Ryanodine receptor 3 (RyR3) (encoded by the [RYR3 gene](/genes/ryr3)) is an intracellular calcium release channel expressed in brain, smooth muscle, and diaphragm. In the nervous system, RyR3 is enriched in the [hippocampus](/brain-regions/hippocampus) and [striatum](/brain-regions/striatum), where it modulates calcium-dependent synaptic plasticity and learning.
Overview
RyR3 is the third isoform of the ryanodine receptor family, forming a homotetrameric ER calcium release channel of similar size to [RyR1](/proteins/ryr1-protein) and [RyR2](/proteins/ryr2-protein)<sup>[1]</sup>. Each subunit is 4,872 amino acids. RyR3 has the most restricted tissue distribution of the three RyR isoforms but is notably enriched in specific brain regions, particularly the [hippocampus](/brain-regions/hippocampus) CA1 region, [striatum](/brain-regions/striatum), and [thalamus](/brain-regions/thalamus)<sup>[2]</sup>. RyR3 knockout mice show enhanced hippocampal [LTP](/mechanisms/long-term-potentiation) and impaired spatial learning, suggesting RyR3 normally provides a brake on calcium signaling that refines plasticity. [@bhatt2014]
Ryanodine receptor 3 (RyR3) (encoded by the [RYR3 gene](/genes/ryr3)) is an intracellular calcium release channel expressed in brain, smooth muscle, and diaphragm. In the nervous system, RyR3 is enriched in the [hippocampus](/brain-regions/hippocampus) and [striatum](/brain-regions/striatum), where it modulates calcium-dependent synaptic plasticity and learning.
Overview
RyR3 is the third isoform of the ryanodine receptor family, forming a homotetrameric ER calcium release channel of similar size to [RyR1](/proteins/ryr1-protein) and [RyR2](/proteins/ryr2-protein)<sup>[1]</sup>. Each subunit is 4,872 amino acids. RyR3 has the most restricted tissue distribution of the three RyR isoforms but is notably enriched in specific brain regions, particularly the [hippocampus](/brain-regions/hippocampus) CA1 region, [striatum](/brain-regions/striatum), and [thalamus](/brain-regions/thalamus)<sup>[2]</sup>. RyR3 knockout mice show enhanced hippocampal [LTP](/mechanisms/long-term-potentiation) and impaired spatial learning, suggesting RyR3 normally provides a brake on calcium signaling that refines plasticity. [@bhatt2014]
Functional brake: RyR3 may dampen excessive ER Ca²⁺ release, preventing calcium overload
Role in Neurodegeneration
Synaptic Plasticity and Memory
RyR3 dysregulation affects processes impaired in neurodegenerative diseases<sup>[3]</sup>:
Spatial memory: RyR3 KO mice have impaired Morris water maze performance
Social memory: Deficits in social recognition memory in RyR3 KO
Fear conditioning: Altered amygdala-dependent learning
LTP refinement: Loss of RyR3 causes exaggerated LTP → impaired learning (too much plasticity is as bad as too little)
Disease Connections
[Alzheimer's disease](/diseases/alzheimers-disease): RyR3 expression altered in AD hippocampus; calcium dysregulation contributes to synaptic failure<sup>[4]</sup>
[Huntington's disease](/diseases/huntington-disease): RyR3 is enriched in striatal medium spiny neurons that degenerate in HD; mutant [huntingtin](/proteins/huntingtin) sensitizes RyR channels
Aging: RyR3 expression declines with aging in hippocampus, potentially contributing to age-related memory decline
Protein Interactions
| Interactor | Type | Function | |-----------|------|----------| | FKBP12 | Stabilizer | Calstabin-1; stabilizes closed channel state | | Calmodulin | Modulator | Calcium-dependent regulation | | [RyR1](/proteins/ryr1-protein) | Hetero-oligomer | May form heteromeric channels in brain | | [RyR2](/proteins/ryr2-protein) | Co-expressed | Complementary ER calcium release in hippocampus |
See Also
[RYR3 Gene](/genes/ryr3)
[RyR1 Protein](/proteins/ryr1-protein)
[RyR2 Protein](/proteins/ryr2-protein)
[Calcium Dysregulation in Neurodegeneration](/mechanisms/calcium-dysregulation-neurodegeneration)