JPH3
Identifiers
Aliases	JPH3, CAGL237, HDL2, JP-3, JP3, TNRC22, junctophilin 3
External IDs	OMIM: 605268 MGI: 1891497 HomoloGene: 10762 GeneCards: JPH3
Gene location (Human) Chr. Chromosome 16 (human)[1] Band 16q24.2 Start 87,601,835 bp[1] End 87,698,156 bp[1]
Gene location (Mouse) Chr. Chromosome 8 (mouse)[2] Band 8|8 E1 Start 122,456,362 bp[2] End 122,521,015 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in postcentral gyrus sural nerve entorhinal cortex superior frontal gyrus nucleus accumbens amygdala dorsolateral prefrontal cortex prefrontal cortex hippocampus proper caudate nucleus Top expressed in entorhinal cortex dentate gyrus cingulate gyrus superior frontal gyrus primary motor cortex Region I of hippocampus proper superior colliculus olfactory tubercle subiculum prefrontal cortex More reference expression data BioGPS More reference expression data
Gene ontology Molecular function calcium-release channel activity molecular function Cellular component plasma membrane endoplasmic reticulum endoplasmic reticulum membrane membrane junctional sarcoplasmic reticulum membrane junctional membrane complex integral component of membrane Biological process regulation of neuronal synaptic plasticity release of sequestered calcium ion into cytosol calcium ion transport into cytosol memory learning exploration behavior locomotion neuromuscular process controlling balance regulation of ryanodine-sensitive calcium-release channel activity regulation of synaptic plasticity Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 57338 57340 Ensembl ENSG00000154118 ENSMUSG00000025318 UniProt Q8WXH2 Q9ET77 RefSeq (mRNA) NM_001271604 NM_001271605 NM_020655 NM_020605 RefSeq (protein) NP_001258533 NP_001258534 NP_065706 NP_065630 Location (UCSC) Chr 16: 87.6 – 87.7 Mb Chr 8: 122.46 – 122.52 Mb PubMed search [3] [4]
Wikidata
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Junctophilin-3 is a protein in humans that is encoded by the JPH3 gene. The gene is approximately 97 kilobases long and is located at position 16q24.2. Junctophilin proteins are associated with the formation of junctional membrane complexes, linking the plasma membrane with the endoplasmic reticulum in excitable cells.^[5] Junctophilin-3 is specific to the brain and has an active role in neurons involved in motor coordination and memory.^[6]

The protein contains 748 amino acid residues and is composed of a C-terminal hydrophobic segment that spans the endoplasmic/sarcoplasmic reticulum membrane, and a cytoplasmic domain that shows specific affinity for the plasma membrane. The protein contains several MORN (membrane occupation and recognition nexus) repeats that contribute to plasma membrane binding through interactions with phospholipids.

Junctophilin-3 is primarily expressed in the brain, specifically in the dorsolateral prefrontal cortex. Although the precise function of the protein has not been determined, it has been shown to play a role in motor coordination and memory through efficient calcium ion signaling^[7] and the stabilization of neuronal cellular architecture.^[8]

The JPH3 gene contains a CAG/CTG trinucleotide repeat segment. This segment's expansion is associated with several polyglutamine diseases (polyQ), which include spinocerebellar ataxia, Huntington's disease, and Huntington's disease-like 2 (HDL2). The pathological expansion of the CAG repeat region leads to an expanded polyglutamine tract,^[9] which can aggregate in neurons, leading to the degeneration of specific neuronal subpopulations.^[10]