{"gene":"CACNA1S","run_date":"2026-06-09T22:57:17","timeline":{"discoveries":[{"year":1994,"finding":"CACNA1S (CACNL1A3) maps to chromosome 1q31-32, co-segregating with the hypokalaemic periodic paralysis (HypoPP) locus without recombinants, establishing it as the causative gene for HypoPP.","method":"Genome-wide linkage analysis using polymorphic dinucleotide repeats and intragenic microsatellite markers in three European families","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic linkage established across three independent families with co-segregation without recombinants","pmids":["8012389"],"is_preprint":false},{"year":1995,"finding":"Missense mutations Arg528His and Arg1239His in the voltage-sensor segment S4 of CACNA1S are the predominant causative mutations for hypokalemic periodic paralysis type 1 (HypoPP-1), with the Arg528His mutation showing incomplete penetrance.","method":"DNA sequence analysis and cosegregation analysis in 16 Caucasian HypoPP families","journal":"American journal of human genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — co-segregation demonstrated in 16 independent families, replicated across subsequent studies","pmids":["7847370"],"is_preprint":false},{"year":2005,"finding":"The distal C terminus of CaV1.1 (CACNA1S) is proteolytically cleaved in vivo at alanine 1664, and the cleaved distal C-terminal domain (aa 1802–1841) noncovalently associates with a proximal C-terminal region (aa 1556–1612) of the channel. This complex serves as the docking site for AKAP15 and PKA, which are required for cAMP-dependent potentiation of Ca2+ channel activity.","method":"Yeast two-hybrid deletion mapping, tandem mass spectrometry of purified skeletal muscle CaV1.1, and expression in mammalian nonmuscle cells","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro mass spectrometry identified proteolytic site, yeast two-hybrid mapped interaction domain, multiple orthogonal methods in single rigorous study","pmids":["15793008"],"is_preprint":false},{"year":2006,"finding":"JP-45, a junctional SR protein, directly interacts with two domains of CaV1.1: the I-II loop (via the alpha-interacting domain) and the C-terminal region. The beta1a subunit reduces JP-45 interaction with the I-II loop. JP-45 overexpression decreases peak charge-movement and shifts voltage-dependence; JP-45 depletion decreases both CaV1.1 content and peak charge-movement, demonstrating that JP-45 regulates functional expression of CaV1.1.","method":"Co-immunoprecipitation, GST pulldown, charge-movement recordings in C2C12 myotubes with JP-45 overexpression or siRNA depletion","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal binding assays combined with functional electrophysiology, multiple orthogonal methods in one study","pmids":["16638807"],"is_preprint":false},{"year":2007,"finding":"CaV1.1 (CACNA1S) exhibits Ca2+-dependent inactivation (CDI) mediated by calmodulin: CDI is maximal (~30%) at potentials evoking peak inward current, eliminated by Ba2+ substitution or BAPTA, and abolished by expression of Ca2+-binding-deficient CaM1234. FRET imaging confirmed direct association of CaM with CaV1.1 in dysgenic myotubes.","method":"Whole-cell patch-clamp in mouse myotubes, FRET between fluorescently tagged CaV1.1 and CaM, overexpression of dominant-negative CaM1234","journal":"Pflugers Archiv : European journal of physiology","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — electrophysiology with pharmacological controls plus FRET for direct protein association, multiple orthogonal methods","pmids":["17899167"],"is_preprint":false},{"year":2008,"finding":"Sequence differences in the IQ motif of CaV1.1 (His1532, Met1537) compared to CaV1.2 (Tyr1657, Lys1662) underlie the weak CaM binding and absence of Ca2+-dependent inactivation in CaV1.1. Reciprocal substitution of these two residues into CaV1.2 eliminates CDI, while introduction of CaV1.2 residues into CaV1.1 confers CaM binding.","method":"Native gel electrophoresis of CaM binding to C-terminal peptides, expression of mutant channels in intact myotubes, whole-cell electrophysiology","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — mutagenesis combined with binding assays and functional recordings, multiple orthogonal methods","pmids":["18718913"],"is_preprint":false},{"year":2009,"finding":"A CaV1.1 splice variant lacking exon 29 (CaV1.1Δ29) shows 30-mV left-shifted voltage-dependence of activation, eightfold increased current density, and accelerated kinetics compared to the adult isoform. This variant is expressed at high levels (~80%) in developing myotubes and supports skeletal EC coupling. Its robust Ca2+ influx substantially contributes to depolarization-induced Ca2+ transients in developing muscle.","method":"Expression of GFP-tagged CaV1.1Δ29 in dysgenic (α1S-null) myotubes, patch-clamp and Ca2+ imaging, analysis of human and mouse muscle expression levels","journal":"Biophysical journal","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — reconstitution in null myotubes with rigorous electrophysiology and Ca2+ imaging, expression confirmed in native tissue","pmids":["19134469"],"is_preprint":false},{"year":2009,"finding":"R528H and R1239H/G mutations in CaV1.1 HypoPP-1 have 'loss-of-function' features: D4/S4 mutations shift channel equilibrium toward closed states (reduced open probability, shorter openings, smaller currents); D2/S4 mutation (R528H) slows activation. HypoPP histidine mutants favor a second open state (O2) with possibly lower channel selectivity.","method":"Heterologous expression of wild-type and HypoPP-1 mutations in HEK-293 cells, whole-cell patch-clamp, global kinetic model fitting","journal":"Pflugers Archiv : European journal of physiology","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — rigorous in vitro kinetic modeling in single lab using heterologous system (cardiac channel analog), not replicated independently","pmids":["17333249"],"is_preprint":false},{"year":2011,"finding":"The IQ motif (residues mutated to IQ→AA) of CaV1.1 is essential for Ca2+ current and excitation-contraction coupling: dysgenic myotubes expressing YFP-CaV1.1(AA) show neither Ca2+ currents nor evoked Ca2+ transients, despite normal targeting to the sarcolemma and normal maximal charge movement (Qmax), suggesting the IQ motif is a structural and functional coupling site between DHPR and RyR.","method":"Expression of IQ-motif mutant CaV1.1 in dysgenic myotubes, whole-cell Ca2+ current recordings, Ca2+ transient imaging, charge movement recordings","journal":"Journal of biomedicine & biotechnology","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — functional rescue experiment in null myotubes, single lab, single study","pmids":["22162637"],"is_preprint":false},{"year":2011,"finding":"Caveolin-3 directly interacts with the I-II loop of CaV1.1 (apparent affinity ~60 nM), co-localizes with DHPR within T-tubular membrane, and co-immunoprecipitates from triadic membrane preparations. Expression of the P104L caveolin-3 mutant or siRNA knockdown of caveolin-3 significantly decreases L-type Ca2+ channel maximal conductance.","method":"GST-fusion pulldown with CaV1.1 I-II loop peptides, co-immunoprecipitation from triadic membranes, immunolocalization, whole-cell patch-clamp in C2C12 myotubes with siRNA or mutant caveolin-3 expression","journal":"The international journal of biochemistry & cell biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal binding assays, co-IP from native tissue, and functional electrophysiology, multiple orthogonal methods in one study","pmids":["21262376"],"is_preprint":false},{"year":2013,"finding":"CaV1.1 (α1S subunit) acts as voltage sensor for activation of IP3-dependent Ca2+ signals that regulate gene expression in skeletal muscle, and is required for frequency-dependent ATP release through pannexin-1 channels. Myotubes lacking CaV1.1-α1S release almost no ATP after electrical stimulation. ATP release and frequency-specific transcriptional programs (fast-to-slow transition) at 20 Hz (but not 90 Hz) require CaV1.1 function independently of its ion channel activity.","method":"Electrical stimulation of CaV1.1-α1S null myotubes, pharmacological blockade/activation of CaV1.1, ATP release measurements, IP3 measurements, gene expression analysis in adult flexor digitorum brevis fibers","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Moderate — null cell rescue experiment plus pharmacological confirmation plus multiple readouts (ATP, IP3, transcription)","pmids":["23321639"],"is_preprint":false},{"year":2015,"finding":"Ca2+ binding/permeation through the CaV1.1 pore (E1014K pore mutation abolishes it) is coupled to CaMKII activation and sarcoplasmic reticulum Ca2+ store refilling during sustained muscle activity. Loss of this permeation leads to decreased CaMKII and downstream Ras/Erk/mTORC1 signaling, reduced muscle protein synthesis, increased fatigue, decreased fiber size, and increased type IIb fibers.","method":"Knock-in mouse with E1014K CaV1.1 pore mutation, Ca2+ imaging, western blotting, proximity ligation assays, SUnSET protein synthesis assay, isolated muscle force-frequency and fatigue measurements","journal":"Skeletal muscle","confidence":"High","confidence_rationale":"Tier 2 / Moderate — in vivo knock-in model with multiple orthogonal functional assays (Ca2+ imaging, biochemistry, force measurements) in single rigorous study","pmids":["25717360"],"is_preprint":false},{"year":2015,"finding":"CaV1.1-mediated CaMKII activation (via Ca2+ permeation through E1014K pore) regulates the intracellular distribution of fatty acid transport protein CD36 and mitochondrial β-oxidation in skeletal muscle, through a CaV1.1→CaMKII→NOS pathway. Blocking this pathway decreases energy expenditure and increases body fat.","method":"E1014K knock-in mice, Ca2+ imaging, Western blotting, immunohistochemistry, pharmacological NOS inhibition, metabolic phenotyping","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — in vivo knock-in model, single lab, multiple readouts but pathway confirmation relies on correlative evidence","pmids":["26245899"],"is_preprint":false},{"year":2016,"finding":"Troponin T3 (TnT3) transcriptionally regulates Cacna1s (CaV1.1) expression by binding to the Cacna1s promoter. Knocking down TnT3 in vivo downregulates CaV1.1; TnT3 overexpression increases Cacna1s promoter activity; this effect requires the TnT3 nuclear localization sequence. Calpain inhibition prevents TnT3 fragmentation, restoring Cacna1s/CaV1.1 levels and muscle force in aging mice.","method":"In vivo TnT3 knockdown, Cacna1s promoter-reporter assays, TnT3 nuclear localization sequence truncation, calpain inhibitor (BDA-410) treatment in aged mice, muscle force measurements","journal":"Aging cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function and gain-of-function with promoter assays and in vivo rescue, multiple orthogonal methods","pmids":["26892246"],"is_preprint":false},{"year":2016,"finding":"Recessive and dominant mutations in CACNA1S cause a distinct congenital myopathy (DHPR congenital myopathy) characterized by SR dilatation and impaired Ca2+ release induced by depolarization in cultured myotubes, with decreased CACNA1S protein levels.","method":"Exome sequencing in 11 patients, Ca2+ release measurements in cultured myotubes from patients, protein level quantification by western blot","journal":"Acta neuropathologica","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional Ca2+ release assays in patient-derived myotubes with multiple mutations, replicated across patient cohort","pmids":["28012042"],"is_preprint":false},{"year":2016,"finding":"T cells express a specific CaV1.1 splice variant lacking exon 29 but with five new N-terminal exons substituting for exons 1 and 2. Knockdown of CaV1.1 in T cells abrogates Ca2+ entry after TCR stimulation, demonstrating that CaV1.1 channels are required for TCR-mediated Ca2+ entry.","method":"Sequencing and cloning of T cell CaV1.1 cDNA, overexpression in HEK293 cells, siRNA knockdown in T cells with Ca2+ flux measurements after TCR stimulation","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — siRNA knockdown with functional Ca2+ readout in single lab, single study","pmids":["26815481"],"is_preprint":false},{"year":2018,"finding":"Coexpression of STAC3 dramatically increases plasma membrane expression of human CaV1.1 in Xenopus oocytes, enabling functional studies. Using this system, HypoPP mutations R528H and R528G in S4 of domain II are shown to generate gating pore currents (anomalous conductance through the voltage sensor domain); R528H does not conduct protons unlike other R/H HypoPP mutations.","method":"Cut-open oocyte voltage clamp of human CaV1.1 coexpressed with α2-δ1b, β1a, and STAC3 in Xenopus oocytes; ionic current and gating charge measurements","journal":"The Journal of general physiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — rigorous voltage-clamp electrophysiology with direct measurement of gating pore currents, mutation-specific analysis in high-expression system","pmids":["29386226"],"is_preprint":false},{"year":2021,"finding":"Each of the four voltage-sensing domains (VSDs) of human CaV1.1 has unique biophysical properties: VSD-I activation kinetics match ionic current activation and contributes the most energy (~75 meV) toward stabilizing open states, driving CaV1.1 pore opening primarily. VSDs II, III, and IV activate faster, compatible with RYR1 Ca2+ release kinetics. The R174W charge-neutralizing mutation in VSD-I abolishes CaV1.1 current at physiological potentials without affecting other VSDs.","method":"Opto-electrophysiology (voltage clamp fluorometry) measuring VSD-specific fluorescence changes plus ionic currents in human CaV1.1 expressed in Xenopus oocytes; allosteric model analysis; VSD-I R174W mutant characterization","journal":"The Journal of general physiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — rigorous voltage clamp fluorometry with mutagenesis and allosteric modeling, multiple orthogonal approaches in single rigorous study","pmids":["34546289"],"is_preprint":false},{"year":2021,"finding":"CaV1.1 domain III (DIII) HypoPP mutations R897S and R900G generate gating pore currents, while R900S does not. R897S (R1 of DIII) produces exceptionally large gating pore currents correlating with severe clinical phenotype. The previously reported charge-conserving R897K does not produce gating pore currents, consistent with requirement for charge neutralization to create anomalous VSD conduction.","method":"Expression of DIII CaV1.1 HypoPP mutants with STAC3 in Xenopus oocytes, cut-open oocyte voltage clamp for gating pore current measurement","journal":"The Journal of general physiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct electrophysiological measurement of gating pore currents with multiple mutations tested and charge-conserving negative control","pmids":["34463712"],"is_preprint":false},{"year":2021,"finding":"CaV1.1 and Pannexin-1 (Panx1) regulate each other reciprocally in skeletal muscle. CaV1.1 knockdown causes chronically elevated extracellular ATP at rest, disrupting normal Panx1 activity control. Conversely, Panx1 knockdown impairs both transcription activation and CaV1.1 control of contraction. This bidirectional coupling links excitation-contraction and excitation-transcription processes.","method":"Knockdown of CaV1.1 or Panx1 in adult skeletal muscle fibers, measurement of extracellular ATP, Ca2+ transients, force, and gene expression","journal":"The Journal of general physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal knockdown experiments with multiple functional readouts, single lab","pmids":["34636893"],"is_preprint":false},{"year":2022,"finding":"The γ1 subunit reduces CaV1.1 current density by >50% specifically for the adult (CaV1.1a, contains exon 29) splice variant but not the embryonic (CaV1.1e, lacks exon 29) variant. This current-reducing effect depends on inclusion of exon 29 and is distinct from γ1's effect on voltage-dependence of inactivation (which occurs in both variants). Molecular modeling suggests ionic interactions between the IVS3-S4 loop (encoded by exon 29) and γ1, with allosteric mechanism rather than direct contact mediating current reduction.","method":"Stable HEK293 cell lines expressing α2δ-1, β3, STAC3 with γ1 and CaV1.1a or CaV1.1e; patch-clamp electrophysiology; alanine substitution mutagenesis; molecular structure modeling","journal":"The Journal of general physiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — electrophysiology with mutagenesis and structural modeling, multiple orthogonal methods, clear mechanistic dissection","pmids":["35349630"],"is_preprint":false},{"year":2025,"finding":"STAC3 interaction with the CaV1.1 proximal C-terminus is necessary and sufficient for CaV1.1 functional expression and minimal EC coupling, while STAC3 interaction with the II-III loop of CaV1.1 is not essential for EC coupling but facilitates and enhances conformational coupling with RyR1. A patient with STAC3 disorder carrying a mutation deleting the II-III loop-interacting domain confirms this functional distinction.","method":"Expression of CaV1.1 constructs with selective STAC3-interaction domain disruptions in dysgenic myotubes, Ca2+ imaging, electrophysiology, patient genetic analysis","journal":"JCI insight","confidence":"High","confidence_rationale":"Tier 2 / Moderate — domain-specific rescue experiments in null myotubes with functional EC coupling readout plus human genetic validation","pmids":["40779452"],"is_preprint":false},{"year":2015,"finding":"Raptor (mTORC1) ablation in skeletal muscle alters the ratio of ryanodine receptors to DHPRs (CaV1.1), increases voltage sensor-uncoupled RyRs, and increases frequency and mass of elementary calcium release events (sparks) in FDB fibers, while not significantly affecting global Ca2+ transient amplitude, indicating mTORC1 signaling modulates the composition and function of the EC coupling complex including CaV1.1.","method":"Muscle-specific raptor knockout mice, 3H-ryanodine and 3H-PN200-110 equilibrium binding, Ca2+ imaging in FDB fibers, hyper-osmotic shock spark analysis","journal":"The Biochemical journal","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — genetic knockout with direct binding assays and Ca2+ imaging, single lab","pmids":["25431931"],"is_preprint":false},{"year":2020,"finding":"CACNA1S haploinsufficiency renders cells and mice resistant to New World arenavirus (Junín and Tacaribe) infection, and reduces the dosage of VGCC antagonists needed to block infection, demonstrating that the α1S voltage-gated calcium channel is required for cellular binding and entry of these arenaviruses.","method":"CACNA1S haploinsufficient cell lines and mice infected with Junín and Tacaribe virus; VGCC antagonist dose-response experiments","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — loss-of-function in cells and in vivo with viral entry readout, single lab, single study","pmids":["32719120"],"is_preprint":false},{"year":2021,"finding":"MRTF-A (myocardin-related transcription factor A) activates CACNA1S transcription by binding to a CarG box in the CACNA1S promoter. In mdx mice, MRTF-A expression is decreased and phosphorylation increased, correlating with reduced CACNA1S expression and impaired Ca2+ release through CaV1.1.","method":"Promoter-reporter assay with CarG box, ChIP/binding assay, qPCR and western blot in mdx mice, Ca2+ release measurements","journal":"Journal of biosciences","confidence":"Low","confidence_rationale":"Tier 3 / Weak — promoter binding shown but mechanism confirmed only by correlative expression data in disease model, single lab","pmids":["33969828"],"is_preprint":false},{"year":2015,"finding":"The β1a490-508 peptide (19 residues from C-terminal tail of the CaV1.1 β1a subunit) is sufficient to potentiate voltage-dependent Ca2+ release flux (~49% increase) and RyR1 channel activity in adult skeletal muscle fibers, and also increases CaV1.1 Ca2+ currents, demonstrating that the β1a C-terminal tail modulates EC coupling between CaV1.1 and RyR1.","method":"Voltage-clamp of adult skeletal muscle fibers with peptide perfusion, Ca2+ release flux measurements, RyR1 single-channel bilayer recordings; scrambled peptide negative control","journal":"Biophysical journal","confidence":"Medium","confidence_rationale":"Tier 1-2 / Weak — rigorous electrophysiology and bilayer single-channel recordings with appropriate controls, but single lab and peptide approach","pmids":["24507594"],"is_preprint":false},{"year":2015,"finding":"Antibody previously reported to detect CACNA1S (CaV1.1) at ON bipolar cell dendritic tips in retina cross-reacts with GPR179; mass spectrometry of immunoprecipitated protein failed to detect CACNA1S peptides. This negative finding undermines proposed role of CACNA1S in DBC (depolarizing bipolar cell) signal transduction based solely on immunohistochemistry.","method":"Western blot, immunoprecipitation followed by mass spectrometric peptide identification, immunohistochemistry in GPR179 mutant retinas and HEK293T cells expressing GPR179","journal":"Visual neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal negative-finding methods (western, IP-MS, IHC in multiple models) demonstrating antibody cross-reactivity","pmids":["27471951"],"is_preprint":false},{"year":2013,"finding":"CaV1.1-R528H knock-in mice develop hypokalaemic periodic paralysis, and treatment with bumetanide (a chloride cotransporter inhibitor) protects against muscle weakness from low K+ challenge in vitro and loss of muscle excitability in vivo, demonstrating a critical role of the chloride gradient in modulating susceptibility to ictal weakness caused by CACNA1S mutations.","method":"CaV1.1-R528H knock-in mouse model, in vitro low-K+ challenge with force measurements, in vivo glucose+insulin infusion with EMG, bumetanide treatment","journal":"Brain : a journal of neurology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo knock-in mouse model with pharmacological rescue, multiple functional readouts","pmids":["24142145"],"is_preprint":false}],"current_model":"CACNA1S encodes CaV1.1, the pore-forming α1S subunit of the skeletal muscle dihydropyridine receptor (DHPR), which functions primarily as a voltage sensor for excitation-contraction (EC) coupling by directly and conformationally coupling to RyR1 to trigger SR Ca2+ release; VSD-I is the dominant voltage sensor driving pore opening, while its interaction with STAC3 (via the proximal C-terminus, essential; and II-III loop, facilitating) and RyR1 is required for functional EC coupling. Ca2+ permeation through the pore is not required for EC coupling but modulates CaMKII, SR store refilling, and downstream metabolic signaling (Ras/Erk/mTORC1, CD36/β-oxidation). CaV1.1 also acts as voltage sensor for IP3-dependent Ca2+ signals and frequency-dependent ATP release (via pannexin-1) that regulate gene expression and muscle fiber phenotype. The channel is regulated by calmodulin (via an IQ motif crucial for CDI and RyR coupling), the γ1 subunit (which reduces current density specifically in the exon-29-containing adult isoform), JP-45 (which modulates charge movement), caveolin-3 (which interacts with the I-II loop and regulates conductance), and PKA anchored via AKAP15 to the proteolytically cleaved distal C-terminus. HypoPP-causing S4 arginine mutations create anomalous gating pore currents in the voltage sensor domain, causing paradoxical membrane depolarization and weakness in low potassium."},"narrative":{"mechanistic_narrative":"CACNA1S encodes CaV1.1, the pore-forming α1S subunit of the skeletal muscle dihydropyridine receptor, which functions chiefly as a voltage sensor that conformationally couples membrane depolarization to RyR1-mediated SR Ca2+ release during excitation-contraction (EC) coupling [PMID:23321639, PMID:34546289]. Among its four voltage-sensing domains, VSD-I dominates pore opening, contributing the most energy toward stabilizing open states, while VSDs II–IV activate faster in a manner compatible with RyR1 Ca2+ release kinetics [PMID:34546289]. Functional expression and EC coupling depend on STAC3: its interaction with the proximal C-terminus is necessary and sufficient for minimal coupling, whereas its interaction with the II-III loop facilitates and enhances conformational coupling with RyR1 [PMID:40779452]. The IQ motif is a structural and functional coupling site, required for both Ca2+ current and evoked Ca2+ transients [PMID:22162637], and mediates the weak calmodulin-dependent Ca2+-dependent inactivation that distinguishes CaV1.1 from CaV1.2 [PMID:17899167, PMID:18718913]. Ca2+ permeation through the pore is dispensable for EC coupling but drives CaMKII activation, SR store refilling, and downstream Ras/Erk/mTORC1 signaling controlling protein synthesis and fiber type, as well as a CaMKII→NOS pathway regulating CD36 distribution and β-oxidation [PMID:25717360, PMID:26245899]. Beyond contraction, CaV1.1 acts as a voltage sensor for IP3-dependent Ca2+ signals and frequency-dependent ATP release through pannexin-1, with which it is reciprocally coupled, linking excitation to transcriptional programs governing fiber phenotype [PMID:23321639, PMID:34636893]. The channel is regulated by multiple partners: caveolin-3 binds the I-II loop and sets conductance [PMID:21262376]; JP-45 binds the I-II loop and C-terminus to control functional channel expression [PMID:16638807]; the γ1 subunit reduces current density specifically in the exon-29-containing adult isoform [PMID:35349630]; and PKA is anchored via AKAP15 to the proteolytically cleaved distal C-terminus for cAMP-dependent potentiation [PMID:15793008]. CACNA1S is the causative gene for hypokalaemic periodic paralysis, in which S4 arginine mutations create anomalous gating pore currents in the voltage sensor domains [PMID:8012389, PMID:7847370, PMID:29386226, PMID:34463712], and dominant and recessive mutations also cause a distinct DHPR congenital myopathy [PMID:28012042].","teleology":[{"year":1995,"claim":"Establishing CACNA1S as the cause of hypokalaemic periodic paralysis and localizing the predominant mutations to S4 voltage-sensor arginines defined the channel's voltage-sensing region as the disease-relevant locus.","evidence":"Genome-wide linkage in three families and mutation/cosegregation analysis in 16 HypoPP families","pmids":["8012389","7847370"],"confidence":"High","gaps":["Linkage and sequencing did not establish the biophysical mechanism by which S4 mutations cause paralysis","Incomplete penetrance of R528H was unexplained"]},{"year":2005,"claim":"Identifying in vivo proteolytic cleavage of the distal C-terminus and its docking of AKAP15/PKA explained how cAMP-dependent signaling potentiates CaV1.1 activity.","evidence":"Yeast two-hybrid mapping, mass spectrometry of purified skeletal muscle CaV1.1, and expression in nonmuscle cells","pmids":["15793008"],"confidence":"High","gaps":["Did not establish the physiological trigger or magnitude of PKA potentiation in intact muscle","Protease responsible for cleavage not identified"]},{"year":2008,"claim":"Defining the molecular basis of calmodulin binding and Ca2+-dependent inactivation pinpointed IQ-motif residues that distinguish CaV1.1 from CaV1.2 gating behavior.","evidence":"Whole-cell patch-clamp and FRET in myotubes plus native-gel CaM binding and reciprocal IQ-motif mutagenesis","pmids":["17899167","18718913"],"confidence":"High","gaps":["Functional consequence of weak CDI for muscle physiology not resolved","Did not address whether CaM contributes to RyR1 coupling"]},{"year":2009,"claim":"Characterizing the exon-29-lacking splice variant showed that developmental isoform switching tunes CaV1.1 voltage-dependence and Ca2+ influx, and kinetic modeling of HypoPP histidine mutants revealed loss-of-function gating shifts.","evidence":"Reconstitution in dysgenic myotubes with patch-clamp/Ca2+ imaging, and heterologous HEK-293 expression with kinetic modeling","pmids":["19134469","17333249"],"confidence":"Medium","gaps":["The HypoPP gating studies used a heterologous/cardiac channel analog and were not independently replicated","Loss-of-function gating did not yet explain paradoxical depolarization"]},{"year":2011,"claim":"Demonstrating that the IQ motif is essential for EC coupling and that caveolin-3 binds the I-II loop to set conductance expanded the inventory of structural elements and regulatory partners controlling channel function.","evidence":"IQ-motif mutant rescue in dysgenic myotubes and GST pulldown/co-IP plus electrophysiology for caveolin-3","pmids":["22162637","21262376"],"confidence":"Medium","gaps":["IQ-motif coupling role demonstrated in single lab","Mechanism by which caveolin-3 P104L lowers conductance not fully resolved"]},{"year":2013,"claim":"Identifying CaV1.1 as the voltage sensor for IP3 signals and pannexin-1-dependent ATP release, and a bumetanide-responsive role for chloride gradient in HypoPP, separated the channel's excitation-transcription role from contraction and clarified disease modulation.","evidence":"Null-myotube rescue with ATP/IP3/transcription readouts, and R528H knock-in mice with low-K+ challenge and pharmacology","pmids":["23321639","24142145"],"confidence":"Medium","gaps":["Single-lab excitation-transcription findings","How chloride gradient interacts with gating pore currents not established"]},{"year":2015,"claim":"Knock-in of a pore mutation that abolishes Ca2+ permeation dissociated ion conduction from EC coupling, revealing a CaV1.1→CaMKII→Ras/Erk/mTORC1 and →NOS/CD36 metabolic signaling axis, while β1a peptide and raptor studies further defined modulation of the EC coupling complex.","evidence":"E1014K knock-in mice with imaging/biochemistry/force assays, β1a peptide perfusion with bilayer recordings, and muscle-specific raptor knockout with binding assays","pmids":["25717360","26245899","24507594","25431931"],"confidence":"Medium","gaps":["Pathway linkages partly correlative and from single labs","Direct molecular targets of CaMKII in this context not fully mapped"]},{"year":2016,"claim":"Discovery that CACNA1S mutations cause a distinct DHPR congenital myopathy, that TnT3 transcriptionally regulates Cacna1s, and that a non-muscle CaV1.1 splice variant supports TCR Ca2+ entry broadened the channel's disease and physiological scope.","evidence":"Exome sequencing with patient-myotube Ca2+ assays, promoter-reporter and in vivo knockdown for TnT3, and T-cell siRNA with TCR Ca2+ flux","pmids":["28012042","26892246","26815481"],"confidence":"Medium","gaps":["T-cell CaV1.1 role from single study","Genotype-phenotype correlation for congenital myopathy mutations incomplete"]},{"year":2021,"claim":"Voltage-clamp fluorometry resolved domain-specific roles of the four VSDs and established VSD-I as the primary driver of pore opening, while gating-pore-current measurements across S4 mutations established the anomalous-conduction mechanism of HypoPP requiring charge neutralization.","evidence":"Opto-electrophysiology with allosteric modeling, and cut-open oocyte voltage clamp of multiple HypoPP mutants with charge-conserving negative controls","pmids":["34546289","29386226","34463712","34636893"],"confidence":"High","gaps":["How VSD-specific kinetics translate to RyR1 conformational coupling in situ not directly shown","Reciprocal CaV1.1/Panx1 coupling characterized in single lab"]},{"year":2022,"claim":"Dissecting γ1 subunit modulation showed that current reduction is exon-29-dependent and allosteric, linking adult splice isoform identity to channel current density.","evidence":"Patch-clamp in HEK293 with γ1 and CaV1.1a/CaV1.1e plus alanine mutagenesis and structural modeling","pmids":["35349630"],"confidence":"High","gaps":["Allosteric mechanism inferred from modeling rather than direct structure","Physiological role of γ1 current reduction in adult muscle not established"]},{"year":2025,"claim":"Domain-specific dissection of STAC3 binding resolved that the proximal C-terminus interaction is necessary and sufficient for functional expression while the II-III loop interaction facilitates RyR1 coupling, integrating STAC3 into the EC coupling machinery and a human disorder.","evidence":"Selective STAC3-interaction disruption rescues in dysgenic myotubes with Ca2+ imaging/electrophysiology and patient genetic analysis","pmids":["40779452"],"confidence":"High","gaps":["Structural basis of the two STAC3 contacts not resolved","How STAC3 binding cooperates with other partners during trafficking unclear"]},{"year":null,"claim":"How VSD-specific gating, STAC3 binding, and the CaV1.1-RyR1 conformational interface 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disease.","date":"2016","source":"Cytotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/27550174","citation_count":8,"is_preprint":false},{"pmid":"17418573","id":"PMC_17418573","title":"Hypokalaemic periodic paralysis due to the CACNA1S R1239H mutation in a large African family.","date":"2007","source":"Neuromuscular disorders : NMD","url":"https://pubmed.ncbi.nlm.nih.gov/17418573","citation_count":8,"is_preprint":false},{"pmid":"18229654","id":"PMC_18229654","title":"Myopathy as the first symptom of hypokalemic periodic paralysis--case report of a girl from a Polish family with CACNA1S (R1239G) mutation.","date":"2007","source":"Advances in medical sciences","url":"https://pubmed.ncbi.nlm.nih.gov/18229654","citation_count":8,"is_preprint":false},{"pmid":"2600936","id":"PMC_2600936","title":"Purification of low molecular weight forms of seminal vesicle specific antigen by immunoaffinity chromatography on bound monoclonal antibody MHS-5.","date":"1989","source":"Journal of reproductive immunology","url":"https://pubmed.ncbi.nlm.nih.gov/2600936","citation_count":8,"is_preprint":false},{"pmid":"31380823","id":"PMC_31380823","title":"Hypokalemic periodic paralysis due to CACNA1S gene mutation.","date":"2019","source":"Neurosciences (Riyadh, Saudi Arabia)","url":"https://pubmed.ncbi.nlm.nih.gov/31380823","citation_count":7,"is_preprint":false},{"pmid":"36825457","id":"PMC_36825457","title":"CACNA1S mutation-associated dental anomalies: A calcium channelopathy.","date":"2023","source":"Oral diseases","url":"https://pubmed.ncbi.nlm.nih.gov/36825457","citation_count":6,"is_preprint":false},{"pmid":"11216663","id":"PMC_11216663","title":"Does the A3333G mutation in the CACNL1A3 gene, detected in malignant hyperthermia, also occur in central core disease?","date":"2000","source":"Genetic testing","url":"https://pubmed.ncbi.nlm.nih.gov/11216663","citation_count":6,"is_preprint":false},{"pmid":"32104981","id":"PMC_32104981","title":"The expanding phenotype of hypokalemic periodic paralysis in a Japanese family with p.Val876Glu mutation in CACNA1S.","date":"2020","source":"Molecular genetics & genomic medicine","url":"https://pubmed.ncbi.nlm.nih.gov/32104981","citation_count":6,"is_preprint":false},{"pmid":"30937521","id":"PMC_30937521","title":"Strength and muscle structure preserved during long-term therapy in a patient with hypokalemic periodic paralysis (Cav1.1-R1239G).","date":"2019","source":"Journal of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/30937521","citation_count":6,"is_preprint":false},{"pmid":"12636044","id":"PMC_12636044","title":"Identification of new polymorphisms in the CACNA1S gene.","date":"2003","source":"Clinical chemistry and laboratory medicine","url":"https://pubmed.ncbi.nlm.nih.gov/12636044","citation_count":6,"is_preprint":false},{"pmid":"37510268","id":"PMC_37510268","title":"Congenital Myopathy as a Phenotypic Expression of CACNA1S Gene Mutation: Case Report and Systematic Review of the Literature.","date":"2023","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/37510268","citation_count":5,"is_preprint":false},{"pmid":"36900039","id":"PMC_36900039","title":"A Mutation in CACNA1S Is Associated with Multiple Supernumerary Cusps and Root Maldevelopment.","date":"2023","source":"Diagnostics (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/36900039","citation_count":5,"is_preprint":false},{"pmid":"26433613","id":"PMC_26433613","title":"The R900S mutation in CACNA1S associated with hypokalemic periodic paralysis.","date":"2015","source":"Neuromuscular disorders : NMD","url":"https://pubmed.ncbi.nlm.nih.gov/26433613","citation_count":5,"is_preprint":false},{"pmid":"9436445","id":"PMC_9436445","title":"[Mutation analysis of the CACNL1A3 gene in Japanese hypokalemic periodic paralysis families].","date":"1997","source":"Nihon rinsho. Japanese journal of clinical medicine","url":"https://pubmed.ncbi.nlm.nih.gov/9436445","citation_count":4,"is_preprint":false},{"pmid":"12066739","id":"PMC_12066739","title":"No evidence of mutations in the CACNA1S gene in the UK malignant hyperthermia population.","date":"2002","source":"British journal of anaesthesia","url":"https://pubmed.ncbi.nlm.nih.gov/12066739","citation_count":4,"is_preprint":false},{"pmid":"29048924","id":"PMC_29048924","title":"De novo Mutation in CACNA1S Gene in a 20-Year-Old Man Diagnosed with Metabolic Myopathy.","date":"2017","source":"Archives of Iranian medicine","url":"https://pubmed.ncbi.nlm.nih.gov/29048924","citation_count":4,"is_preprint":false},{"pmid":"25779869","id":"PMC_25779869","title":"Apparent lack of physical or functional interaction between CaV1.1 and its distal C terminus.","date":"2015","source":"The Journal of general physiology","url":"https://pubmed.ncbi.nlm.nih.gov/25779869","citation_count":4,"is_preprint":false},{"pmid":"17906876","id":"PMC_17906876","title":"Absence of regulation of the T-type calcium current by Cav1.1, beta1a and gamma1 dihydropyridine receptor subunits in skeletal muscle cells.","date":"2007","source":"Pflugers Archiv : European journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/17906876","citation_count":4,"is_preprint":false},{"pmid":"37840943","id":"PMC_37840943","title":"Case report: A novel CACNA1S mutation associated with hypokalemic periodic paralysis.","date":"2023","source":"Frontiers in neurology","url":"https://pubmed.ncbi.nlm.nih.gov/37840943","citation_count":3,"is_preprint":false},{"pmid":"33184660","id":"PMC_33184660","title":"Morphological Alterations of the Sarcotubular System in Permanent Myopathy of Hereditary Hypokalemic Periodic Paralysis with a Mutation in the CACNA1S Gene.","date":"2020","source":"Journal of neuropathology and experimental neurology","url":"https://pubmed.ncbi.nlm.nih.gov/33184660","citation_count":3,"is_preprint":false},{"pmid":"1373781","id":"PMC_1373781","title":"The detection of prostate specific antigen, MHS-5, and other markers in invasive prostate cancer and seminal vesicle.","date":"1992","source":"The Journal of urology","url":"https://pubmed.ncbi.nlm.nih.gov/1373781","citation_count":3,"is_preprint":false},{"pmid":"37930228","id":"PMC_37930228","title":"Two zebrafish cacna1s loss-of-function variants provide models of mild and severe CACNA1S-related myopathy.","date":"2024","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/37930228","citation_count":2,"is_preprint":false},{"pmid":"17333247","id":"PMC_17333247","title":"Gating of the HypoPP-1 mutations: II. Effects of a calcium-channel agonist BayK 8644.","date":"2007","source":"Pflugers Archiv : European journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/17333247","citation_count":2,"is_preprint":false},{"pmid":"40779452","id":"PMC_40779452","title":"STAC3 binding to CaV1.1 II-III loop is nonessential but critically supports skeletal muscle excitation-contraction coupling.","date":"2025","source":"JCI insight","url":"https://pubmed.ncbi.nlm.nih.gov/40779452","citation_count":2,"is_preprint":false},{"pmid":"38426167","id":"PMC_38426167","title":"Case report: Dihydropyridine receptor (CACNA1S) congenital myopathy, a novel phenotype with early onset periodic paralysis.","date":"2024","source":"Frontiers in neurology","url":"https://pubmed.ncbi.nlm.nih.gov/38426167","citation_count":2,"is_preprint":false},{"pmid":"38788083","id":"PMC_38788083","title":"Early-Onset Autosomal Dominant Myopathy with Vacuolated Fibers and Tubular Aggregates but No Periodic Paralysis, in a Patient with the c.1583G>A (p.R528H) mutation in the CACNA1S Gene.","date":"2024","source":"Journal of neuromuscular diseases","url":"https://pubmed.ncbi.nlm.nih.gov/38788083","citation_count":2,"is_preprint":false},{"pmid":"34777470","id":"PMC_34777470","title":"Case Report: A Novel CACNA1S Mutation Associated With Hypokalemic Periodic Paralysis in a Chinese Family.","date":"2021","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/34777470","citation_count":2,"is_preprint":false},{"pmid":"38111203","id":"PMC_38111203","title":"Biallellic variants in CACNA1S cause fetal akinesia sequence, progressive hydrops and stillbirth.","date":"2023","source":"Prenatal diagnosis","url":"https://pubmed.ncbi.nlm.nih.gov/38111203","citation_count":2,"is_preprint":false},{"pmid":"40277085","id":"PMC_40277085","title":"Terahertz wave induces the structural and functional changes in voltage-gated calcium channel Cav1.1: A molecular dynamics study.","date":"2025","source":"The Journal of chemical physics","url":"https://pubmed.ncbi.nlm.nih.gov/40277085","citation_count":2,"is_preprint":false},{"pmid":"16767662","id":"PMC_16767662","title":"[R1239H mutation of CACNA1S gene in a Chinese family with hypokalaemic periodic paralysis].","date":"2006","source":"Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/16767662","citation_count":2,"is_preprint":false},{"pmid":"34804722","id":"PMC_34804722","title":"Vacuolar Myopathy Associated to CACNA1S Mutation as a Rare Cause of Late-Onset Limb-Girdle Myopathy: A Case Report.","date":"2021","source":"Cureus","url":"https://pubmed.ncbi.nlm.nih.gov/34804722","citation_count":2,"is_preprint":false},{"pmid":"40018084","id":"PMC_40018084","title":"CACNA1S-associated triadopathy presenting with myalgia, muscle weakness, and asymptomatic hyperCKemia.","date":"2025","source":"Therapeutic advances in neurological disorders","url":"https://pubmed.ncbi.nlm.nih.gov/40018084","citation_count":1,"is_preprint":false},{"pmid":"33969828","id":"PMC_33969828","title":"MRTF-A regulates Ca2+ release through CACNA1S.","date":"2021","source":"Journal of biosciences","url":"https://pubmed.ncbi.nlm.nih.gov/33969828","citation_count":1,"is_preprint":false},{"pmid":"21774221","id":"PMC_21774221","title":"[The relationships between the single nueleotide polymorphisms of CACNA1S gene 11 exon and thyrotoxic hypokalemic periodic paralysis in the people of Han Nationality in Sichuan Province, China].","date":"2011","source":"Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi","url":"https://pubmed.ncbi.nlm.nih.gov/21774221","citation_count":1,"is_preprint":false},{"pmid":"35039355","id":"PMC_35039355","title":"Novel CACNA1S mutation in hypokalaemic periodic paralysis.","date":"2022","source":"BMJ case reports","url":"https://pubmed.ncbi.nlm.nih.gov/35039355","citation_count":1,"is_preprint":false},{"pmid":"18368309","id":"PMC_18368309","title":"Cloning, sequencing and identification of single nucleotide polymorphisms of partial sequence on the porcine CACNA1S gene.","date":"2008","source":"Science in China. Series C, Life sciences","url":"https://pubmed.ncbi.nlm.nih.gov/18368309","citation_count":1,"is_preprint":false},{"pmid":"39104734","id":"PMC_39104734","title":"Core myopathy in two siblings with a biallelic variant in the CACNA1S gene-A case series study.","date":"2024","source":"Clinical case reports","url":"https://pubmed.ncbi.nlm.nih.gov/39104734","citation_count":1,"is_preprint":false},{"pmid":"40460485","id":"PMC_40460485","title":"Troponin T3 ameliorates sepsis-induced diaphragm dysfunction in rats through modulation of Cacna1s.","date":"2025","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/40460485","citation_count":1,"is_preprint":false},{"pmid":"33088529","id":"PMC_33088529","title":"CACNA1S Arg528Cys mutation in a young Chinese man with thyrotoxic hypokalemic periodic paralysis.","date":"2020","source":"Clinical case reports","url":"https://pubmed.ncbi.nlm.nih.gov/33088529","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":45893,"output_tokens":7804,"usd":0.127369,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":17208,"output_tokens":4496,"usd":0.09922,"stage2_stop_reason":"end_turn"},"total_usd":0.226589,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1994,\n      \"finding\": \"CACNA1S (CACNL1A3) maps to chromosome 1q31-32, co-segregating with the hypokalaemic periodic paralysis (HypoPP) locus without recombinants, establishing it as the causative gene for HypoPP.\",\n      \"method\": \"Genome-wide linkage analysis using polymorphic dinucleotide repeats and intragenic microsatellite markers in three European families\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic linkage established across three independent families with co-segregation without recombinants\",\n      \"pmids\": [\"8012389\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Missense mutations Arg528His and Arg1239His in the voltage-sensor segment S4 of CACNA1S are the predominant causative mutations for hypokalemic periodic paralysis type 1 (HypoPP-1), with the Arg528His mutation showing incomplete penetrance.\",\n      \"method\": \"DNA sequence analysis and cosegregation analysis in 16 Caucasian HypoPP families\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — co-segregation demonstrated in 16 independent families, replicated across subsequent studies\",\n      \"pmids\": [\"7847370\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"The distal C terminus of CaV1.1 (CACNA1S) is proteolytically cleaved in vivo at alanine 1664, and the cleaved distal C-terminal domain (aa 1802–1841) noncovalently associates with a proximal C-terminal region (aa 1556–1612) of the channel. This complex serves as the docking site for AKAP15 and PKA, which are required for cAMP-dependent potentiation of Ca2+ channel activity.\",\n      \"method\": \"Yeast two-hybrid deletion mapping, tandem mass spectrometry of purified skeletal muscle CaV1.1, and expression in mammalian nonmuscle cells\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro mass spectrometry identified proteolytic site, yeast two-hybrid mapped interaction domain, multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"15793008\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"JP-45, a junctional SR protein, directly interacts with two domains of CaV1.1: the I-II loop (via the alpha-interacting domain) and the C-terminal region. The beta1a subunit reduces JP-45 interaction with the I-II loop. JP-45 overexpression decreases peak charge-movement and shifts voltage-dependence; JP-45 depletion decreases both CaV1.1 content and peak charge-movement, demonstrating that JP-45 regulates functional expression of CaV1.1.\",\n      \"method\": \"Co-immunoprecipitation, GST pulldown, charge-movement recordings in C2C12 myotubes with JP-45 overexpression or siRNA depletion\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal binding assays combined with functional electrophysiology, multiple orthogonal methods in one study\",\n      \"pmids\": [\"16638807\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"CaV1.1 (CACNA1S) exhibits Ca2+-dependent inactivation (CDI) mediated by calmodulin: CDI is maximal (~30%) at potentials evoking peak inward current, eliminated by Ba2+ substitution or BAPTA, and abolished by expression of Ca2+-binding-deficient CaM1234. FRET imaging confirmed direct association of CaM with CaV1.1 in dysgenic myotubes.\",\n      \"method\": \"Whole-cell patch-clamp in mouse myotubes, FRET between fluorescently tagged CaV1.1 and CaM, overexpression of dominant-negative CaM1234\",\n      \"journal\": \"Pflugers Archiv : European journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — electrophysiology with pharmacological controls plus FRET for direct protein association, multiple orthogonal methods\",\n      \"pmids\": [\"17899167\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Sequence differences in the IQ motif of CaV1.1 (His1532, Met1537) compared to CaV1.2 (Tyr1657, Lys1662) underlie the weak CaM binding and absence of Ca2+-dependent inactivation in CaV1.1. Reciprocal substitution of these two residues into CaV1.2 eliminates CDI, while introduction of CaV1.2 residues into CaV1.1 confers CaM binding.\",\n      \"method\": \"Native gel electrophoresis of CaM binding to C-terminal peptides, expression of mutant channels in intact myotubes, whole-cell electrophysiology\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — mutagenesis combined with binding assays and functional recordings, multiple orthogonal methods\",\n      \"pmids\": [\"18718913\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"A CaV1.1 splice variant lacking exon 29 (CaV1.1Δ29) shows 30-mV left-shifted voltage-dependence of activation, eightfold increased current density, and accelerated kinetics compared to the adult isoform. This variant is expressed at high levels (~80%) in developing myotubes and supports skeletal EC coupling. Its robust Ca2+ influx substantially contributes to depolarization-induced Ca2+ transients in developing muscle.\",\n      \"method\": \"Expression of GFP-tagged CaV1.1Δ29 in dysgenic (α1S-null) myotubes, patch-clamp and Ca2+ imaging, analysis of human and mouse muscle expression levels\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — reconstitution in null myotubes with rigorous electrophysiology and Ca2+ imaging, expression confirmed in native tissue\",\n      \"pmids\": [\"19134469\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"R528H and R1239H/G mutations in CaV1.1 HypoPP-1 have 'loss-of-function' features: D4/S4 mutations shift channel equilibrium toward closed states (reduced open probability, shorter openings, smaller currents); D2/S4 mutation (R528H) slows activation. HypoPP histidine mutants favor a second open state (O2) with possibly lower channel selectivity.\",\n      \"method\": \"Heterologous expression of wild-type and HypoPP-1 mutations in HEK-293 cells, whole-cell patch-clamp, global kinetic model fitting\",\n      \"journal\": \"Pflugers Archiv : European journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — rigorous in vitro kinetic modeling in single lab using heterologous system (cardiac channel analog), not replicated independently\",\n      \"pmids\": [\"17333249\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"The IQ motif (residues mutated to IQ→AA) of CaV1.1 is essential for Ca2+ current and excitation-contraction coupling: dysgenic myotubes expressing YFP-CaV1.1(AA) show neither Ca2+ currents nor evoked Ca2+ transients, despite normal targeting to the sarcolemma and normal maximal charge movement (Qmax), suggesting the IQ motif is a structural and functional coupling site between DHPR and RyR.\",\n      \"method\": \"Expression of IQ-motif mutant CaV1.1 in dysgenic myotubes, whole-cell Ca2+ current recordings, Ca2+ transient imaging, charge movement recordings\",\n      \"journal\": \"Journal of biomedicine & biotechnology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — functional rescue experiment in null myotubes, single lab, single study\",\n      \"pmids\": [\"22162637\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Caveolin-3 directly interacts with the I-II loop of CaV1.1 (apparent affinity ~60 nM), co-localizes with DHPR within T-tubular membrane, and co-immunoprecipitates from triadic membrane preparations. Expression of the P104L caveolin-3 mutant or siRNA knockdown of caveolin-3 significantly decreases L-type Ca2+ channel maximal conductance.\",\n      \"method\": \"GST-fusion pulldown with CaV1.1 I-II loop peptides, co-immunoprecipitation from triadic membranes, immunolocalization, whole-cell patch-clamp in C2C12 myotubes with siRNA or mutant caveolin-3 expression\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal binding assays, co-IP from native tissue, and functional electrophysiology, multiple orthogonal methods in one study\",\n      \"pmids\": [\"21262376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"CaV1.1 (α1S subunit) acts as voltage sensor for activation of IP3-dependent Ca2+ signals that regulate gene expression in skeletal muscle, and is required for frequency-dependent ATP release through pannexin-1 channels. Myotubes lacking CaV1.1-α1S release almost no ATP after electrical stimulation. ATP release and frequency-specific transcriptional programs (fast-to-slow transition) at 20 Hz (but not 90 Hz) require CaV1.1 function independently of its ion channel activity.\",\n      \"method\": \"Electrical stimulation of CaV1.1-α1S null myotubes, pharmacological blockade/activation of CaV1.1, ATP release measurements, IP3 measurements, gene expression analysis in adult flexor digitorum brevis fibers\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — null cell rescue experiment plus pharmacological confirmation plus multiple readouts (ATP, IP3, transcription)\",\n      \"pmids\": [\"23321639\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Ca2+ binding/permeation through the CaV1.1 pore (E1014K pore mutation abolishes it) is coupled to CaMKII activation and sarcoplasmic reticulum Ca2+ store refilling during sustained muscle activity. Loss of this permeation leads to decreased CaMKII and downstream Ras/Erk/mTORC1 signaling, reduced muscle protein synthesis, increased fatigue, decreased fiber size, and increased type IIb fibers.\",\n      \"method\": \"Knock-in mouse with E1014K CaV1.1 pore mutation, Ca2+ imaging, western blotting, proximity ligation assays, SUnSET protein synthesis assay, isolated muscle force-frequency and fatigue measurements\",\n      \"journal\": \"Skeletal muscle\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo knock-in model with multiple orthogonal functional assays (Ca2+ imaging, biochemistry, force measurements) in single rigorous study\",\n      \"pmids\": [\"25717360\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"CaV1.1-mediated CaMKII activation (via Ca2+ permeation through E1014K pore) regulates the intracellular distribution of fatty acid transport protein CD36 and mitochondrial β-oxidation in skeletal muscle, through a CaV1.1→CaMKII→NOS pathway. Blocking this pathway decreases energy expenditure and increases body fat.\",\n      \"method\": \"E1014K knock-in mice, Ca2+ imaging, Western blotting, immunohistochemistry, pharmacological NOS inhibition, metabolic phenotyping\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — in vivo knock-in model, single lab, multiple readouts but pathway confirmation relies on correlative evidence\",\n      \"pmids\": [\"26245899\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Troponin T3 (TnT3) transcriptionally regulates Cacna1s (CaV1.1) expression by binding to the Cacna1s promoter. Knocking down TnT3 in vivo downregulates CaV1.1; TnT3 overexpression increases Cacna1s promoter activity; this effect requires the TnT3 nuclear localization sequence. Calpain inhibition prevents TnT3 fragmentation, restoring Cacna1s/CaV1.1 levels and muscle force in aging mice.\",\n      \"method\": \"In vivo TnT3 knockdown, Cacna1s promoter-reporter assays, TnT3 nuclear localization sequence truncation, calpain inhibitor (BDA-410) treatment in aged mice, muscle force measurements\",\n      \"journal\": \"Aging cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function and gain-of-function with promoter assays and in vivo rescue, multiple orthogonal methods\",\n      \"pmids\": [\"26892246\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Recessive and dominant mutations in CACNA1S cause a distinct congenital myopathy (DHPR congenital myopathy) characterized by SR dilatation and impaired Ca2+ release induced by depolarization in cultured myotubes, with decreased CACNA1S protein levels.\",\n      \"method\": \"Exome sequencing in 11 patients, Ca2+ release measurements in cultured myotubes from patients, protein level quantification by western blot\",\n      \"journal\": \"Acta neuropathologica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional Ca2+ release assays in patient-derived myotubes with multiple mutations, replicated across patient cohort\",\n      \"pmids\": [\"28012042\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"T cells express a specific CaV1.1 splice variant lacking exon 29 but with five new N-terminal exons substituting for exons 1 and 2. Knockdown of CaV1.1 in T cells abrogates Ca2+ entry after TCR stimulation, demonstrating that CaV1.1 channels are required for TCR-mediated Ca2+ entry.\",\n      \"method\": \"Sequencing and cloning of T cell CaV1.1 cDNA, overexpression in HEK293 cells, siRNA knockdown in T cells with Ca2+ flux measurements after TCR stimulation\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — siRNA knockdown with functional Ca2+ readout in single lab, single study\",\n      \"pmids\": [\"26815481\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Coexpression of STAC3 dramatically increases plasma membrane expression of human CaV1.1 in Xenopus oocytes, enabling functional studies. Using this system, HypoPP mutations R528H and R528G in S4 of domain II are shown to generate gating pore currents (anomalous conductance through the voltage sensor domain); R528H does not conduct protons unlike other R/H HypoPP mutations.\",\n      \"method\": \"Cut-open oocyte voltage clamp of human CaV1.1 coexpressed with α2-δ1b, β1a, and STAC3 in Xenopus oocytes; ionic current and gating charge measurements\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — rigorous voltage-clamp electrophysiology with direct measurement of gating pore currents, mutation-specific analysis in high-expression system\",\n      \"pmids\": [\"29386226\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Each of the four voltage-sensing domains (VSDs) of human CaV1.1 has unique biophysical properties: VSD-I activation kinetics match ionic current activation and contributes the most energy (~75 meV) toward stabilizing open states, driving CaV1.1 pore opening primarily. VSDs II, III, and IV activate faster, compatible with RYR1 Ca2+ release kinetics. The R174W charge-neutralizing mutation in VSD-I abolishes CaV1.1 current at physiological potentials without affecting other VSDs.\",\n      \"method\": \"Opto-electrophysiology (voltage clamp fluorometry) measuring VSD-specific fluorescence changes plus ionic currents in human CaV1.1 expressed in Xenopus oocytes; allosteric model analysis; VSD-I R174W mutant characterization\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — rigorous voltage clamp fluorometry with mutagenesis and allosteric modeling, multiple orthogonal approaches in single rigorous study\",\n      \"pmids\": [\"34546289\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CaV1.1 domain III (DIII) HypoPP mutations R897S and R900G generate gating pore currents, while R900S does not. R897S (R1 of DIII) produces exceptionally large gating pore currents correlating with severe clinical phenotype. The previously reported charge-conserving R897K does not produce gating pore currents, consistent with requirement for charge neutralization to create anomalous VSD conduction.\",\n      \"method\": \"Expression of DIII CaV1.1 HypoPP mutants with STAC3 in Xenopus oocytes, cut-open oocyte voltage clamp for gating pore current measurement\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct electrophysiological measurement of gating pore currents with multiple mutations tested and charge-conserving negative control\",\n      \"pmids\": [\"34463712\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CaV1.1 and Pannexin-1 (Panx1) regulate each other reciprocally in skeletal muscle. CaV1.1 knockdown causes chronically elevated extracellular ATP at rest, disrupting normal Panx1 activity control. Conversely, Panx1 knockdown impairs both transcription activation and CaV1.1 control of contraction. This bidirectional coupling links excitation-contraction and excitation-transcription processes.\",\n      \"method\": \"Knockdown of CaV1.1 or Panx1 in adult skeletal muscle fibers, measurement of extracellular ATP, Ca2+ transients, force, and gene expression\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal knockdown experiments with multiple functional readouts, single lab\",\n      \"pmids\": [\"34636893\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"The γ1 subunit reduces CaV1.1 current density by >50% specifically for the adult (CaV1.1a, contains exon 29) splice variant but not the embryonic (CaV1.1e, lacks exon 29) variant. This current-reducing effect depends on inclusion of exon 29 and is distinct from γ1's effect on voltage-dependence of inactivation (which occurs in both variants). Molecular modeling suggests ionic interactions between the IVS3-S4 loop (encoded by exon 29) and γ1, with allosteric mechanism rather than direct contact mediating current reduction.\",\n      \"method\": \"Stable HEK293 cell lines expressing α2δ-1, β3, STAC3 with γ1 and CaV1.1a or CaV1.1e; patch-clamp electrophysiology; alanine substitution mutagenesis; molecular structure modeling\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — electrophysiology with mutagenesis and structural modeling, multiple orthogonal methods, clear mechanistic dissection\",\n      \"pmids\": [\"35349630\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"STAC3 interaction with the CaV1.1 proximal C-terminus is necessary and sufficient for CaV1.1 functional expression and minimal EC coupling, while STAC3 interaction with the II-III loop of CaV1.1 is not essential for EC coupling but facilitates and enhances conformational coupling with RyR1. A patient with STAC3 disorder carrying a mutation deleting the II-III loop-interacting domain confirms this functional distinction.\",\n      \"method\": \"Expression of CaV1.1 constructs with selective STAC3-interaction domain disruptions in dysgenic myotubes, Ca2+ imaging, electrophysiology, patient genetic analysis\",\n      \"journal\": \"JCI insight\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain-specific rescue experiments in null myotubes with functional EC coupling readout plus human genetic validation\",\n      \"pmids\": [\"40779452\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Raptor (mTORC1) ablation in skeletal muscle alters the ratio of ryanodine receptors to DHPRs (CaV1.1), increases voltage sensor-uncoupled RyRs, and increases frequency and mass of elementary calcium release events (sparks) in FDB fibers, while not significantly affecting global Ca2+ transient amplitude, indicating mTORC1 signaling modulates the composition and function of the EC coupling complex including CaV1.1.\",\n      \"method\": \"Muscle-specific raptor knockout mice, 3H-ryanodine and 3H-PN200-110 equilibrium binding, Ca2+ imaging in FDB fibers, hyper-osmotic shock spark analysis\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — genetic knockout with direct binding assays and Ca2+ imaging, single lab\",\n      \"pmids\": [\"25431931\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CACNA1S haploinsufficiency renders cells and mice resistant to New World arenavirus (Junín and Tacaribe) infection, and reduces the dosage of VGCC antagonists needed to block infection, demonstrating that the α1S voltage-gated calcium channel is required for cellular binding and entry of these arenaviruses.\",\n      \"method\": \"CACNA1S haploinsufficient cell lines and mice infected with Junín and Tacaribe virus; VGCC antagonist dose-response experiments\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — loss-of-function in cells and in vivo with viral entry readout, single lab, single study\",\n      \"pmids\": [\"32719120\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MRTF-A (myocardin-related transcription factor A) activates CACNA1S transcription by binding to a CarG box in the CACNA1S promoter. In mdx mice, MRTF-A expression is decreased and phosphorylation increased, correlating with reduced CACNA1S expression and impaired Ca2+ release through CaV1.1.\",\n      \"method\": \"Promoter-reporter assay with CarG box, ChIP/binding assay, qPCR and western blot in mdx mice, Ca2+ release measurements\",\n      \"journal\": \"Journal of biosciences\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — promoter binding shown but mechanism confirmed only by correlative expression data in disease model, single lab\",\n      \"pmids\": [\"33969828\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The β1a490-508 peptide (19 residues from C-terminal tail of the CaV1.1 β1a subunit) is sufficient to potentiate voltage-dependent Ca2+ release flux (~49% increase) and RyR1 channel activity in adult skeletal muscle fibers, and also increases CaV1.1 Ca2+ currents, demonstrating that the β1a C-terminal tail modulates EC coupling between CaV1.1 and RyR1.\",\n      \"method\": \"Voltage-clamp of adult skeletal muscle fibers with peptide perfusion, Ca2+ release flux measurements, RyR1 single-channel bilayer recordings; scrambled peptide negative control\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Weak — rigorous electrophysiology and bilayer single-channel recordings with appropriate controls, but single lab and peptide approach\",\n      \"pmids\": [\"24507594\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Antibody previously reported to detect CACNA1S (CaV1.1) at ON bipolar cell dendritic tips in retina cross-reacts with GPR179; mass spectrometry of immunoprecipitated protein failed to detect CACNA1S peptides. This negative finding undermines proposed role of CACNA1S in DBC (depolarizing bipolar cell) signal transduction based solely on immunohistochemistry.\",\n      \"method\": \"Western blot, immunoprecipitation followed by mass spectrometric peptide identification, immunohistochemistry in GPR179 mutant retinas and HEK293T cells expressing GPR179\",\n      \"journal\": \"Visual neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal negative-finding methods (western, IP-MS, IHC in multiple models) demonstrating antibody cross-reactivity\",\n      \"pmids\": [\"27471951\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"CaV1.1-R528H knock-in mice develop hypokalaemic periodic paralysis, and treatment with bumetanide (a chloride cotransporter inhibitor) protects against muscle weakness from low K+ challenge in vitro and loss of muscle excitability in vivo, demonstrating a critical role of the chloride gradient in modulating susceptibility to ictal weakness caused by CACNA1S mutations.\",\n      \"method\": \"CaV1.1-R528H knock-in mouse model, in vitro low-K+ challenge with force measurements, in vivo glucose+insulin infusion with EMG, bumetanide treatment\",\n      \"journal\": \"Brain : a journal of neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo knock-in mouse model with pharmacological rescue, multiple functional readouts\",\n      \"pmids\": [\"24142145\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CACNA1S encodes CaV1.1, the pore-forming α1S subunit of the skeletal muscle dihydropyridine receptor (DHPR), which functions primarily as a voltage sensor for excitation-contraction (EC) coupling by directly and conformationally coupling to RyR1 to trigger SR Ca2+ release; VSD-I is the dominant voltage sensor driving pore opening, while its interaction with STAC3 (via the proximal C-terminus, essential; and II-III loop, facilitating) and RyR1 is required for functional EC coupling. Ca2+ permeation through the pore is not required for EC coupling but modulates CaMKII, SR store refilling, and downstream metabolic signaling (Ras/Erk/mTORC1, CD36/β-oxidation). CaV1.1 also acts as voltage sensor for IP3-dependent Ca2+ signals and frequency-dependent ATP release (via pannexin-1) that regulate gene expression and muscle fiber phenotype. The channel is regulated by calmodulin (via an IQ motif crucial for CDI and RyR coupling), the γ1 subunit (which reduces current density specifically in the exon-29-containing adult isoform), JP-45 (which modulates charge movement), caveolin-3 (which interacts with the I-II loop and regulates conductance), and PKA anchored via AKAP15 to the proteolytically cleaved distal C-terminus. HypoPP-causing S4 arginine mutations create anomalous gating pore currents in the voltage sensor domain, causing paradoxical membrane depolarization and weakness in low potassium.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CACNA1S encodes CaV1.1, the pore-forming \\u03b11S subunit of the skeletal muscle dihydropyridine receptor, which functions chiefly as a voltage sensor that conformationally couples membrane depolarization to RyR1-mediated SR Ca2+ release during excitation-contraction (EC) coupling [#10, #17]. Among its four voltage-sensing domains, VSD-I dominates pore opening, contributing the most energy toward stabilizing open states, while VSDs II\\u2013IV activate faster in a manner compatible with RyR1 Ca2+ release kinetics [#17]. Functional expression and EC coupling depend on STAC3: its interaction with the proximal C-terminus is necessary and sufficient for minimal coupling, whereas its interaction with the II-III loop facilitates and enhances conformational coupling with RyR1 [#21]. The IQ motif is a structural and functional coupling site, required for both Ca2+ current and evoked Ca2+ transients [#8], and mediates the weak calmodulin-dependent Ca2+-dependent inactivation that distinguishes CaV1.1 from CaV1.2 [#4, #5]. Ca2+ permeation through the pore is dispensable for EC coupling but drives CaMKII activation, SR store refilling, and downstream Ras/Erk/mTORC1 signaling controlling protein synthesis and fiber type, as well as a CaMKII\\u2192NOS pathway regulating CD36 distribution and \\u03b2-oxidation [#11, #12]. Beyond contraction, CaV1.1 acts as a voltage sensor for IP3-dependent Ca2+ signals and frequency-dependent ATP release through pannexin-1, with which it is reciprocally coupled, linking excitation to transcriptional programs governing fiber phenotype [#10, #19]. The channel is regulated by multiple partners: caveolin-3 binds the I-II loop and sets conductance [#9]; JP-45 binds the I-II loop and C-terminus to control functional channel expression [#3]; the \\u03b31 subunit reduces current density specifically in the exon-29-containing adult isoform [#20]; and PKA is anchored via AKAP15 to the proteolytically cleaved distal C-terminus for cAMP-dependent potentiation [#2]. CACNA1S is the causative gene for hypokalaemic periodic paralysis, in which S4 arginine mutations create anomalous gating pore currents in the voltage sensor domains [#0, #1, #16, #18], and dominant and recessive mutations also cause a distinct DHPR congenital myopathy [#14].\",\n  \"teleology\": [\n    {\n      \"year\": 1995,\n      \"claim\": \"Establishing CACNA1S as the cause of hypokalaemic periodic paralysis and localizing the predominant mutations to S4 voltage-sensor arginines defined the channel's voltage-sensing region as the disease-relevant locus.\",\n      \"evidence\": \"Genome-wide linkage in three families and mutation/cosegregation analysis in 16 HypoPP families\",\n      \"pmids\": [\"8012389\", \"7847370\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Linkage and sequencing did not establish the biophysical mechanism by which S4 mutations cause paralysis\", \"Incomplete penetrance of R528H was unexplained\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identifying in vivo proteolytic cleavage of the distal C-terminus and its docking of AKAP15/PKA explained how cAMP-dependent signaling potentiates CaV1.1 activity.\",\n      \"evidence\": \"Yeast two-hybrid mapping, mass spectrometry of purified skeletal muscle CaV1.1, and expression in nonmuscle cells\",\n      \"pmids\": [\"15793008\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not establish the physiological trigger or magnitude of PKA potentiation in intact muscle\", \"Protease responsible for cleavage not identified\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Defining the molecular basis of calmodulin binding and Ca2+-dependent inactivation pinpointed IQ-motif residues that distinguish CaV1.1 from CaV1.2 gating behavior.\",\n      \"evidence\": \"Whole-cell patch-clamp and FRET in myotubes plus native-gel CaM binding and reciprocal IQ-motif mutagenesis\",\n      \"pmids\": [\"17899167\", \"18718913\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of weak CDI for muscle physiology not resolved\", \"Did not address whether CaM contributes to RyR1 coupling\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Characterizing the exon-29-lacking splice variant showed that developmental isoform switching tunes CaV1.1 voltage-dependence and Ca2+ influx, and kinetic modeling of HypoPP histidine mutants revealed loss-of-function gating shifts.\",\n      \"evidence\": \"Reconstitution in dysgenic myotubes with patch-clamp/Ca2+ imaging, and heterologous HEK-293 expression with kinetic modeling\",\n      \"pmids\": [\"19134469\", \"17333249\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The HypoPP gating studies used a heterologous/cardiac channel analog and were not independently replicated\", \"Loss-of-function gating did not yet explain paradoxical depolarization\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Demonstrating that the IQ motif is essential for EC coupling and that caveolin-3 binds the I-II loop to set conductance expanded the inventory of structural elements and regulatory partners controlling channel function.\",\n      \"evidence\": \"IQ-motif mutant rescue in dysgenic myotubes and GST pulldown/co-IP plus electrophysiology for caveolin-3\",\n      \"pmids\": [\"22162637\", \"21262376\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"IQ-motif coupling role demonstrated in single lab\", \"Mechanism by which caveolin-3 P104L lowers conductance not fully resolved\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identifying CaV1.1 as the voltage sensor for IP3 signals and pannexin-1-dependent ATP release, and a bumetanide-responsive role for chloride gradient in HypoPP, separated the channel's excitation-transcription role from contraction and clarified disease modulation.\",\n      \"evidence\": \"Null-myotube rescue with ATP/IP3/transcription readouts, and R528H knock-in mice with low-K+ challenge and pharmacology\",\n      \"pmids\": [\"23321639\", \"24142145\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab excitation-transcription findings\", \"How chloride gradient interacts with gating pore currents not established\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Knock-in of a pore mutation that abolishes Ca2+ permeation dissociated ion conduction from EC coupling, revealing a CaV1.1\\u2192CaMKII\\u2192Ras/Erk/mTORC1 and \\u2192NOS/CD36 metabolic signaling axis, while \\u03b21a peptide and raptor studies further defined modulation of the EC coupling complex.\",\n      \"evidence\": \"E1014K knock-in mice with imaging/biochemistry/force assays, \\u03b21a peptide perfusion with bilayer recordings, and muscle-specific raptor knockout with binding assays\",\n      \"pmids\": [\"25717360\", \"26245899\", \"24507594\", \"25431931\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Pathway linkages partly correlative and from single labs\", \"Direct molecular targets of CaMKII in this context not fully mapped\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Discovery that CACNA1S mutations cause a distinct DHPR congenital myopathy, that TnT3 transcriptionally regulates Cacna1s, and that a non-muscle CaV1.1 splice variant supports TCR Ca2+ entry broadened the channel's disease and physiological scope.\",\n      \"evidence\": \"Exome sequencing with patient-myotube Ca2+ assays, promoter-reporter and in vivo knockdown for TnT3, and T-cell siRNA with TCR Ca2+ flux\",\n      \"pmids\": [\"28012042\", \"26892246\", \"26815481\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"T-cell CaV1.1 role from single study\", \"Genotype-phenotype correlation for congenital myopathy mutations incomplete\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Voltage-clamp fluorometry resolved domain-specific roles of the four VSDs and established VSD-I as the primary driver of pore opening, while gating-pore-current measurements across S4 mutations established the anomalous-conduction mechanism of HypoPP requiring charge neutralization.\",\n      \"evidence\": \"Opto-electrophysiology with allosteric modeling, and cut-open oocyte voltage clamp of multiple HypoPP mutants with charge-conserving negative controls\",\n      \"pmids\": [\"34546289\", \"29386226\", \"34463712\", \"34636893\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How VSD-specific kinetics translate to RyR1 conformational coupling in situ not directly shown\", \"Reciprocal CaV1.1/Panx1 coupling characterized in single lab\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Dissecting \\u03b31 subunit modulation showed that current reduction is exon-29-dependent and allosteric, linking adult splice isoform identity to channel current density.\",\n      \"evidence\": \"Patch-clamp in HEK293 with \\u03b31 and CaV1.1a/CaV1.1e plus alanine mutagenesis and structural modeling\",\n      \"pmids\": [\"35349630\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Allosteric mechanism inferred from modeling rather than direct structure\", \"Physiological role of \\u03b31 current reduction in adult muscle not established\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Domain-specific dissection of STAC3 binding resolved that the proximal C-terminus interaction is necessary and sufficient for functional expression while the II-III loop interaction facilitates RyR1 coupling, integrating STAC3 into the EC coupling machinery and a human disorder.\",\n      \"evidence\": \"Selective STAC3-interaction disruption rescues in dysgenic myotubes with Ca2+ imaging/electrophysiology and patient genetic analysis\",\n      \"pmids\": [\"40779452\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the two STAC3 contacts not resolved\", \"How STAC3 binding cooperates with other partners during trafficking unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How VSD-specific gating, STAC3 binding, and the CaV1.1-RyR1 conformational interface integrate into a unified structural mechanism of EC coupling, and how this is perturbed across the spectrum of disease mutations, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No high-resolution structural model of the gating-coupling transition is captured in the corpus\", \"Mechanistic basis of incomplete penetrance and genotype-phenotype variability in HypoPP not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005262\", \"supporting_discovery_ids\": [17, 9]},\n      {\"term_id\": \"GO:0140299\", \"supporting_discovery_ids\": [10, 17]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [10, 17]},\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [11, 16]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [8, 16, 9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-397014\", \"supporting_discovery_ids\": [10, 11, 21]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [11, 12, 10]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [0, 1, 14]}\n    ],\n    \"complexes\": [\"dihydropyridine receptor (DHPR)\", \"skeletal muscle triad EC coupling complex\"],\n    \"partners\": [\"RYR1\", \"STAC3\", \"CALM1\", \"CAV3\", \"CACNB1\", \"STAC3\", \"JSRP1\", \"PANX1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}