Affinage

UNC80

Protein unc-80 homolog · UniProt Q8N2C7

Length
3258 aa
Mass
363.4 kDa
Annotated
2026-04-28
21 papers in source corpus 11 papers cited in narrative 11 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

UNC80 is an essential auxiliary subunit of the NALCN sodium-leak channel complex that scaffolds signaling components and controls channel trafficking, activity, and neuronal excitability. UNC80 forms a large piler-shaped heterodimer with UNC79 that tethers to NALCN's intracellular loops via tripartite interactions: two contacts are required for NALCN cell-surface localization, and a third relieves NALCN autoinhibition by displacing the C-terminal Interacting Helix, thereby activating Na⁺-leak current (PMID:35550517, PMID:32620897). UNC80 also recruits Src family kinases to enable G-protein-independent activation of NALCN by neuropeptides such as substance P, and its C-terminal domain directs dendritic localization of the channel complex to regulate local membrane potential (PMID:19092807, PMID:19535918, PMID:32620897). Loss-of-function mutations in human UNC80 cause a syndrome of hypotonia, severe intellectual disability, and dyskinesia, and Unc80-knockout mice are neonatal lethal (PMID:26545877, PMID:26708751, PMID:32620897).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2007 High

    Identification of UNC-80 as a novel conserved neuronal protein required for proper axonal localization of NCA/NALCN channels established it as a channel-associated factor rather than a generic neuronal protein.

    Evidence C. elegans suppressor screen, genetic epistasis with synaptojanin, and immunolocalization of NCA-1/NCA-2

    PMID:17825559

    Open questions at the time
    • Biochemical interaction with NCA channels not yet demonstrated
    • Mechanism of localization control unknown
    • Mammalian relevance unconfirmed
  2. 2008 High

    Demonstration that UNC-80 is required for substance P- and neurotensin-induced NALCN activation via a G-protein-independent, Src-kinase-dependent pathway established UNC80 as a signaling scaffold within the channel complex, not merely a trafficking factor.

    Evidence Electrophysiology in hippocampal and VTA neurons with pharmacological dissection of G-protein versus Src kinase pathways; C. elegans calcium imaging and localization

    PMID:18336069 PMID:19092807

    Open questions at the time
    • Direct physical interaction between UNC80 and Src not yet shown
    • Structural basis of scaffold function unknown
  3. 2009 Medium

    Biochemical evidence that UNC80 directly binds Src kinases and recruits them into the NALCN complex confirmed the scaffold model for G-protein-independent neuropeptide signaling.

    Evidence Co-immunoprecipitation and pulldown assays

    PMID:19535918

    Open questions at the time
    • Single Co-IP/pulldown from one lab without reciprocal validation in native tissue
    • Binding domain on UNC80 not mapped
    • Stoichiometry of Src within the complex unknown
  4. 2010 High

    Establishing that UNC80 bridges NALCN to UNC79 within the same complex and that this trimeric assembly is required for Ca²⁺-sensing-dependent Na⁺-leak current activation defined UNC80 as a central organizer coupling diverse extracellular signals to NALCN gating.

    Evidence Electrophysiology in cultured hippocampal neurons from nalcn and unc79 knockout mice with pharmacological G-protein manipulation

    PMID:21040849

    Open questions at the time
    • Structural basis of UNC79–UNC80 interaction unknown
    • How UNC80 couples to Ca²⁺-sensing GPCR signaling mechanistically unclear
  5. 2013 High

    Reciprocal co-IP in Drosophila brain confirmed conserved complex formation and revealed that loss of UNC80 causes post-transcriptional degradation of all three subunits, indicating UNC80 stabilizes the complex beyond merely trafficking the channel.

    Evidence Immunoprecipitation from Drosophila brain, tissue-specific RNAi/rescue, western blotting

    PMID:24223770

    Open questions at the time
    • Degradation pathway of unassembled subunits not identified
    • Functional roles of UNC80 and UNC79 in circadian neurons beyond expression not defined
  6. 2015 High

    Human genetic studies linked UNC80 loss-of-function and missense mutations to a neurodevelopmental syndrome and directly demonstrated that patient-derived mutations abolish NALCN currents, confirming UNC80's essential role in human NALCN channel function.

    Evidence Whole-exome sequencing with Sanger validation (p.R51*); patch-clamp electrophysiology of p.Pro1700Ser in HEK293T cells

    PMID:26545877 PMID:26708751

    Open questions at the time
    • No channel recordings from patient-derived neurons
    • Genotype–phenotype correlation across mutation spectrum incomplete
  7. 2020 High

    Domain-dissection studies revealed that UNC80's C-terminus mediates UNC79 interaction and contains a dendritic targeting signal separable from its channel-activating function, establishing that UNC80 independently regulates subcellular distribution of the NALCN complex.

    Evidence Co-IP, electrophysiology, live imaging in neurons, UNC80 knockout mice (neonatal lethal), domain deletion with patient mutations

    PMID:32620897

    Open questions at the time
    • Molecular identity of dendritic targeting signal not mapped to residues
    • How dendritic versus somatic NALCN pools differentially affect excitability not quantified
  8. 2022 High

    The cryo-EM structure of the quaternary NALCN–FAM155A–UNC79–UNC80 complex resolved how UNC79–UNC80 form a piler-shaped heterodimer anchored to NALCN via three intracellular-loop contacts, two promoting surface expression and one relieving autoinhibition by displacing the CIH, providing a complete structural mechanism for UNC80-dependent channel activation.

    Evidence Cryo-EM structure determination with mutagenesis-based functional validation of localization and channel activity

    PMID:35550517

    Open questions at the time
    • Conformational changes during channel gating not captured
    • How Src kinase docks onto the structurally resolved complex remains unmodeled
    • Structure determined in detergent — lipid bilayer context missing
  9. 2024 Medium

    Discovery that Unc80 mRNA undergoes brain-specific ADAR2-dependent A-to-I RNA editing that modulates basal neuronal activity and glutamate levels in olfactory circuits introduced post-transcriptional regulation of UNC80 as a mechanism tuning channel complex function.

    Evidence CRISPR knock-in mouse models (gain- and loss-of-editing), neuronal activity measurements, glutamate quantification, behavioral assays

    PMID:38892173

    Open questions at the time
    • Edited residue's effect on UNC80 protein structure/function not determined
    • Single lab study awaiting independent replication
    • Whether editing alters NALCN current directly not tested electrophysiologically

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include how Src kinase docks onto the structurally resolved NALCN–UNC80 complex, the identity of the dendritic targeting motif at residue-level resolution, and whether RNA editing of UNC80 directly modulates NALCN channel biophysics.
  • Src binding site on UNC80 not structurally mapped
  • Dendritic targeting signal not mapped to specific residues
  • Functional consequence of RNA editing on NALCN currents not tested electrophysiologically

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 4 GO:0098772 molecular function regulator activity 3
Localization
GO:0005886 plasma membrane 4 GO:0005829 cytosol 2
Pathway
R-HSA-112316 Neuronal System 4 R-HSA-382551 Transport of small molecules 4 R-HSA-162582 Signal Transduction 3
Partners
FAM155ANALCNSRCUNC79
Complex memberships
NALCN–FAM155A–UNC79–UNC80 channel complex

Evidence

Reading pass · 11 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2008 UNC-80 (C. elegans ortholog) is required for proper localization of NCA-1 and NCA-2 ion channel subunits along axons at non-synaptic regions, and is itself enriched at non-synaptic regions; loss of UNC-80 reduces synaptic calcium transients and neuromuscular junction transmission C. elegans genetics (loss-of-function mutants), in vivo calcium imaging, immunolocalization PLoS biology High 18336069
2007 UNC-80 (C. elegans) encodes a novel conserved neuronal protein required for proper localization of NCA-1 and NCA-2 ion channel subunits; loss of unc-80 partially suppresses synaptojanin mutant locomotory and vesicle depletion defects, placing UNC-80/NCA channels downstream of PIP2 during synaptic vesicle recycling C. elegans suppressor screen, genetic epistasis, immunolocalization Current biology High 17825559
2008 UNC-80 is a component of the NALCN channel complex required for activation of NALCN by substance P and neurotensin; activation by substance P through TACR1 occurs via a G-protein-independent mechanism requiring Src family kinases and UNC-80 Electrophysiology in hippocampal and VTA neurons, pharmacological dissection of G-protein vs. Src kinase pathways Nature High 19092807
2009 UNC80 binds Src kinases and recruits Src into the NALCN channel complex, functioning as a scaffold for Src kinases to enable G-protein-independent activation of NALCN by substance P Co-immunoprecipitation, pulldown assays Channels Medium 19535918
2010 UNC80 bridges NALCN to UNC79 within the same channel complex; this UNC79-UNC80-NALCN complex is required for the coupling between extracellular Ca2+ sensing (via a Ca2+-sensing GPCR and G-proteins) and NALCN-dependent Na+-leak current activation; the last amino acid of NALCN's intracellular tail is also required Electrophysiology in cultured hippocampal neurons from nalcn and unc79 knockout mice, pharmacological G-protein manipulation Neuron High 21040849
2013 Drosophila UNC80 forms a complex with NARROW ABDOMEN (NALCN ortholog) and UNC79 in the brain; loss of unc80 leads to decreased expression of all three proteins (NA, UNC79, UNC80) post-transcriptionally; UNC80 and UNC79 have functional requirements in circadian pacemaker neurons beyond merely promoting channel subunit expression Immunoprecipitation from Drosophila brain, loss-of-function genetics, tissue-specific RNAi/rescue, western blotting PloS one High 24223770
2015 A truncating UNC80 mutation (p.R51*) in humans abolishes NALCN-dependent basal Na+ leak conductance in neurons, causing a syndrome of hypotonia, severe intellectual disability, and dyskinesia phenotypically similar to NALCN mutations, confirming UNC80's essential role in NALCN function in vivo Whole exome sequencing, Sanger sequencing, genetic linkage; functional inference from NALCN channel physiology Journal of medical genetics Medium 26545877
2015 UNC80 p.Pro1700Ser missense mutation markedly decreases NALCN channel currents in HEK293T cells, demonstrating that UNC80 is required for NALCN channel activity; UNC80 is established as a large component of the NALCN sodium-leak channel complex Electrophysiology (patch clamp) in HEK293T cells transfected with mutant UNC80 expression plasmid American journal of human genetics High 26708751
2020 UNC80 and UNC79 are bona fide subunits of the NALCN complex; the C-terminus of UNC80 contains a domain that interacts with UNC79 and contains a signal that overcomes soma-retention to achieve dendritic localization of the complex; UNC80 lacking this C-terminal domain still supports whole-cell NALCN currents but fails to localize to dendrites, demonstrating a role for UNC80 in regulating dendritic membrane potential; UNC80 knockout mice are neonatal lethal Co-immunoprecipitation, electrophysiology, live imaging/immunofluorescence localization in neurons, UNC80 knockout mouse generation, domain deletion analysis with patient-derived mutations Nature communications High 32620897
2022 Cryo-EM structure of the mammalian NALCN-FAM155A-UNC79-UNC80 quaternary complex reveals that UNC79-UNC80 form a large piler-shaped heterodimer tethered to the intracellular side of NALCN through tripartite interactions with NALCN's cytoplasmic loops; two of these interactions are essential for NALCN cell-surface localization; a third interaction relieves NALCN self-inhibition by pulling the auto-inhibitory CTD Interacting Helix (CIH) out of its binding site Cryo-EM structure determination with functional validation of localization and channel activity Nature communications High 35550517
2024 Unc80 undergoes ADAR2-dependent A-to-I RNA editing exclusively in the brain; mice with gain-of-editing variant (Unc80G/G) show heightened basal neuronal activity in olfactory regions and increased glutamate levels in olfactory bulbs compared to loss-of-editing mice; Unc80 deficiency and loss-of-editing both alter olfactory behavioral responses CRISPR/Cas9 knock-in mouse models, neuronal activity measurements, glutamate quantification, behavioral analysis, transcriptomics International journal of molecular sciences Medium 38892173

Source papers

Stage 0 corpus · 21 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2010 Extracellular calcium controls background current and neuronal excitability via an UNC79-UNC80-NALCN cation channel complex. Neuron 162 21040849
2008 Peptide neurotransmitters activate a cation channel complex of NALCN and UNC-80. Nature 130 19092807
2008 A putative cation channel, NCA-1, and a novel protein, UNC-80, transmit neuronal activity in C. elegans. PLoS biology 99 18336069
2007 UNC-80 and the NCA ion channels contribute to endocytosis defects in synaptojanin mutants. Current biology : CB 74 17825559
2015 UNC80 mutation causes a syndrome of hypotonia, severe intellectual disability, dyskinesia and dysmorphism, similar to that caused by mutations in its interacting cation channel NALCN. Journal of medical genetics 42 26545877
2015 Biallelic Mutations in UNC80 Cause Persistent Hypotonia, Encephalopathy, Growth Retardation, and Severe Intellectual Disability. American journal of human genetics 42 26708751
2018 Genetic variants in components of the NALCN-UNC80-UNC79 ion channel complex cause a broad clinical phenotype (NALCN channelopathies). Human genetics 40 30167850
2015 Mutations in UNC80, Encoding Part of the UNC79-UNC80-NALCN Channel Complex, Cause Autosomal-Recessive Severe Infantile Encephalopathy. American journal of human genetics 38 26708753
2013 UNC79 and UNC80, putative auxiliary subunits of the NARROW ABDOMEN ion channel, are indispensable for robust circadian locomotor rhythms in Drosophila. PloS one 37 24223770
2022 Structure and mechanism of NALCN-FAM155A-UNC79-UNC80 channel complex. Nature communications 26 35550517
2009 UNC80 functions as a scaffold for Src kinases in NALCN channel function. Channels (Austin, Tex.) 24 19535918
2020 Intellectual disability-associated UNC80 mutations reveal inter-subunit interaction and dendritic function of the NALCN channel complex. Nature communications 22 32620897
2019 Whole exome sequencing revealed mutations in FBXL4, UNC80, and ADK in Thai patients with severe intellectual disabilities. Gene 14 30771478
2018 Identification of a novel homozygous UNC80 variant in a child with infantile hypotonia with psychomotor retardation and characteristic facies-2 (IHPRF2). Metabolic brain disease 13 29430593
2021 Case Report: Complete Maternal Uniparental Disomy of Chromosome 2 With a Novel UNC80 Splicing Variant c.5609-4G> A in a Chinese Patient With Infantile Hypotonia With Psychomotor Retardation and Characteristic Facies 2. Frontiers in genetics 7 34594366
2023 Novel nonsense mutation in UNC80 in a Turkish patient further validates the sociable skill and severe gastrointestinal problems as part of disease spectrum. American journal of medical genetics. Part A 4 37067163
2019 Atypical Presentation of Viral Gastroenteritis in a Three-year-old Child Due to a UNC80 Mutation. Cureus 4 31223553
2018 Case Report of Pediatric Channelopathies With UNC80 and KCNJ11 Mutations Having Abnormal Respiratory Control Treated With Positive Airway Pressure Therapy. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine 4 30092901
2024 Imbalance in Unc80 RNA Editing Disrupts Dynamic Neuronal Activity and Olfactory Perception. International journal of molecular sciences 1 38892173
2025 Integrated Genomic Approach: A Five Exon Intragenic Deletion in UNC80 Combines With a Novel Splice Variant to Cause IHPRF2 Syndrome in an Italian Family. American journal of medical genetics. Part A 0 40801661
2025 Clinical Utility of Whole-Exome Sequencing in a Consanguineous Family with UNC80-related Neurodevelopmental Disorder: A Case Series and Review of the Literature. Cureus 0 41458659