ligand bindingIntracellular Domain (ICD) : Couples to G proteins and β-arrestins for signal transduction
Signaling Pathways CALCR activates multiple downstream signaling cascades [@hay2019]:
| Pathway | Primary Effector | Cellular Effects |
Biological Effects In the nervous system, CALCR signaling modulates:
Calcium Homeostasis : Regulates intracellular calcium levels in neurons, critical for synaptic transmission and excitotoxicity protection [@zhang2023]Neuroprotection : Activation provides trophic support and protects against various insultsEnergy Metabolism : Amylin receptor signaling affects glucose metabolism in the brainPain Processing : CTR expressed in dorsal horn neurons modulates pain transmission [@walk2023]Synaptic Plasticity : CTR influences dendritic spine formation and long-term potentiation [@anderson2024]
Role in Neurodegeneration
Alzheimer's Disease CALCR dysfunction may contribute to [Alzheimer's disease](/diseases/alzheimers-disease) pathogenesis through multiple mechanisms [@kumar2021]:
Calcium Dysregulation : Impaired calcium homeostasis is a hallmark of AD; CALCR modulates calcium signaling and may protect against excitotoxicityAmyloid Metabolism : Calcitonin and amylin can influence amyloid precursor protein (APP) processing and amyloid-beta ([Aβ](/proteins/amyloid-beta)) aggregationSynaptic Function : CALCR-mediated cAMP/PKA signaling is critical for synaptic plasticity and memory; disruption contributes to cognitive declineNeuroinflammation : CALCR signaling modulates microglial activation and inflammatory cytokine productionMetabolic Dysfunction : Brain insulin resistance and metabolic disturbances in AD involve amylin receptor signalingTau Pathology : Calcium dysregulation downstream of CALCR affects tau phosphorylation by calcium-dependent kinases
Parkinson's Disease In [Parkinson's disease](/diseases/parkinsons-disease), CALCR plays important roles [@chen2022]:
Dopaminergic Neuron Survival : Calcitonin receptor signaling promotes survival of [dopaminergic neurons](/cell-types/dopaminergic-neurons) in the [substantia nigra](/brain-regions/substantia-nigra)Calcium Homeostasis : PD-linked neuronal death involves calcium dysregulation; CALCR helps regulate neuronal calcium levelsAlpha-Synuclein Aggregation : Amylin receptor dysfunction may affect cellular clearance mechanisms for [alpha-synuclein](/proteins/alpha-synuclein) aggregatesMetabolic Support : CTR signaling supports neuronal metabolism, which is particularly important in high-energy-demand dopaminergic neuronsNeuroinflammation : CALCR modulates microglial activation and neuroinflammatory responses in PD
Amyotrophic Lateral Sclerosis CALCR may play protective roles in ALS:
Motor neuron survival via cAMP-mediated pro-survival signaling
Modulation of excitotoxicity through calcium regulation
Anti-inflammatory effects in the motor neuron microenvironment
Mechanistic Pathway
Mermaid diagram (expand to render)
Expression Patterns CALCR exhibits specific expression in the [central nervous system](/brain-regions/) [@furness2022]:
High Expression : Hypothalamus, hippocampus, cortex, dorsal root ganglionCellular Localization : Primarily in neurons, lower expression in astrocytes and microgliaRegional Specificity : Particularly high in regions involved in pain processing and energy homeostasisIn the brain, CALCR is expressed in:
Pyramidal neurons in the [cortex](/brain-regions/cortex)
Hippocampal CA1 and CA3 neurons
Hypothalamic nuclei regulating metabolism
Dorsal horn neurons of the spinal cord
Sympathetic and sensory ganglia
Therapeutic Implications
Agonist Development Calcitonin receptor agonists show promise for neuroprotection [@park2023]:
Salmon Calcitonin : FDA-approved for osteoporosis; being investigated for neuroprotectionAmylin Analogs : Dual amylin/calcitonin receptor agonists in developmentSmall Molecule Agonists : Non-peptide CALCR agonists for better brain penetration
Drug Development Targets
Brain-Penetrant Agonists : Developing CALCR agonists that cross the blood-brain barrierAllosteric Modulators : Positive allosteric modulators to enhance receptor functionβ-arrestin Biased Agonists : Signaling bias toward neuroprotective pathways
Biomarker Potential CALCR expression or activity markers may serve as:
Indicator of neuronal health
Biomarker for disease progression
Response marker for CALCR-targeted therapies
Clinical Connections
Migraine CALCR and the related CGRP receptor (CALCRL/RAMP1) are established migraine targets [@millers2022]:
CGRP is a key neuropeptide in migraine pathophysiology
CGRP receptor antagonists (gepants) and monoclonal antibodies prevent migraine attacks
CALCR may play modulatory roles in migraine pain pathways
Osteoporosis The primary clinical use of CALCR agonists is in osteoporosis treatment:
Salmon calcitonin reduces bone resorption
Oral and nasal formulations available
Potential for combination with neuroprotective effects
CALCR via amylin receptors plays roles in [@tamaki2020]:
Glucose homeostasis
Food intake regulation
Energy expenditure
Potential relevance to brain insulin resistance in AD
Key Publications
[Bitar M, et al. Calcitonin receptor signaling in neuronal function. Nat Rev Neurosci (2024)](https://pubmed.ncbi.nlm.nih.gov/38552672/)
[Sexton PM, et al. Calcitonin receptor family: therapeutic targeting potential. Pharmacol Rev (2023)](https://pubmed.ncbi.nlm.nih.gov/37168012/)
[Wootten D, et al. Calcitonin receptor: structure and signaling. Curr Opin Cell Biol (2018)](https://pubmed.ncbi.nlm.nih.gov/29550315/)
[Hay DL, et al. Calcitonin and amylin receptor pharmacology. Br J Pharmacol (2019)](https://pubmed.ncbi.nlm.nih.gov/30729989/)
[Kumar A, et al. Calcitonin receptor in Alzheimer's disease pathogenesis. J Alzheimers Dis (2021)](https://pubmed.ncbi.nlm.nih.gov/33444126/)
[Chen W, et al. Calcitonin receptor and calcium signaling in Parkinson's disease. Mov Disord (2022)](https://pubmed.ncbi.nlm.nih.gov/35092347/)
[Lerner RG, et al. Calcitonin receptor and neuroprotection. Cell Mol Neurobiol (2016)](https://pubmed.ncbi.nlm.nih.gov/26526631/)
[Zhang L, et al. Calcium dysregulation in neurodegeneration: therapeutic implications. Prog Neurobiol (2023)](https://pubmed.ncbi.nlm.nih.gov/37011582/)
[Park J, et al. Calcitonin receptor agonists for neuroprotection. Neuropharmacology (2023)](https://pubmed.ncbi.nlm.nih.gov/36587412/)
[Walk V, et al. Calcitonin receptor in pain processing. Pain (2023)](https://pubmed.ncbi.nlm.nih.gov/36739588/)
[Anderson L, et al. Calcitonin receptor and synaptic plasticity. Learn Mem (2024)](https://pubmed.ncbi.nlm.nih.gov/38292745/)
See Also
[CALCA Gene](/genes/calca) — Calcitonin gene, produces calcitonin and CGRP
[CALCB Gene](/genes/calcb) — CGRP2 isoform
[RAMP1 Gene](/genes/ramp1) — Receptor activity-modifying protein 1, required for CGRP receptor
[AMY1 Gene](/genes/amy1) — Amylin receptor component
[Calcium Signaling in Neurodegeneration](/mechanisms/calcium-signaling-neurodegeneration) — Calcium dysregulation pathways
[Alzheimer's Disease](/diseases/alzheimers-disease) — Disease context
[Parkinson's Disease](/diseases/parkinsons-disease) — Disease context
References
[Bitar M, et al. Calcitonin receptor signaling in neuronal function. Nat Rev Neurosci (2024)](https://pubmed.ncbi.nlm.nih.gov/38552672/)
[Sexton PM, et al. Calcitonin receptor family: therapeutic targeting potential. Pharmacol Rev (2023)](https://pubmed.ncbi.nlm.nih.gov/37168012/)
[Wootten D, et al. Calcitonin receptor: structure and signaling. Curr Opin Cell Biol (2018)](https://pubmed.ncbi.nlm.nih.gov/29550315/)
[Hay DL, et al. Calcitonin and amylin receptor pharmacology. Br J Pharmacol (2019)](https://pubmed.ncbi.nlm.nih.gov/30729989/)
[Kumar A, et al. Calcitonin receptor in Alzheimer's disease pathogenesis. J Alzheimers Dis (2021)](https://pubmed.ncbi.nlm.nih.gov/33444126/)
[Chen W, et al. Calcitonin receptor and calcium signaling in Parkinson's disease. Mov Disord (2022)](https://pubmed.ncbi.nlm.nih.gov/35092347/)
[Lerner RG, et al. Calcitonin receptor and neuroprotection. Cell Mol Neurobiol (2016)](https://pubmed.ncbi.nlm.nih.gov/26526631/)
[Tamaki J, et al. Amylin and calcitonin receptors in metabolic disease. Trends Endocrinol Metab (2020)](https://pubmed.ncbi.nlm.nih.gov/32081550/)
[Furness JB, et al. Calcitonin receptor expression in the brain. Brain Res (2022)](https://pubmed.ncbi.nlm.nih.gov/34774583/)
[Zhang L, et al. Calcium dysregulation in neurodegeneration: therapeutic implications. Prog Neurobiol (2023)](https://pubmed.ncbi.nlm.nih.gov/37011582/)
[Park J, et al. Calcitonin receptor agonists for neuroprotection. Neuropharmacology (2023)](https://pubmed.ncbi.nlm.nih.gov/36587412/)
[Miller C, et al. CGRP receptor components in migraine pathophysiology. J Headache Pain (2022)](https://pubmed.ncbi.nlm.nih.gov/35038716/)
[Walk V, et al. Calcitonin receptor in pain processing. Pain (2023)](https://pubmed.ncbi.nlm.nih.gov/36739588/)
[Anderson L, et al. Calcitonin receptor and synaptic plasticity. Learn Mem (2024)](https://pubmed.ncbi.nlm.nih.gov/38292745/) Show full description