{"gene":"MCOLN2","run_date":"2026-04-28T18:30:28","timeline":{"discoveries":[{"year":2006,"finding":"TRPML2 homomultimers localize to lysosomes, and TRPML2 interacts with TRPML1 and TRPML3 to form homo- and heteromultimers; TRPML2 directs TRPML3 localization to lysosomes when co-expressed, establishing a hierarchy where TRPML1 and TRPML2 dictate TRPML3 subcellular distribution but not vice versa.","method":"Co-immunoprecipitation, co-expression localization studies, subcellular fractionation/immunofluorescence","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP and localization experiments replicated with multiple constructs; foundational paper with >100 citations","pmids":["16606612"],"is_preprint":false},{"year":2009,"finding":"Wild-type human TRPML2 is a constitutively active, inwardly rectifying, non-selective cation channel permeable to Ca2+, functional at the plasma membrane; channel activity is inhibited by low extracytosolic pH but not regulated by Ca2+; constitutive activity causes Ca2+ overload and cell death; mutagenesis confirmed shared structural and regulatory features with TRPML1 and TRPML3.","method":"Electrophysiology (patch-clamp), functional mutation analysis, cell death assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — in vitro electrophysiology with mutagenesis, multiple orthogonal readouts","pmids":["19940139"],"is_preprint":false},{"year":2009,"finding":"TRPML1 transcriptionally regulates TRPML2 (short variant) expression in lymphoid and kidney tissues; TRPML1 knockdown reduces TRPML2 mRNA, which is rescued by TRPML1 re-expression; TRPML2lv-Va (varitint-waddler mutation) is an active, inwardly rectifying channel.","method":"RNA interference, quantitative RT-PCR, heterologous expression with electrophysiology","journal":"Pflugers Archiv : European journal of physiology","confidence":"Medium","confidence_rationale":"Tier 2 — multiple methods (RNAi, qPCR, rescue, electrophysiology) in single lab","pmids":["19763610"],"is_preprint":false},{"year":2012,"finding":"TRPML2 is activated by lowering extracellular sodium concentration and by a subset of small chemical compounds previously identified as TRPML3 activators, confirming functional activity at the plasma membrane and suggesting similar gating mechanisms to TRPML3; mutagenesis of Glu-361 in the second extracellular loop of TRPML3 revealed its role in sodium-mediated block, implying analogous mechanism in TRPML2.","method":"Electrophysiology, site-directed mutagenesis, pharmacological activation","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 1 — electrophysiology with mutagenesis in single lab","pmids":["22753890"],"is_preprint":false},{"year":2014,"finding":"PAX5 (BSAP) is the transcriptional activator of the MCOLN2 gene; PAX5 overexpression increases endogenous MCOLN2 transcript and TRPML2 protein levels; PAX5 RNAi reduces this effect; the core promoter and PAX5 binding region maps to −79 to −60 bp upstream of the transcriptional start site.","method":"Dual-luciferase reporter assay, overexpression, RNA interference, site-directed mutagenesis of promoter","journal":"Gene","confidence":"Medium","confidence_rationale":"Tier 2 — reporter assay with mutagenesis and RNAi rescue, single lab","pmids":["25445271"],"is_preprint":false},{"year":2015,"finding":"Endogenous TRPML2 primarily localizes to recycling endosomes in macrophages; TRPML2 expression is upregulated by TLR activation; TRPML2-knockout mice show severely reduced production of CCL2 and impaired recruitment of peripheral macrophages in response to LPS or live bacteria, demonstrating a direct role in innate immune chemokine production.","method":"Immunofluorescence, quantitative RT-PCR, TRPML2-knockout mouse model, in vivo LPS/bacterial challenge assays","journal":"Journal of immunology","confidence":"High","confidence_rationale":"Tier 2 — genetic KO with defined cellular phenotype, localization by immunofluorescence, multiple in vivo readouts","pmids":["26432893"],"is_preprint":false},{"year":2018,"finding":"TRPML2 directly mediates CCL2 chemokine trafficking and secretion from macrophages; activation with isoform-selective agonist ML2-SA1 directly stimulates CCL2 release and macrophage migration; endogenous TRPML2 resides in early/recycling endosomes (confirmed by endolysosomal patch-clamp); ML2-SA1 promotes trafficking through the early/recycling endosomal pathway.","method":"Endolysosomal patch-clamp electrophysiology, selective agonist ML2-SA1, ELISA for CCL2, macrophage migration assay, TRPML2-KO comparison","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1–2 — direct electrophysiology, selective pharmacological tool, KO controls, multiple orthogonal functional readouts","pmids":["30479274"],"is_preprint":false},{"year":2019,"finding":"Crystal structures of the human TRPML2 extracytosolic/lumenal domain (ELD) at pH 6.5 (2.0 Å) and 4.5 (2.95 Å) reveal a tetrameric architecture; isothermal titration calorimetry shows Ca2+ binds the highly acidic central pre-pore loop and this binding is abrogated at low pH, supporting a pH-dependent channel regulation model; native mass spectrometry shows pH or Ca2+ changes can affect ELD oligomer integrity.","method":"X-ray crystallography, isothermal titration calorimetry, SAXS, native mass spectrometry","journal":"Structure","confidence":"High","confidence_rationale":"Tier 1 — high-resolution crystal structure with functional Ca2+-binding validation by ITC and MS","pmids":["31178222"],"is_preprint":false},{"year":2020,"finding":"TRPML2 is a hypotonicity/mechanosensitive endolysosomal cation channel; the phosphoinositide binding pocket is required for hypotonicity sensitivity (L314R mutation completely abolishes it); the hypotonicity-insensitive L314R mutant slows the fast-recycling pathway in immune cells, demonstrating that mechanosensitive TRPML2 accelerates endolysosomal recycling.","method":"Endolysosomal patch-clamp, site-directed mutagenesis, recycling assays in immune cells","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 1 — electrophysiology with mutagenesis and functional recycling assay linking mechanism to cell biology","pmids":["33177082"],"is_preprint":false},{"year":2021,"finding":"Cryo-EM structure of full-length mouse TRPML2 in lipid nanodiscs at 3.14 Å resolution reveals a homotetrameric architecture in an inactive (apo) conformation at pH 7.4, with unique features of the extracytosolic/luminal domain and voltage sensor-like domain relevant to the ion-conducting pathway.","method":"Cryo-EM structural determination in lipid nanodiscs","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — near-atomic resolution cryo-EM structure of full-length channel","pmids":["34915027"],"is_preprint":false},{"year":2021,"finding":"MCOLN2 promotes prostate cancer cell proliferation, migration, invasion, and xenograft tumor growth; MCOLN2 promotes IL-1β production and release; luciferase reporter assay confirmed MCOLN2 activates the IL-1β/NF-κB signaling pathway.","method":"siRNA knockdown, overexpression, cell viability/transwell assays, in vivo xenograft, cytokine array, ELISA, luciferase reporter assay","journal":"British journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 — multiple functional assays with pathway placement by reporter assay, single lab","pmids":["34548638"],"is_preprint":false},{"year":2023,"finding":"MCOLN2/TRPML2 conducts Mg2+ out of endolysosomes; human genetic variation in MCOLN2 affects intracellular S. Typhi replication; Mg2+ currents through TRPML2 were directly measured by endolysosomal patch-clamp, and Mg2+ deprivation (mediated by TRPML2) restricts S. Typhi replication as a component of nutritional immunity.","method":"Genome-wide association study (cellular), endolysosomal patch-clamp for Mg2+ currents, intracellular S. Typhi transcriptomics, Mg2+ availability manipulation","journal":"Cell genomics","confidence":"High","confidence_rationale":"Tier 1–2 — direct electrophysiological measurement of Mg2+ currents plus GWAS and in-cell functional validation","pmids":["37228749"],"is_preprint":false},{"year":2026,"finding":"Obinutuzumab internalization into acidic compartments causes sphingomyelin (SM) accumulation that inhibits TRPML2-mediated lysosomal Ca2+ release; SM-dependent inhibition of TRPML2 sensitizes lysosomes to obinutuzumab-induced stress, lowering the threshold for lysosomal membrane permeabilization (LMP) and direct cell death; restoration of TRPML2 function by SMase treatment or blockade of OBI internalization attenuates LMP.","method":"Imaging, genetic knockdown, biochemical approaches, SMase treatment, Ca2+ measurement, LMP assays","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal methods (imaging, genetics, biochemistry) in single lab, newly published","pmids":["41634107"],"is_preprint":false},{"year":2026,"finding":"Two scorpion venom peptides (BmP05 and BmKK12) were identified as TRPML2 agonists via co-immunoprecipitation/LC-MS/MS screening; both peptides activate TRPML2 to induce Ca2+ influx (calcium imaging) and inhibit Zika virus replication, while weaker TRPML2 activators lacked antiviral activity, linking TRPML2 activation to impaired ZIKV internalization.","method":"Co-immunoprecipitation with LC-MS/MS, molecular docking, calcium imaging, antiviral assays","journal":"Toxins","confidence":"Medium","confidence_rationale":"Tier 2–3 — binding identified by Co-IP/MS and functional Ca2+ imaging with antiviral correlation, single study","pmids":["41745776"],"is_preprint":false}],"current_model":"MCOLN2/TRPML2 is a constitutively active, inwardly rectifying, non-selective endolysosomal cation channel (permeable to Ca2+, Na+, Fe2+, and Mg2+) that resides primarily in recycling endosomes of immune cells (directed there partly through heterodimerization with TRPML1), is transcriptionally activated by PAX5, upregulated by TLR signaling, acts as a hypotonicity/mechanosensor via its phosphoinositide-binding pocket (L314) to accelerate endolysosomal recycling, directly mediates CCL2 chemokine secretion and macrophage migration, conducts Mg2+ out of endolysosomes to restrict intracellular bacterial replication, and can activate the IL-1β/NF-κB pathway; its activity is inhibited by low luminal pH (via the ELD Ca2+-binding pre-pore loop) and by sphingomyelin accumulation."},"narrative":{"teleology":[{"year":2006,"claim":"Establishing that TRPML2 forms homo- and heteromultimers with TRPML1 and TRPML3 answered the fundamental question of channel quaternary structure and revealed a hierarchy in which TRPML1/2 direct TRPML3 localization to lysosomes, placing TRPML2 in the endolysosomal compartment.","evidence":"Reciprocal co-immunoprecipitation and co-expression localization studies with immunofluorescence in heterologous cells","pmids":["16606612"],"confidence":"High","gaps":["Stoichiometry of heteromultimers not determined","Endogenous heteromultimerization not confirmed in primary cells","Functional consequence of heteromultimerization on channel conductance unknown"]},{"year":2009,"claim":"Demonstrating that TRPML2 is a constitutively active, inwardly rectifying, non-selective cation channel inhibited by low extracytosolic pH established its core biophysical identity and separated it functionally from TRPML1 and TRPML3.","evidence":"Whole-cell patch-clamp electrophysiology with functional mutagenesis and cell death assays; complemented by transcriptional regulation showing TRPML1 controls TRPML2 short-variant expression","pmids":["19940139","19763610"],"confidence":"High","gaps":["Endogenous single-channel conductance not measured","Physiological role of constitutive activity unclear","Mechanism by which low pH inhibits channel gating not structurally resolved"]},{"year":2014,"claim":"Identification of PAX5 as the transcriptional activator of MCOLN2 explained the gene's lymphoid-restricted expression pattern and mapped the core promoter element to a specific 20-bp region upstream of the TSS.","evidence":"Dual-luciferase reporter assay with promoter mutagenesis, PAX5 overexpression and RNAi in cell lines","pmids":["25445271"],"confidence":"Medium","gaps":["ChIP-seq validation of PAX5 occupancy at the endogenous MCOLN2 promoter not shown","Whether additional transcription factors cooperate with PAX5 not addressed","Regulation in non-lymphoid immune cells (macrophages) not explained by PAX5 alone"]},{"year":2015,"claim":"Genetic knockout in mice revealed that TRPML2 localizes to recycling endosomes in macrophages, is upregulated by TLR signaling, and is required for CCL2 chemokine production and macrophage recruitment during innate immune responses, establishing the channel's physiological role in immunity.","evidence":"TRPML2-knockout mouse challenged with LPS and live bacteria; immunofluorescence localization, qRT-PCR, and in vivo macrophage recruitment assays","pmids":["26432893"],"confidence":"High","gaps":["Mechanism linking channel ion flux to CCL2 transcription/secretion not delineated","Which TLR-downstream signaling pathway upregulates TRPML2 not identified","Whether TRPML2 regulates other chemokines beyond CCL2 not tested"]},{"year":2018,"claim":"Using the isoform-selective agonist ML2-SA1 and endolysosomal patch-clamp demonstrated that TRPML2 directly mediates CCL2 vesicular trafficking and secretion through the early/recycling endosomal pathway, connecting channel activity to the cargo-specific secretory mechanism.","evidence":"Endolysosomal patch-clamp electrophysiology with ML2-SA1, ELISA for CCL2 release, macrophage migration assays, TRPML2-KO controls","pmids":["30479274"],"confidence":"High","gaps":["Whether TRPML2 acts via Ca²⁺ release, membrane fusion, or vesicle budding not resolved","Other cargo trafficked by TRPML2 not systematically catalogued"]},{"year":2019,"claim":"Crystal structures of the TRPML2 extracytosolic/luminal domain at two pH values revealed a tetrameric architecture with a Ca²⁺-binding pre-pore loop whose affinity is abolished at low pH, providing the first structural explanation for pH-dependent gating.","evidence":"X-ray crystallography at 2.0 Å (pH 6.5) and 2.95 Å (pH 4.5), ITC for Ca²⁺ binding, native mass spectrometry","pmids":["31178222"],"confidence":"High","gaps":["Full-length channel structure in open/conducting state not available at this point","How Ca²⁺ binding at the ELD transduces to pore gating not determined"]},{"year":2021,"claim":"Cryo-EM of full-length mouse TRPML2 in lipid nanodiscs at 3.14 Å captured the channel in an inactive apo conformation and revealed unique features of the voltage sensor-like domain, providing the first complete structural framework for the channel.","evidence":"Cryo-EM in lipid nanodiscs at pH 7.4","pmids":["34915027"],"confidence":"High","gaps":["Active/open-state structure not captured","Agonist-bound or PI-bound structures not determined","Mechanism of selectivity among divalent cations not structurally explained"]},{"year":2020,"claim":"Discovery that TRPML2 is a hypotonicity/mechanosensitive channel dependent on its phosphoinositide-binding pocket (L314) linked the channel's lipid-sensing capability to regulation of the fast-recycling endosomal pathway in immune cells.","evidence":"Endolysosomal patch-clamp with hypotonicity stimulation, L314R mutagenesis, recycling assays in immune cells","pmids":["33177082"],"confidence":"High","gaps":["Identity of the endogenous phosphoinositide species activating TRPML2 not confirmed","Whether mechanosensitivity operates in non-immune cell types not tested","Structural basis of mechanosensitive gating not resolved"]},{"year":2021,"claim":"MCOLN2 was shown to promote IL-1β production, NF-κB activation, and prostate cancer cell proliferation and invasion, extending the channel's signaling repertoire beyond chemokine trafficking to inflammatory cytokine pathways.","evidence":"siRNA knockdown and overexpression in prostate cancer cell lines, xenograft model, cytokine array, NF-κB luciferase reporter assay","pmids":["34548638"],"confidence":"Medium","gaps":["Mechanism linking TRPML2 ion flux to NF-κB activation not identified","Relevance to primary immune cells not established","Single-lab finding without independent replication"]},{"year":2023,"claim":"Direct measurement of Mg²⁺ currents through TRPML2 and human GWAS linking MCOLN2 variants to intracellular S. Typhi replication established a nutritional immunity function: TRPML2 depletes endolysosomal Mg²⁺ to restrict bacterial growth.","evidence":"Endolysosomal patch-clamp for Mg²⁺ currents, GWAS in cellular infection model, S. Typhi transcriptomics, Mg²⁺ manipulation experiments","pmids":["37228749"],"confidence":"High","gaps":["Whether Mg²⁺ restriction applies to other intracellular pathogens not shown","Relative contribution of TRPML2 vs other transporters to endolysosomal Mg²⁺ not quantified","In vivo validation of MCOLN2 variants in S. Typhi susceptibility not performed"]},{"year":2026,"claim":"Sphingomyelin accumulation was identified as an endogenous lipid inhibitor of TRPML2-mediated lysosomal Ca²⁺ release; this inhibition sensitizes lysosomes to membrane permeabilization, providing a mechanistic basis for obinutuzumab-induced direct cell death.","evidence":"Imaging, genetic knockdown, SMase rescue, Ca²⁺ measurement, and lysosomal membrane permeabilization assays in B-cell lymphoma models","pmids":["41634107"],"confidence":"Medium","gaps":["Direct binding site for sphingomyelin on TRPML2 not mapped","Whether SM inhibition is specific to TRPML2 or also affects TRPML1/3 not fully resolved","Clinical relevance of TRPML2 inhibition in obinutuzumab therapy not validated in patients"]},{"year":null,"claim":"Key unresolved questions include the structural basis of TRPML2 in an open/agonist-bound state, the precise signaling intermediates connecting TRPML2 ion flux to NF-κB activation and chemokine vesicle fusion, and the full spectrum of pathogens subject to TRPML2-mediated nutritional immunity.","evidence":"","pmids":[],"confidence":"Low","gaps":["No agonist-bound or open-state structure available","Signaling cascade from TRPML2 Ca²⁺/Mg²⁺ flux to NF-κB not mapped","Comprehensive in vivo phenotyping of TRPML2-KO mice in diverse infection models lacking"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005215","term_label":"transporter activity","supporting_discovery_ids":[1,3,6,8,11]},{"term_id":"GO:0140299","term_label":"molecular sensor activity","supporting_discovery_ids":[8]}],"localization":[{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[0,7,9,12]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[5,6,8]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[5,6,8]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[5,6,11]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[10]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[6,8]}],"complexes":["TRPML2 homotetramer","TRPML1–TRPML2 heteromultimer","TRPML2–TRPML3 heteromultimer"],"partners":["MCOLN1","MCOLN3","PAX5"],"other_free_text":[]},"mechanistic_narrative":"MCOLN2/TRPML2 is a constitutively active, inwardly rectifying, non-selective cation channel that resides primarily on recycling endosomes and lysosomes of immune cells, where it conducts Ca²⁺, Na⁺, Fe²⁺, and Mg²⁺ to regulate endolysosomal trafficking, chemokine secretion, and innate immune defense. The channel assembles as a homotetramer and can heterodimerize with TRPML1 and TRPML3, which determines its subcellular targeting; its activity is gated by luminal pH through a Ca²⁺-binding pre-pore loop in the extracytosolic domain and by phosphoinositide-dependent mechanosensitivity that accelerates endosomal recycling [PMID:16606612, PMID:19940139, PMID:31178222, PMID:33177082]. Transcriptionally activated by PAX5 and upregulated by TLR signaling, TRPML2 directly mediates CCL2 chemokine trafficking and secretion from macrophages and conducts Mg²⁺ out of endolysosomes to restrict intracellular Salmonella Typhi replication as a component of nutritional immunity [PMID:25445271, PMID:26432893, PMID:30479274, PMID:37228749]. Sphingomyelin accumulation in the lysosomal membrane inhibits TRPML2-mediated Ca²⁺ release, sensitizing lysosomes to membrane permeabilization, while TRPML2 activation can also engage the IL-1β/NF-κB signaling axis [PMID:34548638, PMID:41634107]."},"prefetch_data":{"uniprot":{"accession":"Q8IZK6","full_name":"Mucolipin-2","aliases":["Transient receptor potential channel mucolipin 2","TRPML2"],"length_aa":566,"mass_kda":65.9,"function":"Nonselective cation channel probably playing a role in the regulation of membrane trafficking events. Acts as a Ca(2+)-permeable cation channel with inwardly rectifying activity (PubMed:19885840, PubMed:19940139). May activate ARF6 and be involved in the trafficking of GPI-anchored cargo proteins to the cell surface via the ARF6-regulated recycling pathway (PubMed:17662026). May play a role in immune processes. In adaptive immunity, TRPML2 and TRPML1 may play redundant roles in the function of the specialized lysosomes of B cells (By similarity). In the innate immune response, may play a role in the regulation of chemokine secretion and macrophage migration (By similarity). Through a possible and probably tissue-specific heteromerization with MCOLN1 may be at least in part involved in many lysosome-dependent cellular events (PubMed:19885840). Also functions as a Fe(2+) permeable channel (By similarity)","subcellular_location":"Cell membrane; Late endosome membrane; Lysosome membrane; Recycling endosome membrane","url":"https://www.uniprot.org/uniprotkb/Q8IZK6/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MCOLN2","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"MCOLN1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/MCOLN2","total_profiled":1310},"omim":[{"mim_id":"607400","title":"MUCOLIPIN 3; MCOLN3","url":"https://www.omim.org/entry/607400"},{"mim_id":"607399","title":"MUCOLIPIN 2; MCOLN2","url":"https://www.omim.org/entry/607399"},{"mim_id":"605248","title":"MUCOLIPIN 1; MCOLN1","url":"https://www.omim.org/entry/605248"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"adrenal gland","ntpm":8.5},{"tissue":"intestine","ntpm":14.1},{"tissue":"lymphoid tissue","ntpm":12.3}],"url":"https://www.proteinatlas.org/search/MCOLN2"},"hgnc":{"alias_symbol":["TRPML2","FLJ36691","TRP-ML2"],"prev_symbol":[]},"alphafold":{"accession":"Q8IZK6","domains":[{"cath_id":"-","chopping":"118-280","consensus_level":"high","plddt":84.7212,"start":118,"end":280},{"cath_id":"1.20.120","chopping":"65-84_285-400","consensus_level":"high","plddt":89.3707,"start":65,"end":400},{"cath_id":"1.10.287","chopping":"407-520","consensus_level":"high","plddt":92.808,"start":407,"end":520}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8IZK6","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8IZK6-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8IZK6-F1-predicted_aligned_error_v6.png","plddt_mean":82.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MCOLN2","jax_strain_url":"https://www.jax.org/strain/search?query=MCOLN2"},"sequence":{"accession":"Q8IZK6","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8IZK6.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8IZK6/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8IZK6"}},"corpus_meta":[{"pmid":"16606612","id":"PMC_16606612","title":"Lysosomal 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physiology","url":"https://pubmed.ncbi.nlm.nih.gov/19763610","citation_count":61,"is_preprint":false},{"pmid":"33177082","id":"PMC_33177082","title":"TRPML2 is an osmo/mechanosensitive cation channel in endolysosomal organelles.","date":"2020","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/33177082","citation_count":51,"is_preprint":false},{"pmid":"26336837","id":"PMC_26336837","title":"The mucolipin-2 (TRPML2) ion channel: a tissue-specific protein crucial to normal cell function.","date":"2015","source":"Pflugers Archiv : European journal of physiology","url":"https://pubmed.ncbi.nlm.nih.gov/26336837","citation_count":45,"is_preprint":false},{"pmid":"19940139","id":"PMC_19940139","title":"Constitutive activity of the human TRPML2 channel induces cell degeneration.","date":"2009","source":"The Journal of biological 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Treatment.","date":"2022","source":"Biomolecules","url":"https://pubmed.ncbi.nlm.nih.gov/35053255","citation_count":7,"is_preprint":false},{"pmid":"35054871","id":"PMC_35054871","title":"Functional In Vitro Assessment of VEGFA/NOTCH2 Signaling Pathway and pRB Proteasomal Degradation and the Clinical Relevance of Mucolipin TRPML2 Overexpression in Glioblastoma Patients.","date":"2022","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/35054871","citation_count":7,"is_preprint":false},{"pmid":"35887088","id":"PMC_35887088","title":"Coexpression of TRPML1 and TRPML2 Mucolipin Channels Affects the Survival of Glioblastoma Patients.","date":"2022","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/35887088","citation_count":6,"is_preprint":false},{"pmid":"38901736","id":"PMC_38901736","title":"Zika virus replication is impaired by a selective agonist of the TRPML2 ion channel.","date":"2024","source":"Antiviral research","url":"https://pubmed.ncbi.nlm.nih.gov/38901736","citation_count":5,"is_preprint":false},{"pmid":"38306561","id":"PMC_38306561","title":"Role of PAX6, TRPA1, BCL11B, MCOLN2, CUX1, EMX1 in colorectal cancer and osteosarcoma.","date":"2024","source":"Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/38306561","citation_count":4,"is_preprint":false},{"pmid":"41634107","id":"PMC_41634107","title":"Obinutuzumab induces lysosomal destabilization via sphingomyelin-dependent inhibition of TRPML2.","date":"2026","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/41634107","citation_count":0,"is_preprint":false},{"pmid":"41745776","id":"PMC_41745776","title":"Discovery of Two Novel Scorpion Venom Peptides Activating TRPML2 to Impair ZIKV Internalization.","date":"2026","source":"Toxins","url":"https://pubmed.ncbi.nlm.nih.gov/41745776","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13433,"output_tokens":3543,"usd":0.046722},"stage2":{"model":"claude-opus-4-6","input_tokens":6962,"output_tokens":3520,"usd":0.184215},"total_usd":0.230937,"stage1_batch_id":"msgbatch_01Mgbec4vM6c9vXht7JVJzss","stage2_batch_id":"msgbatch_01JkuuH5RB2BdJNsgnhjbC6s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2006,\n      \"finding\": \"TRPML2 homomultimers localize to lysosomes, and TRPML2 interacts with TRPML1 and TRPML3 to form homo- and heteromultimers; TRPML2 directs TRPML3 localization to lysosomes when co-expressed, establishing a hierarchy where TRPML1 and TRPML2 dictate TRPML3 subcellular distribution but not vice versa.\",\n      \"method\": \"Co-immunoprecipitation, co-expression localization studies, subcellular fractionation/immunofluorescence\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP and localization experiments replicated with multiple constructs; foundational paper with >100 citations\",\n      \"pmids\": [\"16606612\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Wild-type human TRPML2 is a constitutively active, inwardly rectifying, non-selective cation channel permeable to Ca2+, functional at the plasma membrane; channel activity is inhibited by low extracytosolic pH but not regulated by Ca2+; constitutive activity causes Ca2+ overload and cell death; mutagenesis confirmed shared structural and regulatory features with TRPML1 and TRPML3.\",\n      \"method\": \"Electrophysiology (patch-clamp), functional mutation analysis, cell death assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro electrophysiology with mutagenesis, multiple orthogonal readouts\",\n      \"pmids\": [\"19940139\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"TRPML1 transcriptionally regulates TRPML2 (short variant) expression in lymphoid and kidney tissues; TRPML1 knockdown reduces TRPML2 mRNA, which is rescued by TRPML1 re-expression; TRPML2lv-Va (varitint-waddler mutation) is an active, inwardly rectifying channel.\",\n      \"method\": \"RNA interference, quantitative RT-PCR, heterologous expression with electrophysiology\",\n      \"journal\": \"Pflugers Archiv : European journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple methods (RNAi, qPCR, rescue, electrophysiology) in single lab\",\n      \"pmids\": [\"19763610\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"TRPML2 is activated by lowering extracellular sodium concentration and by a subset of small chemical compounds previously identified as TRPML3 activators, confirming functional activity at the plasma membrane and suggesting similar gating mechanisms to TRPML3; mutagenesis of Glu-361 in the second extracellular loop of TRPML3 revealed its role in sodium-mediated block, implying analogous mechanism in TRPML2.\",\n      \"method\": \"Electrophysiology, site-directed mutagenesis, pharmacological activation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — electrophysiology with mutagenesis in single lab\",\n      \"pmids\": [\"22753890\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"PAX5 (BSAP) is the transcriptional activator of the MCOLN2 gene; PAX5 overexpression increases endogenous MCOLN2 transcript and TRPML2 protein levels; PAX5 RNAi reduces this effect; the core promoter and PAX5 binding region maps to −79 to −60 bp upstream of the transcriptional start site.\",\n      \"method\": \"Dual-luciferase reporter assay, overexpression, RNA interference, site-directed mutagenesis of promoter\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reporter assay with mutagenesis and RNAi rescue, single lab\",\n      \"pmids\": [\"25445271\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Endogenous TRPML2 primarily localizes to recycling endosomes in macrophages; TRPML2 expression is upregulated by TLR activation; TRPML2-knockout mice show severely reduced production of CCL2 and impaired recruitment of peripheral macrophages in response to LPS or live bacteria, demonstrating a direct role in innate immune chemokine production.\",\n      \"method\": \"Immunofluorescence, quantitative RT-PCR, TRPML2-knockout mouse model, in vivo LPS/bacterial challenge assays\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with defined cellular phenotype, localization by immunofluorescence, multiple in vivo readouts\",\n      \"pmids\": [\"26432893\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"TRPML2 directly mediates CCL2 chemokine trafficking and secretion from macrophages; activation with isoform-selective agonist ML2-SA1 directly stimulates CCL2 release and macrophage migration; endogenous TRPML2 resides in early/recycling endosomes (confirmed by endolysosomal patch-clamp); ML2-SA1 promotes trafficking through the early/recycling endosomal pathway.\",\n      \"method\": \"Endolysosomal patch-clamp electrophysiology, selective agonist ML2-SA1, ELISA for CCL2, macrophage migration assay, TRPML2-KO comparison\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — direct electrophysiology, selective pharmacological tool, KO controls, multiple orthogonal functional readouts\",\n      \"pmids\": [\"30479274\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Crystal structures of the human TRPML2 extracytosolic/lumenal domain (ELD) at pH 6.5 (2.0 Å) and 4.5 (2.95 Å) reveal a tetrameric architecture; isothermal titration calorimetry shows Ca2+ binds the highly acidic central pre-pore loop and this binding is abrogated at low pH, supporting a pH-dependent channel regulation model; native mass spectrometry shows pH or Ca2+ changes can affect ELD oligomer integrity.\",\n      \"method\": \"X-ray crystallography, isothermal titration calorimetry, SAXS, native mass spectrometry\",\n      \"journal\": \"Structure\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — high-resolution crystal structure with functional Ca2+-binding validation by ITC and MS\",\n      \"pmids\": [\"31178222\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TRPML2 is a hypotonicity/mechanosensitive endolysosomal cation channel; the phosphoinositide binding pocket is required for hypotonicity sensitivity (L314R mutation completely abolishes it); the hypotonicity-insensitive L314R mutant slows the fast-recycling pathway in immune cells, demonstrating that mechanosensitive TRPML2 accelerates endolysosomal recycling.\",\n      \"method\": \"Endolysosomal patch-clamp, site-directed mutagenesis, recycling assays in immune cells\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — electrophysiology with mutagenesis and functional recycling assay linking mechanism to cell biology\",\n      \"pmids\": [\"33177082\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Cryo-EM structure of full-length mouse TRPML2 in lipid nanodiscs at 3.14 Å resolution reveals a homotetrameric architecture in an inactive (apo) conformation at pH 7.4, with unique features of the extracytosolic/luminal domain and voltage sensor-like domain relevant to the ion-conducting pathway.\",\n      \"method\": \"Cryo-EM structural determination in lipid nanodiscs\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — near-atomic resolution cryo-EM structure of full-length channel\",\n      \"pmids\": [\"34915027\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MCOLN2 promotes prostate cancer cell proliferation, migration, invasion, and xenograft tumor growth; MCOLN2 promotes IL-1β production and release; luciferase reporter assay confirmed MCOLN2 activates the IL-1β/NF-κB signaling pathway.\",\n      \"method\": \"siRNA knockdown, overexpression, cell viability/transwell assays, in vivo xenograft, cytokine array, ELISA, luciferase reporter assay\",\n      \"journal\": \"British journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple functional assays with pathway placement by reporter assay, single lab\",\n      \"pmids\": [\"34548638\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"MCOLN2/TRPML2 conducts Mg2+ out of endolysosomes; human genetic variation in MCOLN2 affects intracellular S. Typhi replication; Mg2+ currents through TRPML2 were directly measured by endolysosomal patch-clamp, and Mg2+ deprivation (mediated by TRPML2) restricts S. Typhi replication as a component of nutritional immunity.\",\n      \"method\": \"Genome-wide association study (cellular), endolysosomal patch-clamp for Mg2+ currents, intracellular S. Typhi transcriptomics, Mg2+ availability manipulation\",\n      \"journal\": \"Cell genomics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — direct electrophysiological measurement of Mg2+ currents plus GWAS and in-cell functional validation\",\n      \"pmids\": [\"37228749\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Obinutuzumab internalization into acidic compartments causes sphingomyelin (SM) accumulation that inhibits TRPML2-mediated lysosomal Ca2+ release; SM-dependent inhibition of TRPML2 sensitizes lysosomes to obinutuzumab-induced stress, lowering the threshold for lysosomal membrane permeabilization (LMP) and direct cell death; restoration of TRPML2 function by SMase treatment or blockade of OBI internalization attenuates LMP.\",\n      \"method\": \"Imaging, genetic knockdown, biochemical approaches, SMase treatment, Ca2+ measurement, LMP assays\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (imaging, genetics, biochemistry) in single lab, newly published\",\n      \"pmids\": [\"41634107\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Two scorpion venom peptides (BmP05 and BmKK12) were identified as TRPML2 agonists via co-immunoprecipitation/LC-MS/MS screening; both peptides activate TRPML2 to induce Ca2+ influx (calcium imaging) and inhibit Zika virus replication, while weaker TRPML2 activators lacked antiviral activity, linking TRPML2 activation to impaired ZIKV internalization.\",\n      \"method\": \"Co-immunoprecipitation with LC-MS/MS, molecular docking, calcium imaging, antiviral assays\",\n      \"journal\": \"Toxins\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — binding identified by Co-IP/MS and functional Ca2+ imaging with antiviral correlation, single study\",\n      \"pmids\": [\"41745776\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MCOLN2/TRPML2 is a constitutively active, inwardly rectifying, non-selective endolysosomal cation channel (permeable to Ca2+, Na+, Fe2+, and Mg2+) that resides primarily in recycling endosomes of immune cells (directed there partly through heterodimerization with TRPML1), is transcriptionally activated by PAX5, upregulated by TLR signaling, acts as a hypotonicity/mechanosensor via its phosphoinositide-binding pocket (L314) to accelerate endolysosomal recycling, directly mediates CCL2 chemokine secretion and macrophage migration, conducts Mg2+ out of endolysosomes to restrict intracellular bacterial replication, and can activate the IL-1β/NF-κB pathway; its activity is inhibited by low luminal pH (via the ELD Ca2+-binding pre-pore loop) and by sphingomyelin accumulation.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"MCOLN2/TRPML2 is a constitutively active, inwardly rectifying, non-selective cation channel that resides primarily on recycling endosomes and lysosomes of immune cells, where it conducts Ca²⁺, Na⁺, Fe²⁺, and Mg²⁺ to regulate endolysosomal trafficking, chemokine secretion, and innate immune defense. The channel assembles as a homotetramer and can heterodimerize with TRPML1 and TRPML3, which determines its subcellular targeting; its activity is gated by luminal pH through a Ca²⁺-binding pre-pore loop in the extracytosolic domain and by phosphoinositide-dependent mechanosensitivity that accelerates endosomal recycling [PMID:16606612, PMID:19940139, PMID:31178222, PMID:33177082]. Transcriptionally activated by PAX5 and upregulated by TLR signaling, TRPML2 directly mediates CCL2 chemokine trafficking and secretion from macrophages and conducts Mg²⁺ out of endolysosomes to restrict intracellular Salmonella Typhi replication as a component of nutritional immunity [PMID:25445271, PMID:26432893, PMID:30479274, PMID:37228749]. Sphingomyelin accumulation in the lysosomal membrane inhibits TRPML2-mediated Ca²⁺ release, sensitizing lysosomes to membrane permeabilization, while TRPML2 activation can also engage the IL-1β/NF-κB signaling axis [PMID:34548638, PMID:41634107].\",\n  \"teleology\": [\n    {\n      \"year\": 2006,\n      \"claim\": \"Establishing that TRPML2 forms homo- and heteromultimers with TRPML1 and TRPML3 answered the fundamental question of channel quaternary structure and revealed a hierarchy in which TRPML1/2 direct TRPML3 localization to lysosomes, placing TRPML2 in the endolysosomal compartment.\",\n      \"evidence\": \"Reciprocal co-immunoprecipitation and co-expression localization studies with immunofluorescence in heterologous cells\",\n      \"pmids\": [\"16606612\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Stoichiometry of heteromultimers not determined\",\n        \"Endogenous heteromultimerization not confirmed in primary cells\",\n        \"Functional consequence of heteromultimerization on channel conductance unknown\"\n      ]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Demonstrating that TRPML2 is a constitutively active, inwardly rectifying, non-selective cation channel inhibited by low extracytosolic pH established its core biophysical identity and separated it functionally from TRPML1 and TRPML3.\",\n      \"evidence\": \"Whole-cell patch-clamp electrophysiology with functional mutagenesis and cell death assays; complemented by transcriptional regulation showing TRPML1 controls TRPML2 short-variant expression\",\n      \"pmids\": [\"19940139\", \"19763610\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Endogenous single-channel conductance not measured\",\n        \"Physiological role of constitutive activity unclear\",\n        \"Mechanism by which low pH inhibits channel gating not structurally resolved\"\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identification of PAX5 as the transcriptional activator of MCOLN2 explained the gene's lymphoid-restricted expression pattern and mapped the core promoter element to a specific 20-bp region upstream of the TSS.\",\n      \"evidence\": \"Dual-luciferase reporter assay with promoter mutagenesis, PAX5 overexpression and RNAi in cell lines\",\n      \"pmids\": [\"25445271\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"ChIP-seq validation of PAX5 occupancy at the endogenous MCOLN2 promoter not shown\",\n        \"Whether additional transcription factors cooperate with PAX5 not addressed\",\n        \"Regulation in non-lymphoid immune cells (macrophages) not explained by PAX5 alone\"\n      ]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Genetic knockout in mice revealed that TRPML2 localizes to recycling endosomes in macrophages, is upregulated by TLR signaling, and is required for CCL2 chemokine production and macrophage recruitment during innate immune responses, establishing the channel's physiological role in immunity.\",\n      \"evidence\": \"TRPML2-knockout mouse challenged with LPS and live bacteria; immunofluorescence localization, qRT-PCR, and in vivo macrophage recruitment assays\",\n      \"pmids\": [\"26432893\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Mechanism linking channel ion flux to CCL2 transcription/secretion not delineated\",\n        \"Which TLR-downstream signaling pathway upregulates TRPML2 not identified\",\n        \"Whether TRPML2 regulates other chemokines beyond CCL2 not tested\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Using the isoform-selective agonist ML2-SA1 and endolysosomal patch-clamp demonstrated that TRPML2 directly mediates CCL2 vesicular trafficking and secretion through the early/recycling endosomal pathway, connecting channel activity to the cargo-specific secretory mechanism.\",\n      \"evidence\": \"Endolysosomal patch-clamp electrophysiology with ML2-SA1, ELISA for CCL2 release, macrophage migration assays, TRPML2-KO controls\",\n      \"pmids\": [\"30479274\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether TRPML2 acts via Ca²⁺ release, membrane fusion, or vesicle budding not resolved\",\n        \"Other cargo trafficked by TRPML2 not systematically catalogued\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Crystal structures of the TRPML2 extracytosolic/luminal domain at two pH values revealed a tetrameric architecture with a Ca²⁺-binding pre-pore loop whose affinity is abolished at low pH, providing the first structural explanation for pH-dependent gating.\",\n      \"evidence\": \"X-ray crystallography at 2.0 Å (pH 6.5) and 2.95 Å (pH 4.5), ITC for Ca²⁺ binding, native mass spectrometry\",\n      \"pmids\": [\"31178222\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Full-length channel structure in open/conducting state not available at this point\",\n        \"How Ca²⁺ binding at the ELD transduces to pore gating not determined\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Cryo-EM of full-length mouse TRPML2 in lipid nanodiscs at 3.14 Å captured the channel in an inactive apo conformation and revealed unique features of the voltage sensor-like domain, providing the first complete structural framework for the channel.\",\n      \"evidence\": \"Cryo-EM in lipid nanodiscs at pH 7.4\",\n      \"pmids\": [\"34915027\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Active/open-state structure not captured\",\n        \"Agonist-bound or PI-bound structures not determined\",\n        \"Mechanism of selectivity among divalent cations not structurally explained\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Discovery that TRPML2 is a hypotonicity/mechanosensitive channel dependent on its phosphoinositide-binding pocket (L314) linked the channel's lipid-sensing capability to regulation of the fast-recycling endosomal pathway in immune cells.\",\n      \"evidence\": \"Endolysosomal patch-clamp with hypotonicity stimulation, L314R mutagenesis, recycling assays in immune cells\",\n      \"pmids\": [\"33177082\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Identity of the endogenous phosphoinositide species activating TRPML2 not confirmed\",\n        \"Whether mechanosensitivity operates in non-immune cell types not tested\",\n        \"Structural basis of mechanosensitive gating not resolved\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"MCOLN2 was shown to promote IL-1β production, NF-κB activation, and prostate cancer cell proliferation and invasion, extending the channel's signaling repertoire beyond chemokine trafficking to inflammatory cytokine pathways.\",\n      \"evidence\": \"siRNA knockdown and overexpression in prostate cancer cell lines, xenograft model, cytokine array, NF-κB luciferase reporter assay\",\n      \"pmids\": [\"34548638\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanism linking TRPML2 ion flux to NF-κB activation not identified\",\n        \"Relevance to primary immune cells not established\",\n        \"Single-lab finding without independent replication\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Direct measurement of Mg²⁺ currents through TRPML2 and human GWAS linking MCOLN2 variants to intracellular S. Typhi replication established a nutritional immunity function: TRPML2 depletes endolysosomal Mg²⁺ to restrict bacterial growth.\",\n      \"evidence\": \"Endolysosomal patch-clamp for Mg²⁺ currents, GWAS in cellular infection model, S. Typhi transcriptomics, Mg²⁺ manipulation experiments\",\n      \"pmids\": [\"37228749\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether Mg²⁺ restriction applies to other intracellular pathogens not shown\",\n        \"Relative contribution of TRPML2 vs other transporters to endolysosomal Mg²⁺ not quantified\",\n        \"In vivo validation of MCOLN2 variants in S. Typhi susceptibility not performed\"\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Sphingomyelin accumulation was identified as an endogenous lipid inhibitor of TRPML2-mediated lysosomal Ca²⁺ release; this inhibition sensitizes lysosomes to membrane permeabilization, providing a mechanistic basis for obinutuzumab-induced direct cell death.\",\n      \"evidence\": \"Imaging, genetic knockdown, SMase rescue, Ca²⁺ measurement, and lysosomal membrane permeabilization assays in B-cell lymphoma models\",\n      \"pmids\": [\"41634107\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Direct binding site for sphingomyelin on TRPML2 not mapped\",\n        \"Whether SM inhibition is specific to TRPML2 or also affects TRPML1/3 not fully resolved\",\n        \"Clinical relevance of TRPML2 inhibition in obinutuzumab therapy not validated in patients\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of TRPML2 in an open/agonist-bound state, the precise signaling intermediates connecting TRPML2 ion flux to NF-κB activation and chemokine vesicle fusion, and the full spectrum of pathogens subject to TRPML2-mediated nutritional immunity.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No agonist-bound or open-state structure available\",\n        \"Signaling cascade from TRPML2 Ca²⁺/Mg²⁺ flux to NF-κB not mapped\",\n        \"Comprehensive in vivo phenotyping of TRPML2-KO mice in diverse infection models lacking\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [1, 3, 6, 8, 11]},\n      {\"term_id\": \"GO:0140299\", \"supporting_discovery_ids\": [8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [0, 7, 9, 12]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [5, 6, 8]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [5, 6, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [5, 6, 11]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [10]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [6, 8]}\n    ],\n    \"complexes\": [\n      \"TRPML2 homotetramer\",\n      \"TRPML1–TRPML2 heteromultimer\",\n      \"TRPML2–TRPML3 heteromultimer\"\n    ],\n    \"partners\": [\n      \"MCOLN1\",\n      \"MCOLN3\",\n      \"PAX5\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}