{"gene":"TMEM63A","run_date":"2026-06-10T10:51:55","timeline":{"discoveries":[{"year":2016,"finding":"Co-expression of all three mouse TMEM63 family members (TMEM63A, TMEM63B, and TMEM63C) in HEK293 cells is required to reconstitute hyperosmolarity-activated ion currents; no two-subtype combination was sufficient, suggesting TMEM63A contributes to an osmosensitive ion channel complex.","method":"Heterologous expression in HEK293 cells with patch-clamp electrophysiology under hypertonic stimulation","journal":"Cell biochemistry and function","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — direct electrophysiological readout in reconstituted system, but single lab and single method; requires all three family members making TMEM63A-specific contribution ambiguous","pmids":["27045885"],"is_preprint":false},{"year":2019,"finding":"Heterozygous missense variants in the pore-forming domain of TMEM63A strongly attenuate stretch-activated (mechanosensitive) ion currents when expressed in naive cells, establishing TMEM63A as a mechanically activated (MA) ion channel whose pore domain is essential for stretch-activated current.","method":"Patch-clamp electrophysiology (stretch-activated current recording) in cells expressing disease-associated TMEM63A variants","journal":"American journal of human genetics","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct electrophysiological reconstitution with disease variant mutagenesis, replicated across four independent variants in the same study","pmids":["31587869"],"is_preprint":false},{"year":2022,"finding":"TMEM63A localizes to endoplasmic reticulum and lysosome membranes, interacts with VCP (valosin-containing protein) and its cofactor DERL1 (derlin 1), undergoes TOLLIP-mediated autophagic degradation, and is stabilized by VCP through blockade of lysosomal degradation; TMEM63A in turn stabilizes DERL1 by preventing TOLLIP-mediated autophagic degradation.","method":"Co-immunoprecipitation, subcellular fractionation/co-localization, knockdown/overexpression in vitro and xenograft in vivo, pharmacological VCP inhibition (CB-5083)","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP plus functional rescue experiments, single lab but multiple orthogonal methods","pmids":["35920704"],"is_preprint":false},{"year":2022,"finding":"TMEM63A is expressed in non-peptidergic nociceptors of the dorsal root ganglion (DRG); Tmem63a knockout mice show significantly reduced mechanical allodynia (but not heat or cold allodynia) in inflammatory and post-amputation states, and TMEM63A deletion reduces macrophage infiltration into the DRG, revealing a role for TMEM63A-mediated mechanosensing in nociceptor-macrophage crosstalk during chronic post-amputation pain.","method":"Tmem63a knockout mice, behavioral pain testing (von Frey, heat, cold), histology, qRT-PCR, macrophage ablation experiments","journal":"Neuroscience bulletin","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO with multiple behavioral readouts and macrophage ablation epistasis, single lab","pmids":["35821338"],"is_preprint":false},{"year":2024,"finding":"TMEM63A forms a monomeric structure with eleven transmembrane helices (resolved by cryo-EM in the presence of calcium), distinct from the homodimeric architecture of plant OSCA orthologs; the ion permeation pathway is located within this monomeric configuration and a non-protein density resembling lipid is observed.","method":"Single-particle cryo-EM of human TMEM63A protein","journal":"Proteins","confidence":"High","confidence_rationale":"Tier 1 / Moderate — atomic-resolution cryo-EM structure with ion permeation pathway identification; single study but structural data is direct","pmids":["38217391"],"is_preprint":false},{"year":2024,"finding":"TMEM63A mediates pressure-dependent, voltage-independent cation currents in cell-attached membrane patches with slow activation/deactivation kinetics, no inactivation over 5 s, sensitivity to Gd3+, and a high threshold for pressure activation; in whole cells stretched on flexible membranes, TMEM63A expression increases intracellular Ca2+ responses, indicating it sustains a Ca2+ increase upon high stretch.","method":"High-speed pressure clamp patch-clamp electrophysiology in Piezo1-KO HEK293T cells expressing TMEM63A; GCaMP5 Ca2+ imaging during IsoStretcher-induced whole-cell stretch","journal":"American journal of physiology. Cell physiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct electrophysiology with defined biophysical parameters plus orthogonal Ca2+ imaging in whole cells; single lab with two independent methods","pmids":["38189136"],"is_preprint":false},{"year":2024,"finding":"TMEM63A and TMEM63B are predominantly localized at the limiting membrane of the lamellar body (LB) in alveolar type 2 (AT2) cells; loss of TMEM63A/B causes surfactant secretion deficits, atelectasis, and respiratory failure in mice; activation of TMEM63A/B during cell stretch facilitates surfactant and ATP release from LBs fusing with the plasma membrane, and released ATP evokes Ca2+ signaling that potentiates further LB exocytosis.","method":"TMEM63A/B double-knockout mice (respiratory phenotype), subcellular localization imaging, in vitro cell-stretch assays, ATP/surfactant secretion assays, Ca2+ signaling measurements","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO with defined physiological phenotype, subcellular localization, and mechanistic dissection of ATP-Ca2+ signaling cascade; multiple orthogonal methods in single rigorous study","pmids":["38127458"],"is_preprint":false},{"year":2025,"finding":"TMEM63A-mediated Ca2+ influx is required for oligodendrocyte precursor cell (OPC) differentiation; Tmem63a knockout mice exhibit transient hypomyelination at P14 due to impaired OPC differentiation that resolves by P28; lentiviral re-expression of wild-type TMEM63A (but not the loss-of-function A632T variant) rescues OPC differentiation in vitro and myelination in vivo, demonstrating cell-autonomous Ca2+ channel function in oligodendrocyte development.","method":"Tmem63a knockout mice, primary OPC culture differentiation assays, Ca2+ influx assay, lentiviral rescue with WT vs. mutant TMEM63A","journal":"Neuroscience bulletin","confidence":"High","confidence_rationale":"Tier 2 / Moderate — genetic KO phenotype plus lentiviral rescue with mutant vs. WT, Ca2+ assay, multiple orthogonal methods in single study","pmids":["39982638"],"is_preprint":false},{"year":2025,"finding":"TMEM63A is present at the plasma membrane and on lysosomes in oligodendrocytes; OL-specific conditional knockout of Tmem63a causes transient reductions in myelin (cell-autonomous effect); HLD19-associated TMEM63A patient variants block trafficking of the protein to the cell membrane, indicating a trafficking-dependent mechanism for pathogenesis.","method":"OL-specific conditional Tmem63a knockout mice (mouse and zebrafish models), subcellular localization imaging, trafficking assays for disease-associated variants","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Moderate — cell-type-specific conditional KO plus localization and variant trafficking assay; two model organisms; single lab with multiple orthogonal methods","pmids":["40694323"],"is_preprint":false},{"year":2026,"finding":"TMEM63A is a lysosome-resident non-selective cation channel that, when gated by mechanical tension on the lysosomal membrane, drives monovalent cation flux out of the lysosomal lumen, relieving hydrostatic pressure and membrane tension; lysosomes lacking TMEM63A (by deletion or expression of disease-causing variants) are ~10-fold more sensitive to lysis upon increased membrane tension, demonstrating that TMEM63A confers mechano-resilience to lysosomes.","method":"TMEM63A deletion and disease-variant expression in cells, lysosomal rupture/lysis assays, osmotic and mechanical perturbation experiments, lipid acquisition assays","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — genetic deletion plus disease variant functional assays with quantitative lysis readout; single lab with multiple orthogonal methods","pmids":["41811130"],"is_preprint":false},{"year":2025,"finding":"TMEM63A (and TMEM63B) function as mechanically activated lipid scramblases in addition to ion channels: phospholipids can be translocated through the open pore of TMEM63A; mutating key groove-lining residues differentially affects lipid vs. ion passage; cholesterol inhibits lipid scrambling by stabilizing the closed state and slowing translocation; this scramblase activity is activated by mechanical forces and contributes to membrane morphological remodeling and cellular mechano-resilience.","method":"In vitro lipid scramblase assays, cellular lipid translocation assays, computational/MD simulations, groove-lining residue mutagenesis, cholesterol manipulation experiments","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro reconstitution and mutagenesis with computational support, but preprint not yet peer-reviewed and single lab","pmids":["bio_10.1101_2025.07.26.664997"],"is_preprint":true}],"current_model":"TMEM63A is a mechanosensitive, non-selective cation channel with a monomeric eleven-transmembrane-helix architecture that localizes to the plasma membrane, endoplasmic reticulum, and lysosomal membranes; it is gated by membrane tension to conduct cations (and possibly scramble lipids), mediating Ca2+ influx critical for oligodendrocyte differentiation and myelination, surfactant secretion from alveolar type 2 cells, and lysosomal mechano-resilience by relieving hydrostatic pressure, while disease-causing variants in its pore domain attenuate stretch-activated currents or block plasma membrane trafficking, causing hypomyelinating leukodystrophy."},"narrative":{"mechanistic_narrative":"TMEM63A is a mechanically activated, non-selective cation channel that converts membrane tension into Ca2+ and monovalent cation flux to support tissue-specific mechanotransduction [PMID:31587869, PMID:38189136]. It mediates pressure-dependent, voltage-independent currents with slow activation, no inactivation, sensitivity to Gd3+, and a high pressure threshold, and sustains stretch-evoked intracellular Ca2+ increases [PMID:38189136]; cryo-EM resolves it as a monomeric protein with eleven transmembrane helices harboring the ion permeation pathway, architecturally distinct from the homodimeric plant OSCA channels [PMID:38217391]. The protein localizes to plasma membrane, endoplasmic reticulum, and lysosomal membranes [PMID:35920704, PMID:40694323]. At the lysosome it conducts cations out of the lumen to relieve hydrostatic pressure and membrane tension, conferring mechano-resilience against tension-induced lysis [PMID:41811130]. Through this channel activity TMEM63A drives oligodendrocyte precursor differentiation and myelination via cell-autonomous Ca2+ influx [PMID:39982638, PMID:40694323], facilitates stretch-triggered surfactant and ATP release from lamellar bodies of alveolar type 2 cells [PMID:38127458], and mediates mechanical nociception in dorsal root ganglion nociceptors with downstream macrophage crosstalk in chronic pain [PMID:35821338]. Heterozygous missense variants in the pore domain attenuate stretch-activated currents [PMID:31587869] and disease-associated variants block trafficking to the plasma membrane, causing hypomyelinating leukodystrophy (HLD19) [PMID:40694323].","teleology":[{"year":2016,"claim":"Established the first functional link between the TMEM63 family and osmosensitive ion conduction, raising the possibility that TMEM63A participates in an osmo-/mechanosensitive channel.","evidence":"Heterologous co-expression of all three mouse TMEM63 members in HEK293 cells with patch-clamp under hypertonic stimulation","pmids":["27045885"],"confidence":"Medium","gaps":["Required all three family members, leaving TMEM63A-specific contribution ambiguous","Single lab and single method","Did not establish mechanical (stretch) gating directly"]},{"year":2019,"claim":"Defined TMEM63A itself as a mechanically activated channel and localized its activity to the pore domain by showing disease variants attenuate stretch-activated current.","evidence":"Patch-clamp stretch-activated current recording of disease-associated TMEM63A variants in naive cells","pmids":["31587869"],"confidence":"High","gaps":["Did not resolve channel architecture or ion selectivity","Mechanism linking variant to disease tissue not yet defined"]},{"year":2022,"claim":"Placed TMEM63A in a protein-stability circuit at ER/lysosomal membranes, connecting it to VCP/DERL1 and TOLLIP-mediated autophagic turnover.","evidence":"Reciprocal Co-IP, fractionation/co-localization, knockdown/overexpression, xenograft, and pharmacological VCP inhibition (CB-5083)","pmids":["35920704"],"confidence":"Medium","gaps":["Single lab","Relationship between this stability circuit and channel gating function unclear","No structural basis for the interactions"]},{"year":2022,"claim":"Demonstrated an in vivo sensory role for TMEM63A in mechanical (but not thermal) nociception and uncovered nociceptor-macrophage crosstalk in chronic pain.","evidence":"Tmem63a knockout mice with von Frey/heat/cold behavioral testing, histology, and macrophage ablation","pmids":["35821338"],"confidence":"Medium","gaps":["Single lab","Molecular signal from nociceptor to macrophage not defined","Channel biophysics in DRG neurons not measured directly"]},{"year":2024,"claim":"Resolved the channel architecture as a monomeric eleven-TM protein with a defined permeation pathway, distinguishing it from homodimeric plant OSCA orthologs.","evidence":"Single-particle cryo-EM of human TMEM63A in the presence of calcium","pmids":["38217391"],"confidence":"High","gaps":["Captured in a single state, not an open/gated conformation","Functional role of observed lipid-like density unresolved","No variant structures to explain loss of function"]},{"year":2024,"claim":"Quantified the biophysical signature of TMEM63A as a high-threshold, slowly gating, non-inactivating cation channel that sustains stretch-evoked Ca2+ rise.","evidence":"High-speed pressure-clamp patch-clamp in Piezo1-KO HEK293T cells plus GCaMP5 Ca2+ imaging under whole-cell stretch","pmids":["38189136"],"confidence":"High","gaps":["Single lab","Ion selectivity not fully dissected","Native gating tension in physiological membranes unknown"]},{"year":2024,"claim":"Identified a physiological function in the lung: TMEM63A localizes to lamellar body membranes and couples stretch to surfactant/ATP release driving Ca2+-amplified exocytosis.","evidence":"TMEM63A/B double-knockout mice, localization imaging, cell-stretch assays, ATP/surfactant secretion and Ca2+ measurements","pmids":["38127458"],"confidence":"High","gaps":["Redundancy with TMEM63B not separated for TMEM63A alone","Direct conduction at the lamellar body membrane not recorded"]},{"year":2025,"claim":"Established the cell-autonomous requirement for TMEM63A-mediated Ca2+ influx in oligodendrocyte precursor differentiation and myelination, with variant-specific rescue.","evidence":"Tmem63a knockout mice, primary OPC differentiation and Ca2+ influx assays, lentiviral rescue with WT vs. A632T variant","pmids":["39982638"],"confidence":"High","gaps":["Transient hypomyelination resolving by P28 leaves compensatory mechanism undefined","Downstream Ca2+-dependent differentiation effectors not identified"]},{"year":2025,"claim":"Linked HLD19 pathogenesis to defective trafficking, showing patient variants fail to reach the plasma membrane, and confirmed cell-autonomous oligodendrocyte function by conditional knockout.","evidence":"OL-specific conditional Tmem63a knockout in mouse and zebrafish, localization imaging, and trafficking assays of disease variants","pmids":["40694323"],"confidence":"High","gaps":["Whether trafficking loss versus pore loss dominates across all variants not delineated","Mechanism retaining variants intracellularly unknown"]},{"year":2026,"claim":"Defined a lysosomal role: tension-gated cation efflux relieves luminal pressure and confers ~10-fold mechano-resilience against lysis.","evidence":"TMEM63A deletion and disease-variant expression with lysosomal lysis assays and osmotic/mechanical perturbation","pmids":["41811130"],"confidence":"High","gaps":["Single lab","In vivo relevance of lysosomal mechano-resilience to disease not established","Coupling between lysosomal and plasma-membrane pools unclear"]},{"year":2025,"claim":"Proposed an additional mechanically activated lipid scramblase activity through the same pore, regulated by cholesterol, expanding the protein's role to membrane remodeling.","evidence":"In vitro lipid scramblase and cellular translocation assays, groove-lining mutagenesis, MD simulations, cholesterol manipulation (preprint)","pmids":["bio_10.1101_2025.07.26.664997"],"confidence":"Medium","gaps":["Preprint, not yet peer-reviewed","Single lab","Physiological contribution of scrambling relative to ion conduction unquantified in vivo"]},{"year":null,"claim":"How TMEM63A's channel, scramblase, and trafficking/stability functions are integrated across its plasma membrane, ER, and lysosomal pools to produce tissue-specific mechanotransduction remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No open-state structure linking gating to permeation","Native gating tension thresholds in each tissue undefined","Relative contributions of ion flux versus lipid scrambling in vivo unknown"]}],"mechanism_profile":{"molecular_activity":[],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[8]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[2]},{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[8,9]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,5]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[7,8]}],"complexes":[],"partners":["VCP","DERL1","TOLLIP","TMEM63B"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O94886","full_name":"Mechanosensitive cation channel TMEM63A","aliases":["Transmembrane protein 63A","hTMEM63A"],"length_aa":807,"mass_kda":92.1,"function":"Mechanosensitive cation channel with low conductance and high activation threshold (PubMed:30382938, PubMed:31587869, PubMed:37543036). In contrast to TMEM63B, does not show phospholipid scramblase activity (PubMed:39716028). Acts as a regulator of lysosomal morphology by mediating lysosomal mechanosensitivity (By similarity). Important for the baby's first breath and respiration throughout life (PubMed:38127458). Upon lung inflation conducts cation currents in alveolar type 1 and 2 cells triggering lamellar body exocytosis and surfactant secretion into airspace (PubMed:38127458). Also acts as an osmosensitive cation channel preferentially activated by hypotonic stress (By similarity)","subcellular_location":"Lysosome membrane; Early endosome membrane; Cell membrane","url":"https://www.uniprot.org/uniprotkb/O94886/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TMEM63A","classification":"Not Classified","n_dependent_lines":6,"n_total_lines":1208,"dependency_fraction":0.004966887417218543},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/TMEM63A","total_profiled":1310},"omim":[{"mim_id":"619953","title":"TRANSMEMBRANE PROTEIN 63C; TMEM63C","url":"https://www.omim.org/entry/619953"},{"mim_id":"619952","title":"TRANSMEMBRANE PROTEIN 63B; TMEM63B","url":"https://www.omim.org/entry/619952"},{"mim_id":"618688","title":"LEUKODYSTROPHY, HYPOMYELINATING, 19, TRANSIENT INFANTILE; HLD19","url":"https://www.omim.org/entry/618688"},{"mim_id":"618685","title":"TRANSMEMBRANE PROTEIN 63A; TMEM63A","url":"https://www.omim.org/entry/618685"},{"mim_id":"312080","title":"PELIZAEUS-MERZBACHER DISEASE; PMD","url":"https://www.omim.org/entry/312080"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Vesicles","reliability":"Enhanced"},{"location":"Centriolar satellite","reliability":"Enhanced"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"brain","ntpm":153.0}],"url":"https://www.proteinatlas.org/search/TMEM63A"},"hgnc":{"alias_symbol":[],"prev_symbol":["KIAA0792"]},"alphafold":{"accession":"O94886","domains":[{"cath_id":"-","chopping":"41-89_114-221_412-532_544-722","consensus_level":"medium","plddt":81.4658,"start":41,"end":722},{"cath_id":"3.30.70.330","chopping":"226-398","consensus_level":"medium","plddt":86.4215,"start":226,"end":398}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O94886","model_url":"https://alphafold.ebi.ac.uk/files/AF-O94886-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O94886-F1-predicted_aligned_error_v6.png","plddt_mean":74.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TMEM63A","jax_strain_url":"https://www.jax.org/strain/search?query=TMEM63A"},"sequence":{"accession":"O94886","fasta_url":"https://rest.uniprot.org/uniprotkb/O94886.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O94886/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O94886"}},"corpus_meta":[{"pmid":"31587869","id":"PMC_31587869","title":"Heterozygous Variants in the Mechanosensitive Ion Channel TMEM63A Result in Transient Hypomyelination during Infancy.","date":"2019","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/31587869","citation_count":78,"is_preprint":false},{"pmid":"35920704","id":"PMC_35920704","title":"TOLLIP-mediated autophagic degradation pathway links the VCP-TMEM63A-DERL1 signaling axis to triple-negative breast cancer progression.","date":"2022","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/35920704","citation_count":47,"is_preprint":false},{"pmid":"38127458","id":"PMC_38127458","title":"Mechanosensitive channels TMEM63A and TMEM63B mediate lung inflation-induced surfactant secretion.","date":"2024","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/38127458","citation_count":38,"is_preprint":false},{"pmid":"27045885","id":"PMC_27045885","title":"Co-expression of mouse TMEM63A, TMEM63B and TMEM63C confers hyperosmolarity activated ion currents in HEK293 cells.","date":"2016","source":"Cell biochemistry and function","url":"https://pubmed.ncbi.nlm.nih.gov/27045885","citation_count":31,"is_preprint":false},{"pmid":"34598833","id":"PMC_34598833","title":"A novel de novo TMEM63A variant in a patient with severe hypomyelination and global developmental delay.","date":"2021","source":"Brain & development","url":"https://pubmed.ncbi.nlm.nih.gov/34598833","citation_count":25,"is_preprint":false},{"pmid":"33785861","id":"PMC_33785861","title":"Spinal cord involvement and paroxysmal events in \"Infantile Onset Transient Hypomyelination\" due to TMEM63A mutation.","date":"2021","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/33785861","citation_count":23,"is_preprint":false},{"pmid":"35821338","id":"PMC_35821338","title":"Mechanosensitive Ion Channel TMEM63A Gangs Up with Local Macrophages to Modulate Chronic Post-amputation Pain.","date":"2022","source":"Neuroscience bulletin","url":"https://pubmed.ncbi.nlm.nih.gov/35821338","citation_count":18,"is_preprint":false},{"pmid":"39982638","id":"PMC_39982638","title":"Cation Channel TMEM63A Autonomously Facilitates Oligodendrocyte Differentiation at an Early Stage.","date":"2025","source":"Neuroscience bulletin","url":"https://pubmed.ncbi.nlm.nih.gov/39982638","citation_count":9,"is_preprint":false},{"pmid":"38217391","id":"PMC_38217391","title":"A monomeric structure of human TMEM63A protein.","date":"2024","source":"Proteins","url":"https://pubmed.ncbi.nlm.nih.gov/38217391","citation_count":9,"is_preprint":false},{"pmid":"38189136","id":"PMC_38189136","title":"Stretch response of the mechano-gated channel TMEM63A in membrane patches and single cells.","date":"2024","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/38189136","citation_count":6,"is_preprint":false},{"pmid":"40694323","id":"PMC_40694323","title":"TMEM63A, associated with hypomyelinating leukodystrophies, is an evolutionarily conserved regulator of myelination.","date":"2025","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/40694323","citation_count":5,"is_preprint":false},{"pmid":"38790154","id":"PMC_38790154","title":"A TMEM63A Nonsense Heterozygous Variant Linked to Infantile Transient Hypomyelinating Leukodystrophy Type 19?","date":"2024","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/38790154","citation_count":5,"is_preprint":false},{"pmid":"41811130","id":"PMC_41811130","title":"Mechanoresilience of lysosomes conferred by TMEM63A.","date":"2026","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/41811130","citation_count":3,"is_preprint":false},{"pmid":"41272208","id":"PMC_41272208","title":"Spatial lipidomics reveals altered lipid profiles in TMEM63A mutant rats with hypomyelination.","date":"2025","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/41272208","citation_count":0,"is_preprint":false},{"pmid":"42220953","id":"PMC_42220953","title":"Novel TMEM63A mutation associated with transient hypomyelination of infancy - lessons from a previously negative whole-exome sequencing case: Three case reports.","date":"2026","source":"World journal of clinical pediatrics","url":"https://pubmed.ncbi.nlm.nih.gov/42220953","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.04.07.647591","title":"Conditional deletion of  <i>Tmem63b</i>  does not impact mouse voiding behavior","date":"2025-04-11","source":"bioRxiv","url":"https://doi.org/10.1101/2025.04.07.647591","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.07.26.664997","title":"TMEM63 proteins act as mechanically activated cholesterol modulated lipid scramblases contributing to membrane mechano-resilience","date":"2025-07-26","source":"bioRxiv","url":"https://doi.org/10.1101/2025.07.26.664997","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10417,"output_tokens":3028,"usd":0.038336,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10482,"output_tokens":3714,"usd":0.07263,"stage2_stop_reason":"end_turn"},"total_usd":0.110966,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2016,\n      \"finding\": \"Co-expression of all three mouse TMEM63 family members (TMEM63A, TMEM63B, and TMEM63C) in HEK293 cells is required to reconstitute hyperosmolarity-activated ion currents; no two-subtype combination was sufficient, suggesting TMEM63A contributes to an osmosensitive ion channel complex.\",\n      \"method\": \"Heterologous expression in HEK293 cells with patch-clamp electrophysiology under hypertonic stimulation\",\n      \"journal\": \"Cell biochemistry and function\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — direct electrophysiological readout in reconstituted system, but single lab and single method; requires all three family members making TMEM63A-specific contribution ambiguous\",\n      \"pmids\": [\"27045885\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Heterozygous missense variants in the pore-forming domain of TMEM63A strongly attenuate stretch-activated (mechanosensitive) ion currents when expressed in naive cells, establishing TMEM63A as a mechanically activated (MA) ion channel whose pore domain is essential for stretch-activated current.\",\n      \"method\": \"Patch-clamp electrophysiology (stretch-activated current recording) in cells expressing disease-associated TMEM63A variants\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct electrophysiological reconstitution with disease variant mutagenesis, replicated across four independent variants in the same study\",\n      \"pmids\": [\"31587869\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"TMEM63A localizes to endoplasmic reticulum and lysosome membranes, interacts with VCP (valosin-containing protein) and its cofactor DERL1 (derlin 1), undergoes TOLLIP-mediated autophagic degradation, and is stabilized by VCP through blockade of lysosomal degradation; TMEM63A in turn stabilizes DERL1 by preventing TOLLIP-mediated autophagic degradation.\",\n      \"method\": \"Co-immunoprecipitation, subcellular fractionation/co-localization, knockdown/overexpression in vitro and xenograft in vivo, pharmacological VCP inhibition (CB-5083)\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP plus functional rescue experiments, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"35920704\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"TMEM63A is expressed in non-peptidergic nociceptors of the dorsal root ganglion (DRG); Tmem63a knockout mice show significantly reduced mechanical allodynia (but not heat or cold allodynia) in inflammatory and post-amputation states, and TMEM63A deletion reduces macrophage infiltration into the DRG, revealing a role for TMEM63A-mediated mechanosensing in nociceptor-macrophage crosstalk during chronic post-amputation pain.\",\n      \"method\": \"Tmem63a knockout mice, behavioral pain testing (von Frey, heat, cold), histology, qRT-PCR, macrophage ablation experiments\",\n      \"journal\": \"Neuroscience bulletin\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with multiple behavioral readouts and macrophage ablation epistasis, single lab\",\n      \"pmids\": [\"35821338\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"TMEM63A forms a monomeric structure with eleven transmembrane helices (resolved by cryo-EM in the presence of calcium), distinct from the homodimeric architecture of plant OSCA orthologs; the ion permeation pathway is located within this monomeric configuration and a non-protein density resembling lipid is observed.\",\n      \"method\": \"Single-particle cryo-EM of human TMEM63A protein\",\n      \"journal\": \"Proteins\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — atomic-resolution cryo-EM structure with ion permeation pathway identification; single study but structural data is direct\",\n      \"pmids\": [\"38217391\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"TMEM63A mediates pressure-dependent, voltage-independent cation currents in cell-attached membrane patches with slow activation/deactivation kinetics, no inactivation over 5 s, sensitivity to Gd3+, and a high threshold for pressure activation; in whole cells stretched on flexible membranes, TMEM63A expression increases intracellular Ca2+ responses, indicating it sustains a Ca2+ increase upon high stretch.\",\n      \"method\": \"High-speed pressure clamp patch-clamp electrophysiology in Piezo1-KO HEK293T cells expressing TMEM63A; GCaMP5 Ca2+ imaging during IsoStretcher-induced whole-cell stretch\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct electrophysiology with defined biophysical parameters plus orthogonal Ca2+ imaging in whole cells; single lab with two independent methods\",\n      \"pmids\": [\"38189136\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"TMEM63A and TMEM63B are predominantly localized at the limiting membrane of the lamellar body (LB) in alveolar type 2 (AT2) cells; loss of TMEM63A/B causes surfactant secretion deficits, atelectasis, and respiratory failure in mice; activation of TMEM63A/B during cell stretch facilitates surfactant and ATP release from LBs fusing with the plasma membrane, and released ATP evokes Ca2+ signaling that potentiates further LB exocytosis.\",\n      \"method\": \"TMEM63A/B double-knockout mice (respiratory phenotype), subcellular localization imaging, in vitro cell-stretch assays, ATP/surfactant secretion assays, Ca2+ signaling measurements\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO with defined physiological phenotype, subcellular localization, and mechanistic dissection of ATP-Ca2+ signaling cascade; multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"38127458\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TMEM63A-mediated Ca2+ influx is required for oligodendrocyte precursor cell (OPC) differentiation; Tmem63a knockout mice exhibit transient hypomyelination at P14 due to impaired OPC differentiation that resolves by P28; lentiviral re-expression of wild-type TMEM63A (but not the loss-of-function A632T variant) rescues OPC differentiation in vitro and myelination in vivo, demonstrating cell-autonomous Ca2+ channel function in oligodendrocyte development.\",\n      \"method\": \"Tmem63a knockout mice, primary OPC culture differentiation assays, Ca2+ influx assay, lentiviral rescue with WT vs. mutant TMEM63A\",\n      \"journal\": \"Neuroscience bulletin\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO phenotype plus lentiviral rescue with mutant vs. WT, Ca2+ assay, multiple orthogonal methods in single study\",\n      \"pmids\": [\"39982638\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TMEM63A is present at the plasma membrane and on lysosomes in oligodendrocytes; OL-specific conditional knockout of Tmem63a causes transient reductions in myelin (cell-autonomous effect); HLD19-associated TMEM63A patient variants block trafficking of the protein to the cell membrane, indicating a trafficking-dependent mechanism for pathogenesis.\",\n      \"method\": \"OL-specific conditional Tmem63a knockout mice (mouse and zebrafish models), subcellular localization imaging, trafficking assays for disease-associated variants\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-type-specific conditional KO plus localization and variant trafficking assay; two model organisms; single lab with multiple orthogonal methods\",\n      \"pmids\": [\"40694323\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"TMEM63A is a lysosome-resident non-selective cation channel that, when gated by mechanical tension on the lysosomal membrane, drives monovalent cation flux out of the lysosomal lumen, relieving hydrostatic pressure and membrane tension; lysosomes lacking TMEM63A (by deletion or expression of disease-causing variants) are ~10-fold more sensitive to lysis upon increased membrane tension, demonstrating that TMEM63A confers mechano-resilience to lysosomes.\",\n      \"method\": \"TMEM63A deletion and disease-variant expression in cells, lysosomal rupture/lysis assays, osmotic and mechanical perturbation experiments, lipid acquisition assays\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic deletion plus disease variant functional assays with quantitative lysis readout; single lab with multiple orthogonal methods\",\n      \"pmids\": [\"41811130\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TMEM63A (and TMEM63B) function as mechanically activated lipid scramblases in addition to ion channels: phospholipids can be translocated through the open pore of TMEM63A; mutating key groove-lining residues differentially affects lipid vs. ion passage; cholesterol inhibits lipid scrambling by stabilizing the closed state and slowing translocation; this scramblase activity is activated by mechanical forces and contributes to membrane morphological remodeling and cellular mechano-resilience.\",\n      \"method\": \"In vitro lipid scramblase assays, cellular lipid translocation assays, computational/MD simulations, groove-lining residue mutagenesis, cholesterol manipulation experiments\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro reconstitution and mutagenesis with computational support, but preprint not yet peer-reviewed and single lab\",\n      \"pmids\": [\"bio_10.1101_2025.07.26.664997\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"TMEM63A is a mechanosensitive, non-selective cation channel with a monomeric eleven-transmembrane-helix architecture that localizes to the plasma membrane, endoplasmic reticulum, and lysosomal membranes; it is gated by membrane tension to conduct cations (and possibly scramble lipids), mediating Ca2+ influx critical for oligodendrocyte differentiation and myelination, surfactant secretion from alveolar type 2 cells, and lysosomal mechano-resilience by relieving hydrostatic pressure, while disease-causing variants in its pore domain attenuate stretch-activated currents or block plasma membrane trafficking, causing hypomyelinating leukodystrophy.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TMEM63A is a mechanically activated, non-selective cation channel that converts membrane tension into Ca2+ and monovalent cation flux to support tissue-specific mechanotransduction [#1, #5]. It mediates pressure-dependent, voltage-independent currents with slow activation, no inactivation, sensitivity to Gd3+, and a high pressure threshold, and sustains stretch-evoked intracellular Ca2+ increases [#5]; cryo-EM resolves it as a monomeric protein with eleven transmembrane helices harboring the ion permeation pathway, architecturally distinct from the homodimeric plant OSCA channels [#4]. The protein localizes to plasma membrane, endoplasmic reticulum, and lysosomal membranes [#2, #8]. At the lysosome it conducts cations out of the lumen to relieve hydrostatic pressure and membrane tension, conferring mechano-resilience against tension-induced lysis [#9]. Through this channel activity TMEM63A drives oligodendrocyte precursor differentiation and myelination via cell-autonomous Ca2+ influx [#7, #8], facilitates stretch-triggered surfactant and ATP release from lamellar bodies of alveolar type 2 cells [#6], and mediates mechanical nociception in dorsal root ganglion nociceptors with downstream macrophage crosstalk in chronic pain [#3]. Heterozygous missense variants in the pore domain attenuate stretch-activated currents [#1] and disease-associated variants block trafficking to the plasma membrane, causing hypomyelinating leukodystrophy (HLD19) [#8].\",\n  \"teleology\": [\n    {\n      \"year\": 2016,\n      \"claim\": \"Established the first functional link between the TMEM63 family and osmosensitive ion conduction, raising the possibility that TMEM63A participates in an osmo-/mechanosensitive channel.\",\n      \"evidence\": \"Heterologous co-expression of all three mouse TMEM63 members in HEK293 cells with patch-clamp under hypertonic stimulation\",\n      \"pmids\": [\"27045885\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Required all three family members, leaving TMEM63A-specific contribution ambiguous\", \"Single lab and single method\", \"Did not establish mechanical (stretch) gating directly\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Defined TMEM63A itself as a mechanically activated channel and localized its activity to the pore domain by showing disease variants attenuate stretch-activated current.\",\n      \"evidence\": \"Patch-clamp stretch-activated current recording of disease-associated TMEM63A variants in naive cells\",\n      \"pmids\": [\"31587869\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Did not resolve channel architecture or ion selectivity\", \"Mechanism linking variant to disease tissue not yet defined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed TMEM63A in a protein-stability circuit at ER/lysosomal membranes, connecting it to VCP/DERL1 and TOLLIP-mediated autophagic turnover.\",\n      \"evidence\": \"Reciprocal Co-IP, fractionation/co-localization, knockdown/overexpression, xenograft, and pharmacological VCP inhibition (CB-5083)\",\n      \"pmids\": [\"35920704\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Single lab\", \"Relationship between this stability circuit and channel gating function unclear\", \"No structural basis for the interactions\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Demonstrated an in vivo sensory role for TMEM63A in mechanical (but not thermal) nociception and uncovered nociceptor-macrophage crosstalk in chronic pain.\",\n      \"evidence\": \"Tmem63a knockout mice with von Frey/heat/cold behavioral testing, histology, and macrophage ablation\",\n      \"pmids\": [\"35821338\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Single lab\", \"Molecular signal from nociceptor to macrophage not defined\", \"Channel biophysics in DRG neurons not measured directly\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Resolved the channel architecture as a monomeric eleven-TM protein with a defined permeation pathway, distinguishing it from homodimeric plant OSCA orthologs.\",\n      \"evidence\": \"Single-particle cryo-EM of human TMEM63A in the presence of calcium\",\n      \"pmids\": [\"38217391\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Captured in a single state, not an open/gated conformation\", \"Functional role of observed lipid-like density unresolved\", \"No variant structures to explain loss of function\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Quantified the biophysical signature of TMEM63A as a high-threshold, slowly gating, non-inactivating cation channel that sustains stretch-evoked Ca2+ rise.\",\n      \"evidence\": \"High-speed pressure-clamp patch-clamp in Piezo1-KO HEK293T cells plus GCaMP5 Ca2+ imaging under whole-cell stretch\",\n      \"pmids\": [\"38189136\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Single lab\", \"Ion selectivity not fully dissected\", \"Native gating tension in physiological membranes unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified a physiological function in the lung: TMEM63A localizes to lamellar body membranes and couples stretch to surfactant/ATP release driving Ca2+-amplified exocytosis.\",\n      \"evidence\": \"TMEM63A/B double-knockout mice, localization imaging, cell-stretch assays, ATP/surfactant secretion and Ca2+ measurements\",\n      \"pmids\": [\"38127458\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Redundancy with TMEM63B not separated for TMEM63A alone\", \"Direct conduction at the lamellar body membrane not recorded\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Established the cell-autonomous requirement for TMEM63A-mediated Ca2+ influx in oligodendrocyte precursor differentiation and myelination, with variant-specific rescue.\",\n      \"evidence\": \"Tmem63a knockout mice, primary OPC differentiation and Ca2+ influx assays, lentiviral rescue with WT vs. A632T variant\",\n      \"pmids\": [\"39982638\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Transient hypomyelination resolving by P28 leaves compensatory mechanism undefined\", \"Downstream Ca2+-dependent differentiation effectors not identified\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Linked HLD19 pathogenesis to defective trafficking, showing patient variants fail to reach the plasma membrane, and confirmed cell-autonomous oligodendrocyte function by conditional knockout.\",\n      \"evidence\": \"OL-specific conditional Tmem63a knockout in mouse and zebrafish, localization imaging, and trafficking assays of disease variants\",\n      \"pmids\": [\"40694323\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Whether trafficking loss versus pore loss dominates across all variants not delineated\", \"Mechanism retaining variants intracellularly unknown\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Defined a lysosomal role: tension-gated cation efflux relieves luminal pressure and confers ~10-fold mechano-resilience against lysis.\",\n      \"evidence\": \"TMEM63A deletion and disease-variant expression with lysosomal lysis assays and osmotic/mechanical perturbation\",\n      \"pmids\": [\"41811130\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Single lab\", \"In vivo relevance of lysosomal mechano-resilience to disease not established\", \"Coupling between lysosomal and plasma-membrane pools unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Proposed an additional mechanically activated lipid scramblase activity through the same pore, regulated by cholesterol, expanding the protein's role to membrane remodeling.\",\n      \"evidence\": \"In vitro lipid scramblase and cellular translocation assays, groove-lining mutagenesis, MD simulations, cholesterol manipulation (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.07.26.664997\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Preprint, not yet peer-reviewed\", \"Single lab\", \"Physiological contribution of scrambling relative to ion conduction unquantified in vivo\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How TMEM63A's channel, scramblase, and trafficking/stability functions are integrated across its plasma membrane, ER, and lysosomal pools to produce tissue-specific mechanotransduction remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No open-state structure linking gating to permeation\", \"Native gating tension thresholds in each tissue undefined\", \"Relative contributions of ion flux versus lipid scrambling in vivo unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005216\", \"supporting_discovery_ids\": [1, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [8]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [8, 9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 5]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [7, 8]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"VCP\", \"DERL1\", \"TOLLIP\", \"TMEM63B\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}