{"uniprot":"Q8N2G6","gene":"ZCCHC24","name":"Zinc finger CCHC domain-containing protein 24","organism":"Homo sapiens (Human)","status":"dark","length":241,"sequence":"MSLLSAIDTSAASVYQPAQLLNWVYLSLQDTHQASAFDAFRPEPTAGAAPPELAFGKGRPEQLGSPLHSSYLNSFFQLQRGEALSNSVYKGASPYGSLNNIADGLSSLTEHFSDLTLTSEARKPSKRPPPNYLCHLCFNKGHYIKDCPQARPKGEGLTPYQGKKRCFGEYKCPKCKRKWMSGNSWANMGQECIKCHINVYPHKQRPLEKPDGLDVSDQSKEHPQHLCEKCKVLGYYCRRVQ","function_summary":"A cytoplasm-enriched RNA-binding protein that uses tandem zinc-finger modules to recognize and assemble target transcripts into higher-order ribonucleoprotein complexes. By nucleating cytoplasmic assemblies and recruiting translational repressors through its C-terminal region, it enforces a silenced state on associated mRNAs and thereby dampens protein synthesis. Transient nucleoplasmic pools likely support assembly and handoff of RNP precursors before cytoplasmic concentration and repression.","plain_language":"ZCCHC24 has barely been studied. The model's best guess: A cytoplasm-enriched RNA-binding protein that uses tandem zinc-finger modules to recognize and assemble target transcripts into higher-order ribonucleoprotein complexes. By nucleating cytoplasmic assemblies and recruiting translational repressors through its C-terminal region, it enforces a silenced state on associated mRNAs and thereby dampens protein synthesis.","uniprot_summary":"Binds RNA.","go_terms":{"molecular_function":[{"id":"GO:0003723","label":"RNA binding"}],"biological_process":[{"id":"GO:0017148","label":"negative regulation of translation"}],"cellular_component":[{"id":"GO:0005737","label":"cytoplasm"},{"id":"GO:0005654","label":"nucleoplasm"}]},"interpro":[{"id":"IPR036875","name":"Zinc finger, CCHC-type superfamily","type":"homologous_superfamily","start":123,"end":156},{"id":"IPR025829","name":"Zinc knuckle CX2CX3GHX4C","type":"domain","start":129,"end":149},{"id":"IPR001878","name":"Zinc finger, CCHC-type","type":"domain","start":134,"end":149},{"id":"IPR033446","name":"Zinc finger domain-containing protein 24, 3CxxC-type zinc finger","type":"domain","start":164,"end":206},{"id":"IPR027377","name":"ZAR1/RTP1-5-like, 3CxxC-type zinc finger","type":"domain","start":165,"end":233},{"id":"IPR057809","name":"Zinc finger domain-containing protein 24, C-terminal domain","type":"domain","start":207,"end":241}],"reasoning":"I begin with the InterPro architecture. The central region from residues 123–156 carries IPR036875 (Zinc finger, CCHC-type superfamily), and within it a tight knuckle core is annotated by IPR025829 (Zinc knuckle CX2CX3GHX4C, residues 129–149) and IPR001878 (Zinc finger, CCHC-type, residues 134–149). This tandem of a canonical CCHC knuckle embedded in the broader CCHC superfamily establishes a classical nucleic-acid–binding module that coordinates zinc to stabilize a compact fold specialized for single-stranded nucleic acids. Immediately downstream, residues 164–206 form IPR033446 (Zinc finger domain-containing protein 24, 3CxxC-type zinc finger), and residues 165–233 extend this to IPR027377 (ZAR1/RTP1-5-like, 3CxxC-type zinc finger). The second zinc-finger block suggests multivalent nucleic-acid recognition and oligomerization surfaces typical of RNA-binding scaffolds that assemble ribonucleoprotein particles. The C-terminus is capped by IPR057809 (Zinc finger domain-containing protein 24, C-terminal domain, residues 207–241), a region often used to recruit effector proteins or to tune subcellular partitioning. The ordered layout—an N-terminal CCHC knuckle followed by a second 3CxxC-type finger and a dedicated C-terminal module—creates a bipartite RNA-binding core with an interaction-rich tail.\n\nThis architecture causes RNA affinity and assembly of higher-order ribonucleoprotein complexes, which directly supports GO:0003723 RNA binding as the molecular function. The presence of two distinct zinc-finger modules increases avidity and specificity for structured or AU-rich RNA segments and enables cooperative binding that nucleates cytoplasmic RNP condensates.\n\nFrom this molecular function, the biological role follows: RNA-binding scaffolds that sequester transcripts and recruit translational repressors typically attenuate ribosome initiation and mRNA stability. The tandem zinc fingers and extended 3CxxC-type finger provide the physical basis for translational silencing, aligning with GO:0017148 negative regulation of translation. By concentrating target mRNAs and inhibitory factors into cytoplasmic assemblies, the protein enforces a repressed translational state.\n\nCellular localization is dictated by the same architecture. The absence of transmembrane segments and the propensity of CCHC-containing proteins to form soluble assemblies point to a cytosolic residence, consistent with GO:0005737 cytoplasm. The presence of a defined C-terminal domain and shuttling-prone low-complexity regions also rationalizes transient nuclear access and nucleoplasmic pools (GO:0005654 nucleoplasm), where RNP assembly and RNA surveillance can initiate before export to cytoplasmic granules.\n\nMechanistically, I hypothesize that the protein binds specific mRNA cohorts via its CCHC knuckle and 3CxxC-type finger, then recruits translational repressors and RNA decay factors through its C-terminal domain to build cytoplasmic RNP condensates. Likely partners include poly(A)-binding and cap-binding regulators that gate initiation, as well as stress-granule and mRNA-silencing assemblies. In the nucleus, it may preassemble with RNA-processing factors before concentrating in cytoplasmic repression hubs. Together, these features explain cytoplasmic enrichment with nucleoplasmic transit, RNA-binding–driven assembly, and repression of translation as the emergent function.","category":"dark","control_evaluation":null,"validation_plan":null,"structure":{"source":"AlphaFold DB","pdb":"/structures/AF-Q8N2G6.pdb","alphafold":"https://alphafold.ebi.ac.uk/entry/Q8N2G6"},"links":{"uniprot":"https://www.uniprot.org/uniprotkb/Q8N2G6/entry","atlas":"/p/Q8N2G6"},"provenance":{"model":"BioReason-Pro (ESM3 esm3-sm-open-v1)","source_list":"Pharos Tdark","note":"AI prediction, not experimentally verified"}}