Affinage

CHRNA1

Acetylcholine receptor subunit alpha · UniProt P02708

Length
457 aa
Mass
51.8 kDa
Annotated
2026-04-28
27 papers in source corpus 11 papers cited in narrative 11 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

CHRNA1 encodes the α1 subunit of the muscle nicotinic acetylcholine receptor (AChR), an essential ligand-gated ion channel component required for neuromuscular junction formation, AChR clustering, and myogenic differentiation. Alternative splicing of CHRNA1 pre-mRNA is tightly controlled by a network of RNA-binding proteins — hnRNP H and PTB bind an intronic silencer and polypyrimidine tract in intron 3 to suppress inclusion of the non-functional exon P3A, while hnRNP L promotes PTB binding and hnRNP LL antagonizes this suppression; disruption of this regulatory circuit by intronic or coding mutations causes AChR-deficiency congenital myasthenic syndrome (PMID:18806275, PMID:24121633, PMID:36634413). CHRNA1 transcription in thymic epithelial cells is driven by IRF8 and AIRE to establish central self-tolerance, and its post-transcriptional levels in muscle are modulated by a circAtxn10–miR-143-3p sponge axis and by Stau1-dependent mRNA localization to postsynaptic sites (PMID:17687331, PMID:40701844, PMID:22884571). Gain-of-function studies show that CHRNA1 overexpression in skeletal muscle drives sarcopenia-like denervation and atrophy, while in sweat glands it promotes excessive secretion through a PAI1-regulated pathway amenable to pharmacological blockade by cisatracurium (PMID:35809807, PMID:37542348, PMID:35393764).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 2007 High

    How CHRNA1 is transcribed outside muscle was unknown; discovery that IRF8 and AIRE directly transactivate the CHRNA1 promoter in thymic epithelial cells established the mechanism for promiscuous thymic expression underlying central tolerance to AChR.

    Evidence Promoter sequencing, IRF8–DNA binding assays, transactivation assays, and ex vivo mRNA quantification in human medullary thymic epithelial cells

    PMID:17687331

    Open questions at the time
    • Whether IRF8/AIRE regulation extends to other AChR subunit genes
    • Mechanism linking reduced thymic CHRNA1 expression to autoimmune myasthenia gravis susceptibility
  2. 2008 High

    The mechanism enforcing skipping of the non-functional exon P3A was undefined; identification of hnRNP H binding to an intronic splicing silencer in intron 3, and demonstration that a patient mutation (IVS3-8G>A) abolishes this binding to cause constitutive P3A inclusion, established the first cis-regulatory element and trans-acting factor controlling CHRNA1 alternative splicing.

    Evidence Patient mutation identification, in vitro binding/affinity measurements, siRNA knockdown, hnRNP H tethering assay, minigene splicing reporter

    PMID:18806275

    Open questions at the time
    • Structural basis of hnRNP H–ISS recognition
    • Whether additional splicing factors cooperate with hnRNP H at this element
  3. 2009 Medium

    Whether other splicing regulators independently control P3A skipping was unclear; PTB was shown to bind near intron 3 and suppress P3A inclusion, and tannic acid was identified as a PTB inducer that ameliorates aberrant splicing caused by the IVS3-8G>A mutation.

    Evidence PTB binding/deletion assays, promoter analysis, bioactive compound screen, tannic acid dose–response

    PMID:19147685

    Open questions at the time
    • In vivo efficacy of tannic acid for CMS
    • Whether PTB and hnRNP H act independently or cooperatively at intron 3
  4. 2012 Medium

    How CHRNA1 mRNA is positioned at the neuromuscular synapse was unknown; Stau1 was shown to bind Chrna1 mRNA and mediate its co-localization with AChR clusters upon agrin stimulation, linking mRNA transport to postsynaptic differentiation.

    Evidence RNA immunoprecipitation (Stau1–Chrna1 mRNA), RNAi knockdown, AChR clustering assay in C2C12 myotubes

    PMID:22884571

    Open questions at the time
    • Cis-element in Chrna1 mRNA recognized by Stau1
    • Whether other AChR subunit mRNAs are co-transported
    • Independent replication in primary myotubes or in vivo
  5. 2013 High

    The interplay among splicing regulators at CHRNA1 intron 3 was unresolved; hnRNP L was found to bind CHRNA1 pre-mRNA and recruit PTB via its proline-rich domain, blocking U2AF65/U1 snRNP association with exon P3A, while its paralog hnRNP LL lacks this domain and antagonistically promotes inclusion — revealing an antagonistic switch that fine-tunes P3A splicing.

    Evidence Reciprocal co-immunoprecipitation of hnRNP L–PTB, siRNA knockdown, minigene splicing assays, RNA pulldown

    PMID:24121633

    Open questions at the time
    • Relative expression levels of hnRNP L vs. hnRNP LL across muscle developmental stages
    • Whether hnRNP L/LL ratio is altered in myasthenic patients without known mutations
  6. 2021 Medium

    CHRNA1 function in non-muscle tissues was poorly defined; CHRNA1 upregulation in sweat glands was shown to drive excessive sweat secretion via downstream AQP5 and CACNA1C, establishing a non-canonical role for this receptor outside the neuromuscular junction.

    Evidence siRNA knockdown in pilocarpine-induced hyperhidrosis mouse model, TEM, ELISA, immunohistochemistry

    PMID:33476802

    Open questions at the time
    • Whether CHRNA1 forms a canonical pentameric channel in sweat glands
    • Identity of the acetylcholine source activating glandular CHRNA1
  7. 2022 Medium

    Whether elevated CHRNA1 is a cause or consequence of age-related denervation was unknown; AAV9-mediated CHRNA1 overexpression in mouse hindlimb directly reduced NMJ innervation, muscle mass, and contractile function, establishing CHRNA1 gain-of-function as sufficient to drive sarcopenia-like pathology.

    Evidence AAV9-CHRNA1 injection in mouse hindlimb, immunofluorescence for innervation, electrophysiology, muscle morphometry

    PMID:35809807

    Open questions at the time
    • Mechanism by which excess α1-subunit causes denervation
    • Whether CHRNA1 reduction in aged muscle is protective
  8. 2022 Medium

    Pharmacological targeting of CHRNA1 channel activity in hyperhidrosis was untested; cisatracurium was demonstrated to block CHRNA1 ion channel function and alleviate hyperhidrosis, with genetic epistasis (overexpression abolishes and knockdown precludes drug effect) proving on-target specificity.

    Evidence Heterologous CHRNA1 expression in HEK293 cells, cisatracurium treatment in hyperhidrosis mouse model, overexpression/siRNA epistasis

    PMID:35393764

    Open questions at the time
    • Whether cisatracurium acts on homomeric α1 channels or requires co-expressed subunits
    • Clinical translatability to human hyperhidrosis
  9. 2022 Medium

    Whether coding variants outside intron 3 can cause P3A-dependent CMS was unclear; c.257G>A (p.Arg86His) was shown across nine kindreds to trigger exon P3A inclusion and produce a non-functional α1 subunit, causing AChR-deficiency CMS with distinctive facial and distal weakness.

    Evidence Whole-exome sequencing of 13 patients from nine kindreds, clinical phenotyping, molecular characterization of P3A inclusion

    PMID:36634413

    Open questions at the time
    • Structural basis by which the Arg86His substitution promotes P3A inclusion
    • Whether this variant also affects receptor assembly independently of splicing
  10. 2023 Medium

    Upstream regulators of CHRNA1 in the sweat gland pathway were undefined; PAI1 (SERPINE1) was placed upstream of CHRNA1 as a negative regulator, with Serpine1 KO increasing and transgenic overexpression decreasing Chrna1 and hyperhidrosis markers, confirmed by CHRNA1-AAV rescue and cisatracurium epistasis.

    Evidence Serpine1 KO and Tg mice, pilocarpine hyperhidrosis model, Chrna1-AAV rescue, cisatracurium reversal, ELISA, RT-PCR, Western blot

    PMID:37542348

    Open questions at the time
    • Mechanism by which PAI1 suppresses CHRNA1 transcription or stability
    • Whether PAI1–CHRNA1 axis operates in tissues beyond sweat glands
  11. 2025 Medium

    Post-transcriptional regulation of CHRNA1 levels in differentiating muscle was uncharacterized; circAtxn10 was identified as a miR-143-3p sponge that de-represses Chrna1 via three 3ʹ-UTR binding sites, and Chrna1 overexpression dramatically enhanced myotube formation, establishing a circRNA–miRNA–mRNA regulatory axis for myogenesis.

    Evidence RNA pulldown and luciferase reporters for circAtxn10–miR-143-3p and miR-143-3p–Chrna1 interactions, miRNA mimics, siRNA/overexpression, myogenic differentiation assays

    PMID:40701844

    Open questions at the time
    • In vivo relevance of the circAtxn10–miR-143-3p–Chrna1 axis in muscle regeneration
    • Whether this axis is disrupted in myopathies

Open questions

Synthesis pass · forward-looking unresolved questions
  • The structural basis of exon P3A recognition by the hnRNP H/PTB/hnRNP L complex, the mechanism by which CHRNA1 overexpression causes denervation, and the signal linking PAI1 to CHRNA1 transcriptional repression remain unresolved.
  • No structural model of the ISS–hnRNP H–PTB ternary complex
  • Mechanism by which excess α1-subunit disrupts NMJ maintenance
  • Signal transduction pathway connecting PAI1 to CHRNA1 expression

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0005215 transporter activity 2
Localization
GO:0005886 plasma membrane 3
Pathway
R-HSA-8953854 Metabolism of RNA 4 R-HSA-112316 Neuronal System 3 R-HSA-168256 Immune System 1
Partners
HNRNPH1HNRNPLHNRNPLLPTBP1SERPINE1STAU1
Complex memberships
muscle nicotinic acetylcholine receptor (AChR)

Evidence

Reading pass · 11 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2007 IRF8 binds the CHRNA1 promoter and drives its transcription in thymic epithelial cells; a promoter variant prevents IRF8 binding and abrogates CHRNA1 promoter activity. AIRE also transactivates CHRNA1 in medullary thymic epithelial cells, and together IRF8 and AIRE regulate promiscuous CHRNA1 expression to set the threshold for self-tolerance. Promoter re-sequencing, in vitro transcription/binding assays (IRF8–promoter interaction), transactivation assay in thymic epithelial cells, ex vivo mRNA quantification from human medullary thymic epithelial cells Nature High 17687331
2008 hnRNP H binds an intronic splicing silencer (ISS) near the 3' end of CHRNA1 intron 3 and promotes skipping of the non-functional exon P3A; a congenital myasthenic syndrome mutation (IVS3-8G>A) disrupts the ISS, reduces hnRNP H affinity ~100-fold, and causes exclusive inclusion of exon P3A, producing a non-functional acetylcholine receptor α-subunit. Patient mutation identification, in vitro binding/affinity assays (ISS–hnRNP H), siRNA knockdown of hnRNP H, hnRNP H tethering assay, minigene splicing reporter Human molecular genetics High 18806275
2009 Polypyrimidine tract binding protein (PTB) binds near the 3' end of CHRNA1 intron 3 and induces skipping of exon P3A; tannic acid increases PTB expression and ameliorates aberrant exon P3A inclusion caused by the IVS3-8G>A mutation without altering hnRNP H levels. PTB deletion/binding assays, PTB promoter deletion analysis, compound screen (960 bioactive compounds), tannic acid dose–response for PTB expression Human molecular genetics Medium 19147685
2013 hnRNP L binds hnRNP L-binding sites in CHRNA1 pre-mRNA and interacts with PTB through its proline-rich region, promoting PTB binding to the polypyrimidine tract upstream of exon P3A; this inhibits U2AF65 and U1 snRNP association, blocking exon P3A definition and thus promoting exon skipping. hnRNP LL, which lacks the proline-rich region, cannot bind PTB and instead promotes exon P3A inclusion — the two proteins antagonistically modulate PTB-mediated splicing suppression. Co-immunoprecipitation (hnRNP L–PTB interaction), siRNA knockdown, minigene splicing assays, patient mutation analysis, RNA pulldown Scientific reports High 24121633
2012 Agrin stimulation induces co-localization of Chrna1 mRNA with assembled nicotinic acetylcholine receptor (AChR) at postsynaptic clusters in C2C12 myotubes; Stau1 protein interacts with Chrna1 mRNA, and Stau1 knockdown causes defective AChR clustering, implicating mRNA localization in neuromuscular junction formation. RT-PCR of AChR affinity-column and ultracentrifugation fractions, RNA immunoprecipitation (Stau1–Chrna1 mRNA), RNAi knockdown of Stau1, AChR clustering assay FEBS letters Medium 22884571
2022 AAV9-mediated overexpression of CHRNA1 in hindlimb muscle decreases neuromuscular junction innervation percentage and reduces skeletal muscle mass (gastrocnemius mass index and fiber cross-sectional area), compound muscle action potential, and contractility, demonstrating that elevated CHRNA1 drives sarcopenia-like muscle denervation and atrophy. AAV9-CHRNA1 local injection in mouse hindlimb, immunofluorescence for innervation, electrophysiology (compound muscle action potential), muscle mass/fiber morphometry Experimental gerontology Medium 35809807
2021 CHRNA1 upregulation in sweat glands promotes excessive sweat secretion; siRNA-mediated CHRNA1 silencing decreases sweat secretion, reduces sweat secretory granules, lowers serum acetylcholine, and downregulates AQP5 and CACNA1C in sweat glands, as well as BDNF and NRG-1 in sympathetic ganglia axons. siRNA knockdown in pilocarpine-induced hyperhidrosis mouse model, transmission electron microscopy, ELISA, immunohistochemistry, Western blot, qRT-PCR Molecular and cellular neurosciences Medium 33476802
2022 Cisatracurium, an antagonist of CHRNA1, blocks the CHRNA1 ion channel (without altering CHRNA1 gene or protein expression) and alleviates hyperhidrosis in mice; overexpression of CHRNA1 abolishes cisatracurium's effect while CHRNA1 knockdown prevents additional benefit, establishing that cisatracurium acts specifically through CHRNA1 channel blockade. HEK293 cell expression of Chrna1, cisatracurium treatment in vivo (hyperhidrosis mouse model), CHRNA1 overexpression/siRNA epistasis experiments, sweat secretion quantification, Western blot Annals of clinical and translational neurology Medium 35393764
2023 PAI1 (SERPINE1) negatively regulates CHRNA1 expression in sweat glands; Serpine1 knockout increases Chrna1 expression and hyperhidrosis markers (ACH, CACNA1C, AQP5), while Serpine1 transgenic overexpression reduces them. CHRNA1-expressing AAV rescues hyperhidrosis in Serpine1-Tg mice, and CHRNA1 antagonist cisatracurium reverses the Pai1-KO hyperhidrosis phenotype, placing PAI1 upstream of CHRNA1 in this pathway. Serpine1 KO and Tg mice, pilocarpine hyperhidrosis model, Chrna1-expressing AAV rescue, cisatracurium antagonism, ELISA, RT-PCR, Western blot Orphanet journal of rare diseases Medium 37542348
2022 The CHRNA1 variant c.257G>A (p.Arg86His) causes inclusion of the alternatively-spliced evolutionary exon P3A, producing a non-functional AChR α-subunit that leads to AChR-deficiency congenital myasthenic syndrome with a distinctive phenotype of facial and distal weakness. Whole-exome sequencing of 13 patients from nine kindreds, clinical phenotyping, molecular characterization of P3A inclusion Neuromuscular disorders : NMD Medium 36634413
2025 circAtxn10 acts as a sponge for miR-143-3p through direct binding; miR-143-3p directly targets three binding sites in the Chrna1 3'-UTR to suppress its expression. Chrna1 knockdown impairs myogenesis, while Chrna1 overexpression dramatically enhances myogenic marker expression and myotube formation, establishing a circAtxn10–miR-143-3p–Chrna1 regulatory axis in skeletal muscle differentiation. RNA pulldown/luciferase reporter for circAtxn10–miR-143-3p interaction, 3'-UTR luciferase reporter for miR-143-3p–Chrna1 targeting, miR-143-3p mimic, siRNA knockdown and overexpression of Chrna1, myogenic differentiation assays The Korean journal of physiology & pharmacology Medium 40701844

Source papers

Stage 0 corpus · 27 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2007 An IRF8-binding promoter variant and AIRE control CHRNA1 promiscuous expression in thymus. Nature 147 17687331
2008 Smokers with the CHRNA lung cancer-associated variants are exposed to higher levels of nicotine equivalents and a carcinogenic tobacco-specific nitrosamine. Cancer research 124 19010884
2008 Mutation analysis of CHRNA1, CHRNB1, CHRND, and RAPSN genes in multiple pterygium syndrome/fetal akinesia patients. American journal of human genetics 81 18179903
1994 Involvement of human muscle acetylcholine receptor alpha-subunit gene (CHRNA) in susceptibility to myasthenia gravis. Proceedings of the National Academy of Sciences of the United States of America 64 7910962
2008 hnRNP H enhances skipping of a nonfunctional exon P3A in CHRNA1 and a mutation disrupting its binding causes congenital myasthenic syndrome. Human molecular genetics 52 18806275
2013 HnRNP L and hnRNP LL antagonistically modulate PTB-mediated splicing suppression of CHRNA1 pre-mRNA. Scientific reports 39 24121633
2009 Tannic acid facilitates expression of the polypyrimidine tract binding protein and alleviates deleterious inclusion of CHRNA1 exon P3A due to an hnRNP H-disrupting mutation in congenital myasthenic syndrome. Human molecular genetics 29 19147685
1996 Human muscle acetylcholine receptor alpha-subunit gene (CHRNA1) association with autoimmune myasthenia gravis in black, mixed-ancestry and Caucasian subjects. Journal of autoimmunity 26 8738961
1997 Association of the AChRalpha-subunit gene (CHRNA), DQA1*0101, and the DR3 haplotype in myasthenia gravis. Evidence for a three-gene disease model in a subgroup of patients. Journal of autoimmunity 23 9237805
2017 Genes Involved in Neurodevelopment, Neuroplasticity, and Bipolar Disorder: CACNA1C, CHRNA1, and MAPK1. Neuropsychobiology 19 28494468
2014 Role of SLCO1B1, ABCB1, and CHRNA1 gene polymorphisms on the efficacy of rocuronium in Chinese patients. Journal of clinical pharmacology 16 25279974
2010 Identification of previously unreported mutations in CHRNA1, CHRNE and RAPSN genes in three unrelated Italian patients with congenital myasthenic syndromes. Journal of neurology 14 20157724
2013 High expression of CHRNA1 is associated with reduced survival in early stage lung adenocarcinoma after complete resection. Annals of surgical oncology 12 23775407
2022 CHRNA1 induces sarcopenia through neuromuscular synaptic elimination. Experimental gerontology 11 35809807
2021 CHRNA1 promotes the pathogenesis of primary focal hyperhidrosis. Molecular and cellular neurosciences 11 33476802
2012 Agrin induces association of Chrna1 mRNA and nicotinic acetylcholine receptor in C2C12 myotubes. FEBS letters 10 22884571
2012 Association study of nicotinic acetylcholine receptor genes identifies a novel lung cancer susceptibility locus near CHRNA1 in African-Americans. Oncotarget 9 23232035
2022 Epidemiological evidence for associations between variants in CHRNA genes and risk of lung cancer and chronic obstructive pulmonary disease. Frontiers in oncology 8 36276121
2022 A novel phenotype of AChR-deficiency syndrome with predominant facial and distal weakness resulting from the inclusion of an evolutionary alternatively-spliced exon in CHRNA1. Neuromuscular disorders : NMD 6 36634413
2022 Antagonist of Chrna1 prevents the pathogenesis of primary focal hyperhidrosis. Annals of clinical and translational neurology 5 35393764
2013 Clinical phenotype and the lack of mutations in the CHRNG, CHRND, and CHRNA1 genes in two Indian families with Escobar syndrome. Clinical dysmorphology 5 23448903
2007 Analysis and mapping of CACNB4, CHRNA1, KCNJ3, SCN2A and SPG4, physiological candidate genes for porcine congenital progressive ataxia and spastic paresis. Journal of animal breeding and genetics = Zeitschrift fur Tierzuchtung und Zuchtungsbiologie 5 17868079
2023 PAI1 inhibits the pathogenesis of primary focal hyperhidrosis by targeting CHRNA1. Orphanet journal of rare diseases 4 37542348
2022 Case Report: Novel compound heterozygous variants in CHRNA1 gene leading to lethal multiple pterygium syndrome: A case report. Frontiers in genetics 3 36092864
2025 Causal Variants in CHRNA1 and CHRNB1 Genes for Anti-acetylcholine Receptor Antibody Positive Myasthenia Gravis: Evidence from Bayesian Fine-Mapping and Genetic Association Study. Molecular neurobiology 2 40279038
2025 PAI1 regulating CHRNA1 contributes to primary focal hyperhidrosis: Clinical and experimental studies. Molecular therapy. Nucleic acids 1 40503176
2025 Circular RNA circAtxn10 regulates skeletal muscle cell differentiation by targeting miR-143-3p and Chrna1. The Korean journal of physiology & pharmacology : official journal of the Korean Physiological Society and the Korean Society of Pharmacology 1 40701844