{"gene":"MARCHF7","run_date":"2026-06-10T02:59:50","timeline":{"discoveries":[{"year":2008,"finding":"MARCH7 undergoes autoubiquitylation and is stabilized by two deubiquitylating enzymes in a compartment-specific manner: USP9X deubiquitylates MARCH7 in the cytosol and USP7 deubiquitylates MARCH7 in the nucleus, preventing its proteasomal degradation.","method":"Co-immunoprecipitation, siRNA knockdown, exogenous expression, subcellular fractionation","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP plus siRNA depletion and overexpression in two compartments, single lab with multiple orthogonal methods","pmids":["18410486"],"is_preprint":false},{"year":2018,"finding":"MARCH7 physically interacts with Mdm2 and catalyzes K63-linked polyubiquitination of Mdm2, which blocks Mdm2 autoubiquitination and degradation, thereby stabilizing Mdm2 and promoting Mdm2-dependent polyubiquitination and degradation of p53.","method":"Co-immunoprecipitation, in vitro ubiquitination assay, ubiquitin linkage-specific analysis, cell-based degradation assays","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro ubiquitination assay plus Co-IP and cell-based epistasis, single lab with multiple orthogonal methods","pmids":["29295817"],"is_preprint":false},{"year":2014,"finding":"Axotrophin/MARCH7 interacts with tau protein via amino acids 552–682 (the RING-variant domain), mono-ubiquitinates tau in vitro, and this ubiquitination diminishes tau's microtubule-binding capacity. In Alzheimer's disease brain, axotrophin loses nuclear localization and associates with neurofibrillary tangles.","method":"Yeast two-hybrid, co-immunoprecipitation, co-localization, in vitro ubiquitination assay, microtubule-binding assay","journal":"Biochimica et biophysica acta","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro ubiquitination with recombinant protein plus Co-IP and functional microtubule-binding assay, single lab multiple orthogonal methods","pmids":["24905733"],"is_preprint":false},{"year":2017,"finding":"MARCH7 directly binds NPHP5 (nephrocystin-5) and K48-ubiquitinates it, triggering NPHP5 proteasomal degradation and cilia loss. USP9X sequesters MARCH7 away from the centrosome during interphase to protect NPHP5; upon USP9X depletion or inhibition, MARCH7 accumulates at the centrosome and ubiquitinates NPHP5.","method":"Co-immunoprecipitation, siRNA knockdown, ubiquitin linkage-specific analysis, immunofluorescence/localization, ciliogenesis assays","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP, linkage-specific ubiquitination, localization experiments, and functional ciliogenesis readout, single lab multiple orthogonal methods","pmids":["28498859"],"is_preprint":false},{"year":2012,"finding":"MARCH7 is expressed in developing spermatids, localizes to the caudal end of the developing acrosome (co-localizing with β-actin/acroplaxome) and developing flagella, and catalyzes K48-linked ubiquitination, suggesting a role in spermiogenesis.","method":"Northern blot, in situ hybridization, immunohistochemistry, co-localization, ubiquitin linkage-specific immunostaining","journal":"Histochemistry and cell biology","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — direct localization with functional-context readout plus K48 ubiquitin activity shown in cells, single lab","pmids":["23104140"],"is_preprint":false},{"year":2018,"finding":"MARCH7 interacts with TGFβR2 and regulates the TGF-β-Smad2/3 signaling pathway; it also acts as a competing endogenous RNA (ceRNA) to regulate ATG7 expression by competing for miR-200a. MARCH7 silencing inhibits autophagy, invasion, and metastasis of ovarian cancer cells in vitro and in vivo.","method":"Co-immunoprecipitation, ChIP assay, luciferase reporter assay, wound healing, Matrigel invasion, orthotopic xenograft","journal":"Cellular physiology and biochemistry","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — Co-IP for TGFβR2 interaction plus multiple functional assays, single lab; ceRNA mechanism is inferential","pmids":["29794480"],"is_preprint":false},{"year":2015,"finding":"MARCH7 silencing inhibits NF-κB and Wnt/β-catenin pathways in ovarian cancer cells, and MARCH7 overexpression activates both pathways, placing MARCH7 upstream of these oncogenic cascades.","method":"siRNA knockdown, ectopic overexpression, western blot pathway analysis, in vivo xenograft","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2–3 / Weak — epistasis via loss/gain-of-function with pathway readout, single lab, single set of methods","pmids":["25895127"],"is_preprint":false},{"year":2018,"finding":"MARCH7 interacts with VAV2 and its silencing inhibits the VAV2-RAC1-CDC42 signaling pathway in cervical cancer cells, implicating MARCH7 as an upstream regulator of this GTPase cascade.","method":"Co-immunoprecipitation, siRNA knockdown, western blot pathway analysis","journal":"Oncology letters","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP for interaction plus pathway-level western blots, single lab","pmids":["30008934"],"is_preprint":false},{"year":2019,"finding":"MARCH7 promotes invasion and metastasis of endometrial cancer cells via a Snail-mediated epithelial-to-mesenchymal transition pathway, and is itself a direct target of miR-27b-3p which suppresses MARCH7 expression.","method":"Dual-luciferase reporter assay, transwell invasion assay, xenograft model, western blot","journal":"Acta biochimica et biophysica Sinica","confidence":"Low","confidence_rationale":"Tier 3 / Weak — functional assays with pathway inference, miR targeting confirmed by luciferase, single lab","pmids":["31006800"],"is_preprint":false},{"year":2023,"finding":"MARCH7 ubiquitinates ATG14 with mixed K6-, K11-, and K63-linked polyubiquitin chains, triggering ATG14 aggregation and insolubility, reducing its interaction with STX17, and thereby inhibiting autophagy flux. MARCH7 depletion decreases aggresome-like induced structures (ALISs).","method":"Co-immunoprecipitation, ubiquitination assay with linkage-specific analysis, solubility fractionation, autophagy flux assay, ALIS quantification","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in-cell ubiquitination assay with linkage mapping plus solubility/interaction and functional autophagy readouts, single lab multiple orthogonal methods","pmids":["37632749"],"is_preprint":false},{"year":2023,"finding":"MARCH7 interacts with NLRP3 and promotes its proteasomal degradation via ubiquitination; a ubiquitin-ligase-inactive mutant (W589A/I556A) of MARCH7 fails to degrade NLRP3 or inhibit NAFLD. GAS5 lncRNA sequesters miR-28a-5p, which targets MARCH7 mRNA to suppress its translation.","method":"Co-immunoprecipitation, proteasome inhibitor rescue, E3-dead mutant analysis, miR target validation, in vivo NAFLD models","journal":"Cell death and differentiation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP for NLRP3 interaction, catalytic mutant validation, and in vivo functional rescue, single lab","pmids":["37337032"],"is_preprint":false},{"year":2023,"finding":"Zebrafish MARCH7 negatively regulates type I IFN antiviral responses by interacting with TBK1 and promoting its K48-linked ubiquitination and proteasomal degradation. The C-terminal RING domain of MARCH7 is essential for TBK1 degradation and IFN suppression.","method":"Co-immunoprecipitation, ectopic expression, siRNA knockdown, ubiquitin linkage assay, RING domain truncation mutants, IFN promoter reporter assay, viral replication assay","journal":"International journal of biological macromolecules","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus linkage-specific ubiquitination plus domain mutants and functional antiviral readout; zebrafish ortholog, single lab","pmids":["37054851"],"is_preprint":false},{"year":2024,"finding":"MARCH7 interacts with NLRP3 and mediates its ubiquitination and proteasomal degradation to suppress M1 macrophage polarization and pyroptosis. siMARCH7 transfection reversed the inhibitory effect on NLRP3 inflammasome formation.","method":"Co-immunoprecipitation, siRNA knockdown, flow cytometry, immunofluorescence (ASC speck), western blot","journal":"Journal of ethnopharmacology","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — Co-IP for NLRP3 binding, siRNA rescue experiments, multiple functional readouts; corroborates earlier NLRP3 findings, single lab","pmids":["38246482"],"is_preprint":false},{"year":2025,"finding":"MARCHF7 promotes K27-linked ubiquitination of SARS-CoV-2 nsp16, leading to its proteasomal degradation and independently suppressing SARS-CoV-2 replication in cell cultures and in mice.","method":"Co-immunoprecipitation, ubiquitination assay, proteasome inhibitor rescue, cell-based and in vivo viral replication assays","journal":"eLife","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus ubiquitin linkage assay plus in vivo replication data, single lab multiple orthogonal methods","pmids":["40358464"],"is_preprint":false},{"year":2025,"finding":"MARCHF7 binds PXMP4 (a peroxisomal membrane protein) and ubiquitinates it at lysine 20 in PEX1-deficient cells, creating a recognition signal for the autophagy receptor NBR1 and driving pexophagy. TBK1 (activated by ROS upon PEX1 depletion) phosphorylates MARCHF7 to modulate this pathway.","method":"Functional screening, co-immunoprecipitation, site-directed mutagenesis (K20 mutant), siRNA knockdown, pexophagy flux assay, TBK1 phosphorylation assay","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — binding confirmed by Co-IP, K20 ubiquitination confirmed by mutant rescue, functional pexophagy readout; single lab","pmids":["41267209"],"is_preprint":false},{"year":2026,"finding":"MARCH7 suppresses ferroptosis via two mechanisms: (1) K48-linked ubiquitination of NCOA4 at Lys42, promoting its proteasomal degradation and reducing the labile iron pool; (2) K63-linked ubiquitination of transferrin receptor 1 (TFR1) at Lys53, restricting TFR1 plasma membrane translocation and inhibiting cellular iron uptake.","method":"Multi-omics, in vitro ubiquitination assay, site-directed mutagenesis (K42, K53), membrane fractionation, ferroptosis assays, rodent cardioprotection models","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — in vitro ubiquitination with site-specific mutagenesis at two substrates, membrane translocation assay, and in vivo functional validation; single lab but multiple orthogonal methods and two independent substrates","pmids":["42049018"],"is_preprint":false},{"year":2010,"finding":"MARCH7 regulates the LIF-receptor in T lymphocytes; T cells lacking MARCH7 are hyper-responsive to activation signals, show elevated LIF activity, and permit Nanog expression during G1/S phase. Addition of LIF to MARCH7-null T cells further induces Nanog ~13-fold.","method":"MARCH7 knockout mouse cells, cell cycle synchronization, transcript and protein expression analysis, miRNA profiling","journal":"Cell cycle (Georgetown, Tex.)","confidence":"Low","confidence_rationale":"Tier 3 / Weak — genetic loss-of-function with expression readouts but no direct biochemical mechanism linking MARCH7 to LIF-receptor ubiquitination demonstrated in this paper","pmids":["20962578"],"is_preprint":false}],"current_model":"MARCH7 (MARCHF7) is a RING-variant domain E3 ubiquitin ligase that undergoes autoubiquitylation and is stabilized by the deubiquitylases USP9X (cytosol) and USP7 (nucleus); it ubiquitinates a broad range of substrates with distinct linkage types—including K48 on NCOA4 (promoting ferritin degradation/iron release suppression), Mdm2 (K63, stabilizing Mdm2 to destabilize p53), TFR1 (K63, restricting iron uptake), ATG14 (mixed K6/K11/K63, inhibiting autophagy flux), NPHP5 (K48, controlling ciliogenesis), NLRP3 (proteasomal degradation, suppressing pyroptosis), PXMP4 (K20, driving pexophagy), SARS-CoV-2 nsp16 (K27, antiviral), TBK1 (K48, attenuating IFN responses), and tau (mono-ubiquitination, impairing microtubule binding)—thereby acting as a pleiotropic regulator of iron homeostasis/ferroptosis, autophagy, ciliogenesis, innate immunity, and tumor-relevant signaling pathways."},"narrative":{"mechanistic_narrative":"MARCHF7 (MARCH7/axotrophin) is a RING-variant domain E3 ubiquitin ligase that functions as a pleiotropic post-translational regulator, ubiquitinating diverse substrates with distinct chain linkages to control iron homeostasis, autophagy, ciliogenesis, innate immunity, and oncogenic signaling [PMID:42049018, PMID:37632749, PMID:28498859]. Its own abundance is set by autoubiquitylation counteracted by compartment-specific deubiquitylases—USP9X in the cytosol and USP7 in the nucleus—which protect MARCHF7 from proteasomal degradation [PMID:18410486]; USP9X further sequesters MARCHF7 away from the centrosome to limit its access to substrates such as NPHP5 [PMID:28498859]. Catalysis depends on an intact C-terminal RING-variant domain and conserved catalytic residues, as ligase-dead mutants fail to ubiquitinate substrates [PMID:37337032, PMID:37054851]. MARCHF7 suppresses ferroptosis through dual substrate targeting: K48-linked ubiquitination of NCOA4 at Lys42 to lower the labile iron pool, and K63-linked ubiquitination of TFR1 at Lys53 to restrict iron uptake [PMID:42049018]. It controls protein homeostasis and selective autophagy by ubiquitinating ATG14 with mixed K6/K11/K63 chains to inhibit autophagy flux [PMID:37632749] and by modifying the peroxisomal protein PXMP4 at Lys20 to license NBR1-dependent pexophagy [PMID:41267209]. In innate immunity, MARCHF7 degrades NLRP3 to suppress inflammasome activation and pyroptosis [PMID:37337032, PMID:38246482] and targets viral nsp16 (K27-linked) to restrict SARS-CoV-2 replication [PMID:40358464]. It also degrades NPHP5 (K48) to govern ciliogenesis [PMID:28498859] and stabilizes Mdm2 via K63-linked ubiquitination to destabilize p53 [PMID:29295817]. Beyond these substrate-defined roles, MARCHF7 is repeatedly implicated as an upstream promoter of cancer cell invasion and metastasis.","teleology":[{"year":2008,"claim":"Established how MARCHF7 protein levels are controlled, showing it is an autoubiquitylating E3 whose stability is set by compartment-specific deubiquitylases rather than constitutive expression.","evidence":"Co-IP, siRNA knockdown, overexpression and subcellular fractionation identifying USP9X (cytosol) and USP7 (nucleus)","pmids":["18410486"],"confidence":"High","gaps":["Substrates of MARCHF7 not identified in this study","Functional consequence of compartment-specific stabilization unresolved"]},{"year":2010,"claim":"First in vivo loss-of-function evidence that MARCHF7 restrains lymphocyte activation, linking it to LIF-receptor signaling and Nanog regulation.","evidence":"MARCH7 knockout mouse T cells with cell-cycle synchronization and expression profiling","pmids":["20962578"],"confidence":"Low","gaps":["No direct ubiquitination of LIF-receptor demonstrated","Mechanism connecting MARCHF7 to Nanog is correlative"]},{"year":2012,"claim":"Tied MARCHF7 to a tissue-specific developmental context, showing localized expression and K48-linked activity in spermiogenesis.","evidence":"Northern blot, in situ hybridization, IHC and linkage-specific ubiquitin immunostaining in developing spermatids","pmids":["23104140"],"confidence":"Medium","gaps":["No substrate identified in spermatids","Functional requirement in fertility not tested genetically"]},{"year":2014,"claim":"Provided the first defined substrate and a disease-relevant role, showing MARCHF7 mono-ubiquitinates tau via its RING-variant domain to impair microtubule binding.","evidence":"Yeast two-hybrid, Co-IP, in vitro ubiquitination and microtubule-binding assays plus Alzheimer brain localization","pmids":["24905733"],"confidence":"High","gaps":["Causal contribution to neurofibrillary tangle pathology not established","Loss of nuclear localization in AD brain mechanistically unexplained"]},{"year":2017,"claim":"Linked MARCHF7 to organelle biogenesis by identifying NPHP5 as a K48-ubiquitination substrate whose degradation drives cilia loss, and connected this to USP9X-mediated spatial control.","evidence":"Reciprocal Co-IP, linkage-specific ubiquitination, centrosomal localization and ciliogenesis assays","pmids":["28498859"],"confidence":"High","gaps":["Physiological trigger for MARCHF7 centrosomal recruitment beyond USP9X loss unclear","In vivo ciliopathy relevance not addressed"]},{"year":2018,"claim":"Defined a substrate-specific oncogenic mechanism in which MARCHF7 K63-ubiquitinates Mdm2 to stabilize it and thereby promote p53 degradation.","evidence":"Co-IP, in vitro ubiquitination with linkage analysis and cell-based degradation/epistasis assays","pmids":["29295817"],"confidence":"High","gaps":["Structural basis for linkage selectivity not defined","In vivo tumor-suppressor consequences not tested"]},{"year":2018,"claim":"Implicated MARCHF7 in cancer cell signaling and autophagy through TGFβR2 interaction and a proposed ceRNA mechanism controlling ATG7.","evidence":"Co-IP, ChIP, luciferase reporters and invasion/metastasis assays in ovarian cancer cells and xenografts","pmids":["29794480"],"confidence":"Medium","gaps":["ceRNA mechanism is inferential, not biochemically demonstrated","No ubiquitination substrate identified in this pathway"]},{"year":2015,"claim":"Positioned MARCHF7 upstream of NF-κB and Wnt/β-catenin pathways in ovarian cancer via gain- and loss-of-function epistasis.","evidence":"siRNA knockdown, overexpression, pathway western blots and xenografts","pmids":["25895127"],"confidence":"Medium","gaps":["No direct substrate linking MARCHF7 to these pathways shown","Mechanism of pathway activation unresolved"]},{"year":2018,"claim":"Connected MARCHF7 to GTPase signaling by showing it interacts with VAV2 and supports VAV2-RAC1-CDC42 activity in cervical cancer.","evidence":"Single Co-IP plus pathway-level western blots after siRNA knockdown","pmids":["30008934"],"confidence":"Low","gaps":["Single Co-IP without reciprocal validation","No ubiquitination of VAV2 demonstrated"]},{"year":2019,"claim":"Extended the oncogenic role to endometrial cancer via Snail-mediated EMT and identified miR-27b-3p as an upstream suppressor of MARCHF7.","evidence":"Dual-luciferase, transwell invasion, xenograft and western blot","pmids":["31006800"],"confidence":"Low","gaps":["EMT linkage is pathway-level and inferential","No direct enzymatic substrate identified"]},{"year":2023,"claim":"Established a direct autophagy-regulatory mechanism in which MARCHF7 ubiquitinates ATG14 with mixed chains to drive its aggregation and block autophagosome-lysosome fusion.","evidence":"Co-IP, linkage-specific ubiquitination, solubility fractionation, STX17 interaction and autophagy flux/ALIS assays","pmids":["37632749"],"confidence":"High","gaps":["Trigger regulating MARCHF7-ATG14 targeting unknown","Structural basis of mixed-linkage chain assembly undefined"]},{"year":2023,"claim":"Identified MARCHF7 as a negative regulator of the NLRP3 inflammasome by promoting its proteasomal degradation, validated with a catalytically dead mutant.","evidence":"Co-IP, proteasome rescue, E3-dead mutant and in vivo NAFLD models","pmids":["37337032"],"confidence":"Medium","gaps":["Linkage type on NLRP3 not mapped","Endogenous regulatory cues for NLRP3 targeting unclear"]},{"year":2023,"claim":"Defined an antiviral innate-immune brake, showing MARCHF7 K48-ubiquitinates TBK1 for degradation and dampens type I IFN responses, with RING domain dependence.","evidence":"Co-IP, linkage assay, RING truncation mutants and IFN reporter/viral replication assays in zebrafish","pmids":["37054851"],"confidence":"Medium","gaps":["Demonstrated in zebrafish ortholog; human conservation not confirmed here","Context determining IFN suppression vs antiviral activity unresolved"]},{"year":2024,"claim":"Corroborated NLRP3 as a substrate by showing MARCHF7-mediated degradation suppresses M1 macrophage polarization and pyroptosis.","evidence":"Co-IP, siRNA rescue, ASC speck imaging and flow cytometry","pmids":["38246482"],"confidence":"Medium","gaps":["Linkage type and ubiquitination site on NLRP3 not defined","Single-lab functional readouts"]},{"year":2025,"claim":"Revealed a direct antiviral effector role, with MARCHF7 K27-ubiquitinating SARS-CoV-2 nsp16 to degrade it and restrict viral replication in vivo.","evidence":"Co-IP, ubiquitination/linkage assay, proteasome rescue and cell-based and mouse replication assays","pmids":["40358464"],"confidence":"Medium","gaps":["nsp16 ubiquitination site not mapped","Reconciliation with IFN-suppressive TBK1 role not addressed"]},{"year":2025,"claim":"Connected MARCHF7 to selective peroxisome autophagy by showing K20 ubiquitination of PXMP4 creates an NBR1 recognition signal, with TBK1 phosphorylating MARCHF7 as upstream control.","evidence":"Functional screen, Co-IP, K20 mutagenesis, siRNA, pexophagy flux and TBK1 phosphorylation assays","pmids":["41267209"],"confidence":"Medium","gaps":["Phosphosite(s) on MARCHF7 not defined","Generality beyond PEX1-deficient cells untested"]},{"year":2026,"claim":"Defined the most fully resolved physiological role, showing MARCHF7 suppresses ferroptosis through site-specific dual ubiquitination of NCOA4 (K48, Lys42) and TFR1 (K63, Lys53) to lower iron availability.","evidence":"Multi-omics, in vitro ubiquitination with site-directed mutagenesis, membrane fractionation, ferroptosis assays and rodent cardioprotection models","pmids":["42049018"],"confidence":"High","gaps":["Upstream signals coordinating dual-substrate targeting unresolved","How linkage selectivity for the two substrates is achieved structurally unknown"]},{"year":null,"claim":"How MARCHF7 selects among its many substrates and assembles distinct chain linkages (K27/K48/K63/mixed) in different compartments and physiological contexts remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of substrate or linkage selectivity","Mechanism integrating compartment-specific DUBs with substrate access not defined","Apparent opposing immune roles (TBK1 degradation vs antiviral nsp16/NLRP3 control) not mechanistically reconciled"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[1,2,3,9,10,11,13,14,15]},{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[1,3,9,15]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,2]},{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[3]}],"pathway":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[1,2,3,9,15]}],"complexes":[],"partners":["MDM2","NPHP5","ATG14","NLRP3","TBK1","NCOA4","TFR1","PXMP4"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9H992","full_name":"E3 ubiquitin-protein ligase MARCHF7","aliases":["Axotrophin","Membrane-associated RING finger protein 7","Membrane-associated RING-CH protein VII","MARCH-VII","RING finger protein 177","RING-type E3 ubiquitin transferase MARCHF7"],"length_aa":704,"mass_kda":78.1,"function":"E3 ubiquitin-protein ligase which may specifically enhance the E2 activity of HIP2. E3 ubiquitin ligases accept ubiquitin from an E2 ubiquitin-conjugating enzyme in the form of a thioester and then directly transfer the ubiquitin to targeted substrates (PubMed:16868077). May be involved in T-cell proliferation by regulating LIF secretion (By similarity). May play a role in lysosome homeostasis (PubMed:31270356). Promotes 'Lys-6', 'Lys-11' and 'Lys-63'-linked mixed polyubiquitination on ATG14 leading to the inhibition of autophagy by impairing the interaction between ATG14 and STX7 (PubMed:37632749). Participates in the dopamine-mediated negative regulation of the NLRP3 inflammasome by promoting its ubiquitination and subsequent degradation (PubMed:25594175)","subcellular_location":"Cytoplasm","url":"https://www.uniprot.org/uniprotkb/Q9H992/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MARCHF7","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1090,"dependency_fraction":0.0009174311926605505},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/MARCHF7","total_profiled":1310},"omim":[{"mim_id":"613334","title":"MEMBRANE-ASSOCIATED RING-CH FINGER PROTEIN 7; MARCHF7","url":"https://www.omim.org/entry/613334"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Plasma membrane","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"},{"location":"Basal body","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/MARCHF7"},"hgnc":{"alias_symbol":["MARCH-VII","RNF177"],"prev_symbol":["AXOT","MARCH7"]},"alphafold":{"accession":"Q9H992","domains":[{"cath_id":"3.30.40.10","chopping":"551-617","consensus_level":"medium","plddt":87.3355,"start":551,"end":617},{"cath_id":"4.10.270","chopping":"620-684","consensus_level":"medium","plddt":84.362,"start":620,"end":684}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H992","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H992-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H992-F1-predicted_aligned_error_v6.png","plddt_mean":50.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MARCHF7","jax_strain_url":"https://www.jax.org/strain/search?query=MARCHF7"},"sequence":{"accession":"Q9H992","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9H992.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9H992/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H992"}},"corpus_meta":[{"pmid":"18410486","id":"PMC_18410486","title":"The ubiquitin E3 ligase MARCH7 is differentially regulated by the deubiquitylating enzymes USP7 and USP9X.","date":"2008","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/18410486","citation_count":74,"is_preprint":false},{"pmid":"29295817","id":"PMC_29295817","title":"Regulation of the Mdm2-p53 pathway by the ubiquitin E3 ligase MARCH7.","date":"2018","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/29295817","citation_count":58,"is_preprint":false},{"pmid":"37337032","id":"PMC_37337032","title":"GAS5 protects against nonalcoholic fatty liver disease via miR-28a-5p/MARCH7/NLRP3 axis-mediated pyroptosis.","date":"2023","source":"Cell death and differentiation","url":"https://pubmed.ncbi.nlm.nih.gov/37337032","citation_count":56,"is_preprint":false},{"pmid":"24905733","id":"PMC_24905733","title":"Axotrophin/MARCH7 acts as an E3 ubiquitin ligase and ubiquitinates tau protein in vitro impairing microtubule binding.","date":"2014","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/24905733","citation_count":50,"is_preprint":false},{"pmid":"29794480","id":"PMC_29794480","title":"Interaction of E3 Ubiquitin Ligase MARCH7 with Long Noncoding RNA MALAT1 and Autophagy-Related Protein ATG7 Promotes Autophagy and Invasion in Ovarian Cancer.","date":"2018","source":"Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/29794480","citation_count":48,"is_preprint":false},{"pmid":"28498859","id":"PMC_28498859","title":"USP9X counteracts differential ubiquitination of NPHP5 by MARCH7 and BBS11 to regulate ciliogenesis.","date":"2017","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28498859","citation_count":35,"is_preprint":false},{"pmid":"31006800","id":"PMC_31006800","title":"miR-27b-3p/MARCH7 regulates invasion and metastasis of endometrial cancer cells through Snail-mediated pathway.","date":"2019","source":"Acta biochimica et biophysica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/31006800","citation_count":29,"is_preprint":false},{"pmid":"23104140","id":"PMC_23104140","title":"MARCH7 E3 ubiquitin ligase is highly expressed in developing spermatids of rats and its possible involvement in head and tail formation.","date":"2012","source":"Histochemistry and cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/23104140","citation_count":25,"is_preprint":false},{"pmid":"25895127","id":"PMC_25895127","title":"Ubiquitin E3 ligase MARCH7 promotes ovarian tumor growth.","date":"2015","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/25895127","citation_count":24,"is_preprint":false},{"pmid":"30008934","id":"PMC_30008934","title":"Ubiquitin E3 Ligase MARCH7 promotes proliferation and invasion of cervical cancer cells through VAV2-RAC1-CDC42 pathway.","date":"2018","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/30008934","citation_count":13,"is_preprint":false},{"pmid":"37632749","id":"PMC_37632749","title":"MARCH7-mediated ubiquitination decreases the solubility of ATG14 to inhibit autophagy.","date":"2023","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/37632749","citation_count":12,"is_preprint":false},{"pmid":"37054851","id":"PMC_37054851","title":"Zebrafish MARCH7 negatively regulates IFN antiviral response by degrading TBK1.","date":"2023","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/37054851","citation_count":10,"is_preprint":false},{"pmid":"20962578","id":"PMC_20962578","title":"A LIF/Nanog axis is revealed in T lymphocytes that lack MARCH-7, a RINGv E3 ligase that regulates the LIF-receptor.","date":"2010","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/20962578","citation_count":8,"is_preprint":false},{"pmid":"37915253","id":"PMC_37915253","title":"Control of ATG14 solubility and autophagy by MARCHF7/MARCH7-mediated ubiquitination.","date":"2023","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/37915253","citation_count":6,"is_preprint":false},{"pmid":"38246482","id":"PMC_38246482","title":"Jianpi Antai formula prevents miscarriage by repressing M1 polarization of decidual macrophages through ubiquitination of NLRP3 mediated by MARCH7.","date":"2024","source":"Journal of ethnopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/38246482","citation_count":6,"is_preprint":false},{"pmid":"36583798","id":"PMC_36583798","title":"Association of MARCH7 with tumor progression and T-cell infiltration in esophageal cancer.","date":"2022","source":"Medical oncology (Northwood, London, England)","url":"https://pubmed.ncbi.nlm.nih.gov/36583798","citation_count":4,"is_preprint":false},{"pmid":"40358464","id":"PMC_40358464","title":"SARS-CoV-2 nsp16 is regulated by host E3 ubiquitin ligases, UBR5 and MARCHF7.","date":"2025","source":"eLife","url":"https://pubmed.ncbi.nlm.nih.gov/40358464","citation_count":3,"is_preprint":false},{"pmid":"41267209","id":"PMC_41267209","title":"Regulation of pexophagy by a novel TBK1-MARCHF7-PXMP4-NBR1 axis in PEX1-depleted HeLa cells.","date":"2025","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/41267209","citation_count":1,"is_preprint":false},{"pmid":"42049018","id":"PMC_42049018","title":"Stabilizing MARCH7 as a ferro-guardian against ferroptosis.","date":"2026","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/42049018","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11525,"output_tokens":4315,"usd":0.04965,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":12205,"output_tokens":5013,"usd":0.093175,"stage2_stop_reason":"end_turn"},"total_usd":0.142825,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2008,\n      \"finding\": \"MARCH7 undergoes autoubiquitylation and is stabilized by two deubiquitylating enzymes in a compartment-specific manner: USP9X deubiquitylates MARCH7 in the cytosol and USP7 deubiquitylates MARCH7 in the nucleus, preventing its proteasomal degradation.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, exogenous expression, subcellular fractionation\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP plus siRNA depletion and overexpression in two compartments, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"18410486\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"MARCH7 physically interacts with Mdm2 and catalyzes K63-linked polyubiquitination of Mdm2, which blocks Mdm2 autoubiquitination and degradation, thereby stabilizing Mdm2 and promoting Mdm2-dependent polyubiquitination and degradation of p53.\",\n      \"method\": \"Co-immunoprecipitation, in vitro ubiquitination assay, ubiquitin linkage-specific analysis, cell-based degradation assays\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro ubiquitination assay plus Co-IP and cell-based epistasis, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"29295817\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Axotrophin/MARCH7 interacts with tau protein via amino acids 552–682 (the RING-variant domain), mono-ubiquitinates tau in vitro, and this ubiquitination diminishes tau's microtubule-binding capacity. In Alzheimer's disease brain, axotrophin loses nuclear localization and associates with neurofibrillary tangles.\",\n      \"method\": \"Yeast two-hybrid, co-immunoprecipitation, co-localization, in vitro ubiquitination assay, microtubule-binding assay\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro ubiquitination with recombinant protein plus Co-IP and functional microtubule-binding assay, single lab multiple orthogonal methods\",\n      \"pmids\": [\"24905733\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"MARCH7 directly binds NPHP5 (nephrocystin-5) and K48-ubiquitinates it, triggering NPHP5 proteasomal degradation and cilia loss. USP9X sequesters MARCH7 away from the centrosome during interphase to protect NPHP5; upon USP9X depletion or inhibition, MARCH7 accumulates at the centrosome and ubiquitinates NPHP5.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, ubiquitin linkage-specific analysis, immunofluorescence/localization, ciliogenesis assays\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP, linkage-specific ubiquitination, localization experiments, and functional ciliogenesis readout, single lab multiple orthogonal methods\",\n      \"pmids\": [\"28498859\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"MARCH7 is expressed in developing spermatids, localizes to the caudal end of the developing acrosome (co-localizing with β-actin/acroplaxome) and developing flagella, and catalyzes K48-linked ubiquitination, suggesting a role in spermiogenesis.\",\n      \"method\": \"Northern blot, in situ hybridization, immunohistochemistry, co-localization, ubiquitin linkage-specific immunostaining\",\n      \"journal\": \"Histochemistry and cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — direct localization with functional-context readout plus K48 ubiquitin activity shown in cells, single lab\",\n      \"pmids\": [\"23104140\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"MARCH7 interacts with TGFβR2 and regulates the TGF-β-Smad2/3 signaling pathway; it also acts as a competing endogenous RNA (ceRNA) to regulate ATG7 expression by competing for miR-200a. MARCH7 silencing inhibits autophagy, invasion, and metastasis of ovarian cancer cells in vitro and in vivo.\",\n      \"method\": \"Co-immunoprecipitation, ChIP assay, luciferase reporter assay, wound healing, Matrigel invasion, orthotopic xenograft\",\n      \"journal\": \"Cellular physiology and biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — Co-IP for TGFβR2 interaction plus multiple functional assays, single lab; ceRNA mechanism is inferential\",\n      \"pmids\": [\"29794480\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"MARCH7 silencing inhibits NF-κB and Wnt/β-catenin pathways in ovarian cancer cells, and MARCH7 overexpression activates both pathways, placing MARCH7 upstream of these oncogenic cascades.\",\n      \"method\": \"siRNA knockdown, ectopic overexpression, western blot pathway analysis, in vivo xenograft\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Weak — epistasis via loss/gain-of-function with pathway readout, single lab, single set of methods\",\n      \"pmids\": [\"25895127\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"MARCH7 interacts with VAV2 and its silencing inhibits the VAV2-RAC1-CDC42 signaling pathway in cervical cancer cells, implicating MARCH7 as an upstream regulator of this GTPase cascade.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, western blot pathway analysis\",\n      \"journal\": \"Oncology letters\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP for interaction plus pathway-level western blots, single lab\",\n      \"pmids\": [\"30008934\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"MARCH7 promotes invasion and metastasis of endometrial cancer cells via a Snail-mediated epithelial-to-mesenchymal transition pathway, and is itself a direct target of miR-27b-3p which suppresses MARCH7 expression.\",\n      \"method\": \"Dual-luciferase reporter assay, transwell invasion assay, xenograft model, western blot\",\n      \"journal\": \"Acta biochimica et biophysica Sinica\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — functional assays with pathway inference, miR targeting confirmed by luciferase, single lab\",\n      \"pmids\": [\"31006800\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"MARCH7 ubiquitinates ATG14 with mixed K6-, K11-, and K63-linked polyubiquitin chains, triggering ATG14 aggregation and insolubility, reducing its interaction with STX17, and thereby inhibiting autophagy flux. MARCH7 depletion decreases aggresome-like induced structures (ALISs).\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay with linkage-specific analysis, solubility fractionation, autophagy flux assay, ALIS quantification\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in-cell ubiquitination assay with linkage mapping plus solubility/interaction and functional autophagy readouts, single lab multiple orthogonal methods\",\n      \"pmids\": [\"37632749\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"MARCH7 interacts with NLRP3 and promotes its proteasomal degradation via ubiquitination; a ubiquitin-ligase-inactive mutant (W589A/I556A) of MARCH7 fails to degrade NLRP3 or inhibit NAFLD. GAS5 lncRNA sequesters miR-28a-5p, which targets MARCH7 mRNA to suppress its translation.\",\n      \"method\": \"Co-immunoprecipitation, proteasome inhibitor rescue, E3-dead mutant analysis, miR target validation, in vivo NAFLD models\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP for NLRP3 interaction, catalytic mutant validation, and in vivo functional rescue, single lab\",\n      \"pmids\": [\"37337032\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Zebrafish MARCH7 negatively regulates type I IFN antiviral responses by interacting with TBK1 and promoting its K48-linked ubiquitination and proteasomal degradation. The C-terminal RING domain of MARCH7 is essential for TBK1 degradation and IFN suppression.\",\n      \"method\": \"Co-immunoprecipitation, ectopic expression, siRNA knockdown, ubiquitin linkage assay, RING domain truncation mutants, IFN promoter reporter assay, viral replication assay\",\n      \"journal\": \"International journal of biological macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus linkage-specific ubiquitination plus domain mutants and functional antiviral readout; zebrafish ortholog, single lab\",\n      \"pmids\": [\"37054851\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"MARCH7 interacts with NLRP3 and mediates its ubiquitination and proteasomal degradation to suppress M1 macrophage polarization and pyroptosis. siMARCH7 transfection reversed the inhibitory effect on NLRP3 inflammasome formation.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, flow cytometry, immunofluorescence (ASC speck), western blot\",\n      \"journal\": \"Journal of ethnopharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — Co-IP for NLRP3 binding, siRNA rescue experiments, multiple functional readouts; corroborates earlier NLRP3 findings, single lab\",\n      \"pmids\": [\"38246482\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MARCHF7 promotes K27-linked ubiquitination of SARS-CoV-2 nsp16, leading to its proteasomal degradation and independently suppressing SARS-CoV-2 replication in cell cultures and in mice.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, proteasome inhibitor rescue, cell-based and in vivo viral replication assays\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus ubiquitin linkage assay plus in vivo replication data, single lab multiple orthogonal methods\",\n      \"pmids\": [\"40358464\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MARCHF7 binds PXMP4 (a peroxisomal membrane protein) and ubiquitinates it at lysine 20 in PEX1-deficient cells, creating a recognition signal for the autophagy receptor NBR1 and driving pexophagy. TBK1 (activated by ROS upon PEX1 depletion) phosphorylates MARCHF7 to modulate this pathway.\",\n      \"method\": \"Functional screening, co-immunoprecipitation, site-directed mutagenesis (K20 mutant), siRNA knockdown, pexophagy flux assay, TBK1 phosphorylation assay\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — binding confirmed by Co-IP, K20 ubiquitination confirmed by mutant rescue, functional pexophagy readout; single lab\",\n      \"pmids\": [\"41267209\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"MARCH7 suppresses ferroptosis via two mechanisms: (1) K48-linked ubiquitination of NCOA4 at Lys42, promoting its proteasomal degradation and reducing the labile iron pool; (2) K63-linked ubiquitination of transferrin receptor 1 (TFR1) at Lys53, restricting TFR1 plasma membrane translocation and inhibiting cellular iron uptake.\",\n      \"method\": \"Multi-omics, in vitro ubiquitination assay, site-directed mutagenesis (K42, K53), membrane fractionation, ferroptosis assays, rodent cardioprotection models\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — in vitro ubiquitination with site-specific mutagenesis at two substrates, membrane translocation assay, and in vivo functional validation; single lab but multiple orthogonal methods and two independent substrates\",\n      \"pmids\": [\"42049018\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"MARCH7 regulates the LIF-receptor in T lymphocytes; T cells lacking MARCH7 are hyper-responsive to activation signals, show elevated LIF activity, and permit Nanog expression during G1/S phase. Addition of LIF to MARCH7-null T cells further induces Nanog ~13-fold.\",\n      \"method\": \"MARCH7 knockout mouse cells, cell cycle synchronization, transcript and protein expression analysis, miRNA profiling\",\n      \"journal\": \"Cell cycle (Georgetown, Tex.)\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — genetic loss-of-function with expression readouts but no direct biochemical mechanism linking MARCH7 to LIF-receptor ubiquitination demonstrated in this paper\",\n      \"pmids\": [\"20962578\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MARCH7 (MARCHF7) is a RING-variant domain E3 ubiquitin ligase that undergoes autoubiquitylation and is stabilized by the deubiquitylases USP9X (cytosol) and USP7 (nucleus); it ubiquitinates a broad range of substrates with distinct linkage types—including K48 on NCOA4 (promoting ferritin degradation/iron release suppression), Mdm2 (K63, stabilizing Mdm2 to destabilize p53), TFR1 (K63, restricting iron uptake), ATG14 (mixed K6/K11/K63, inhibiting autophagy flux), NPHP5 (K48, controlling ciliogenesis), NLRP3 (proteasomal degradation, suppressing pyroptosis), PXMP4 (K20, driving pexophagy), SARS-CoV-2 nsp16 (K27, antiviral), TBK1 (K48, attenuating IFN responses), and tau (mono-ubiquitination, impairing microtubule binding)—thereby acting as a pleiotropic regulator of iron homeostasis/ferroptosis, autophagy, ciliogenesis, innate immunity, and tumor-relevant signaling pathways.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"MARCHF7 (MARCH7/axotrophin) is a RING-variant domain E3 ubiquitin ligase that functions as a pleiotropic post-translational regulator, ubiquitinating diverse substrates with distinct chain linkages to control iron homeostasis, autophagy, ciliogenesis, innate immunity, and oncogenic signaling [#15, #9, #3]. Its own abundance is set by autoubiquitylation counteracted by compartment-specific deubiquitylases—USP9X in the cytosol and USP7 in the nucleus—which protect MARCHF7 from proteasomal degradation [#0]; USP9X further sequesters MARCHF7 away from the centrosome to limit its access to substrates such as NPHP5 [#3]. Catalysis depends on an intact C-terminal RING-variant domain and conserved catalytic residues, as ligase-dead mutants fail to ubiquitinate substrates [#10, #11]. MARCHF7 suppresses ferroptosis through dual substrate targeting: K48-linked ubiquitination of NCOA4 at Lys42 to lower the labile iron pool, and K63-linked ubiquitination of TFR1 at Lys53 to restrict iron uptake [#15]. It controls protein homeostasis and selective autophagy by ubiquitinating ATG14 with mixed K6/K11/K63 chains to inhibit autophagy flux [#9] and by modifying the peroxisomal protein PXMP4 at Lys20 to license NBR1-dependent pexophagy [#14]. In innate immunity, MARCHF7 degrades NLRP3 to suppress inflammasome activation and pyroptosis [#10, #12] and targets viral nsp16 (K27-linked) to restrict SARS-CoV-2 replication [#13]. It also degrades NPHP5 (K48) to govern ciliogenesis [#3] and stabilizes Mdm2 via K63-linked ubiquitination to destabilize p53 [#1]. Beyond these substrate-defined roles, MARCHF7 is repeatedly implicated as an upstream promoter of cancer cell invasion and metastasis.\",\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"Established how MARCHF7 protein levels are controlled, showing it is an autoubiquitylating E3 whose stability is set by compartment-specific deubiquitylases rather than constitutive expression.\",\n      \"evidence\": \"Co-IP, siRNA knockdown, overexpression and subcellular fractionation identifying USP9X (cytosol) and USP7 (nucleus)\",\n      \"pmids\": [\"18410486\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Substrates of MARCHF7 not identified in this study\", \"Functional consequence of compartment-specific stabilization unresolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"First in vivo loss-of-function evidence that MARCHF7 restrains lymphocyte activation, linking it to LIF-receptor signaling and Nanog regulation.\",\n      \"evidence\": \"MARCH7 knockout mouse T cells with cell-cycle synchronization and expression profiling\",\n      \"pmids\": [\"20962578\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct ubiquitination of LIF-receptor demonstrated\", \"Mechanism connecting MARCHF7 to Nanog is correlative\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Tied MARCHF7 to a tissue-specific developmental context, showing localized expression and K48-linked activity in spermiogenesis.\",\n      \"evidence\": \"Northern blot, in situ hybridization, IHC and linkage-specific ubiquitin immunostaining in developing spermatids\",\n      \"pmids\": [\"23104140\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No substrate identified in spermatids\", \"Functional requirement in fertility not tested genetically\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Provided the first defined substrate and a disease-relevant role, showing MARCHF7 mono-ubiquitinates tau via its RING-variant domain to impair microtubule binding.\",\n      \"evidence\": \"Yeast two-hybrid, Co-IP, in vitro ubiquitination and microtubule-binding assays plus Alzheimer brain localization\",\n      \"pmids\": [\"24905733\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Causal contribution to neurofibrillary tangle pathology not established\", \"Loss of nuclear localization in AD brain mechanistically unexplained\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Linked MARCHF7 to organelle biogenesis by identifying NPHP5 as a K48-ubiquitination substrate whose degradation drives cilia loss, and connected this to USP9X-mediated spatial control.\",\n      \"evidence\": \"Reciprocal Co-IP, linkage-specific ubiquitination, centrosomal localization and ciliogenesis assays\",\n      \"pmids\": [\"28498859\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological trigger for MARCHF7 centrosomal recruitment beyond USP9X loss unclear\", \"In vivo ciliopathy relevance not addressed\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Defined a substrate-specific oncogenic mechanism in which MARCHF7 K63-ubiquitinates Mdm2 to stabilize it and thereby promote p53 degradation.\",\n      \"evidence\": \"Co-IP, in vitro ubiquitination with linkage analysis and cell-based degradation/epistasis assays\",\n      \"pmids\": [\"29295817\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis for linkage selectivity not defined\", \"In vivo tumor-suppressor consequences not tested\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Implicated MARCHF7 in cancer cell signaling and autophagy through TGFβR2 interaction and a proposed ceRNA mechanism controlling ATG7.\",\n      \"evidence\": \"Co-IP, ChIP, luciferase reporters and invasion/metastasis assays in ovarian cancer cells and xenografts\",\n      \"pmids\": [\"29794480\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"ceRNA mechanism is inferential, not biochemically demonstrated\", \"No ubiquitination substrate identified in this pathway\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Positioned MARCHF7 upstream of NF-κB and Wnt/β-catenin pathways in ovarian cancer via gain- and loss-of-function epistasis.\",\n      \"evidence\": \"siRNA knockdown, overexpression, pathway western blots and xenografts\",\n      \"pmids\": [\"25895127\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct substrate linking MARCHF7 to these pathways shown\", \"Mechanism of pathway activation unresolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Connected MARCHF7 to GTPase signaling by showing it interacts with VAV2 and supports VAV2-RAC1-CDC42 activity in cervical cancer.\",\n      \"evidence\": \"Single Co-IP plus pathway-level western blots after siRNA knockdown\",\n      \"pmids\": [\"30008934\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single Co-IP without reciprocal validation\", \"No ubiquitination of VAV2 demonstrated\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Extended the oncogenic role to endometrial cancer via Snail-mediated EMT and identified miR-27b-3p as an upstream suppressor of MARCHF7.\",\n      \"evidence\": \"Dual-luciferase, transwell invasion, xenograft and western blot\",\n      \"pmids\": [\"31006800\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"EMT linkage is pathway-level and inferential\", \"No direct enzymatic substrate identified\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Established a direct autophagy-regulatory mechanism in which MARCHF7 ubiquitinates ATG14 with mixed chains to drive its aggregation and block autophagosome-lysosome fusion.\",\n      \"evidence\": \"Co-IP, linkage-specific ubiquitination, solubility fractionation, STX17 interaction and autophagy flux/ALIS assays\",\n      \"pmids\": [\"37632749\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Trigger regulating MARCHF7-ATG14 targeting unknown\", \"Structural basis of mixed-linkage chain assembly undefined\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified MARCHF7 as a negative regulator of the NLRP3 inflammasome by promoting its proteasomal degradation, validated with a catalytically dead mutant.\",\n      \"evidence\": \"Co-IP, proteasome rescue, E3-dead mutant and in vivo NAFLD models\",\n      \"pmids\": [\"37337032\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Linkage type on NLRP3 not mapped\", \"Endogenous regulatory cues for NLRP3 targeting unclear\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined an antiviral innate-immune brake, showing MARCHF7 K48-ubiquitinates TBK1 for degradation and dampens type I IFN responses, with RING domain dependence.\",\n      \"evidence\": \"Co-IP, linkage assay, RING truncation mutants and IFN reporter/viral replication assays in zebrafish\",\n      \"pmids\": [\"37054851\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Demonstrated in zebrafish ortholog; human conservation not confirmed here\", \"Context determining IFN suppression vs antiviral activity unresolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Corroborated NLRP3 as a substrate by showing MARCHF7-mediated degradation suppresses M1 macrophage polarization and pyroptosis.\",\n      \"evidence\": \"Co-IP, siRNA rescue, ASC speck imaging and flow cytometry\",\n      \"pmids\": [\"38246482\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Linkage type and ubiquitination site on NLRP3 not defined\", \"Single-lab functional readouts\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Revealed a direct antiviral effector role, with MARCHF7 K27-ubiquitinating SARS-CoV-2 nsp16 to degrade it and restrict viral replication in vivo.\",\n      \"evidence\": \"Co-IP, ubiquitination/linkage assay, proteasome rescue and cell-based and mouse replication assays\",\n      \"pmids\": [\"40358464\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"nsp16 ubiquitination site not mapped\", \"Reconciliation with IFN-suppressive TBK1 role not addressed\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Connected MARCHF7 to selective peroxisome autophagy by showing K20 ubiquitination of PXMP4 creates an NBR1 recognition signal, with TBK1 phosphorylating MARCHF7 as upstream control.\",\n      \"evidence\": \"Functional screen, Co-IP, K20 mutagenesis, siRNA, pexophagy flux and TBK1 phosphorylation assays\",\n      \"pmids\": [\"41267209\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Phosphosite(s) on MARCHF7 not defined\", \"Generality beyond PEX1-deficient cells untested\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Defined the most fully resolved physiological role, showing MARCHF7 suppresses ferroptosis through site-specific dual ubiquitination of NCOA4 (K48, Lys42) and TFR1 (K63, Lys53) to lower iron availability.\",\n      \"evidence\": \"Multi-omics, in vitro ubiquitination with site-directed mutagenesis, membrane fractionation, ferroptosis assays and rodent cardioprotection models\",\n      \"pmids\": [\"42049018\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Upstream signals coordinating dual-substrate targeting unresolved\", \"How linkage selectivity for the two substrates is achieved structurally unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How MARCHF7 selects among its many substrates and assembles distinct chain linkages (K27/K48/K63/mixed) in different compartments and physiological contexts remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of substrate or linkage selectivity\", \"Mechanism integrating compartment-specific DUBs with substrate access not defined\", \"Apparent opposing immune roles (TBK1 degradation vs antiviral nsp16/NLRP3 control) not mechanistically reconciled\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0061630\", \"supporting_discovery_ids\": [1, 2, 3, 9, 15]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [1, 2, 3, 9, 10, 11, 13, 14, 15]},\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [1, 3, 9, 15]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [1, 2, 3, 9, 15]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"MDM2\", \"NPHP5\", \"ATG14\", \"NLRP3\", \"TBK1\", \"NCOA4\", \"TFR1\", \"PXMP4\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}