{"uniprot":"Q5T1N1","gene":"AKNAD1","name":"Protein AKNAD1","organism":"Homo sapiens (Human)","status":"dark","length":836,"sequence":"MDEADFSEHTTYKQEDLPYDGDLSQIKIGNDYSFTSKKDGLEVLNQIIFIADDPQEKAMHSETCGNTAVTIPLGKITENAANKKDEKEKQCTAALHIPANEGDASKSSISDILLHHLSKEPFLRGQGIDCETLPEISNADSFEEEAIIKSIISCYNKNSWPKEQTPELTDQLNPKRDGENSNKPGSATTTEENTSDLEGPVAAGDSSHQENVNVLTKTKGPGDKQKSYQGQSPQKQQTEKANSGNTFKYGQGQVHYQLPDFSKIAPKVKIPKNKIINKPLAIAKQASFSSKSRDKPTLVQDSLETTPESNCVEKQHQEQKGKITEPSQQIQMEPIVHIHQELLTGIESEASLSKLSPTSQKGTSSSSSYIFQKISQGKQMCQKLKEQTDQLKTKVQEFSKRIKQDSPYHLQDKKLVLEKLQGHLELLEQNFLATKDKHLTLQQQVHKHESTIVGDFDPERKVEGEIFKLEMLLEDVKEKMDESKYTSAPSLPVSSPVTLDDLASTFSSLSNEIPKEHPGHPSGPRGSGGSEVTGTPQGGPQEAPNEELCELAPQTYLNGHYGDAAAQNKPDQVAMRLSSNSGEDPNGTPRRQDCAEMTAPSPSCAFCRRLLEWKQNVEKKGHGRINCGRFSIVLHEKAPHSDSTPNSDTGHSFCSDSGTEMQSNKCQDCGTKIPTSRRACRKEPTKEFHYRYNTPGQNYSNHSKRGAFVQPHSLDESKNSSPSFLKPKRICSQRVNSKSFKGEHEPTPGKKKLQAFMTYSSDPATPSPHFYSCRISGSKSLCDFDSTEEIKSEILNSALDHALRTATILKETTDQMIKTIAEDLAKAQRWRNRLKY","function_summary":"A human cytoskeletal organizer that assembles multivalent complexes to control microtubule nucleation and spindle formation. It concentrates at centrosomes and centrioles to seed and stabilize microtubule arrays and tracks along spindle fibers during mitosis, while transiently anchoring to the cell cortex at the plasma membrane. Through scaffolded protein interactions, it also enhances transcriptional programs associated with RNA polymerase II, coupling cytoskeletal state to gene expression. Its mechanism relies on a central interaction module that targets centrosomal and spindle structures and recruits coactivator machinery in the cytosol and nucleocytoplasmic space.","plain_language":"AKNAD1 has barely been studied. The model's best guess: A human cytoskeletal organizer that assembles multivalent complexes to control microtubule nucleation and spindle formation. It concentrates at centrosomes and centrioles to seed and stabilize microtubule arrays and tracks along spindle fibers during mitosis, while transiently anchoring to the cell cortex at the plasma membrane.","uniprot_summary":"Involved in microtubule organization and spindle formation.","go_terms":{"molecular_function":[{"id":"GO:0005515","label":"protein binding"}],"biological_process":[{"id":"GO:0045944","label":"positive regulation of transcription by RNA polymerase II"}],"cellular_component":[{"id":"GO:0005829","label":"cytosol"},{"id":"GO:0005814","label":"centriole"},{"id":"GO:0005886","label":"plasma membrane"},{"id":"GO:0005813","label":"centrosome"},{"id":"GO:0005876","label":"spindle microtubule"}]},"interpro":[{"id":"IPR022150","name":"AKNA domain","type":"domain","start":327,"end":421},{"id":"IPR052655","name":"Microtubule organization protein AKNA/AKNAD1","type":"family","start":1,"end":524}],"reasoning":"I begin with the InterPro architecture. The sequence is assigned to IPR052655 (Microtubule organization protein AKNA/AKNAD1 family) spanning residues 1–524, indicating a full-length member of a cytoskeletal organizer family rather than a localized enzyme. Embedded within this scaffold, residues 327–421 form IPR022150 (AKNA domain), a conserved module characteristic of AKNA/AKNAD1 proteins that mediates higher-order assembly and target recognition. The ordered layout—an N-to-C terminal family scaffold (IPR052655) that houses a central AKNA domain (IPR022150)—creates a multivalent platform optimized for macromolecular assembly rather than catalysis. Such architectures typically drive function through avid protein-protein interactions, supporting a primary molecular function of protein binding (GO:0005515).\n\nFrom this binding-centric core, I infer roles at the heart of microtubule control. The AKNA family signature dictates participation in microtubule organization and spindle formation. This explains occupancy of the cytosol (GO:0005829) and direct association with spindle microtubules (GO:0005876). The same scaffold rationalizes localization to the centrosome (GO:0005813) and centriole (GO:0005814), where microtubule nucleation is orchestrated. The presence at the plasma membrane (GO:0005886) follows from the AKNA domain’s propensity to tether cytoskeletal assemblies to cortical sites, coupling membrane-proximal cues to spindle positioning.\n\nThis binding-driven assembly function extends into transcriptional control. Although the domain architecture lacks canonical DNA-binding motifs, AKNA-family scaffolds can act as transcriptional coactivators by recruiting chromatin and transcriptional machinery to RNA polymerase II-regulated loci. This provides a mechanistic route to positive regulation of transcription by RNA polymerase II (GO:0045944): the scaffold nucleates coactivator complexes that enhance transcriptional output during cell-cycle–coupled states.\n\nThe biological process linkage from microtubule organization to transcription suggests a unified mechanism: during mitosis and spindle assembly, the scaffold concentrates at centrosomes and spindle microtubules, stabilizing microtubule arrays and positioning the spindle. In parallel or subsequently, it engages nuclear or nucleocytoplasmic pathways to boost expression of genes that reinforce cytoskeletal dynamics and cell-cycle progression—captured by GO:0045944.\n\nCellular localization follows directly from these assemblies. The protein operates in the cytosol and at centrosomes/centrioles to seed microtubule nucleation and organization, tracks along spindle microtubules during mitosis, and transiently associates with the plasma membrane where cortical anchoring of the spindle occurs. These placements align with GO:0005829 cytosol, GO:0005813 centrosome, GO:0005814 centriole, GO:0005876 spindle microtubule, and GO:0005886 plasma membrane.\n\nA coherent mechanistic hypothesis emerges: the N-terminal family scaffold (IPR052655) confers overall assembly competence, while the central AKNA domain (IPR022150) provides high-affinity docking surfaces that concentrate the protein at centrosomes and spindle structures. There, it binds and stabilizes microtubule-associated factors, promoting robust spindle formation. Outside of mitosis, or via shuttling, the same scaffold recruits transcriptional coactivators to RNA polymerase II pathways, coupling cytoskeletal state to gene expression. Likely interaction partners include centrosomal organizers (CEP proteins), γ-tubulin ring complex components, and spindle-stabilizing factors; together they explain the observed cytoskeletal and transcriptional regulatory behaviors.","category":"dark","control_evaluation":null,"validation_plan":null,"structure":{"source":"AlphaFold DB","pdb":"/structures/AF-Q5T1N1.pdb","alphafold":"https://alphafold.ebi.ac.uk/entry/Q5T1N1"},"links":{"uniprot":"https://www.uniprot.org/uniprotkb/Q5T1N1/entry","atlas":"/p/Q5T1N1"},"provenance":{"model":"BioReason-Pro (ESM3 esm3-sm-open-v1)","source_list":"Pharos Tdark","note":"AI prediction, not experimentally verified"}}