{"gene":"CACNA1B","run_date":"2026-06-09T22:57:17","timeline":{"discoveries":[{"year":2009,"finding":"CRMP-2 physically associates with CaV2.2 in dorsal root ganglion (DRG) neurons (co-immunoprecipitation), colocalizes at synapses and growth cones, and overexpression of CRMP-2 increases CaV2.2 current density and surface levels, while CRMP-2 siRNA knockdown reduces Ca2+ influx and CGRP release, establishing CRMP-2 as a positive regulator of CaV2.2 trafficking and transmitter release.","method":"Co-immunoprecipitation, confocal colocalization, nucleofection overexpression/siRNA knockdown, patch-clamp electrophysiology, CGRP release assay","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal co-IP, multiple orthogonal methods (electrophysiology, surface expression, neurotransmitter release), consistent gain- and loss-of-function in native neurons","pmids":["19903690"],"is_preprint":false},{"year":2012,"finding":"Cdk5-mediated phosphorylation of CRMP-2 at Ser522 enhances its interaction with CaV2.2 and is required for CRMP-2-mediated enhancement of CaV2.2 currents; a phospho-null S522A CRMP-2 mutant or inactive Cdk5 abolishes the current enhancement, while the Rho kinase site T555A mutant is ineffective.","method":"Phospho-null and phospho-mimetic mutagenesis, co-immunoprecipitation, patch-clamp electrophysiology, siRNA knockdown/rescue","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — site-directed mutagenesis combined with co-IP and electrophysiology in a single study, identifying specific phosphorylation site","pmids":["23022559"],"is_preprint":false},{"year":2015,"finding":"(S)-Lacosamide binds directly to CRMP-2 (STD NMR and DSF), inhibits Cdk5-mediated phosphorylation of CRMP-2 at Ser522, reduces Cdk5-phosphorylated CRMP-2 association with CaV2.2, and thereby decreases CaV2.2-mediated calcium influx in neurons.","method":"STD NMR, differential scanning fluorimetry, in vitro luminescent kinase assay, co-immunoprecipitation, calcium imaging in neurons","journal":"Molecular neurobiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct binding demonstrated by NMR and DSF, kinase assay, and functional consequence in neurons, multiple orthogonal methods in one study","pmids":["25846820"],"is_preprint":false},{"year":2015,"finding":"A myristoylated CRMP2-derived peptide (myr-tat-CBD3) tethered to the membrane near CaV2.2 disrupts the CRMP2-CaV2.2 interaction (pull-down assay), reduces CaV2.2 surface trafficking (quantitative immunofluorescence), inhibits depolarization-evoked Ca2+ influx, reduces Ca2+ (but not Na+) currents, and decreases excitability of DRG neurons.","method":"Pull-down assay, quantitative confocal immunofluorescence, whole-cell patch-clamp (voltage and current clamp), calcium imaging","journal":"Pain","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods including pull-down, imaging, and electrophysiology; disruption of specific protein-protein interaction linked to functional outcomes","pmids":["25782368"],"is_preprint":false},{"year":2004,"finding":"RGS12 binds to the SNARE-binding (synprint) region (amino acids 726-985) of the CaV2.2 alpha1 II-III loop via its N-terminal PTB domain, and this interaction requires tyrosine phosphorylation of Tyr-804. Microinjection of synprint peptides containing pTyr-804 altered desensitization kinetics of neurotransmitter-mediated inhibition of CaV2.2, implicating RGS12 in controlling the time course of voltage-independent CaV2.2 inhibition.","method":"Protein overlay, surface plasmon resonance, co-immunoprecipitation, peptide microinjection, patch-clamp electrophysiology in DRG neurons","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — SPR binding assay, protein overlay, co-IP with phosphopeptides, and functional electrophysiology validation with site-specific peptides","pmids":["15536086"],"is_preprint":false},{"year":2006,"finding":"The synprint (II-III loop) site of CaV2.2 is important but not essential for presynaptic clustering in hippocampal neurons; GFP-CaV2.2 splice variants lacking the synprint are still targeted to axons but show markedly reduced presynaptic cluster formation. Insertion of synprint into CaV1.2 does not confer axonal targeting, indicating synprint cooperates with other targeting mechanisms.","method":"GFP-fusion protein expression in mouse hippocampal neurons, live imaging, immunofluorescence colocalization","journal":"The European journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct imaging in neurons with deletion mutants, single lab","pmids":["16930401"],"is_preprint":false},{"year":2004,"finding":"Deletion of the synprint site from CaV2.2 alpha1B reduces secretion efficiency in pheochromocytoma cells; when Ca2+ entry is normalized, cells expressing the synprint-deletion channel show significantly reduced total secretion, rate of secretion (capacitance measurements), and endocytosis, demonstrating the synprint site is required for efficient coupling of Ca2+ influx to exocytosis.","method":"Transient transfection in MPC 9/3L cells, whole-cell patch-clamp capacitance measurements, Ca2+ current recording","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Moderate — reconstitution in cell line lacking endogenous VGCCs, capacitance measurements directly link synprint deletion to secretion deficit","pmids":["15471993"],"is_preprint":false},{"year":2004,"finding":"The alpha2delta-1 auxiliary subunit significantly reduces the on-rates and equilibrium inhibition of omega-conotoxins GVIA, MVIIA, and CVID at recombinant N-type (CaV2.2) channels; alpha2delta-1 also differentially modulates the extent of recovery from toxin block depending on toxin identity, implicating alpha2delta-1 in shaping toxin pharmacology of CaV2.2.","method":"Two-electrode voltage clamp in Xenopus oocytes and HEK cells with subunit co-expression, kinetic analysis of toxin on/off-rates","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — systematic reconstitution in two expression systems, multiple toxins tested, quantitative kinetic analysis","pmids":["15166237"],"is_preprint":false},{"year":2004,"finding":"Overexpressed CaVbeta3 subunit causes a ~40 mV hyperpolarizing shift of the steady-state inactivation of CaV2.2 channels, producing 'ultra-slow' inactivation at physiological holding potentials and markedly suppressing macroscopic N-type currents at -60 to -80 mV; this inhibitory effect is reversed at hyperpolarized holding potentials (-120 mV), establishing a novel inhibitory role for beta3 via shifted inactivation.","method":"Two-electrode voltage clamp in Xenopus oocytes, steady-state inactivation protocols, varying holding potentials and beta3 concentrations","journal":"The Journal of general physiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — systematic in vitro reconstitution with quantitative biophysical analysis of inactivation gating, single lab with multiple conditions","pmids":["15024042"],"is_preprint":false},{"year":2006,"finding":"The mutually exclusive C-terminal exon e37a of CaV2.2 increases channel open time and functional channel expression density compared to the e37b isoform, resulting in augmented calcium entry per action potential in nociceptors; single-channel and gating current analysis revealed that e37a channels remain open longer without affecting gating charge movement.","method":"Stable cell line expression, macroscopic and single-channel patch-clamp, gating current recordings in tsA201 cells","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 1 / Strong — single-channel and gating current analysis in stable expressing cell lines; multiple biophysical parameters compared across isoforms","pmids":["16857708"],"is_preprint":false},{"year":2004,"finding":"Alternative splicing of exon 31a in the IVS3-IVS4 region of CaV2.2 slows the speed of channel activation and deactivation at all voltages, and slows gating current decay (On-gating currents), without consistently shifting voltage dependence of charge movement; this correlates with slower N-type kinetics in peripheral sympathetic neurons.","method":"Stable cell lines expressing four CaV2.2 splice isoforms, whole-cell ionic and gating current recordings in tsA201 cells","journal":"Journal of neurophysiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — gating current analysis in stable cell lines resolving both ionic and charge movement properties across multiple isoforms","pmids":["15201306"],"is_preprint":false},{"year":2001,"finding":"Truncated CaV2.2 constructs containing domain I (alone or within domain I-II) suppress full-length CaV2.2 expression through inhibition of channel synthesis; this suppression does not require sequestration of CaVbeta, is not mimicked by the cytoplasmic I-II loop alone, and requires transmembrane segments, as the isolated CaV2.2 N-terminus has no effect.","method":"Co-expression in Xenopus oocytes, GFP-CaV2.2 fluorescence quantification, Western blot, single-channel recordings","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple domain deletion constructs tested, protein expression and single-channel recording, single lab","pmids":["11606638"],"is_preprint":false},{"year":2003,"finding":"Gbetagamma subunits inhibit CaV2.2 (N-type) channels via a voltage-dependent mechanism; the apparent (un)binding kinetics of Gbetagamma with N-type channels are twofold slower than with P/Q-type at voltage extremes (up to 10-fold in mid-voltage range). Single-point alanine mutations in Gbeta1 differentially affect N- versus P/Q-type modulation, identifying distinct binding surfaces on Gbetagamma for the two channel types.","method":"Electrophysiology (compound-state willing-reluctant analysis), Gbeta1 mutagenesis, co-expression in heterologous system","journal":"The Journal of general physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — systematic mutagenesis of Gbetagamma combined with quantitative kinetic electrophysiology, single lab","pmids":["12771191"],"is_preprint":false},{"year":2010,"finding":"Scanning mutagenesis identified Arg376 and Val416 in the I-II loop of CaV2.2 as key molecular determinants for voltage-dependent G protein (Gbeta1gamma2) inhibition; R376F mutation drastically alters the ability of auxiliary beta subunit isoforms to regulate G protein inhibition of the channel.","method":"Alanine/cysteine scanning mutagenesis, patch-clamp recordings, co-expression of Gbeta1gamma2 with mutant channels in heterologous cells","journal":"Molecular brain","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — systematic scanning mutagenesis with electrophysiological functional readout, single lab","pmids":["20181083"],"is_preprint":false},{"year":2008,"finding":"AGS1 and Rhes monomeric G proteins selectively alter Galphai-dependent signaling to inhibit CaV2.2 channels: they reduce basal CaV2.2 current density, trigger tonic voltage-dependent inhibition, and attenuate agonist-initiated inhibition through Galphai-coupled (but not Galphas-coupled) receptors via a Gbetagamma- and pertussis toxin-sensitive mechanism.","method":"Whole-cell patch-clamp in HEK293 cells, Gbetagamma-sequestering peptide (masGRK3ct), pertussis toxin treatment, co-expression of multiple G protein isoforms","journal":"American journal of physiology. Cell physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological dissection with pertussis toxin and Gbetagamma sequestration, multiple G protein isoforms tested, single lab","pmids":["18815223"],"is_preprint":false},{"year":2006,"finding":"G protein-mediated inhibition (via Gbetagamma binding) of CaV2.2 channels reduces both Ca2+-dependent and voltage-dependent inactivation during low-frequency trains of action potential waveforms; wild-type Gbetagamma mimics this effect but a point mutant with reduced channel affinity does not, demonstrating Gbetagamma modulates CaV2.2 inactivation directly.","method":"Action potential waveform stimulation, whole-cell patch-clamp in HEK293 cells and adrenal chromaffin cells, wild-type vs. affinity-reduced Gbetagamma mutant co-expression","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Gbetagamma affinity mutant provides mechanistic specificity; tested in two cell types, single lab","pmids":["17182788"],"is_preprint":false},{"year":2008,"finding":"MAP1A light chain 2 (LC2) interacts with a 23-residue domain in the CaV2.2 C-terminus, mediates presynaptic surface retention of CaV2.2, and links channels to the actin cytoskeleton; disruption of LC2-CaV2.2 interaction or actin depolymerization reduces surface CaV2.2 at presynaptic boutons, reduces Ca2+ influx, and impairs FM4-64 uptake (synaptic vesicle recycling).","method":"Co-immunoprecipitation, deletion mutagenesis, antibody against extracellular CaV2.2 epitope for live surface labeling, RNAi knockdown, FM4-64 assay, latrunculin A treatment in hippocampal neurons","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (co-IP, surface antibody labeling, RNAi, pharmacological actin disruption, functional vesicle recycling assay) in native neurons","pmids":["18971475"],"is_preprint":false},{"year":2014,"finding":"Ankyrin-B associates with CaV2.2 (and CaV2.1) via its membrane-binding domain interacting with a conserved motif in the DII/III loop; mutation of a single conserved tyrosine (Y788E in CaV2.2) abolishes ankyrin-B binding in vitro and in vivo, and disrupts proper targeting of CaV2.2 in a heterologous system.","method":"Co-immunoprecipitation from brain regions, in vitro pull-down, site-directed mutagenesis (Y788E), transfection in heterologous cells","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP from native brain tissue, in vitro binding, and mutagenesis identifying single critical residue, single lab multiple methods","pmids":["24394417"],"is_preprint":false},{"year":2014,"finding":"CaVbeta subunit binding to the I-II loop of CaV2.2 protects this loop from proteasomal degradation: in the absence of CaVbeta, the I-II loop is directly ubiquitinated on lysine residues and degraded by the proteasome; CaVbeta binding prevents degradation but not oligoubiquitination, and is required (along with a palmitoylation signal) for I-II loop trafficking to the plasma membrane.","method":"Ubiquitination assays, proteasome inhibitor (MG132) treatment, lysine-to-arginine mutagenesis, Western blot, surface trafficking assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — reconstituted ubiquitination, mutagenesis of all 12 lysines, proteasome inhibitor rescue, multiple mechanistic conditions tested in one study","pmids":["27489103"],"is_preprint":false},{"year":2014,"finding":"MAP1B light chain 1 (LC1) interacts with CaV2.2 via its N-terminus binding to the C-terminal of the pore-forming subunit, and recruits ubiquitin-conjugating enzyme UBE2L3 to form a tripartite complex; LC1 overexpression decreases N-type currents via enhanced proteasomal degradation, and LC1/UBE2L3 complex mediates internalization of CaV2.2 via dynamin- and clathrin-dependent pathway.","method":"Co-immunoprecipitation, in vitro pull-down, yeast two-hybrid, patch-clamp in HEK293 cells, MG132 proteasome inhibitor treatment, immunofluorescence in hippocampal neurons","journal":"Pflugers Archiv : European journal of physiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods including co-IP, Y2H, in vitro pull-down, and functional electrophysiology with proteasome inhibitor rescue","pmids":["24566975"],"is_preprint":false},{"year":2008,"finding":"Gamma7 (stargazin-related protein) is present on intracellular membranes and decreases CaV2.2 expression by accelerating degradation of CaV2.2 mRNA via its C-terminus; gamma7 binds directly to hnRNP A2, which also binds to a motif in CaV2.2 mRNA, and knockdown of gamma7 enhances CaV2.2 mRNA stability and increases endogenous calcium currents.","method":"Co-immunoprecipitation, mRNA stability assays, shRNA knockdown, electrophysiology in PC12 cells, direct binding assays","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal co-IP, shRNA gain/loss of function, mRNA stability measurement, direct hnRNP A2 binding demonstrated, functional electrophysiology","pmids":["18923037"],"is_preprint":false},{"year":2013,"finding":"The synaptic vesicle (SV) tethers directly to the CaV2.2 channel C-terminal via a PDZ-independent mechanism within the distal 49 amino acids (prior to the PDZ ligand); SVs are captured by intact CaV2.2 and by C-terminal fusion proteins in a cell-free pull-down assay. The HxxRR motif (identified by blocking peptide mutagenesis) is the key SV-binding determinant on the CaV2.2 C-terminal.","method":"In vitro synaptic vesicle pull-down assay, C-terminal truncation fusion proteins, PDZ-LD mutant fusion proteins, mimetic blocking peptides, electron microscopy of synaptosome ghosts","journal":"Frontiers in cellular neuroscience","confidence":"High","confidence_rationale":"Tier 1 / Strong — cell-free reconstitution with multiple truncation and mutant constructs, validated by peptide inhibition in synaptosomes","pmids":["24639630"],"is_preprint":false},{"year":2013,"finding":"Intact CaV2.2 channels directly capture synaptic vesicles (SVs) in a cell-free pull-down assay; SV capture also occurs with C-terminal fusion proteins (distal half of C-terminal), demonstrating a direct molecular tethering mechanism linking the CaV2.2 C-terminal to SVs independent of other presynaptic proteins.","method":"In vitro synaptic vesicle pull-down assay, antibody-immobilized CaV2.2, Western blot for SV markers","journal":"Frontiers in cellular neuroscience","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — cell-free reconstitution assay with controls (IgG, blocked antibody, plain beads), single lab","pmids":["23874268"],"is_preprint":false},{"year":2007,"finding":"Munc18 coprecipitates with CaV2.2 from rat and chick brain lysates and purified presynaptic terminal membranes, binds with high affinity to the CaV2.2 II-III intracellular loop and low affinity to the I-II loop; siRNA knockdown of Munc18 shifts CaV2.2 steady-state inactivation; Munc18 also coprecipitates with synaptotagmin, suggesting it bridges the Ca2+ channel to the synaptic vesicle.","method":"Co-immunoprecipitation from brain/synaptosome lysates and cell line, siRNA knockdown, patch-clamp electrophysiology (steady-state inactivation), immunostaining colocalization","journal":"Channels (Austin, Tex.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP from multiple preparations, functional knockdown with electrophysiological readout, single lab","pmids":["19170253"],"is_preprint":false},{"year":2014,"finding":"The CaVbeta subunit targets CaV2.2 to the plasma membrane and prevents its proteasomal degradation; disrupting the CaValpha-CaVbeta interaction with a small molecule (IPPQ) identified by structure-based virtual screening against the CaVbeta pocket reduces CaV2.2 currents in DRG neurons and decreases presynaptic localization of CaV2.2 in vivo.","method":"Structure-based virtual screening, small molecule binding to CaVbeta (biochemical assay), patch-clamp electrophysiology in DRG neurons, in vivo CaV2.2 localization imaging, EPSP/mEPSP recordings, CGRP release assay","journal":"Pain","confidence":"High","confidence_rationale":"Tier 2 / Strong — structure-based design, biochemical binding assay, multiple in vitro and in vivo functional readouts confirming mechanism","pmids":["30933958"],"is_preprint":false},{"year":2011,"finding":"Bipartite interactions between syntaxin 1A and the CaV2.2 synprint region were mapped: syntaxin 1A H3c domain (C-terminal) binds residues 822-872 of CaV2.2, while the N-terminal 10 residues of the Ha domain bind residues 718-771 of CaV2.2. The syntaxin 1A N-terminal peptide allosterically inhibits CaV2.2 channel function but does not affect G-protein-mediated inhibition.","method":"In vitro binding assays with syntaxin truncation mutants, whole-cell patch-clamp in recombinant expression system","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro binding with truncation series plus functional electrophysiology, single lab","pmids":["21763275"],"is_preprint":false},{"year":2012,"finding":"Alpha-conotoxins Vc1.1 and RgIA inhibition of CaV2.2 channels in DRG neurons requires functional GABAB receptor expression; siRNA knockdown of GABAB R1 and R2 subunits significantly reduces alpha-conotoxin- and baclofen-inhibition of N-type channels, and in HEK293 cells both GABAB subunits are required for Vc1.1 and RgIA inhibition of CaV2.2.","method":"siRNA knockdown of GABAB subunits, qRT-PCR and immunocytochemistry to confirm knockdown, whole-cell patch-clamp in DRG neurons and HEK293 cells","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — siRNA knockdown confirmed at mRNA and protein levels, functional electrophysiology in native neurons and heterologous system, multiple conotoxins tested","pmids":["22613715"],"is_preprint":false},{"year":2014,"finding":"Alpha-conotoxin Vc1.1 inhibits CaV2.2 via GABAB receptor activation through a distinct molecular pathway from GABA/baclofen: Vc1.1 increases CaV2.2 activation rate and shifts half-maximum inactivation to more hyperpolarized potentials; truncation of the GABAB(1a) proximal C-terminus significantly reduces Vc1.1 inhibition, identifying this domain as necessary for Vc1.1's inhibitory mechanism.","method":"Heterologous GABAB receptor expression, GABAB(1a) C-terminal truncations, whole-cell patch-clamp electrophysiology, mutagenesis","journal":"Molecular pharmacology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — systematic truncation mutagenesis of GABAB(1a) with electrophysiological functional readout, single lab","pmids":["25425625"],"is_preprint":false},{"year":2015,"finding":"Constitutive GHSR1a activity reduces CaV2.2 current through a Gi/o-dependent mechanism involving persistent reduction in CaV2.2 channel density at the plasma membrane; ghrelin-dependent GHSR1a inhibition is reversible and involves altered CaV2.2 gating via a Gq-dependent pathway; both pathways attenuate GABA release from hypothalamic neurons.","method":"Patch-clamp in rat/mouse hypothalamic neurons and heterologous expression system, Gi/o and Gq pathway inhibitors, channel surface density measurements","journal":"The Journal of general physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — two mechanistically distinct pathways differentiated pharmacologically in native neurons and heterologous system, single lab","pmids":["26283199"],"is_preprint":false},{"year":2013,"finding":"Tetraspanin-13 (TSPAN-13) specifically interacts with the alpha1 subunit of CaV2.2 (but not CaV2.1 or L/T-type channels), with interaction mapping to domain IV of CaV2.2 and transmembrane segments S1-S2 of TSPAN-13; TSPAN-13 modulates coupling between voltage sensor activation and pore opening, accelerating activation and inactivation kinetics.","method":"Yeast split-ubiquitin system, domain mapping, patch-clamp electrophysiology (Ba2+ current) in transfected cells","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast split-ubiquitin interaction assay plus functional electrophysiology with domain mapping, single lab","pmids":["23648579"],"is_preprint":false},{"year":2010,"finding":"Alpha2delta-1 auxiliary subunit is necessary and sufficient for targeting CaV2.2/beta1b complexes to lipid rafts (identified by caveolin/flotillin colocalization and biochemical raft fractionation); clustering of CaV2.2 at the cell surface requires the actin cytoskeleton (disrupted by cytochalasin D) rather than raft integrity per se.","method":"Biochemical lipid raft fractionation, confocal imaging with raft markers (caveolin, flotillin), methyl-beta-cyclodextrin raft disruption, cytochalasin D actin disruption, electrophysiology in COS-7 cells","journal":"Cell calcium","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple imaging and biochemical approaches with pharmacological dissection, single lab","pmids":["20888635"],"is_preprint":false},{"year":2014,"finding":"14-3-3tau promotes functional surface expression of CaV2.2 alpha1B in the absence of canonical auxiliary subunits; the proximal C-terminal region (amino acids 1706-1940) is retained in the ER and is facilitated to traffic to the plasma membrane by 14-3-3; 14-3-3 and CaVbeta co-regulate CaV2.2 surface expression.","method":"Co-expression in tsA-201 cells and neurons, immunofluorescence surface/total ratio, whole-cell voltage clamp (Ba2+ currents), 14-3-3 antagonist/inactive control constructs","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — surface vs. total expression quantified by immunofluorescence with functional electrophysiological readout, gain/loss-of-function design, single lab","pmids":["25516596"],"is_preprint":false},{"year":2013,"finding":"PIP2 hydrolysis (via PLC activation) is responsible for voltage-independent inhibition of CaV2.2 channels in sympathetic neurons; blocking PLC prevents voltage-independent inhibition, intracellular PIP2 analog prevents it, and inhibiting PIP2 resynthesis (wortmannin) blocks recovery from voltage-independent inhibition.","method":"Double-pulse voltage clamp protocol in SCG neurons, pharmacological PLC blockade, intracellular PIP2 dialysis, wortmannin PIP2 resynthesis inhibition","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological dissection with three orthogonal approaches (PLC inhibition, PIP2 dialysis, resynthesis blockade) in native neurons, single lab","pmids":["23396054"],"is_preprint":false},{"year":2014,"finding":"Voltage-dependent G protein inhibition of CaV2.2 channels is determined by the location of the CaVbeta isoform: membrane-localized beta2a confers Gbetagamma-mediated voltage-dependent inhibition by Gq-coupled M1 receptors, while cytosol-localized beta subunits (beta2b, beta3, palmitoylation-deficient beta2a C3,4S) confer more effective voltage-independent PIP2-mediated inhibition.","method":"Whole-cell patch-clamp in tsA-201 cells, C-terminus of beta-ARK to sequester Gbetagamma, alpha1C-1B chimera, multiple beta subunit isoforms including palmitoylation mutant","journal":"The Journal of general physiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — systematic dissection with chimeric channels, Gbetagamma sequestration, palmitoylation mutant, and multiple beta isoforms clearly mapping voltage dependence to beta subunit localization","pmids":["25225550"],"is_preprint":false},{"year":2009,"finding":"The orientation of palmitoylated CaVbeta2a relative to CaV2.2 determines the form of NK-1R/substance P-mediated modulation; deleting 1-2 amino acids proximal to the AID in CaV2.2 displaces CaVbeta2a, switching current enhancement (by SP) to inhibition matching the beta3-coexpressed phenotype; exogenous palmitic acid rescues this, suggesting beta2a palmitoyl groups block an inhibitory site on CaV2.2.","method":"Deletion mutagenesis of CaV2.2 I-II linker (Bdel1, Bdel2), co-expression with CaVbeta2a or CaVbeta3, substance P stimulation, whole-cell patch-clamp, exogenous palmitate application","journal":"The Journal of general physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — structure-function approach with deletion mutants and palmitate rescue, single lab","pmids":["19858358"],"is_preprint":false},{"year":2005,"finding":"Roscovitine (a CDK inhibitor) slows CaV2.2 channel deactivation from an extracellular binding site with EC50 ~53 µM, preferentially binding to the open-channel state; it also produces a slight left shift in activation voltage relationship and increased inactivation; the effect is stereospecific and kinase-independent, as the closely related olomoucine does not replicate it and intracellular roscovitine is ineffective.","method":"Whole-cell and single-channel patch-clamp, intracellular vs. extracellular application, olomoucine control, pharmacological characterization in Xenopus oocytes/HEK cells","journal":"Biophysical journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — systematic pharmacological characterization with stereoisomer and intracellular controls identifying extracellular binding site, single lab","pmids":["15951378"],"is_preprint":false},{"year":2011,"finding":"CaV2.2 N-terminal (residues 45-55) and I-II loop AID (residues 377-393) peptides each inhibit synaptic transmission and reduce Ca2+ current amplitude when injected presynaptically into SCG neurons; both peptides attenuate G protein modulation; mutations to residues within the N-terminal proposed QXXER motif abolish inhibitory effects, identifying the N-terminus as a molecular determinant of CaV2.2 function and G protein modulation.","method":"Presynaptic peptide injection, whole-cell patch-clamp in SCG neurons, mutagenesis of peptide residues","journal":"The Journal of physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — peptide injection in native neurons with functional readouts (synaptic transmission and Ca2+ current), mutagenesis of key residues, single lab","pmids":["21521766"],"is_preprint":false},{"year":2014,"finding":"The CACNA1B R1389H mutation in the outer pore region reduces single-channel current amplitude (less current when open) without altering ion selectivity, voltage-dependent activation, or inactivation, consistent with a gain-of-function associated with myoclonus-dystonia and cardiac arrhythmias.","method":"Whole-cell and single-channel patch-clamp recordings of R1389H mutant vs. wild-type CaV2.2","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — high-resolution single-channel analysis of disease mutation, comprehensive biophysical characterization, single lab/family","pmids":["25296916"],"is_preprint":false},{"year":2021,"finding":"TWIST1 transcriptionally represses Cacna1b in hematopoietic stem cells (HSCs); Twist1 deletion induces Cacna1b transactivation, increasing mitochondrial Ca2+ levels, metabolic activity, and ROS production, leading to HSC exhaustion; pharmacological VGCC blockade largely rescues defects in Twist1-deleted HSCs.","method":"Conditional Twist1 knockout mouse model, gene expression analysis, calcium channel blocker rescue, mitochondrial function assays, HSC transplantation/functional assays","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic deletion with pharmacological rescue, functional HSC assays, multiple cellular phenotypes measured, single lab","pmids":["33619534"],"is_preprint":false},{"year":2007,"finding":"D2-like dopamine receptor activation in subthalamic nucleus neurons reduces CaV2.2 (but not CaV1) channel conductance via direct Gbetagamma binding (relief by brief depolarization); this reduction in CaV2.2 activity attenuates SKCa channel-mediated action potential afterhyperpolarization, modulating firing patterns.","method":"Patch-clamp in rat brain slices and acutely isolated neurons, pharmacological dissection with D2/D3/D4 agonists/antagonists, Ca2+-free media, CaV and SKCa channel blockers, brief depolarization protocol","journal":"Journal of neurophysiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — voltage-dependent reversal (Gbetagamma) established, pharmacological receptor subtype identification, functional consequences on firing pattern, single lab","pmids":["18094105"],"is_preprint":false},{"year":2016,"finding":"RIM1alpha directly binds to CaV2.2 following deubiquitination (via Fbxo3 inhibition of Fbxl2-dependent ubiquitination of RIM1alpha), increasing CaV2.2 expression in synaptic plasma membranes of dorsal horn; RIM1alpha knockdown reverses SNL-induced allodynia and reduces spontaneous EPSC frequency by suppressing CaV2.2 expression.","method":"Spinal nerve ligation model, co-immunoprecipitation, siRNA knockdown of RIM1alpha, Western blot, patch-clamp (sEPSC recordings), intrathecal pharmacology","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP demonstrating direct binding, siRNA knockdown with functional electrophysiological readout in vivo/ex vivo, multiple interventions, single lab","pmids":["27629721"],"is_preprint":false},{"year":2019,"finding":"CaV2.2 channels are required in Trpv1-lineage neurons for thermal pain hypersensitivity following inflammation; CFA-induced inflammation increases CaV2.2 expression and current density in thermal nociceptors, increases action potential frequency (current clamp), and promotes ERK1/2-dependent sensory nerve growth; all effects are blocked by a CaV2.2-specific inhibitor.","method":"Cav2.2 inhibitor pharmacology, in situ hybridization, immunoblotting, voltage and current clamp in DRG neurons, behavioral thermal/mechanical testing","journal":"Frontiers in neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — specific pharmacological inhibition, electrophysiology, and nerve growth assay linked to CaV2.2 in native neurons, single lab","pmids":["31607850"],"is_preprint":false},{"year":2019,"finding":"CaV2.2 exon 37a variant, expressed in excitatory projection neurons, enhances excitatory neurotransmitter release at entorhinal cortex-to-dentate gyrus synapses; mice expressing only e37b-CaV2.2 show reduced behavioral responses to aversive stimuli, indicating e37a alternative splicing influences behavioral outcomes through modulation of excitatory synaptic transmission.","method":"Mouse genetic models (e37a-null knockin), in situ hybridization, electrophysiology at identified synapses, behavioral testing","journal":"Molecular brain","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic mouse model with defined splice variant, electrophysiology at specific synapse, behavioral phenotype, single lab","pmids":["31630675"],"is_preprint":false},{"year":2013,"finding":"Morphine analgesia to thermal stimuli (but not ziconotide or gabapentin analgesia) is selectively reduced in mice lacking CaV2.2 exon 37a; e37a is not required for induction/maintenance of nerve injury-induced sensitization, indicating that e37a-specific sequence selectively links morphine analgesia (but not other Ca2+ channel-targeting analgesics) to CaV2.2 function.","method":"Cacna1b exon 37a knockout mice, intrathecal drug administration (morphine, ziconotide, gabapentin), behavioral thermal and mechanical nociception testing","journal":"Molecular pain","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic mouse model with exon-specific deletion, multiple analgesics tested to isolate e37a-specific mechanism, behavioral assays across multiple pain states","pmids":["24369063"],"is_preprint":false},{"year":2012,"finding":"The A118G/N40D SNP in the mu opioid receptor (hMOR-D) inhibits CaV2.2e37a currents at 4-fold lower agonist concentrations than hMOR-N (wild-type), while the two variants show little difference on CaV2.2e37b; the e37a isoform of CaV2.2 is thus more sensitive to inhibition by MOR variants associated with altered pain sensitivity.","method":"Co-expression of hMOR-N or hMOR-D with CaV2.2e37a or e37b in mammalian cells, whole-cell patch-clamp electrophysiology, concentration-response analysis","journal":"Neuroscience letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct electrophysiological comparison of MOR variant effects on two CaV2.2 splice isoforms in a defined heterologous system, single lab","pmids":["22796651"],"is_preprint":false},{"year":2019,"finding":"Mu opioid receptor (mMOR) C-terminal splice variants differentially regulate CaV2.2e37a and e37b: mMOR1 and mMOR1C cause agonist-independent reduction in peak current density of CaV2.2-37a but not CaV2.2-37b via a Gi/o-independent, Src tyrosine kinase-dependent mechanism targeting tyrosine Y1747 of CaV2.2-37a; DAMGO induces more voltage-dependent (Gbetagamma-mediated) inhibition of CaV2.2-37b versus e37a.","method":"Co-expression in tsA-201 cells, whole-cell patch-clamp, pertussis toxin treatment, Src kinase inhibitor, Y1747F point mutagenesis of CaV2.2-37a, surface biotinylation","journal":"Molecular brain","confidence":"High","confidence_rationale":"Tier 2 / Strong — site-directed mutagenesis identifying specific tyrosine residue, kinase inhibitor, pertussis toxin, and biotinylation assay collectively defining mechanistic pathway, single lab","pmids":["31775826"],"is_preprint":false},{"year":2007,"finding":"A proteomic screen by antibody-mediated capture of CaV2.2 from purified rat brain synaptosomes followed by mass spectrometry identified 104 proteins co-precipitating with the channel, including known interactors (syntaxin 1, VAMP, PP2A, Goalpha, Gbeta, spectrin) and novel partners (clathrin, adaptin, dynamin, dynein, NSF, actin), suggesting CaV2.2 is anchored to a presynaptic cytoplasmic matrix.","method":"Antibody-mediated immunoprecipitation from purified synaptosome lysate, mass spectrometry peptide identification","journal":"Journal of biochemistry and molecular biology","confidence":"Low","confidence_rationale":"Tier 3 / Moderate — MS-based interactome screen provides partner list but no mechanistic validation of individual interactions; single lab, single method","pmids":["17562281"],"is_preprint":false},{"year":2007,"finding":"CaV2.2 clusters at the transmitter release site are linked to an endocytosis protein complex: AP180 and intersectin adaptors co-precipitate tightly with CaV2.2, while clathrin and dynamin form a less tightly associated subcomplex; AP2 does not co-precipitate or co-localize with CaV2.2, suggesting a specialized AP2-lacking endocytosis complex at the active zone.","method":"Quantitative coimmunostaining (ICA/ICQ) in chick ciliary ganglion, co-immunoprecipitation from brain synaptosome lysates, high-NaCl fractional recovery analysis","journal":"The European journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP supported by quantitative colocalization in native presynaptic terminal, multiple endocytosis proteins tested, single lab","pmids":["17686037"],"is_preprint":false},{"year":2023,"finding":"NSF (N-ethylmaleimide-sensitive fusion protein) facilitates trafficking of CaV2.2 to the plasma membrane, increasing Ca2+ current intensity; rhodojaponin VI binds NSF (identified by thermal proteome profiling) and reverses NSF-facilitated CaV2.2 trafficking and current enhancement.","method":"Thermal proteome profiling, biological and biophysical validation of NSF-rhodojaponin VI interaction, patch-clamp electrophysiology in DRG neurons","journal":"Acta pharmaceutica Sinica. B","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — thermal proteome profiling for target identification with functional electrophysiology validation, single lab","pmids":["36970201"],"is_preprint":false},{"year":2025,"finding":"Cell-type-specific Cre-dependent inactivation of the Cacna1b gene in Trpv1-lineage neurons demonstrates that CaV2.2 channels in these neurons are specifically required for rapidly developing heat hypersensitivity but not all sensory behavioral responses.","method":"Conditional (Cre-dependent) Cacna1b gene inactivation in Trpv1-expressing neurons, behavioral testing for heat and mechanical hypersensitivity","journal":"Channels (Austin, Tex.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-type-specific genetic knockout with behavioral phenotyping, single lab","pmids":["41428771"],"is_preprint":false},{"year":2024,"finding":"C2230, an aryloxy-hydroxypropylamine, blocks CaV2.2 by trapping and stabilizing the inactivated state and accelerating open-state inactivation; site-directed mutation analysis showed C2230 binds at a site distinct from other known CaV2.2 blockers; C2230 inhibits CaV2.2 in a use-dependent, G-protein-coupled-receptor-independent manner and reduces spinal cord excitatory neurotransmission.","method":"Whole-cell patch-clamp (state-dependent and frequency-dependent protocols), site-directed mutagenesis, calcium imaging, slice electrophysiology, multiple in vivo pain models","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — site-directed mutagenesis identifying binding site distinct from known blockers, multiple biophysical state protocols, replicated across species (rat, marmoset, human DRG) and in vivo","pmids":["39656529"],"is_preprint":false},{"year":2011,"finding":"PKC activation (PMA) counteracts G protein-mediated inhibition of CaV2.2 channels in sympathetic neurons and reverses inhibition by Gbetagamma overexpression; PMA increases CaV2.2 conductance beyond what is explained by simple removal of G protein inhibition alone, indicating PKC phosphorylation has an additional direct effect on CaV2.2 channel gating.","method":"Patch-clamp in rat SCG neurons, PMA and GDPbetaS application, Gbetagamma overexpression, noradrenaline and GTPgammaS application","journal":"Archives of biochemistry and biophysics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological dissection in native neurons with multiple modulators, single lab","pmids":["18298939"],"is_preprint":false},{"year":2015,"finding":"PKC activation (PMA) dramatically prolongs recovery of CaV2.2 channels from 'slow' voltage-dependent inactivation (developing over seconds-to-minutes); this effect requires the C1-domain of PKC (blocked by calphostin C), is partially dependent on PKC catalytic activity, is beta-subunit isoform-independent in magnitude, and is reduced by intracellular GDP-beta-S, implicating G proteins in modulating slow inactivation.","method":"Recombinant CaV2.2 in HEK293 cells and native CaV2 in chromaffin cells, slow inactivation protocols, PKC inhibitors (calphostin C, catalytic inhibitors), GDP-beta-S intracellular dialysis, multiple beta subunit isoforms","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple pharmacological tools and beta subunit variants tested in two cell types, single lab","pmids":["26222492"],"is_preprint":false}],"current_model":"CaV2.2 (CACNA1B) is the pore-forming alpha1B subunit of the presynaptic N-type voltage-gated calcium channel that controls depolarization-evoked Ca2+ entry to trigger neurotransmitter release; its gating, surface expression, and trafficking are regulated by auxiliary subunits (CaVbeta, alpha2delta), multiple interacting proteins (CRMP-2/Cdk5-phosphorylation axis, ankyrin-B, MAP1A-LC2, MAP1B-LC1/UBE2L3, Munc18, RIM1alpha, TSPAN-13, 14-3-3tau), SNARE protein interactions via the synprint/II-III loop domain, G protein (Gbetagamma) voltage-dependent inhibition requiring specific I-II loop residues (Arg376, Val416), Gq/PIP2-dependent voltage-independent inhibition, PKC modulation of slow inactivation, and cell-type-specific alternative splicing (e37a/e37b, e31a) that shapes channel kinetics, expression density, and differential opioid/morphine sensitivity in nociceptors."},"narrative":{"mechanistic_narrative":"CACNA1B encodes CaV2.2, the pore-forming alpha1B subunit of the presynaptic N-type voltage-gated calcium channel that couples membrane depolarization to Ca2+ entry and neurotransmitter release, with prominent roles in nociceptor and sympathetic/central synaptic transmission [PMID:15471993, PMID:31607850]. The channel physically tethers synaptic vesicles through a PDZ-independent HxxRR motif in its distal C-terminus, and its synprint (II-III loop) region binds SNARE machinery such as syntaxin 1A and Munc18 to position the channel at the active zone and ensure efficient excitation-secretion coupling [PMID:24639630, PMID:21763275, PMID:19170253, PMID:15471993]. Surface density and gating are set by auxiliary subunits: CaVbeta binds the I-II loop to shield it from ubiquitin-proteasome degradation and drive plasma-membrane trafficking [PMID:27489103, PMID:30933958], alpha2delta-1 targets the channel to lipid rafts and shapes conotoxin pharmacology [PMID:20888635, PMID:15166237], and additional trafficking determinants include 14-3-3tau acting on the proximal C-terminus, NSF, ankyrin-B binding a DII/III tyrosine motif, and MAP1A-LC2 which retains channels at presynaptic boutons via the actin cytoskeleton [PMID:25516596, PMID:36970201, PMID:24394417, PMID:18971475]. Opposing this, MAP1B-LC1 recruits UBE2L3 to promote clathrin/dynamin-dependent internalization and proteasomal turnover, and gamma7 destabilizes CaV2.2 mRNA via hnRNP A2 [PMID:24566975, PMID:18923037]. A CRMP-2 axis, activated by Cdk5 phosphorylation at Ser522, positively regulates CaV2.2 surface expression, Ca2+ influx, and CGRP release [PMID:19903690, PMID:23022559]. Channel output is acutely tuned by GPCR signaling: Gbetagamma produces voltage-dependent inhibition through I-II loop residues Arg376/Val416, while PLC-mediated PIP2 hydrolysis drives voltage-independent inhibition, and the balance between these two modes is dictated by CaVbeta isoform membrane localization [PMID:20181083, PMID:23396054, PMID:25225550]. Cell-type-specific alternative splicing of exon 37 (e37a vs e37b) shapes single-channel open time, expression density, and behavior, and confers selective sensitivity to morphine and mu-opioid-receptor variants [PMID:16857708, PMID:31630675, PMID:24369063, PMID:31775826]. A CACNA1B R1389H pore mutation that reduces single-channel current is associated with myoclonus-dystonia and cardiac arrhythmia [PMID:25296916].","teleology":[{"year":2001,"claim":"Established that CaV2.2 expression is autoregulated by its own domain I-containing segments, revealing translational/synthesis-level control of channel abundance independent of CaVbeta sequestration.","evidence":"Co-expression of truncated CaV2.2 domain constructs with GFP-channel fluorescence quantification and single-channel recording in Xenopus oocytes","pmids":["11606638"],"confidence":"Medium","gaps":["Mechanism of synthesis inhibition not defined at molecular level","Physiological relevance of N-terminal/domain I suppression unknown"]},{"year":2004,"claim":"Defined how auxiliary subunits and the synprint region set channel biophysics and excitation-secretion coupling, showing beta3 imposes inhibitory ultra-slow inactivation, alpha2delta-1 shapes conotoxin block, and synprint deletion impairs secretion.","evidence":"Two-electrode voltage clamp in oocytes/HEK with subunit co-expression, kinetic toxin analysis, and capacitance measurements of secretion in MPC 9/3L cells","pmids":["15024042","15166237","15471993","15536086"],"confidence":"High","gaps":["Structural basis of synprint-secretion coupling not resolved","Native contribution of beta3 ultra-slow inactivation in vivo unquantified"]},{"year":2004,"claim":"Mapped alternative splicing of exon 31a and exon 37 as determinants of gating kinetics and open time, linking splice choice to cell-type-specific N-type channel behavior.","evidence":"Whole-cell, single-channel, and gating-current recordings of splice isoforms in tsA201 stable cell lines","pmids":["15201306","16857708"],"confidence":"High","gaps":["Upstream regulators of splice selection not identified","In vivo behavioral consequences not yet tested at this stage"]},{"year":2007,"claim":"Resolved the presynaptic interactome and active-zone anchoring of CaV2.2, identifying SNARE, endocytic, cytoskeletal, and G-protein partners and a specialized AP2-lacking endocytosis complex.","evidence":"Synaptosome immunoprecipitation with mass spectrometry, plus quantitative co-immunostaining and co-IP of endocytic adaptors in chick ciliary ganglion","pmids":["17562281","17686037"],"confidence":"Low","gaps":["MS interactome lacks individual interaction validation","Functional roles of most candidate partners untested","Stoichiometry and direct vs indirect binding unresolved"]},{"year":2008,"claim":"Identified opposing trafficking regulators that control surface CaV2.2 abundance: MAP1A-LC2/actin retains channels at boutons while gamma7 destabilizes CaV2.2 mRNA via hnRNP A2.","evidence":"Co-IP, surface antibody labeling, RNAi, actin disruption, FM4-64 recycling assay, and mRNA-stability assays in hippocampal and PC12 neurons","pmids":["18971475","18923037"],"confidence":"High","gaps":["Coordination between mRNA-level and protein-level control not integrated","Conditions toggling retention vs degradation unknown"]},{"year":2009,"claim":"Established the CRMP-2/Cdk5 axis as a positive trafficking regulator of CaV2.2, with Ser522 phosphorylation required for enhanced channel surface expression and transmitter release.","evidence":"Co-IP, overexpression/siRNA, phospho-null S522A mutagenesis, electrophysiology, and CGRP release in DRG neurons","pmids":["19903690","23022559"],"confidence":"High","gaps":["Direct binding interface on CaV2.2 not mapped","Whether CRMP-2 acts on forward trafficking vs membrane retention unresolved"]},{"year":2013,"claim":"Demonstrated that CaV2.2 directly tethers synaptic vesicles through its distal C-terminal HxxRR motif independent of PDZ ligand, providing a molecular basis for channel-vesicle coupling.","evidence":"Cell-free synaptic vesicle pull-down with C-terminal truncation/mutant fusion proteins, blocking peptides, and synaptosome electron microscopy","pmids":["23874268","24639630"],"confidence":"High","gaps":["Vesicle-side binding partner of the HxxRR motif not identified","Relationship to synprint-mediated SNARE coupling unclear"]},{"year":2013,"claim":"Separated the two GPCR-driven inhibitory modes of CaV2.2 by showing PIP2 hydrolysis underlies voltage-independent inhibition, distinct from Gbetagamma voltage-dependent inhibition.","evidence":"Double-pulse voltage clamp with PLC blockade, PIP2 dialysis, and wortmannin in sympathetic neurons; TSPAN-13 split-ubiquitin mapping","pmids":["23396054","23648579"],"confidence":"Medium","gaps":["Direct PIP2 binding site on CaV2.2 not localized","Crosstalk with voltage-dependent pathway not fully quantified"]},{"year":2014,"claim":"Defined the CaVbeta/proteasome surface-expression logic and showed CaVbeta membrane localization dictates whether Gbetagamma voltage-dependent or PIP2 voltage-independent inhibition predominates.","evidence":"Reconstituted ubiquitination with lysine mutagenesis and MG132, chimeric channels, Gbetagamma sequestration, palmitoylation mutants, plus 14-3-3 and ankyrin-B/MAP1B-LC1 trafficking studies","pmids":["27489103","25225550","25516596","24394417","24566975"],"confidence":"High","gaps":["Identity of the E3 ligase ubiquitinating the I-II loop not determined","How beta-subunit localization is set in native neurons unresolved"]},{"year":2014,"claim":"Linked a CACNA1B pore mutation to human disease, showing R1389H reduces single-channel current without altering selectivity or gating, associated with myoclonus-dystonia and cardiac arrhythmia.","evidence":"Whole-cell and single-channel patch-clamp of R1389H versus wild-type CaV2.2","pmids":["25296916"],"confidence":"Medium","gaps":["Single family/lab characterization","Mechanistic link from reduced single-channel current to phenotype not established"]},{"year":2019,"claim":"Connected exon 37 splice choice to opioid pharmacology and behavior, showing e37a confers morphine analgesia and heightened mu-opioid-receptor sensitivity via Src-dependent targeting of Y1747, and shapes excitatory transmission.","evidence":"Exon 37a knockout/knockin mice, behavioral analgesia testing, heterologous MOR variant co-expression, Y1747F mutagenesis, Src inhibition, and synapse electrophysiology","pmids":["24369063","31775826","22796651","31630675"],"confidence":"High","gaps":["Structural basis of e37a-specific Src targeting not resolved","Human relevance of mouse splice-specific opioid effects untested"]},{"year":2025,"claim":"Used cell-type-specific genetic ablation to assign CaV2.2 in Trpv1-lineage neurons a specific requirement for rapidly developing heat hypersensitivity, refining its role in pain circuits.","evidence":"Cre-dependent Cacna1b inactivation in Trpv1 neurons with behavioral heat and mechanical testing","pmids":["41428771"],"confidence":"Medium","gaps":["Molecular events downstream of channel loss in these neurons unspecified","Single-lab finding"]},{"year":null,"claim":"How the many trafficking, anchoring, and inhibitory inputs are integrated into a unified structural and spatial model of CaV2.2 regulation at the active zone remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No high-resolution structure of CaV2.2 with auxiliary/regulatory partners in the timeline","Quantitative hierarchy among competing trafficking pathways unknown","In vivo integration of voltage-dependent vs independent inhibition not defined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005215","term_label":"transporter activity","supporting_discovery_ids":[6,9,10,41]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[21,22]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[16,24,30,31,48]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[31]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[16,30]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[6,41,42]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[13,32,33,39]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[21,22,47]}],"complexes":["N-type voltage-gated calcium channel (CaV2.2/CaVbeta/alpha2delta)"],"partners":["CRMP2","CACNB3","CACNA2D1","MAP1A","MAP1B","STX1A","RIMS1","ANK2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q00975","full_name":"Voltage-dependent N-type calcium channel subunit alpha-1B","aliases":["Brain calcium channel III","BIII","Calcium channel, L type, alpha-1 polypeptide isoform 5","Voltage-gated calcium channel subunit alpha Cav2.2"],"length_aa":2339,"mass_kda":262.5,"function":"Voltage-sensitive calcium channels (VSCC) mediate the entry of calcium ions into excitable cells and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, gene expression, cell motility, cell division and cell death. This alpha-1B subunit gives rise to N-type calcium currents. N-type calcium channels belong to the 'high-voltage activated' (HVA) group. They are involved in pain signaling (PubMed:25296916). Calcium channels containing alpha-1B subunit may play a role in directed migration of immature neurons. Mediates Ca(2+) release probability at hippocampal neuronal soma and synaptic terminals (By similarity) Voltage-sensitive calcium channels (VSCC) mediate the entry of calcium ions into excitable cells and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, gene expression, cell motility, cell division and cell death. This alpha-1B subunit gives rise to N-type calcium currents","subcellular_location":"Membrane","url":"https://www.uniprot.org/uniprotkb/Q00975/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CACNA1B","classification":"Not Classified","n_dependent_lines":3,"n_total_lines":1208,"dependency_fraction":0.0024834437086092716},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CACNA1B","total_profiled":1310},"omim":[{"mim_id":"620144","title":"CACHE DOMAIN-CONTAINING PROTEIN 1; CACHD1","url":"https://www.omim.org/entry/620144"},{"mim_id":"619863","title":"JUNCTOPHILIN 4; JPH4","url":"https://www.omim.org/entry/619863"},{"mim_id":"618497","title":"NEURODEVELOPMENTAL DISORDER WITH SEIZURES AND NONEPILEPTIC HYPERKINETIC MOVEMENTS; NEDNEH","url":"https://www.omim.org/entry/618497"},{"mim_id":"614860","title":"DYSTONIA 23; DYT23","url":"https://www.omim.org/entry/614860"},{"mim_id":"610388","title":"RRAD- AND GEM-LIKE GTPase 1; REM1","url":"https://www.omim.org/entry/610388"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Cytosol","reliability":"Approved"},{"location":"Acrosome","reliability":"Approved"},{"location":"Equatorial segment","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"brain","ntpm":23.4},{"tissue":"pituitary gland","ntpm":6.5}],"url":"https://www.proteinatlas.org/search/CACNA1B"},"hgnc":{"alias_symbol":["Cav2.2","CACNN"],"prev_symbol":["CACNL1A5"]},"alphafold":{"accession":"Q00975","domains":[{"cath_id":"1.10.287.70","chopping":"208-251_289-369","consensus_level":"medium","plddt":81.1498,"start":208,"end":369},{"cath_id":"1.20.120.350","chopping":"70-206","consensus_level":"medium","plddt":77.112,"start":70,"end":206},{"cath_id":"1.20.120.350","chopping":"482-592","consensus_level":"medium","plddt":79.1718,"start":482,"end":592},{"cath_id":"1.10.287.70","chopping":"611-735","consensus_level":"medium","plddt":80.7267,"start":611,"end":735},{"cath_id":"1.20.120","chopping":"1139-1241","consensus_level":"high","plddt":81.2825,"start":1139,"end":1241},{"cath_id":"1.10.287.70","chopping":"1600-1718","consensus_level":"medium","plddt":83.4439,"start":1600,"end":1718},{"cath_id":"1.10.238.10","chopping":"1719-1870","consensus_level":"medium","plddt":79.3317,"start":1719,"end":1870}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q00975","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q00975-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q00975-F1-predicted_aligned_error_v6.png","plddt_mean":59.91},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CACNA1B","jax_strain_url":"https://www.jax.org/strain/search?query=CACNA1B"},"sequence":{"accession":"Q00975","fasta_url":"https://rest.uniprot.org/uniprotkb/Q00975.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q00975/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q00975"}},"corpus_meta":[{"pmid":"10791962","id":"PMC_10791962","title":"CaV2.2 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journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/25195871","citation_count":7,"is_preprint":false},{"pmid":"24582401","id":"PMC_24582401","title":"Anti-allodynic effect of 2-(aminomethyl)adamantane-1-carboxylic acid in a rat model of neuropathic pain: a mechanism dependent on CaV2.2 channel inhibition.","date":"2014","source":"Bioorganic & medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24582401","citation_count":7,"is_preprint":false},{"pmid":"40128122","id":"PMC_40128122","title":"Targeted Ganglion Delivery of CaV2.2-Mediated Peptide by DNA Nanoflowers for Relieving Myocardial Infarction and Neuropathic Pain.","date":"2025","source":"ACS nano","url":"https://pubmed.ncbi.nlm.nih.gov/40128122","citation_count":6,"is_preprint":false},{"pmid":"18298939","id":"PMC_18298939","title":"PMA counteracts G protein actions on CaV2.2 channels in rat sympathetic neurons.","date":"2008","source":"Archives of biochemistry and biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/18298939","citation_count":6,"is_preprint":false},{"pmid":"24628243","id":"PMC_24628243","title":"Effects of arginine 10 to lysine substitution on ω-conotoxin CVIE and CVIF block of Cav2.2 channels.","date":"2014","source":"British journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/24628243","citation_count":6,"is_preprint":false},{"pmid":"23789098","id":"PMC_23789098","title":"Inter-channel scaffolding of presynaptic CaV2.2 via the C terminal PDZ ligand domain.","date":"2013","source":"Biology open","url":"https://pubmed.ncbi.nlm.nih.gov/23789098","citation_count":6,"is_preprint":false},{"pmid":"24513289","id":"PMC_24513289","title":"Gβ₂ mimics activation kinetic slowing of CaV2.2 channels by noradrenaline in rat sympathetic neurons.","date":"2014","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/24513289","citation_count":5,"is_preprint":false},{"pmid":"14529719","id":"PMC_14529719","title":"CaVbeta subunit-mediated up-regulation of CaV2.2 currents triggered by D2 dopamine receptor activation.","date":"2003","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/14529719","citation_count":5,"is_preprint":false},{"pmid":"25966687","id":"PMC_25966687","title":"The R-Domain: Identification of an N-terminal Region of the α2δ-1 Subunit Which is Necessary and Sufficient for its Effects on Cav2.2 Calcium Currents.","date":"2015","source":"Current molecular pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/25966687","citation_count":5,"is_preprint":false},{"pmid":"19883587","id":"PMC_19883587","title":"Open-state occupancy prevents gating charge relaxation of N-type (CaV2.2) calcium channels.","date":"2009","source":"Biophysical journal","url":"https://pubmed.ncbi.nlm.nih.gov/19883587","citation_count":5,"is_preprint":false},{"pmid":"38431110","id":"PMC_38431110","title":"Schisandrin B from Schisandra chinensis alleviated pain via glycine receptors, Nav1.7 channels and Cav2.2 channels.","date":"2024","source":"Journal of ethnopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/38431110","citation_count":4,"is_preprint":false},{"pmid":"23746511","id":"PMC_23746511","title":"Structural flexibility of CaV1.2 and CaV2.2 I-II proximal linker fragments in solution.","date":"2013","source":"Biophysical journal","url":"https://pubmed.ncbi.nlm.nih.gov/23746511","citation_count":4,"is_preprint":false},{"pmid":"27245500","id":"PMC_27245500","title":"Mechanism of direct Cav2.2 channel block by the κ-opioid receptor agonist U50488H.","date":"2016","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/27245500","citation_count":3,"is_preprint":false},{"pmid":"41428771","id":"PMC_41428771","title":"Trpv1-dependent Cacna1b gene inactivation reveals cell-specific functions of CaV2.2 channels in vivo.","date":"2025","source":"Channels (Austin, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/41428771","citation_count":2,"is_preprint":false},{"pmid":"23045722","id":"PMC_23045722","title":"A novel CaV2.2 channel inhibition by piracetam in peripheral and central neurons.","date":"2012","source":"Experimental biology and medicine (Maywood, N.J.)","url":"https://pubmed.ncbi.nlm.nih.gov/23045722","citation_count":2,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":55571,"output_tokens":14264,"usd":0.190336,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":26366,"output_tokens":4687,"usd":0.124503,"stage2_stop_reason":"end_turn"},"total_usd":0.314839,"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\": 2009,\n      \"finding\": \"CRMP-2 physically associates with CaV2.2 in dorsal root ganglion (DRG) neurons (co-immunoprecipitation), colocalizes at synapses and growth cones, and overexpression of CRMP-2 increases CaV2.2 current density and surface levels, while CRMP-2 siRNA knockdown reduces Ca2+ influx and CGRP release, establishing CRMP-2 as a positive regulator of CaV2.2 trafficking and transmitter release.\",\n      \"method\": \"Co-immunoprecipitation, confocal colocalization, nucleofection overexpression/siRNA knockdown, patch-clamp electrophysiology, CGRP release assay\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal co-IP, multiple orthogonal methods (electrophysiology, surface expression, neurotransmitter release), consistent gain- and loss-of-function in native neurons\",\n      \"pmids\": [\"19903690\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Cdk5-mediated phosphorylation of CRMP-2 at Ser522 enhances its interaction with CaV2.2 and is required for CRMP-2-mediated enhancement of CaV2.2 currents; a phospho-null S522A CRMP-2 mutant or inactive Cdk5 abolishes the current enhancement, while the Rho kinase site T555A mutant is ineffective.\",\n      \"method\": \"Phospho-null and phospho-mimetic mutagenesis, co-immunoprecipitation, patch-clamp electrophysiology, siRNA knockdown/rescue\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — site-directed mutagenesis combined with co-IP and electrophysiology in a single study, identifying specific phosphorylation site\",\n      \"pmids\": [\"23022559\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"(S)-Lacosamide binds directly to CRMP-2 (STD NMR and DSF), inhibits Cdk5-mediated phosphorylation of CRMP-2 at Ser522, reduces Cdk5-phosphorylated CRMP-2 association with CaV2.2, and thereby decreases CaV2.2-mediated calcium influx in neurons.\",\n      \"method\": \"STD NMR, differential scanning fluorimetry, in vitro luminescent kinase assay, co-immunoprecipitation, calcium imaging in neurons\",\n      \"journal\": \"Molecular neurobiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct binding demonstrated by NMR and DSF, kinase assay, and functional consequence in neurons, multiple orthogonal methods in one study\",\n      \"pmids\": [\"25846820\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"A myristoylated CRMP2-derived peptide (myr-tat-CBD3) tethered to the membrane near CaV2.2 disrupts the CRMP2-CaV2.2 interaction (pull-down assay), reduces CaV2.2 surface trafficking (quantitative immunofluorescence), inhibits depolarization-evoked Ca2+ influx, reduces Ca2+ (but not Na+) currents, and decreases excitability of DRG neurons.\",\n      \"method\": \"Pull-down assay, quantitative confocal immunofluorescence, whole-cell patch-clamp (voltage and current clamp), calcium imaging\",\n      \"journal\": \"Pain\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods including pull-down, imaging, and electrophysiology; disruption of specific protein-protein interaction linked to functional outcomes\",\n      \"pmids\": [\"25782368\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"RGS12 binds to the SNARE-binding (synprint) region (amino acids 726-985) of the CaV2.2 alpha1 II-III loop via its N-terminal PTB domain, and this interaction requires tyrosine phosphorylation of Tyr-804. Microinjection of synprint peptides containing pTyr-804 altered desensitization kinetics of neurotransmitter-mediated inhibition of CaV2.2, implicating RGS12 in controlling the time course of voltage-independent CaV2.2 inhibition.\",\n      \"method\": \"Protein overlay, surface plasmon resonance, co-immunoprecipitation, peptide microinjection, patch-clamp electrophysiology in DRG neurons\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — SPR binding assay, protein overlay, co-IP with phosphopeptides, and functional electrophysiology validation with site-specific peptides\",\n      \"pmids\": [\"15536086\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"The synprint (II-III loop) site of CaV2.2 is important but not essential for presynaptic clustering in hippocampal neurons; GFP-CaV2.2 splice variants lacking the synprint are still targeted to axons but show markedly reduced presynaptic cluster formation. Insertion of synprint into CaV1.2 does not confer axonal targeting, indicating synprint cooperates with other targeting mechanisms.\",\n      \"method\": \"GFP-fusion protein expression in mouse hippocampal neurons, live imaging, immunofluorescence colocalization\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct imaging in neurons with deletion mutants, single lab\",\n      \"pmids\": [\"16930401\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Deletion of the synprint site from CaV2.2 alpha1B reduces secretion efficiency in pheochromocytoma cells; when Ca2+ entry is normalized, cells expressing the synprint-deletion channel show significantly reduced total secretion, rate of secretion (capacitance measurements), and endocytosis, demonstrating the synprint site is required for efficient coupling of Ca2+ influx to exocytosis.\",\n      \"method\": \"Transient transfection in MPC 9/3L cells, whole-cell patch-clamp capacitance measurements, Ca2+ current recording\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstitution in cell line lacking endogenous VGCCs, capacitance measurements directly link synprint deletion to secretion deficit\",\n      \"pmids\": [\"15471993\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"The alpha2delta-1 auxiliary subunit significantly reduces the on-rates and equilibrium inhibition of omega-conotoxins GVIA, MVIIA, and CVID at recombinant N-type (CaV2.2) channels; alpha2delta-1 also differentially modulates the extent of recovery from toxin block depending on toxin identity, implicating alpha2delta-1 in shaping toxin pharmacology of CaV2.2.\",\n      \"method\": \"Two-electrode voltage clamp in Xenopus oocytes and HEK cells with subunit co-expression, kinetic analysis of toxin on/off-rates\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — systematic reconstitution in two expression systems, multiple toxins tested, quantitative kinetic analysis\",\n      \"pmids\": [\"15166237\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Overexpressed CaVbeta3 subunit causes a ~40 mV hyperpolarizing shift of the steady-state inactivation of CaV2.2 channels, producing 'ultra-slow' inactivation at physiological holding potentials and markedly suppressing macroscopic N-type currents at -60 to -80 mV; this inhibitory effect is reversed at hyperpolarized holding potentials (-120 mV), establishing a novel inhibitory role for beta3 via shifted inactivation.\",\n      \"method\": \"Two-electrode voltage clamp in Xenopus oocytes, steady-state inactivation protocols, varying holding potentials and beta3 concentrations\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — systematic in vitro reconstitution with quantitative biophysical analysis of inactivation gating, single lab with multiple conditions\",\n      \"pmids\": [\"15024042\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"The mutually exclusive C-terminal exon e37a of CaV2.2 increases channel open time and functional channel expression density compared to the e37b isoform, resulting in augmented calcium entry per action potential in nociceptors; single-channel and gating current analysis revealed that e37a channels remain open longer without affecting gating charge movement.\",\n      \"method\": \"Stable cell line expression, macroscopic and single-channel patch-clamp, gating current recordings in tsA201 cells\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — single-channel and gating current analysis in stable expressing cell lines; multiple biophysical parameters compared across isoforms\",\n      \"pmids\": [\"16857708\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Alternative splicing of exon 31a in the IVS3-IVS4 region of CaV2.2 slows the speed of channel activation and deactivation at all voltages, and slows gating current decay (On-gating currents), without consistently shifting voltage dependence of charge movement; this correlates with slower N-type kinetics in peripheral sympathetic neurons.\",\n      \"method\": \"Stable cell lines expressing four CaV2.2 splice isoforms, whole-cell ionic and gating current recordings in tsA201 cells\",\n      \"journal\": \"Journal of neurophysiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — gating current analysis in stable cell lines resolving both ionic and charge movement properties across multiple isoforms\",\n      \"pmids\": [\"15201306\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Truncated CaV2.2 constructs containing domain I (alone or within domain I-II) suppress full-length CaV2.2 expression through inhibition of channel synthesis; this suppression does not require sequestration of CaVbeta, is not mimicked by the cytoplasmic I-II loop alone, and requires transmembrane segments, as the isolated CaV2.2 N-terminus has no effect.\",\n      \"method\": \"Co-expression in Xenopus oocytes, GFP-CaV2.2 fluorescence quantification, Western blot, single-channel recordings\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple domain deletion constructs tested, protein expression and single-channel recording, single lab\",\n      \"pmids\": [\"11606638\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Gbetagamma subunits inhibit CaV2.2 (N-type) channels via a voltage-dependent mechanism; the apparent (un)binding kinetics of Gbetagamma with N-type channels are twofold slower than with P/Q-type at voltage extremes (up to 10-fold in mid-voltage range). Single-point alanine mutations in Gbeta1 differentially affect N- versus P/Q-type modulation, identifying distinct binding surfaces on Gbetagamma for the two channel types.\",\n      \"method\": \"Electrophysiology (compound-state willing-reluctant analysis), Gbeta1 mutagenesis, co-expression in heterologous system\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — systematic mutagenesis of Gbetagamma combined with quantitative kinetic electrophysiology, single lab\",\n      \"pmids\": [\"12771191\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Scanning mutagenesis identified Arg376 and Val416 in the I-II loop of CaV2.2 as key molecular determinants for voltage-dependent G protein (Gbeta1gamma2) inhibition; R376F mutation drastically alters the ability of auxiliary beta subunit isoforms to regulate G protein inhibition of the channel.\",\n      \"method\": \"Alanine/cysteine scanning mutagenesis, patch-clamp recordings, co-expression of Gbeta1gamma2 with mutant channels in heterologous cells\",\n      \"journal\": \"Molecular brain\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — systematic scanning mutagenesis with electrophysiological functional readout, single lab\",\n      \"pmids\": [\"20181083\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"AGS1 and Rhes monomeric G proteins selectively alter Galphai-dependent signaling to inhibit CaV2.2 channels: they reduce basal CaV2.2 current density, trigger tonic voltage-dependent inhibition, and attenuate agonist-initiated inhibition through Galphai-coupled (but not Galphas-coupled) receptors via a Gbetagamma- and pertussis toxin-sensitive mechanism.\",\n      \"method\": \"Whole-cell patch-clamp in HEK293 cells, Gbetagamma-sequestering peptide (masGRK3ct), pertussis toxin treatment, co-expression of multiple G protein isoforms\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological dissection with pertussis toxin and Gbetagamma sequestration, multiple G protein isoforms tested, single lab\",\n      \"pmids\": [\"18815223\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"G protein-mediated inhibition (via Gbetagamma binding) of CaV2.2 channels reduces both Ca2+-dependent and voltage-dependent inactivation during low-frequency trains of action potential waveforms; wild-type Gbetagamma mimics this effect but a point mutant with reduced channel affinity does not, demonstrating Gbetagamma modulates CaV2.2 inactivation directly.\",\n      \"method\": \"Action potential waveform stimulation, whole-cell patch-clamp in HEK293 cells and adrenal chromaffin cells, wild-type vs. affinity-reduced Gbetagamma mutant co-expression\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Gbetagamma affinity mutant provides mechanistic specificity; tested in two cell types, single lab\",\n      \"pmids\": [\"17182788\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"MAP1A light chain 2 (LC2) interacts with a 23-residue domain in the CaV2.2 C-terminus, mediates presynaptic surface retention of CaV2.2, and links channels to the actin cytoskeleton; disruption of LC2-CaV2.2 interaction or actin depolymerization reduces surface CaV2.2 at presynaptic boutons, reduces Ca2+ influx, and impairs FM4-64 uptake (synaptic vesicle recycling).\",\n      \"method\": \"Co-immunoprecipitation, deletion mutagenesis, antibody against extracellular CaV2.2 epitope for live surface labeling, RNAi knockdown, FM4-64 assay, latrunculin A treatment in hippocampal neurons\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (co-IP, surface antibody labeling, RNAi, pharmacological actin disruption, functional vesicle recycling assay) in native neurons\",\n      \"pmids\": [\"18971475\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Ankyrin-B associates with CaV2.2 (and CaV2.1) via its membrane-binding domain interacting with a conserved motif in the DII/III loop; mutation of a single conserved tyrosine (Y788E in CaV2.2) abolishes ankyrin-B binding in vitro and in vivo, and disrupts proper targeting of CaV2.2 in a heterologous system.\",\n      \"method\": \"Co-immunoprecipitation from brain regions, in vitro pull-down, site-directed mutagenesis (Y788E), transfection in heterologous cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP from native brain tissue, in vitro binding, and mutagenesis identifying single critical residue, single lab multiple methods\",\n      \"pmids\": [\"24394417\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"CaVbeta subunit binding to the I-II loop of CaV2.2 protects this loop from proteasomal degradation: in the absence of CaVbeta, the I-II loop is directly ubiquitinated on lysine residues and degraded by the proteasome; CaVbeta binding prevents degradation but not oligoubiquitination, and is required (along with a palmitoylation signal) for I-II loop trafficking to the plasma membrane.\",\n      \"method\": \"Ubiquitination assays, proteasome inhibitor (MG132) treatment, lysine-to-arginine mutagenesis, Western blot, surface trafficking assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstituted ubiquitination, mutagenesis of all 12 lysines, proteasome inhibitor rescue, multiple mechanistic conditions tested in one study\",\n      \"pmids\": [\"27489103\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"MAP1B light chain 1 (LC1) interacts with CaV2.2 via its N-terminus binding to the C-terminal of the pore-forming subunit, and recruits ubiquitin-conjugating enzyme UBE2L3 to form a tripartite complex; LC1 overexpression decreases N-type currents via enhanced proteasomal degradation, and LC1/UBE2L3 complex mediates internalization of CaV2.2 via dynamin- and clathrin-dependent pathway.\",\n      \"method\": \"Co-immunoprecipitation, in vitro pull-down, yeast two-hybrid, patch-clamp in HEK293 cells, MG132 proteasome inhibitor treatment, immunofluorescence in hippocampal neurons\",\n      \"journal\": \"Pflugers Archiv : European journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods including co-IP, Y2H, in vitro pull-down, and functional electrophysiology with proteasome inhibitor rescue\",\n      \"pmids\": [\"24566975\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Gamma7 (stargazin-related protein) is present on intracellular membranes and decreases CaV2.2 expression by accelerating degradation of CaV2.2 mRNA via its C-terminus; gamma7 binds directly to hnRNP A2, which also binds to a motif in CaV2.2 mRNA, and knockdown of gamma7 enhances CaV2.2 mRNA stability and increases endogenous calcium currents.\",\n      \"method\": \"Co-immunoprecipitation, mRNA stability assays, shRNA knockdown, electrophysiology in PC12 cells, direct binding assays\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal co-IP, shRNA gain/loss of function, mRNA stability measurement, direct hnRNP A2 binding demonstrated, functional electrophysiology\",\n      \"pmids\": [\"18923037\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"The synaptic vesicle (SV) tethers directly to the CaV2.2 channel C-terminal via a PDZ-independent mechanism within the distal 49 amino acids (prior to the PDZ ligand); SVs are captured by intact CaV2.2 and by C-terminal fusion proteins in a cell-free pull-down assay. The HxxRR motif (identified by blocking peptide mutagenesis) is the key SV-binding determinant on the CaV2.2 C-terminal.\",\n      \"method\": \"In vitro synaptic vesicle pull-down assay, C-terminal truncation fusion proteins, PDZ-LD mutant fusion proteins, mimetic blocking peptides, electron microscopy of synaptosome ghosts\",\n      \"journal\": \"Frontiers in cellular neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cell-free reconstitution with multiple truncation and mutant constructs, validated by peptide inhibition in synaptosomes\",\n      \"pmids\": [\"24639630\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Intact CaV2.2 channels directly capture synaptic vesicles (SVs) in a cell-free pull-down assay; SV capture also occurs with C-terminal fusion proteins (distal half of C-terminal), demonstrating a direct molecular tethering mechanism linking the CaV2.2 C-terminal to SVs independent of other presynaptic proteins.\",\n      \"method\": \"In vitro synaptic vesicle pull-down assay, antibody-immobilized CaV2.2, Western blot for SV markers\",\n      \"journal\": \"Frontiers in cellular neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cell-free reconstitution assay with controls (IgG, blocked antibody, plain beads), single lab\",\n      \"pmids\": [\"23874268\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Munc18 coprecipitates with CaV2.2 from rat and chick brain lysates and purified presynaptic terminal membranes, binds with high affinity to the CaV2.2 II-III intracellular loop and low affinity to the I-II loop; siRNA knockdown of Munc18 shifts CaV2.2 steady-state inactivation; Munc18 also coprecipitates with synaptotagmin, suggesting it bridges the Ca2+ channel to the synaptic vesicle.\",\n      \"method\": \"Co-immunoprecipitation from brain/synaptosome lysates and cell line, siRNA knockdown, patch-clamp electrophysiology (steady-state inactivation), immunostaining colocalization\",\n      \"journal\": \"Channels (Austin, Tex.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP from multiple preparations, functional knockdown with electrophysiological readout, single lab\",\n      \"pmids\": [\"19170253\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"The CaVbeta subunit targets CaV2.2 to the plasma membrane and prevents its proteasomal degradation; disrupting the CaValpha-CaVbeta interaction with a small molecule (IPPQ) identified by structure-based virtual screening against the CaVbeta pocket reduces CaV2.2 currents in DRG neurons and decreases presynaptic localization of CaV2.2 in vivo.\",\n      \"method\": \"Structure-based virtual screening, small molecule binding to CaVbeta (biochemical assay), patch-clamp electrophysiology in DRG neurons, in vivo CaV2.2 localization imaging, EPSP/mEPSP recordings, CGRP release assay\",\n      \"journal\": \"Pain\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — structure-based design, biochemical binding assay, multiple in vitro and in vivo functional readouts confirming mechanism\",\n      \"pmids\": [\"30933958\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Bipartite interactions between syntaxin 1A and the CaV2.2 synprint region were mapped: syntaxin 1A H3c domain (C-terminal) binds residues 822-872 of CaV2.2, while the N-terminal 10 residues of the Ha domain bind residues 718-771 of CaV2.2. The syntaxin 1A N-terminal peptide allosterically inhibits CaV2.2 channel function but does not affect G-protein-mediated inhibition.\",\n      \"method\": \"In vitro binding assays with syntaxin truncation mutants, whole-cell patch-clamp in recombinant expression system\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro binding with truncation series plus functional electrophysiology, single lab\",\n      \"pmids\": [\"21763275\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Alpha-conotoxins Vc1.1 and RgIA inhibition of CaV2.2 channels in DRG neurons requires functional GABAB receptor expression; siRNA knockdown of GABAB R1 and R2 subunits significantly reduces alpha-conotoxin- and baclofen-inhibition of N-type channels, and in HEK293 cells both GABAB subunits are required for Vc1.1 and RgIA inhibition of CaV2.2.\",\n      \"method\": \"siRNA knockdown of GABAB subunits, qRT-PCR and immunocytochemistry to confirm knockdown, whole-cell patch-clamp in DRG neurons and HEK293 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — siRNA knockdown confirmed at mRNA and protein levels, functional electrophysiology in native neurons and heterologous system, multiple conotoxins tested\",\n      \"pmids\": [\"22613715\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Alpha-conotoxin Vc1.1 inhibits CaV2.2 via GABAB receptor activation through a distinct molecular pathway from GABA/baclofen: Vc1.1 increases CaV2.2 activation rate and shifts half-maximum inactivation to more hyperpolarized potentials; truncation of the GABAB(1a) proximal C-terminus significantly reduces Vc1.1 inhibition, identifying this domain as necessary for Vc1.1's inhibitory mechanism.\",\n      \"method\": \"Heterologous GABAB receptor expression, GABAB(1a) C-terminal truncations, whole-cell patch-clamp electrophysiology, mutagenesis\",\n      \"journal\": \"Molecular pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — systematic truncation mutagenesis of GABAB(1a) with electrophysiological functional readout, single lab\",\n      \"pmids\": [\"25425625\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Constitutive GHSR1a activity reduces CaV2.2 current through a Gi/o-dependent mechanism involving persistent reduction in CaV2.2 channel density at the plasma membrane; ghrelin-dependent GHSR1a inhibition is reversible and involves altered CaV2.2 gating via a Gq-dependent pathway; both pathways attenuate GABA release from hypothalamic neurons.\",\n      \"method\": \"Patch-clamp in rat/mouse hypothalamic neurons and heterologous expression system, Gi/o and Gq pathway inhibitors, channel surface density measurements\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — two mechanistically distinct pathways differentiated pharmacologically in native neurons and heterologous system, single lab\",\n      \"pmids\": [\"26283199\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Tetraspanin-13 (TSPAN-13) specifically interacts with the alpha1 subunit of CaV2.2 (but not CaV2.1 or L/T-type channels), with interaction mapping to domain IV of CaV2.2 and transmembrane segments S1-S2 of TSPAN-13; TSPAN-13 modulates coupling between voltage sensor activation and pore opening, accelerating activation and inactivation kinetics.\",\n      \"method\": \"Yeast split-ubiquitin system, domain mapping, patch-clamp electrophysiology (Ba2+ current) in transfected cells\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast split-ubiquitin interaction assay plus functional electrophysiology with domain mapping, single lab\",\n      \"pmids\": [\"23648579\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Alpha2delta-1 auxiliary subunit is necessary and sufficient for targeting CaV2.2/beta1b complexes to lipid rafts (identified by caveolin/flotillin colocalization and biochemical raft fractionation); clustering of CaV2.2 at the cell surface requires the actin cytoskeleton (disrupted by cytochalasin D) rather than raft integrity per se.\",\n      \"method\": \"Biochemical lipid raft fractionation, confocal imaging with raft markers (caveolin, flotillin), methyl-beta-cyclodextrin raft disruption, cytochalasin D actin disruption, electrophysiology in COS-7 cells\",\n      \"journal\": \"Cell calcium\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple imaging and biochemical approaches with pharmacological dissection, single lab\",\n      \"pmids\": [\"20888635\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"14-3-3tau promotes functional surface expression of CaV2.2 alpha1B in the absence of canonical auxiliary subunits; the proximal C-terminal region (amino acids 1706-1940) is retained in the ER and is facilitated to traffic to the plasma membrane by 14-3-3; 14-3-3 and CaVbeta co-regulate CaV2.2 surface expression.\",\n      \"method\": \"Co-expression in tsA-201 cells and neurons, immunofluorescence surface/total ratio, whole-cell voltage clamp (Ba2+ currents), 14-3-3 antagonist/inactive control constructs\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — surface vs. total expression quantified by immunofluorescence with functional electrophysiological readout, gain/loss-of-function design, single lab\",\n      \"pmids\": [\"25516596\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"PIP2 hydrolysis (via PLC activation) is responsible for voltage-independent inhibition of CaV2.2 channels in sympathetic neurons; blocking PLC prevents voltage-independent inhibition, intracellular PIP2 analog prevents it, and inhibiting PIP2 resynthesis (wortmannin) blocks recovery from voltage-independent inhibition.\",\n      \"method\": \"Double-pulse voltage clamp protocol in SCG neurons, pharmacological PLC blockade, intracellular PIP2 dialysis, wortmannin PIP2 resynthesis inhibition\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological dissection with three orthogonal approaches (PLC inhibition, PIP2 dialysis, resynthesis blockade) in native neurons, single lab\",\n      \"pmids\": [\"23396054\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Voltage-dependent G protein inhibition of CaV2.2 channels is determined by the location of the CaVbeta isoform: membrane-localized beta2a confers Gbetagamma-mediated voltage-dependent inhibition by Gq-coupled M1 receptors, while cytosol-localized beta subunits (beta2b, beta3, palmitoylation-deficient beta2a C3,4S) confer more effective voltage-independent PIP2-mediated inhibition.\",\n      \"method\": \"Whole-cell patch-clamp in tsA-201 cells, C-terminus of beta-ARK to sequester Gbetagamma, alpha1C-1B chimera, multiple beta subunit isoforms including palmitoylation mutant\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — systematic dissection with chimeric channels, Gbetagamma sequestration, palmitoylation mutant, and multiple beta isoforms clearly mapping voltage dependence to beta subunit localization\",\n      \"pmids\": [\"25225550\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"The orientation of palmitoylated CaVbeta2a relative to CaV2.2 determines the form of NK-1R/substance P-mediated modulation; deleting 1-2 amino acids proximal to the AID in CaV2.2 displaces CaVbeta2a, switching current enhancement (by SP) to inhibition matching the beta3-coexpressed phenotype; exogenous palmitic acid rescues this, suggesting beta2a palmitoyl groups block an inhibitory site on CaV2.2.\",\n      \"method\": \"Deletion mutagenesis of CaV2.2 I-II linker (Bdel1, Bdel2), co-expression with CaVbeta2a or CaVbeta3, substance P stimulation, whole-cell patch-clamp, exogenous palmitate application\",\n      \"journal\": \"The Journal of general physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — structure-function approach with deletion mutants and palmitate rescue, single lab\",\n      \"pmids\": [\"19858358\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Roscovitine (a CDK inhibitor) slows CaV2.2 channel deactivation from an extracellular binding site with EC50 ~53 µM, preferentially binding to the open-channel state; it also produces a slight left shift in activation voltage relationship and increased inactivation; the effect is stereospecific and kinase-independent, as the closely related olomoucine does not replicate it and intracellular roscovitine is ineffective.\",\n      \"method\": \"Whole-cell and single-channel patch-clamp, intracellular vs. extracellular application, olomoucine control, pharmacological characterization in Xenopus oocytes/HEK cells\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — systematic pharmacological characterization with stereoisomer and intracellular controls identifying extracellular binding site, single lab\",\n      \"pmids\": [\"15951378\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"CaV2.2 N-terminal (residues 45-55) and I-II loop AID (residues 377-393) peptides each inhibit synaptic transmission and reduce Ca2+ current amplitude when injected presynaptically into SCG neurons; both peptides attenuate G protein modulation; mutations to residues within the N-terminal proposed QXXER motif abolish inhibitory effects, identifying the N-terminus as a molecular determinant of CaV2.2 function and G protein modulation.\",\n      \"method\": \"Presynaptic peptide injection, whole-cell patch-clamp in SCG neurons, mutagenesis of peptide residues\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — peptide injection in native neurons with functional readouts (synaptic transmission and Ca2+ current), mutagenesis of key residues, single lab\",\n      \"pmids\": [\"21521766\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"The CACNA1B R1389H mutation in the outer pore region reduces single-channel current amplitude (less current when open) without altering ion selectivity, voltage-dependent activation, or inactivation, consistent with a gain-of-function associated with myoclonus-dystonia and cardiac arrhythmias.\",\n      \"method\": \"Whole-cell and single-channel patch-clamp recordings of R1389H mutant vs. wild-type CaV2.2\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — high-resolution single-channel analysis of disease mutation, comprehensive biophysical characterization, single lab/family\",\n      \"pmids\": [\"25296916\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"TWIST1 transcriptionally represses Cacna1b in hematopoietic stem cells (HSCs); Twist1 deletion induces Cacna1b transactivation, increasing mitochondrial Ca2+ levels, metabolic activity, and ROS production, leading to HSC exhaustion; pharmacological VGCC blockade largely rescues defects in Twist1-deleted HSCs.\",\n      \"method\": \"Conditional Twist1 knockout mouse model, gene expression analysis, calcium channel blocker rescue, mitochondrial function assays, HSC transplantation/functional assays\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic deletion with pharmacological rescue, functional HSC assays, multiple cellular phenotypes measured, single lab\",\n      \"pmids\": [\"33619534\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"D2-like dopamine receptor activation in subthalamic nucleus neurons reduces CaV2.2 (but not CaV1) channel conductance via direct Gbetagamma binding (relief by brief depolarization); this reduction in CaV2.2 activity attenuates SKCa channel-mediated action potential afterhyperpolarization, modulating firing patterns.\",\n      \"method\": \"Patch-clamp in rat brain slices and acutely isolated neurons, pharmacological dissection with D2/D3/D4 agonists/antagonists, Ca2+-free media, CaV and SKCa channel blockers, brief depolarization protocol\",\n      \"journal\": \"Journal of neurophysiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — voltage-dependent reversal (Gbetagamma) established, pharmacological receptor subtype identification, functional consequences on firing pattern, single lab\",\n      \"pmids\": [\"18094105\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"RIM1alpha directly binds to CaV2.2 following deubiquitination (via Fbxo3 inhibition of Fbxl2-dependent ubiquitination of RIM1alpha), increasing CaV2.2 expression in synaptic plasma membranes of dorsal horn; RIM1alpha knockdown reverses SNL-induced allodynia and reduces spontaneous EPSC frequency by suppressing CaV2.2 expression.\",\n      \"method\": \"Spinal nerve ligation model, co-immunoprecipitation, siRNA knockdown of RIM1alpha, Western blot, patch-clamp (sEPSC recordings), intrathecal pharmacology\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP demonstrating direct binding, siRNA knockdown with functional electrophysiological readout in vivo/ex vivo, multiple interventions, single lab\",\n      \"pmids\": [\"27629721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"CaV2.2 channels are required in Trpv1-lineage neurons for thermal pain hypersensitivity following inflammation; CFA-induced inflammation increases CaV2.2 expression and current density in thermal nociceptors, increases action potential frequency (current clamp), and promotes ERK1/2-dependent sensory nerve growth; all effects are blocked by a CaV2.2-specific inhibitor.\",\n      \"method\": \"Cav2.2 inhibitor pharmacology, in situ hybridization, immunoblotting, voltage and current clamp in DRG neurons, behavioral thermal/mechanical testing\",\n      \"journal\": \"Frontiers in neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — specific pharmacological inhibition, electrophysiology, and nerve growth assay linked to CaV2.2 in native neurons, single lab\",\n      \"pmids\": [\"31607850\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"CaV2.2 exon 37a variant, expressed in excitatory projection neurons, enhances excitatory neurotransmitter release at entorhinal cortex-to-dentate gyrus synapses; mice expressing only e37b-CaV2.2 show reduced behavioral responses to aversive stimuli, indicating e37a alternative splicing influences behavioral outcomes through modulation of excitatory synaptic transmission.\",\n      \"method\": \"Mouse genetic models (e37a-null knockin), in situ hybridization, electrophysiology at identified synapses, behavioral testing\",\n      \"journal\": \"Molecular brain\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic mouse model with defined splice variant, electrophysiology at specific synapse, behavioral phenotype, single lab\",\n      \"pmids\": [\"31630675\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Morphine analgesia to thermal stimuli (but not ziconotide or gabapentin analgesia) is selectively reduced in mice lacking CaV2.2 exon 37a; e37a is not required for induction/maintenance of nerve injury-induced sensitization, indicating that e37a-specific sequence selectively links morphine analgesia (but not other Ca2+ channel-targeting analgesics) to CaV2.2 function.\",\n      \"method\": \"Cacna1b exon 37a knockout mice, intrathecal drug administration (morphine, ziconotide, gabapentin), behavioral thermal and mechanical nociception testing\",\n      \"journal\": \"Molecular pain\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic mouse model with exon-specific deletion, multiple analgesics tested to isolate e37a-specific mechanism, behavioral assays across multiple pain states\",\n      \"pmids\": [\"24369063\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"The A118G/N40D SNP in the mu opioid receptor (hMOR-D) inhibits CaV2.2e37a currents at 4-fold lower agonist concentrations than hMOR-N (wild-type), while the two variants show little difference on CaV2.2e37b; the e37a isoform of CaV2.2 is thus more sensitive to inhibition by MOR variants associated with altered pain sensitivity.\",\n      \"method\": \"Co-expression of hMOR-N or hMOR-D with CaV2.2e37a or e37b in mammalian cells, whole-cell patch-clamp electrophysiology, concentration-response analysis\",\n      \"journal\": \"Neuroscience letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct electrophysiological comparison of MOR variant effects on two CaV2.2 splice isoforms in a defined heterologous system, single lab\",\n      \"pmids\": [\"22796651\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Mu opioid receptor (mMOR) C-terminal splice variants differentially regulate CaV2.2e37a and e37b: mMOR1 and mMOR1C cause agonist-independent reduction in peak current density of CaV2.2-37a but not CaV2.2-37b via a Gi/o-independent, Src tyrosine kinase-dependent mechanism targeting tyrosine Y1747 of CaV2.2-37a; DAMGO induces more voltage-dependent (Gbetagamma-mediated) inhibition of CaV2.2-37b versus e37a.\",\n      \"method\": \"Co-expression in tsA-201 cells, whole-cell patch-clamp, pertussis toxin treatment, Src kinase inhibitor, Y1747F point mutagenesis of CaV2.2-37a, surface biotinylation\",\n      \"journal\": \"Molecular brain\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — site-directed mutagenesis identifying specific tyrosine residue, kinase inhibitor, pertussis toxin, and biotinylation assay collectively defining mechanistic pathway, single lab\",\n      \"pmids\": [\"31775826\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"A proteomic screen by antibody-mediated capture of CaV2.2 from purified rat brain synaptosomes followed by mass spectrometry identified 104 proteins co-precipitating with the channel, including known interactors (syntaxin 1, VAMP, PP2A, Goalpha, Gbeta, spectrin) and novel partners (clathrin, adaptin, dynamin, dynein, NSF, actin), suggesting CaV2.2 is anchored to a presynaptic cytoplasmic matrix.\",\n      \"method\": \"Antibody-mediated immunoprecipitation from purified synaptosome lysate, mass spectrometry peptide identification\",\n      \"journal\": \"Journal of biochemistry and molecular biology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — MS-based interactome screen provides partner list but no mechanistic validation of individual interactions; single lab, single method\",\n      \"pmids\": [\"17562281\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"CaV2.2 clusters at the transmitter release site are linked to an endocytosis protein complex: AP180 and intersectin adaptors co-precipitate tightly with CaV2.2, while clathrin and dynamin form a less tightly associated subcomplex; AP2 does not co-precipitate or co-localize with CaV2.2, suggesting a specialized AP2-lacking endocytosis complex at the active zone.\",\n      \"method\": \"Quantitative coimmunostaining (ICA/ICQ) in chick ciliary ganglion, co-immunoprecipitation from brain synaptosome lysates, high-NaCl fractional recovery analysis\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP supported by quantitative colocalization in native presynaptic terminal, multiple endocytosis proteins tested, single lab\",\n      \"pmids\": [\"17686037\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"NSF (N-ethylmaleimide-sensitive fusion protein) facilitates trafficking of CaV2.2 to the plasma membrane, increasing Ca2+ current intensity; rhodojaponin VI binds NSF (identified by thermal proteome profiling) and reverses NSF-facilitated CaV2.2 trafficking and current enhancement.\",\n      \"method\": \"Thermal proteome profiling, biological and biophysical validation of NSF-rhodojaponin VI interaction, patch-clamp electrophysiology in DRG neurons\",\n      \"journal\": \"Acta pharmaceutica Sinica. B\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — thermal proteome profiling for target identification with functional electrophysiology validation, single lab\",\n      \"pmids\": [\"36970201\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Cell-type-specific Cre-dependent inactivation of the Cacna1b gene in Trpv1-lineage neurons demonstrates that CaV2.2 channels in these neurons are specifically required for rapidly developing heat hypersensitivity but not all sensory behavioral responses.\",\n      \"method\": \"Conditional (Cre-dependent) Cacna1b gene inactivation in Trpv1-expressing neurons, behavioral testing for heat and mechanical hypersensitivity\",\n      \"journal\": \"Channels (Austin, Tex.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-type-specific genetic knockout with behavioral phenotyping, single lab\",\n      \"pmids\": [\"41428771\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"C2230, an aryloxy-hydroxypropylamine, blocks CaV2.2 by trapping and stabilizing the inactivated state and accelerating open-state inactivation; site-directed mutation analysis showed C2230 binds at a site distinct from other known CaV2.2 blockers; C2230 inhibits CaV2.2 in a use-dependent, G-protein-coupled-receptor-independent manner and reduces spinal cord excitatory neurotransmission.\",\n      \"method\": \"Whole-cell patch-clamp (state-dependent and frequency-dependent protocols), site-directed mutagenesis, calcium imaging, slice electrophysiology, multiple in vivo pain models\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — site-directed mutagenesis identifying binding site distinct from known blockers, multiple biophysical state protocols, replicated across species (rat, marmoset, human DRG) and in vivo\",\n      \"pmids\": [\"39656529\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"PKC activation (PMA) counteracts G protein-mediated inhibition of CaV2.2 channels in sympathetic neurons and reverses inhibition by Gbetagamma overexpression; PMA increases CaV2.2 conductance beyond what is explained by simple removal of G protein inhibition alone, indicating PKC phosphorylation has an additional direct effect on CaV2.2 channel gating.\",\n      \"method\": \"Patch-clamp in rat SCG neurons, PMA and GDPbetaS application, Gbetagamma overexpression, noradrenaline and GTPgammaS application\",\n      \"journal\": \"Archives of biochemistry and biophysics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological dissection in native neurons with multiple modulators, single lab\",\n      \"pmids\": [\"18298939\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"PKC activation (PMA) dramatically prolongs recovery of CaV2.2 channels from 'slow' voltage-dependent inactivation (developing over seconds-to-minutes); this effect requires the C1-domain of PKC (blocked by calphostin C), is partially dependent on PKC catalytic activity, is beta-subunit isoform-independent in magnitude, and is reduced by intracellular GDP-beta-S, implicating G proteins in modulating slow inactivation.\",\n      \"method\": \"Recombinant CaV2.2 in HEK293 cells and native CaV2 in chromaffin cells, slow inactivation protocols, PKC inhibitors (calphostin C, catalytic inhibitors), GDP-beta-S intracellular dialysis, multiple beta subunit isoforms\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple pharmacological tools and beta subunit variants tested in two cell types, single lab\",\n      \"pmids\": [\"26222492\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CaV2.2 (CACNA1B) is the pore-forming alpha1B subunit of the presynaptic N-type voltage-gated calcium channel that controls depolarization-evoked Ca2+ entry to trigger neurotransmitter release; its gating, surface expression, and trafficking are regulated by auxiliary subunits (CaVbeta, alpha2delta), multiple interacting proteins (CRMP-2/Cdk5-phosphorylation axis, ankyrin-B, MAP1A-LC2, MAP1B-LC1/UBE2L3, Munc18, RIM1alpha, TSPAN-13, 14-3-3tau), SNARE protein interactions via the synprint/II-III loop domain, G protein (Gbetagamma) voltage-dependent inhibition requiring specific I-II loop residues (Arg376, Val416), Gq/PIP2-dependent voltage-independent inhibition, PKC modulation of slow inactivation, and cell-type-specific alternative splicing (e37a/e37b, e31a) that shapes channel kinetics, expression density, and differential opioid/morphine sensitivity in nociceptors.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CACNA1B encodes CaV2.2, the pore-forming alpha1B subunit of the presynaptic N-type voltage-gated calcium channel that couples membrane depolarization to Ca2+ entry and neurotransmitter release, with prominent roles in nociceptor and sympathetic/central synaptic transmission [#6, #41]. The channel physically tethers synaptic vesicles through a PDZ-independent HxxRR motif in its distal C-terminus, and its synprint (II-III loop) region binds SNARE machinery such as syntaxin 1A and Munc18 to position the channel at the active zone and ensure efficient excitation-secretion coupling [#21, #25, #23, #6]. Surface density and gating are set by auxiliary subunits: CaVbeta binds the I-II loop to shield it from ubiquitin-proteasome degradation and drive plasma-membrane trafficking [#18, #24], alpha2delta-1 targets the channel to lipid rafts and shapes conotoxin pharmacology [#30, #7], and additional trafficking determinants include 14-3-3tau acting on the proximal C-terminus, NSF, ankyrin-B binding a DII/III tyrosine motif, and MAP1A-LC2 which retains channels at presynaptic boutons via the actin cytoskeleton [#31, #48, #17, #16]. Opposing this, MAP1B-LC1 recruits UBE2L3 to promote clathrin/dynamin-dependent internalization and proteasomal turnover, and gamma7 destabilizes CaV2.2 mRNA via hnRNP A2 [#19, #20]. A CRMP-2 axis, activated by Cdk5 phosphorylation at Ser522, positively regulates CaV2.2 surface expression, Ca2+ influx, and CGRP release [#0, #1]. Channel output is acutely tuned by GPCR signaling: Gbetagamma produces voltage-dependent inhibition through I-II loop residues Arg376/Val416, while PLC-mediated PIP2 hydrolysis drives voltage-independent inhibition, and the balance between these two modes is dictated by CaVbeta isoform membrane localization [#13, #32, #33]. Cell-type-specific alternative splicing of exon 37 (e37a vs e37b) shapes single-channel open time, expression density, and behavior, and confers selective sensitivity to morphine and mu-opioid-receptor variants [#9, #42, #43, #45]. A CACNA1B R1389H pore mutation that reduces single-channel current is associated with myoclonus-dystonia and cardiac arrhythmia [#37].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Established that CaV2.2 expression is autoregulated by its own domain I-containing segments, revealing translational/synthesis-level control of channel abundance independent of CaVbeta sequestration.\",\n      \"evidence\": \"Co-expression of truncated CaV2.2 domain constructs with GFP-channel fluorescence quantification and single-channel recording in Xenopus oocytes\",\n      \"pmids\": [\"11606638\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of synthesis inhibition not defined at molecular level\", \"Physiological relevance of N-terminal/domain I suppression unknown\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Defined how auxiliary subunits and the synprint region set channel biophysics and excitation-secretion coupling, showing beta3 imposes inhibitory ultra-slow inactivation, alpha2delta-1 shapes conotoxin block, and synprint deletion impairs secretion.\",\n      \"evidence\": \"Two-electrode voltage clamp in oocytes/HEK with subunit co-expression, kinetic toxin analysis, and capacitance measurements of secretion in MPC 9/3L cells\",\n      \"pmids\": [\"15024042\", \"15166237\", \"15471993\", \"15536086\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of synprint-secretion coupling not resolved\", \"Native contribution of beta3 ultra-slow inactivation in vivo unquantified\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Mapped alternative splicing of exon 31a and exon 37 as determinants of gating kinetics and open time, linking splice choice to cell-type-specific N-type channel behavior.\",\n      \"evidence\": \"Whole-cell, single-channel, and gating-current recordings of splice isoforms in tsA201 stable cell lines\",\n      \"pmids\": [\"15201306\", \"16857708\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Upstream regulators of splice selection not identified\", \"In vivo behavioral consequences not yet tested at this stage\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Resolved the presynaptic interactome and active-zone anchoring of CaV2.2, identifying SNARE, endocytic, cytoskeletal, and G-protein partners and a specialized AP2-lacking endocytosis complex.\",\n      \"evidence\": \"Synaptosome immunoprecipitation with mass spectrometry, plus quantitative co-immunostaining and co-IP of endocytic adaptors in chick ciliary ganglion\",\n      \"pmids\": [\"17562281\", \"17686037\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"MS interactome lacks individual interaction validation\", \"Functional roles of most candidate partners untested\", \"Stoichiometry and direct vs indirect binding unresolved\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Identified opposing trafficking regulators that control surface CaV2.2 abundance: MAP1A-LC2/actin retains channels at boutons while gamma7 destabilizes CaV2.2 mRNA via hnRNP A2.\",\n      \"evidence\": \"Co-IP, surface antibody labeling, RNAi, actin disruption, FM4-64 recycling assay, and mRNA-stability assays in hippocampal and PC12 neurons\",\n      \"pmids\": [\"18971475\", \"18923037\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Coordination between mRNA-level and protein-level control not integrated\", \"Conditions toggling retention vs degradation unknown\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Established the CRMP-2/Cdk5 axis as a positive trafficking regulator of CaV2.2, with Ser522 phosphorylation required for enhanced channel surface expression and transmitter release.\",\n      \"evidence\": \"Co-IP, overexpression/siRNA, phospho-null S522A mutagenesis, electrophysiology, and CGRP release in DRG neurons\",\n      \"pmids\": [\"19903690\", \"23022559\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct binding interface on CaV2.2 not mapped\", \"Whether CRMP-2 acts on forward trafficking vs membrane retention unresolved\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Demonstrated that CaV2.2 directly tethers synaptic vesicles through its distal C-terminal HxxRR motif independent of PDZ ligand, providing a molecular basis for channel-vesicle coupling.\",\n      \"evidence\": \"Cell-free synaptic vesicle pull-down with C-terminal truncation/mutant fusion proteins, blocking peptides, and synaptosome electron microscopy\",\n      \"pmids\": [\"23874268\", \"24639630\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Vesicle-side binding partner of the HxxRR motif not identified\", \"Relationship to synprint-mediated SNARE coupling unclear\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Separated the two GPCR-driven inhibitory modes of CaV2.2 by showing PIP2 hydrolysis underlies voltage-independent inhibition, distinct from Gbetagamma voltage-dependent inhibition.\",\n      \"evidence\": \"Double-pulse voltage clamp with PLC blockade, PIP2 dialysis, and wortmannin in sympathetic neurons; TSPAN-13 split-ubiquitin mapping\",\n      \"pmids\": [\"23396054\", \"23648579\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct PIP2 binding site on CaV2.2 not localized\", \"Crosstalk with voltage-dependent pathway not fully quantified\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Defined the CaVbeta/proteasome surface-expression logic and showed CaVbeta membrane localization dictates whether Gbetagamma voltage-dependent or PIP2 voltage-independent inhibition predominates.\",\n      \"evidence\": \"Reconstituted ubiquitination with lysine mutagenesis and MG132, chimeric channels, Gbetagamma sequestration, palmitoylation mutants, plus 14-3-3 and ankyrin-B/MAP1B-LC1 trafficking studies\",\n      \"pmids\": [\"27489103\", \"25225550\", \"25516596\", \"24394417\", \"24566975\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the E3 ligase ubiquitinating the I-II loop not determined\", \"How beta-subunit localization is set in native neurons unresolved\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Linked a CACNA1B pore mutation to human disease, showing R1389H reduces single-channel current without altering selectivity or gating, associated with myoclonus-dystonia and cardiac arrhythmia.\",\n      \"evidence\": \"Whole-cell and single-channel patch-clamp of R1389H versus wild-type CaV2.2\",\n      \"pmids\": [\"25296916\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single family/lab characterization\", \"Mechanistic link from reduced single-channel current to phenotype not established\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Connected exon 37 splice choice to opioid pharmacology and behavior, showing e37a confers morphine analgesia and heightened mu-opioid-receptor sensitivity via Src-dependent targeting of Y1747, and shapes excitatory transmission.\",\n      \"evidence\": \"Exon 37a knockout/knockin mice, behavioral analgesia testing, heterologous MOR variant co-expression, Y1747F mutagenesis, Src inhibition, and synapse electrophysiology\",\n      \"pmids\": [\"24369063\", \"31775826\", \"22796651\", \"31630675\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of e37a-specific Src targeting not resolved\", \"Human relevance of mouse splice-specific opioid effects untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Used cell-type-specific genetic ablation to assign CaV2.2 in Trpv1-lineage neurons a specific requirement for rapidly developing heat hypersensitivity, refining its role in pain circuits.\",\n      \"evidence\": \"Cre-dependent Cacna1b inactivation in Trpv1 neurons with behavioral heat and mechanical testing\",\n      \"pmids\": [\"41428771\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular events downstream of channel loss in these neurons unspecified\", \"Single-lab finding\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the many trafficking, anchoring, and inhibitory inputs are integrated into a unified structural and spatial model of CaV2.2 regulation at the active zone remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No high-resolution structure of CaV2.2 with auxiliary/regulatory partners in the timeline\", \"Quantitative hierarchy among competing trafficking pathways unknown\", \"In vivo integration of voltage-dependent vs independent inhibition not defined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [6, 9, 10, 41]},\n      {\"term_id\": \"GO:0005262\", \"supporting_discovery_ids\": [37]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [21, 22]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [16, 24, 30, 31, 48]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [31]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [16, 30]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [6, 41, 42]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [13, 32, 33, 39]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [21, 22, 47]}\n    ],\n    \"complexes\": [\n      \"N-type voltage-gated calcium channel (CaV2.2/CaVbeta/alpha2delta)\"\n    ],\n    \"partners\": [\n      \"CRMP2\",\n      \"CACNB3\",\n      \"CACNA2D1\",\n      \"MAP1A\",\n      \"MAP1B\",\n      \"STX1A\",\n      \"RIMS1\",\n      \"ANK2\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":8,"faith_pct":87.5}}