{"gene":"TMEM230","run_date":"2026-04-28T21:42:59","timeline":{"discoveries":[{"year":2016,"finding":"TMEM230 encodes a transmembrane protein localized to secretory/recycling vesicles, including synaptic vesicles in neurons; disease-linked TMEM230 mutants impair synaptic vesicle trafficking, and pathogenic variants increase alpha-synuclein levels in HEK293 cells.","method":"Cell biology/localization studies in primary neurons and HEK293 cells; live imaging of synaptic vesicle movement; overexpression of PD-linked mutants","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 2 — direct localization with functional consequence (vesicle trafficking impairment) in primary neurons, replicated across multiple PD-linked variants","pmids":["27270108"],"is_preprint":false},{"year":2017,"finding":"TMEM230 is required for retromer cargo (CI-M6PR) trafficking: loss of TMEM230 disrupts retromer localization and autophagic cargo degradation, and inhibits extracellular secretion of p62 and immature lysosomal hydrolases from Golgi-derived vesicles via loss of the small GTPase Rab8a.","method":"siRNA knockdown, immunofluorescence, cargo secretion assays, Rab8a rescue experiments; overexpression of PD-linked TMEM230 variants","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (knockdown, localization, secretion assay, genetic rescue) in single lab with clean functional readouts","pmids":["28115417"],"is_preprint":false},{"year":2017,"finding":"TMEM230 and LRRK2 converge on Rab8a function: LRRK2 knockdown (which phosphorylates Rab8a) similarly impairs retromer trafficking, secretory autophagy, and Golgi-derived vesicle secretion, placing TMEM230 in the same pathway as LRRK2 via Rab8a.","method":"siRNA knockdown of LRRK2, functional assays for retromer trafficking and secretory autophagy, epistasis analysis","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2 — pathway epistasis with functional readout, single lab","pmids":["28115417"],"is_preprint":false},{"year":2018,"finding":"LRRK2 does not interact with, nor phosphorylate, TMEM230; overexpression of TMEM230 does not alter levels of Rab1A, Rab5, Rab7, Rab8A, or Rab11, suggesting TMEM230 does not directly regulate these Rab GTPases.","method":"Co-immunoprecipitation, in vitro kinase assay, western blotting after overexpression","journal":"Animal cells and systems","confidence":"Medium","confidence_rationale":"Tier 2 — direct biochemical assays (Co-IP and kinase assay) with negative result, single lab","pmids":["30460091"],"is_preprint":false},{"year":2021,"finding":"Overexpression of TMEM230 isoform 2 (WT or PD-linked *184Wext*5 mutant) or knockdown of endogenous TMEM230 induces neurodegeneration and impairs retrograde mitochondrial transport in axons of SH-SY5Y cells and mouse primary hippocampal neurons; mutant causes more severe effects than WT.","method":"Overexpression and siRNA knockdown in SH-SY5Y cells and primary neurons; live imaging of mitochondrial transport in axons; neurotoxicity assays","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2 — live-cell imaging with quantified functional readout (mitochondrial transport), single lab with gain- and loss-of-function","pmids":["34002226"],"is_preprint":false},{"year":2024,"finding":"TMEM230 knockout rats generated by CRISPR-Cas9 do not exhibit motor impairments, dopaminergic neuron loss, altered autophagy/Rab/vesicular trafficking protein expression, or glial reactions, suggesting PD-associated TMEM230 mutations act via a gain-of-toxic function mechanism rather than loss of function.","method":"CRISPR-Cas9 knockout rat model; behavioral motor testing; immunohistochemistry for dopaminergic neurons; western blotting for autophagy, Rab, and vesicular trafficking proteins","journal":"Neuroscience letters","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo loss-of-function model with multiple phenotypic readouts, single study supporting gain-of-function mechanism","pmids":["39106917"],"is_preprint":false},{"year":2025,"finding":"TMEM230 was identified as a subunit of ATP8/ATP11 lipid flippase complexes on early endosomes, as determined by crosslinking mass spectrometry of purified human endosomes and structural modeling with AlphaFold, with interaction validated in induced neurons.","method":"Cross-linking mass spectrometry of purified early endosomes, native gel mass spectrometry, AlphaFold structural prediction, validation in induced neurons","journal":"bioRxiv (preprint)","confidence":"Medium","confidence_rationale":"Tier 1-2 — crosslinking MS from native subcellular context plus structural validation, but preprint, single study","pmids":["bio_10.1101_2025.02.07.636106"],"is_preprint":true}],"current_model":"TMEM230 is a transmembrane protein of secretory/recycling vesicles (including synaptic vesicles and early endosomes) that functions in retromer-mediated cargo trafficking, Golgi-derived vesicle secretion, and autophagic cargo degradation via the small GTPase Rab8a, and has been identified as a subunit of ATP8/11 lipid flippase complexes on endosomes; PD-linked mutations impair vesicle trafficking, increase alpha-synuclein levels, and impair retrograde axonal mitochondrial transport, while knockout animal studies support a gain-of-toxic function mechanism for disease-associated variants."},"narrative":{"teleology":[{"year":2016,"claim":"Establishing TMEM230 as a vesicular transmembrane protein: its localization to secretory/recycling and synaptic vesicles, and the demonstration that PD-linked mutants impair vesicle trafficking and elevate alpha-synuclein, placed TMEM230 squarely in the vesicular trafficking pathway relevant to Parkinson disease.","evidence":"Localization studies in primary neurons and HEK293 cells; live imaging of synaptic vesicle movement with overexpressed PD-linked mutants","pmids":["27270108"],"confidence":"High","gaps":["Molecular mechanism by which TMEM230 regulates vesicle trafficking was unknown","Whether alpha-synuclein elevation is a direct or indirect consequence was not resolved","No in vivo loss-of-function model existed"]},{"year":2017,"claim":"TMEM230 was placed mechanistically upstream of retromer-mediated cargo sorting and secretory autophagy: its knockdown disrupted retromer localization, CI-M6PR trafficking, and Golgi-derived secretion, all rescuable by Rab8a, and LRRK2 knockdown phenocopied these defects, linking TMEM230 to the LRRK2–Rab8a axis.","evidence":"siRNA knockdown of TMEM230 and LRRK2; immunofluorescence, cargo secretion assays, and Rab8a rescue experiments","pmids":["28115417"],"confidence":"High","gaps":["Whether TMEM230 directly binds or activates Rab8a was not shown","Epistasis between TMEM230 and LRRK2 was inferred from parallel phenotypes in a single lab, not from double-knockdown experiments","Pathway convergence via Rab8a was challenged by later negative biochemical data"]},{"year":2018,"claim":"The proposed direct functional link between TMEM230 and LRRK2/Rab GTPases was challenged: LRRK2 neither binds nor phosphorylates TMEM230, and TMEM230 overexpression does not alter levels of Rab8A or other Rab proteins, suggesting TMEM230's role in Rab8a-dependent trafficking is indirect.","evidence":"Co-immunoprecipitation, in vitro kinase assay, and western blotting after overexpression","pmids":["30460091"],"confidence":"Medium","gaps":["Negative interaction results from overexpression systems do not exclude context-dependent or transient interactions","The mechanism by which TMEM230 loss leads to Rab8a-dependent phenotypes remained unresolved","Only steady-state Rab levels were measured, not activation or membrane recruitment"]},{"year":2021,"claim":"TMEM230 perturbation was shown to impair retrograde axonal mitochondrial transport and cause neurodegeneration, with PD-linked mutants producing more severe effects than wild-type overexpression, indicating a toxic gain-of-function component.","evidence":"Overexpression and siRNA knockdown in SH-SY5Y cells and mouse primary hippocampal neurons; live imaging of axonal mitochondrial transport","pmids":["34002226"],"confidence":"Medium","gaps":["How TMEM230 influences mitochondrial transport machinery is unknown","Both overexpression and knockdown cause similar phenotypes, complicating interpretation of mechanism","Single lab study; replication in independent models needed"]},{"year":2024,"claim":"In vivo knockout resolved the loss-of-function versus gain-of-function debate: TMEM230 knockout rats showed no motor deficits, dopaminergic neuron loss, or vesicular trafficking alterations, establishing that PD-associated mutations act through a gain-of-toxic-function mechanism.","evidence":"CRISPR-Cas9 knockout rat model; behavioral testing, immunohistochemistry, western blotting for autophagy/Rab/vesicular markers","pmids":["39106917"],"confidence":"Medium","gaps":["A knock-in model of PD-associated mutations is needed to confirm gain-of-function toxicity in vivo","Possible compensatory mechanisms in the knockout rat were not investigated","Single study; no conditional or neuron-specific knockout was performed"]},{"year":2025,"claim":"TMEM230 was identified as a physical subunit of ATP8/ATP11 lipid flippase complexes on early endosomes, providing a molecular basis for its endosomal function.","evidence":"Cross-linking mass spectrometry of purified human endosomes, native gel MS, AlphaFold structural prediction, validation in induced neurons (preprint)","pmids":["bio_10.1101_2025.02.07.636106"],"confidence":"Medium","gaps":["Preprint not yet peer-reviewed","Functional consequence of TMEM230 loss on flippase activity has not been measured","Whether lipid flippase association explains TMEM230's role in retromer trafficking and disease is untested"]},{"year":null,"claim":"The direct molecular mechanism by which TMEM230 regulates vesicle trafficking — whether through lipid flippase function, Rab8a modulation, or another route — and how PD-linked mutations gain toxic function remain open questions.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No reconstituted biochemical activity for TMEM230 has been demonstrated","Structural basis of PD-linked mutant toxicity is unknown","Relationship between flippase complex membership and retromer/secretory autophagy phenotypes is untested"]}],"mechanism_profile":{"molecular_activity":[],"localization":[{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[1,6]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,1]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[1]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[0,4,5]}],"complexes":["ATP8/ATP11 lipid flippase complex"],"partners":["RAB8A"],"other_free_text":[]},"mechanistic_narrative":"TMEM230 is a transmembrane protein of secretory and recycling vesicles that functions in retromer-mediated cargo trafficking, Golgi-derived vesicle secretion, and autophagic cargo degradation. It localizes to synaptic vesicles in neurons and to early endosomes, where it is required for proper retromer localization and CI-M6PR trafficking via the small GTPase Rab8a, and its loss disrupts extracellular secretion of p62 and immature lysosomal hydrolases [PMID:28115417]. Disease-linked TMEM230 mutations impair synaptic vesicle trafficking, increase alpha-synuclein levels, and cause neurodegeneration with disrupted retrograde axonal mitochondrial transport, while TMEM230 knockout rats lack neurodegeneration, indicating that Parkinson disease-associated variants act through a gain-of-toxic-function mechanism rather than haploinsufficiency [PMID:27270108, PMID:34002226, PMID:39106917]."},"prefetch_data":{"uniprot":{"accession":"Q96A57","full_name":"Transmembrane protein 230","aliases":[],"length_aa":120,"mass_kda":13.2,"function":"Involved in trafficking and recycling of synaptic vesicles","subcellular_location":"Membrane; Golgi apparatus, trans-Golgi network; Cytoplasmic vesicle, secretory vesicle, synaptic vesicle; Early endosome; Recycling endosome; Late endosome; Cytoplasmic vesicle, autophagosome","url":"https://www.uniprot.org/uniprotkb/Q96A57/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TMEM230","classification":"Not Classified","n_dependent_lines":240,"n_total_lines":1208,"dependency_fraction":0.1986754966887417},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"CANX","stoichiometry":0.2},{"gene":"GPR107","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/TMEM230","total_profiled":1310},"omim":[{"mim_id":"617019","title":"TRANSMEMBRANE PROTEIN 230; TMEM230","url":"https://www.omim.org/entry/617019"},{"mim_id":"616361","title":"PARKINSON DISEASE 21; PARK21","url":"https://www.omim.org/entry/616361"},{"mim_id":"614334","title":"DNAJ/HSP40 HOMOLOG, SUBFAMILY C, MEMBER 13; DNAJC13","url":"https://www.omim.org/entry/614334"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Endoplasmic reticulum","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/TMEM230"},"hgnc":{"alias_symbol":["HSPC274"],"prev_symbol":["C20orf30"]},"alphafold":{"accession":"Q96A57","domains":[{"cath_id":"1.20.58","chopping":"43-108","consensus_level":"high","plddt":90.1094,"start":43,"end":108}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96A57","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96A57-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96A57-F1-predicted_aligned_error_v6.png","plddt_mean":81.12},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TMEM230","jax_strain_url":"https://www.jax.org/strain/search?query=TMEM230"},"sequence":{"accession":"Q96A57","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96A57.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96A57/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96A57"}},"corpus_meta":[{"pmid":"27270108","id":"PMC_27270108","title":"Identification of TMEM230 mutations in familial Parkinson's disease.","date":"2016","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/27270108","citation_count":140,"is_preprint":false},{"pmid":"28115417","id":"PMC_28115417","title":"The Parkinson's disease-linked protein TMEM230 is required for Rab8a-mediated secretory vesicle trafficking and retromer trafficking.","date":"2017","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28115417","citation_count":48,"is_preprint":false},{"pmid":"27814995","id":"PMC_27814995","title":"TMEM230 mutation analysis in Parkinson's disease in a Chinese population.","date":"2016","source":"Neurobiology of aging","url":"https://pubmed.ncbi.nlm.nih.gov/27814995","citation_count":28,"is_preprint":false},{"pmid":"27818000","id":"PMC_27818000","title":"Lack of evidence for a role of genetic variation in TMEM230 in the risk for Parkinson's disease in the Caucasian population.","date":"2016","source":"Neurobiology of aging","url":"https://pubmed.ncbi.nlm.nih.gov/27818000","citation_count":26,"is_preprint":false},{"pmid":"33212219","id":"PMC_33212219","title":"Controversy of TMEM230 Associated with Parkinson's Disease.","date":"2020","source":"Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/33212219","citation_count":13,"is_preprint":false},{"pmid":"34867197","id":"PMC_34867197","title":"Transmembrane Protein TMEM230, a Target of Glioblastoma Therapy.","date":"2021","source":"Frontiers in cellular neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/34867197","citation_count":12,"is_preprint":false},{"pmid":"28568905","id":"PMC_28568905","title":"TMEM230: How does it fit in the etiology and pathogenesis of Parkinson's disease?","date":"2017","source":"Movement disorders : official journal of the Movement Disorder Society","url":"https://pubmed.ncbi.nlm.nih.gov/28568905","citation_count":11,"is_preprint":false},{"pmid":"30175983","id":"PMC_30175983","title":"The Role of TMEM230 Gene in Parkinson's Disease.","date":"2018","source":"Journal of Parkinson's disease","url":"https://pubmed.ncbi.nlm.nih.gov/30175983","citation_count":10,"is_preprint":false},{"pmid":"34002226","id":"PMC_34002226","title":"Mutant-TMEM230-induced neurodegeneration and impaired axonal mitochondrial transport.","date":"2021","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/34002226","citation_count":10,"is_preprint":false},{"pmid":"28527219","id":"PMC_28527219","title":"TMEM230 Accumulation in Granulovacuolar Degeneration Bodies and Dystrophic Neurites of Alzheimer's Disease.","date":"2017","source":"Journal of Alzheimer's disease : JAD","url":"https://pubmed.ncbi.nlm.nih.gov/28527219","citation_count":9,"is_preprint":false},{"pmid":"28457580","id":"PMC_28457580","title":"TMEM230 in Parkinson's disease.","date":"2017","source":"Neurobiology of aging","url":"https://pubmed.ncbi.nlm.nih.gov/28457580","citation_count":9,"is_preprint":false},{"pmid":"28766910","id":"PMC_28766910","title":"Lack of TMEM230 mutations in patients with familial and sporadic Parkinson's disease in a Taiwanese population.","date":"2017","source":"American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28766910","citation_count":9,"is_preprint":false},{"pmid":"28455698","id":"PMC_28455698","title":"TMEM230 Mutations Are Rare in Han Chinese Patients with Autosomal Dominant Parkinson's Disease.","date":"2017","source":"Molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/28455698","citation_count":9,"is_preprint":false},{"pmid":"30460091","id":"PMC_30460091","title":"Characterization of Parkinson's disease-related pathogenic TMEM230 mutants.","date":"2018","source":"Animal cells and systems","url":"https://pubmed.ncbi.nlm.nih.gov/30460091","citation_count":8,"is_preprint":false},{"pmid":"29305083","id":"PMC_29305083","title":"Genetic analysis of TMEM230 in Japanese patients with familial Parkinson's disease.","date":"2017","source":"Parkinsonism & related disorders","url":"https://pubmed.ncbi.nlm.nih.gov/29305083","citation_count":8,"is_preprint":false},{"pmid":"28709721","id":"PMC_28709721","title":"Screening for TMEM230 mutations in young-onset Parkinson's disease.","date":"2017","source":"Neurobiology of aging","url":"https://pubmed.ncbi.nlm.nih.gov/28709721","citation_count":8,"is_preprint":false},{"pmid":"28446760","id":"PMC_28446760","title":"Genetic analysis of the TMEM230 gene in Chinese Han patients with Parkinson's disease.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/28446760","citation_count":7,"is_preprint":false},{"pmid":"29771939","id":"PMC_29771939","title":"TMEM230 in Parkinson's disease in a southern Spanish population.","date":"2018","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/29771939","citation_count":7,"is_preprint":false},{"pmid":"27872751","id":"PMC_27872751","title":"Novel gene (TMEM230) linked to Parkinson's disease.","date":"2016","source":"Journal of clinical movement disorders","url":"https://pubmed.ncbi.nlm.nih.gov/27872751","citation_count":5,"is_preprint":false},{"pmid":"38612777","id":"PMC_38612777","title":"Transmembrane Protein TMEM230, Regulator of Glial Cell Vascular Mimicry and Endothelial Cell Angiogenesis in High-Grade Heterogeneous Infiltrating Gliomas and Glioblastoma.","date":"2024","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/38612777","citation_count":4,"is_preprint":false},{"pmid":"40141059","id":"PMC_40141059","title":"Glycosylation Regulation by TMEM230 in Aging and Autoimmunity.","date":"2025","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/40141059","citation_count":3,"is_preprint":false},{"pmid":"38960477","id":"PMC_38960477","title":"Transmembrane protein TMEM230, regulator of metalloproteins and motor proteins in gliomas and gliosis.","date":"2024","source":"Advances in protein chemistry and structural biology","url":"https://pubmed.ncbi.nlm.nih.gov/38960477","citation_count":3,"is_preprint":false},{"pmid":"39106917","id":"PMC_39106917","title":"Absence of motor impairments or pathological changes in TMEM230 knockout rats.","date":"2024","source":"Neuroscience letters","url":"https://pubmed.ncbi.nlm.nih.gov/39106917","citation_count":1,"is_preprint":false},{"pmid":"40744139","id":"PMC_40744139","title":"Genetic analysis of TMEM230 variants in Han Chinese patients with Parkinson's disease.","date":"2025","source":"Neuroscience letters","url":"https://pubmed.ncbi.nlm.nih.gov/40744139","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.02.07.636106","title":"EndoMAP.v1, a Structural Protein Complex Landscape of Human Endosomes","date":"2025-02-09","source":"bioRxiv","url":"https://doi.org/10.1101/2025.02.07.636106","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11946,"output_tokens":1760,"usd":0.031119},"stage2":{"model":"claude-opus-4-6","input_tokens":5013,"output_tokens":2066,"usd":0.115072},"total_usd":0.146191,"stage1_batch_id":"msgbatch_01RPbVc9PDH9zQmYK5Hs6srm","stage2_batch_id":"msgbatch_01JVbVLzeKN2yVrsGp3zC8aM","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2016,\n      \"finding\": \"TMEM230 encodes a transmembrane protein localized to secretory/recycling vesicles, including synaptic vesicles in neurons; disease-linked TMEM230 mutants impair synaptic vesicle trafficking, and pathogenic variants increase alpha-synuclein levels in HEK293 cells.\",\n      \"method\": \"Cell biology/localization studies in primary neurons and HEK293 cells; live imaging of synaptic vesicle movement; overexpression of PD-linked mutants\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct localization with functional consequence (vesicle trafficking impairment) in primary neurons, replicated across multiple PD-linked variants\",\n      \"pmids\": [\"27270108\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"TMEM230 is required for retromer cargo (CI-M6PR) trafficking: loss of TMEM230 disrupts retromer localization and autophagic cargo degradation, and inhibits extracellular secretion of p62 and immature lysosomal hydrolases from Golgi-derived vesicles via loss of the small GTPase Rab8a.\",\n      \"method\": \"siRNA knockdown, immunofluorescence, cargo secretion assays, Rab8a rescue experiments; overexpression of PD-linked TMEM230 variants\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (knockdown, localization, secretion assay, genetic rescue) in single lab with clean functional readouts\",\n      \"pmids\": [\"28115417\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"TMEM230 and LRRK2 converge on Rab8a function: LRRK2 knockdown (which phosphorylates Rab8a) similarly impairs retromer trafficking, secretory autophagy, and Golgi-derived vesicle secretion, placing TMEM230 in the same pathway as LRRK2 via Rab8a.\",\n      \"method\": \"siRNA knockdown of LRRK2, functional assays for retromer trafficking and secretory autophagy, epistasis analysis\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — pathway epistasis with functional readout, single lab\",\n      \"pmids\": [\"28115417\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"LRRK2 does not interact with, nor phosphorylate, TMEM230; overexpression of TMEM230 does not alter levels of Rab1A, Rab5, Rab7, Rab8A, or Rab11, suggesting TMEM230 does not directly regulate these Rab GTPases.\",\n      \"method\": \"Co-immunoprecipitation, in vitro kinase assay, western blotting after overexpression\",\n      \"journal\": \"Animal cells and systems\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct biochemical assays (Co-IP and kinase assay) with negative result, single lab\",\n      \"pmids\": [\"30460091\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Overexpression of TMEM230 isoform 2 (WT or PD-linked *184Wext*5 mutant) or knockdown of endogenous TMEM230 induces neurodegeneration and impairs retrograde mitochondrial transport in axons of SH-SY5Y cells and mouse primary hippocampal neurons; mutant causes more severe effects than WT.\",\n      \"method\": \"Overexpression and siRNA knockdown in SH-SY5Y cells and primary neurons; live imaging of mitochondrial transport in axons; neurotoxicity assays\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — live-cell imaging with quantified functional readout (mitochondrial transport), single lab with gain- and loss-of-function\",\n      \"pmids\": [\"34002226\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"TMEM230 knockout rats generated by CRISPR-Cas9 do not exhibit motor impairments, dopaminergic neuron loss, altered autophagy/Rab/vesicular trafficking protein expression, or glial reactions, suggesting PD-associated TMEM230 mutations act via a gain-of-toxic function mechanism rather than loss of function.\",\n      \"method\": \"CRISPR-Cas9 knockout rat model; behavioral motor testing; immunohistochemistry for dopaminergic neurons; western blotting for autophagy, Rab, and vesicular trafficking proteins\",\n      \"journal\": \"Neuroscience letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo loss-of-function model with multiple phenotypic readouts, single study supporting gain-of-function mechanism\",\n      \"pmids\": [\"39106917\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TMEM230 was identified as a subunit of ATP8/ATP11 lipid flippase complexes on early endosomes, as determined by crosslinking mass spectrometry of purified human endosomes and structural modeling with AlphaFold, with interaction validated in induced neurons.\",\n      \"method\": \"Cross-linking mass spectrometry of purified early endosomes, native gel mass spectrometry, AlphaFold structural prediction, validation in induced neurons\",\n      \"journal\": \"bioRxiv (preprint)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 — crosslinking MS from native subcellular context plus structural validation, but preprint, single study\",\n      \"pmids\": [\"bio_10.1101_2025.02.07.636106\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"TMEM230 is a transmembrane protein of secretory/recycling vesicles (including synaptic vesicles and early endosomes) that functions in retromer-mediated cargo trafficking, Golgi-derived vesicle secretion, and autophagic cargo degradation via the small GTPase Rab8a, and has been identified as a subunit of ATP8/11 lipid flippase complexes on endosomes; PD-linked mutations impair vesicle trafficking, increase alpha-synuclein levels, and impair retrograde axonal mitochondrial transport, while knockout animal studies support a gain-of-toxic function mechanism for disease-associated variants.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"TMEM230 is a transmembrane protein of secretory and recycling vesicles that functions in retromer-mediated cargo trafficking, Golgi-derived vesicle secretion, and autophagic cargo degradation. It localizes to synaptic vesicles in neurons and to early endosomes, where it is required for proper retromer localization and CI-M6PR trafficking via the small GTPase Rab8a, and its loss disrupts extracellular secretion of p62 and immature lysosomal hydrolases [PMID:28115417]. Disease-linked TMEM230 mutations impair synaptic vesicle trafficking, increase alpha-synuclein levels, and cause neurodegeneration with disrupted retrograde axonal mitochondrial transport, while TMEM230 knockout rats lack neurodegeneration, indicating that Parkinson disease-associated variants act through a gain-of-toxic-function mechanism rather than haploinsufficiency [PMID:27270108, PMID:34002226, PMID:39106917].\",\n  \"teleology\": [\n    {\n      \"year\": 2016,\n      \"claim\": \"Establishing TMEM230 as a vesicular transmembrane protein: its localization to secretory/recycling and synaptic vesicles, and the demonstration that PD-linked mutants impair vesicle trafficking and elevate alpha-synuclein, placed TMEM230 squarely in the vesicular trafficking pathway relevant to Parkinson disease.\",\n      \"evidence\": \"Localization studies in primary neurons and HEK293 cells; live imaging of synaptic vesicle movement with overexpressed PD-linked mutants\",\n      \"pmids\": [\"27270108\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Molecular mechanism by which TMEM230 regulates vesicle trafficking was unknown\",\n        \"Whether alpha-synuclein elevation is a direct or indirect consequence was not resolved\",\n        \"No in vivo loss-of-function model existed\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"TMEM230 was placed mechanistically upstream of retromer-mediated cargo sorting and secretory autophagy: its knockdown disrupted retromer localization, CI-M6PR trafficking, and Golgi-derived secretion, all rescuable by Rab8a, and LRRK2 knockdown phenocopied these defects, linking TMEM230 to the LRRK2–Rab8a axis.\",\n      \"evidence\": \"siRNA knockdown of TMEM230 and LRRK2; immunofluorescence, cargo secretion assays, and Rab8a rescue experiments\",\n      \"pmids\": [\"28115417\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether TMEM230 directly binds or activates Rab8a was not shown\",\n        \"Epistasis between TMEM230 and LRRK2 was inferred from parallel phenotypes in a single lab, not from double-knockdown experiments\",\n        \"Pathway convergence via Rab8a was challenged by later negative biochemical data\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"The proposed direct functional link between TMEM230 and LRRK2/Rab GTPases was challenged: LRRK2 neither binds nor phosphorylates TMEM230, and TMEM230 overexpression does not alter levels of Rab8A or other Rab proteins, suggesting TMEM230's role in Rab8a-dependent trafficking is indirect.\",\n      \"evidence\": \"Co-immunoprecipitation, in vitro kinase assay, and western blotting after overexpression\",\n      \"pmids\": [\"30460091\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Negative interaction results from overexpression systems do not exclude context-dependent or transient interactions\",\n        \"The mechanism by which TMEM230 loss leads to Rab8a-dependent phenotypes remained unresolved\",\n        \"Only steady-state Rab levels were measured, not activation or membrane recruitment\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"TMEM230 perturbation was shown to impair retrograde axonal mitochondrial transport and cause neurodegeneration, with PD-linked mutants producing more severe effects than wild-type overexpression, indicating a toxic gain-of-function component.\",\n      \"evidence\": \"Overexpression and siRNA knockdown in SH-SY5Y cells and mouse primary hippocampal neurons; live imaging of axonal mitochondrial transport\",\n      \"pmids\": [\"34002226\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"How TMEM230 influences mitochondrial transport machinery is unknown\",\n        \"Both overexpression and knockdown cause similar phenotypes, complicating interpretation of mechanism\",\n        \"Single lab study; replication in independent models needed\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"In vivo knockout resolved the loss-of-function versus gain-of-function debate: TMEM230 knockout rats showed no motor deficits, dopaminergic neuron loss, or vesicular trafficking alterations, establishing that PD-associated mutations act through a gain-of-toxic-function mechanism.\",\n      \"evidence\": \"CRISPR-Cas9 knockout rat model; behavioral testing, immunohistochemistry, western blotting for autophagy/Rab/vesicular markers\",\n      \"pmids\": [\"39106917\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"A knock-in model of PD-associated mutations is needed to confirm gain-of-function toxicity in vivo\",\n        \"Possible compensatory mechanisms in the knockout rat were not investigated\",\n        \"Single study; no conditional or neuron-specific knockout was performed\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"TMEM230 was identified as a physical subunit of ATP8/ATP11 lipid flippase complexes on early endosomes, providing a molecular basis for its endosomal function.\",\n      \"evidence\": \"Cross-linking mass spectrometry of purified human endosomes, native gel MS, AlphaFold structural prediction, validation in induced neurons (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.02.07.636106\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Preprint not yet peer-reviewed\",\n        \"Functional consequence of TMEM230 loss on flippase activity has not been measured\",\n        \"Whether lipid flippase association explains TMEM230's role in retromer trafficking and disease is untested\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The direct molecular mechanism by which TMEM230 regulates vesicle trafficking — whether through lipid flippase function, Rab8a modulation, or another route — and how PD-linked mutations gain toxic function remain open questions.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No reconstituted biochemical activity for TMEM230 has been demonstrated\",\n        \"Structural basis of PD-linked mutant toxicity is unknown\",\n        \"Relationship between flippase complex membership and retromer/secretory autophagy phenotypes is untested\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [1, 6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [0, 4, 5]}\n    ],\n    \"complexes\": [\n      \"ATP8/ATP11 lipid flippase complex\"\n    ],\n    \"partners\": [\n      \"RAB8A\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}