{"uniprot":"Q2M3G4","gene":"SHROOM1","name":"Protein Shroom1","organism":"Homo sapiens (Human)","status":"dark","length":852,"sequence":"MEALGPGGDRASPASSTSSLDLWHLSMRADSAYSSFSAASGGPEPRTQSPGTDLLPYLDWDYVRVVWGGPGPAPPDAALCTSPRPRPAVAARSGPQPTEVPGTPGPLNRQATPLLYALAAEAEAAAQAAEPPSPPASRAAYRQRLQGAQRRVLRETSFQRKELRMSLPARLRPTVPARPPATHPRSASLSHPGGEGEPARSRAPAPGTAGRGPLANQQRKWCFSEPGKLDRVGRGGGPARECLGEACSSSGLPGPEPLEFQHPALAKFEDHEVGWLPETQPQGSMNLDSGSLKLGDAFRPASRSRSASGEVLGSWGGSGGTIPIVQAVPQGAETPRPLFQTKLSRFLPQKEAAVMYPAELPQSSPADSEQRVSETCIVPAWLPSLPDEVFLEEAPLVRMRSPPDPHASQGPPASVHASDQPYGTGLGQRTGQVTVPTEYPLHECPGTAGADDCWQGVNGSVGISRPTSHTPTGTANDNIPTIDPTGLTTNPPTAAESDLLKPVPADALGLSGNDTPGPSHNTALARGTGQPGSRPTWPSQCLEELVQELARLDPSLCDPLASQPSPEPPLGLLDGLIPLAEVRAAMRPACGEAGEEAASTFEPGSYQFSFTQLLPAPREETRLENPATHPVLDQPCGQGLPAPNNSIQGKKVELAARLQKMLQDLHTEQERLQGEAQAWARRQAALEAAVRQACAPQELERFSRFMADLERVLGLLLLLGSRLARVRRALARAASDSDPDEQASLLQRLRLLQRQEEDAKELKEHVARRERAVREVLVRALPVEELRVYCALLAGKAAVLAQQRNLDERIRLLQDQLDAIRDDLGHHAPSPSPARPPGTCPPVQPPFPLLLT","function_summary":"A human cytoskeletal scaffold that organizes actin filament bundles by using a bipartite assembly platform to bind and align cytoskeletal regulators. Through multivalent protein interactions, it concentrates and stabilizes actin-bundling machinery to build higher-order filament arrays within the actin-rich compartment of the cell. Its soluble architecture and lack of catalytic motifs indicate a non-enzymatic organizer that nucleates and consolidates cytoskeletal assemblies to drive filament bundle formation and maintenance.","plain_language":"SHROOM1 has barely been studied. The model's best guess: A human cytoskeletal scaffold that organizes actin filament bundles by using a bipartite assembly platform to bind and align cytoskeletal regulators. Through multivalent protein interactions, it concentrates and stabilizes actin-bundling machinery to build higher-order filament arrays within the actin-rich compartment of the cell.","uniprot_summary":"Involved in actin bundle formation.","go_terms":{"molecular_function":[{"id":"GO:0005515","label":"protein binding"}],"biological_process":[{"id":"GO:0051017","label":"actin filament bundle assembly"}],"cellular_component":[{"id":"GO:0015629","label":"actin cytoskeleton"}]},"interpro":[{"id":"IPR014800","name":"Apx/Shrm Domain 1","type":"domain","start":136,"end":236},{"id":"IPR014799","name":"Apx/Shrm Domain 2","type":"domain","start":543,"end":825},{"id":"IPR027685","name":"Shroom family","type":"family","start":118,"end":829}],"reasoning":"I begin with the InterPro architecture. The polypeptide contains IPR014800 (Apx/Shrm Domain 1, residues 136–236) followed by a long intervening region and then IPR014799 (Apx/Shrm Domain 2, residues 543–825). These two conserved Apx/Shrm modules are embedded within IPR027685 (Shroom family, residues 118–829), indicating a canonical Shroom-family scaffold that spans most of the protein length. The ordered placement of an N-terminal Apx/Shrm domain and a C-terminal Apx/Shrm domain creates a bipartite assembly platform: the N-terminal module nucleates cytoskeletal associations, while the C-terminal module stabilizes higher-order assemblies and adaptor docking. This tandem architecture is characteristic of non-enzymatic cytoskeletal organizers that rely on multivalent protein–protein interactions rather than catalysis.\n\nSuch a scaffolded layout causally supports GO:0005515 protein binding as the molecular function. The absence of catalytic signatures and the presence of two cytoskeleton-associated domains argue that the protein’s primary activity is to bind and organize other proteins—particularly cytoskeletal regulators—through cooperative interfaces provided by the Apx/Shrm modules.\n\nFrom this binding-centric mechanism, the biological role follows. The Shroom-family framework is specialized for assembling and stabilizing higher-order actin structures. By recruiting and aligning actin regulators, the bipartite Apx/Shrm architecture drives GO:0051017 actin filament bundle assembly. This process-level inference is reinforced by the domain arrangement: two cytoskeleton-associated modules separated by flexible linkers typically generate filament crosslinking and bundling by concentrating actin-bundling factors and aligning filaments into stable arrays.\n\nThe cellular context is dictated by the assembly target. Actin filament bundling situates the protein at the GO:0015629 actin cytoskeleton. A soluble, non-membranous scaffold that binds and organizes actin-associated partners will concentrate in cytoplasmic cytoskeletal zones where bundles form and remodel.\n\nMechanistically, I hypothesize that the N-terminal Apx/Shrm Domain 1 initiates cytoskeletal engagement and seeds filament-associated complexes, while the C-terminal Apx/Shrm Domain 2 consolidates these assemblies and recruits accessory adaptors. This bipartite assembly likely positions and stabilizes actin-bundling machinery—such as fascin or filamin—to produce robust bundles. Consequently, the protein is poised to coordinate with small GTPases and actin-nucleation systems to tune bundle formation and maintenance at actin-rich cortical and perinuclear regions.","category":"dark","control_evaluation":null,"validation_plan":null,"structure":{"source":"AlphaFold DB","pdb":"/structures/AF-Q2M3G4.pdb","alphafold":"https://alphafold.ebi.ac.uk/entry/Q2M3G4"},"links":{"uniprot":"https://www.uniprot.org/uniprotkb/Q2M3G4/entry","atlas":"/p/Q2M3G4"},"provenance":{"model":"BioReason-Pro (ESM3 esm3-sm-open-v1)","source_list":"Pharos Tdark","note":"AI prediction, not experimentally verified"}}