{"uniprot":"Q9H019","gene":"MTFR1L","name":"Mitochondrial fission regulator 1-like","organism":"Homo sapiens (Human)","status":"dark","length":292,"sequence":"MSGMEATVTIPIWQNKPHGAARSVVRRIGTNLPLKPCARASFETLPNISDLCLRDVPPVPTLADIAWIAADEEETYARVRSDTRPLRHTWKPSPLIVMQRNASVPNLRGSEERLLALKKPALPALSRTTELQDELSHLRSQIAKIVAADAASASLTPDFLSPGSSNVSSPLPCFGSSFHSTTSFVISDITEETEVEVPELPSVPLLCSASPECCKPEHKAACSSSEEDDCVSLSKASSFADMMGILKDFHRMKQSQDLNRSLLKEEDPAVLISEVLRRKFALKEEDISRKGN","function_summary":"A soluble human adaptor that regulates mitochondrial division. It operates primarily in the cytoplasm as a binding-centric scaffold that assembles and tunes the fission machinery controlling scission of the mitochondrial network. By organizing interaction hubs that feed factors onto mitochondrial surfaces, it shapes mitochondrial morphology and intracellular trafficking. Its cytoplasmic pool likely interfaces with membrane-remodeling systems that also govern Golgi organization, providing a mechanistic bridge between mitochondrial dynamics and broader endomembrane architecture.","plain_language":"MTFR1L has barely been studied. The model's best guess: A soluble human adaptor that regulates mitochondrial division. It operates primarily in the cytoplasm as a binding-centric scaffold that assembles and tunes the fission machinery controlling scission of the mitochondrial network.","uniprot_summary":"Involved in mitochondrial fission and the regulation of mitochondrial morphology.","go_terms":{"molecular_function":[{"id":"GO:0005515","label":"protein binding"}],"biological_process":[{"id":"GO:0007030","label":"Golgi organization"}],"cellular_component":[{"id":"GO:0005737","label":"cytoplasm"}]},"interpro":[{"id":"IPR007972","name":"Mitochondrial fission regulator 1","type":"family","start":2,"end":290}],"reasoning":"I begin with the domain architecture. The sequence is dominated by a single family signature, IPR007972 (Mitochondrial fission regulator 1 family) spanning residues 2–290, essentially covering the full-length polypeptide. A solitary, full-length family domain without embedded catalytic cores or transmembrane segments indicates a soluble, non-enzymatic scaffold/adaptor specialized for mitochondrial dynamics. This architecture typically encodes surfaces for multivalent contacts rather than active sites, which causally supports a binding-centric molecular role consistent with GO:0005515 protein binding.\n\nFrom this binding-centric scaffold, I infer function in mitochondrial fission control. The IPR007972 family is defined by regulators of mitochondrial division, and such regulators commonly tune the assembly and activity of the dynamin-related fission machinery. A soluble adaptor that concentrates at the mitochondrial surface can modulate the recruitment and turnover of fission factors, thereby controlling scission of the mitochondrial network. This binding-driven regulation explains how the protein can influence mitochondrial morphology and trafficking.\n\nThe biological process label GO:0007030 Golgi organization can be reconciled through membrane-trafficking crosstalk. Mitochondrial fission regulators often interface with cytoplasmic scaffolds that coordinate organelle positioning; transient association with Golgi-organizing hubs can arise because mitochondrial dynamics and Golgi ribbon formation are jointly tuned by actin–myosin and membrane-curvature modules. Thus, a cytoplasm-exposed adaptor that governs mitochondrial fission can secondarily impact Golgi organization through shared trafficking machinery.\n\nCellular localization follows from the soluble adaptor nature and the experimentally observed distribution. The absence of transmembrane domains and the presence of a broad family scaffold point to a cytoplasmic pool, aligning with GO:0005737 cytoplasm. Dynamic shuttling between cytoplasm and mitochondria is expected for a fission regulator: cytoplasmic assemblies recruit and prime factors that are delivered to the mitochondrial surface, where curvature and constriction occur.\n\nMechanistically, I hypothesize that the protein forms a cytoplasmic hub that binds and organizes fission machinery. By concentrating dynamin-related GTPases and their adaptors, it promotes productive assembly at mitochondrial constriction sites while buffering off-pathway interactions. Through transient contacts with Golgi-organizing complexes, it coordinates mitochondrial division with broader endomembrane architecture. Likely partners include cytosolic dynamin-family adaptors and mitochondrial fission effectors that together choreograph membrane scission and organelle distribution.","category":"dark","control_evaluation":null,"validation_plan":null,"structure":{"source":"AlphaFold DB","pdb":"/structures/AF-Q9H019.pdb","alphafold":"https://alphafold.ebi.ac.uk/entry/Q9H019"},"links":{"uniprot":"https://www.uniprot.org/uniprotkb/Q9H019/entry","atlas":"/p/Q9H019"},"provenance":{"model":"BioReason-Pro (ESM3 esm3-sm-open-v1)","source_list":"Pharos Tdark","note":"AI prediction, not experimentally verified"}}