Affinage

CDC123

Translation initiation factor eIF2 assembly protein · UniProt O75794

Length
336 aa
Mass
39.1 kDa
Annotated
2026-06-09
20 papers in source corpus 12 papers cited in narrative 12 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

CDC123 (D123/C10orf7) is a dedicated assembly chaperone for the eIF2 heterotrimer and thereby a master regulator of translation initiation and G1 cell cycle progression (PMID:15319434, PMID:23775072). It binds the unassembled eIF2γ subunit—through domain III of eIF2γ contacting domain I of CDC123—without engaging the fully assembled complex, and this interaction is necessary and sufficient to drive eIF2α/β association with eIF2γ; disrupting it abolishes eIF2 assembly, collapses polysomes, and derepresses GCN4 translation (PMID:23775072, PMID:26211610, PMID:37507029). Structurally CDC123 is an ATP-grasp enzyme that binds ATP-Mg²⁺ via conserved residues, and ATP binding—and ATP hydrolysis as an ATPase, not merely ATP-dependent scaffolding—is required for assembly activity and cell viability (PMID:26211610, PMID:37507029, PMID:41461316). Loss or impairment of CDC123 depletes functional eIF2, activates the integrated stress response, and arrests cells in G1 (PMID:15319434, PMID:23775072, PMID:41461316). The activity is conserved from yeast to plants and humans, where in plant immunity an ETI-associated rise in cellular ATP promotes CDC123-mediated eIF2 assembly to reprogram defense translation (PMID:36801014). The CDC123–eIF2γ interface is a druggable target: cannabidiol inhibits this protein–protein interaction, sustaining ISR activation and triggering apoptosis in colorectal cancer cells (PMID:41518300).

Mechanistic history

Synthesis pass · year-by-year structured walk · 8 steps
  1. 1996 Medium

    Established that CDC123 protein abundance is required for cells to traverse G1, the first link between this gene and cell cycle control.

    Evidence Complementation cloning and point-mutation analysis of temperature-sensitive G1-arrested rat fibroblasts with western blot quantification

    PMID:8601400

    Open questions at the time
    • No molecular function or interaction partner identified
    • Mechanism connecting protein level to G1 progression unknown
  2. 2001 Medium

    Showed the G1 arrest arises from accelerated proteasome-dependent turnover of the mutant protein, explaining the abundance defect rather than a loss of intrinsic activity.

    Evidence Cycloheximide chase, overexpression rescue, and proteasome inhibition (lactacystin, MG132) in mutant cell lines

    PMID:10698258 PMID:11699637

    Open questions at the time
    • The proteasome-dependent modification was not ubiquitin and remains unidentified
    • Did not reveal the normal biochemical function of CDC123
  3. 2004 High

    Identified eIF2γ (Gcd11) as the key CDC123 partner and placed it in an essential pathway controlling START, defining its biological context as translation/cell-cycle coupling.

    Evidence Yeast genetics, epistasis, binding-site mapping, and Gcd11 protein quantification, plus CHF1/CHF2 interaction at the Thr-274 site

    PMID:15319434

    Open questions at the time
    • Did not establish how CDC123 controls eIF2γ abundance mechanistically
    • Role of Thr-274 phosphorylation in regulating CDC123 not biochemically defined
  4. 2013 High

    Defined CDC123 as a dedicated eIF2 assembly factor, showing it binds only unassembled eIF2γ via domain III and is required and sufficient for trimer formation.

    Evidence Yeast CDC123 deletion, Co-IP of eIF2 subunits, eIF2γ domain mapping, polysome profiling, GCN4-lacZ reporter, and subunit-overexpression rescue

    PMID:23775072

    Open questions at the time
    • Did not resolve the structural basis of the interaction
    • Enzymatic activity of CDC123 not yet demonstrated
  5. 2015 High

    Provided the structural and enzymatic identity of CDC123 as an ATP-grasp enzyme requiring ATP binding for eIF2 assembly, and mapped the eIF2γD3–domain I interface.

    Evidence X-ray crystallography of apo and eIF2γD3-bound S. pombe Cdc123 with ATP-contact mutagenesis and yeast viability assays; complemented by phylogenetic R2K/RAGNYA classification predicting peptide-ligase activity

    PMID:25976611 PMID:26211610

    Open questions at the time
    • Catalytic role of ATP (binding vs hydrolysis) not resolved in 2015
    • Predicted oligopeptide-tagging ligase activity unvalidated experimentally
  6. 2023 High

    Extended the structural model to the human CDC123–eIF2γD3 complex and demonstrated tight ATP (versus weak ADP) binding required for human protein function, and showed conservation of the assembly role in plant immunity via ATP-coupled translational reprogramming.

    Evidence Crystal structure of human CDC123–eIF2γD3, thermal shift assays, yeast complementation, two-hybrid; plant genetic screen with translational reporter, ATP measurement, and eIF2 assembly assays

    PMID:36801014 PMID:37507029

    Open questions at the time
    • Whether ATP is hydrolyzed during the assembly cycle not directly tested in these studies
    • Regulation of CDC123 by cellular ATP levels in mammalian cells not directly addressed
  7. 2025 High

    Demonstrated CDC123 is a bona fide ATPase whose hydrolytic activity drives eIF2 trimer assembly, and that its impairment activates the ISR through a noncanonical route.

    Evidence ATPase activity assays, eIF2 assembly measurements, translational/polysome assays, ISR markers, and pharmacological/genetic rescue

    PMID:41461316

    Open questions at the time
    • Precise catalytic mechanism and turnover cycle not fully defined
    • Noncanonical ISR activation mechanism not molecularly resolved
  8. 2026 Medium

    Validated the CDC123–eIF2γ interface as a druggable target by showing cannabidiol disrupts the interaction to sustain ISR activation and trigger apoptosis in cancer cells.

    Evidence SDPP target identification, biochemical PPI inhibition assays, ISR and apoptosis readouts in colorectal cancer cell lines

    PMID:41518300

    Open questions at the time
    • CBD binding site on CDC123 not structurally mapped
    • Selectivity and in vivo efficacy not established

Open questions

Synthesis pass · forward-looking unresolved questions
  • How CDC123 activity is physiologically regulated—via Thr-274 phosphorylation, cellular ATP sensing, or checkpoint inputs—and whether it has substrates beyond eIF2 assembly remains unresolved.
  • Function of the conserved Thr-274 phosphosite in mammals uncharacterized
  • Predicted oligopeptide-ligase activity never experimentally demonstrated
  • Connection between the type 2 diabetes-associated locus regulation and CDC123 protein function unestablished

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140657 ATP-dependent activity 3 GO:0044183 protein folding chaperone 2 GO:0016787 hydrolase activity 1
Pathway
R-HSA-1640170 Cell Cycle 2 R-HSA-392499 Metabolism of proteins 2 R-HSA-8953897 Cellular responses to stimuli 1

Evidence

Reading pass · 12 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1996 A single amino acid change in D123 (CDC123) protein causes temperature-sensitive G1-phase arrest in rat fibroblast 3Y1tsD123 cells; the mutant protein is expressed at much lower levels than wild-type, establishing that CDC123 protein quantity is required for cell cycle progression through G1. Functional complementation cloning, point mutation identification by RT-PCR/sequencing, western blot quantification of protein levels Experimental cell research Medium 8601400
1999 Temperature-sensitive G1 arrest in 3Y1tsD123 cells is caused by increased proteasome-mediated degradation of the mutated D123 protein; overexpression of the mutant protein rescues the cell cycle defect by exceeding the degradation capacity. Cycloheximide chase to measure protein stability, cDNA overexpression rescue Cell structure and function Medium 10698258
2001 Mutated D123 protein undergoes a proteasome-dependent modification (increased molecular weight, not ubiquitin) prior to degradation; selective proteasome inhibitors lactacystin and MG132 block this degradation and rescue temperature-sensitive growth arrest. Proteasome inhibitor treatment (lactacystin, MG132), western blot, somatic cell hybridization Cell structure and function Medium 11699637
2004 Yeast Cdc123 (ortholog of mammalian D123/CDC123) physically interacts with Gcd11 (eIF2γ) and controls its abundance; loss of cdc123 depletes Gcd11 (eIF2γ) and causes G1 arrest, placing Cdc123 in an essential pathway for nutritional control of START running parallel to the Tor-Gcn2-Sui2 system. CHF1/CHF2 (RING checkpoint proteins) associate with Cdc123 via the Thr-274 phosphorylatable site and counteract its cell cycle-promoting activity. Yeast genetics (cdc123 mutant isolation, suppressor/epistasis analysis), genetic interaction with CHF1/CHF2, protein interaction mapping (binding-site mutagenesis), western blot of Gcd11 levels The Journal of biological chemistry High 15319434
2013 Cdc123 functions as a dedicated assembly factor for the eIF2 heterotrimer: it binds unassembled eIF2γ (but not the assembled eIF2 complex) via the C-terminal domain III of eIF2γ; this interaction is necessary and sufficient for eIF2α/β association with eIF2γ. Mutations disrupting Cdc123–eIF2γ binding abolish eIF2 assembly and cause loss of eIF2 activity (reduced polysomes, elevated GCN4 translation). High-level overexpression of all three eIF2 subunits rescues an otherwise lethal cdc123 deletion. Yeast CDC123 deletion, polysome profiling, GCN4-lacZ reporter, co-immunoprecipitation of eIF2 subunits, domain mapping with eIF2γ truncations, rescue by subunit overexpression The Journal of biological chemistry High 23775072
2015 Crystal structure of S. pombe Cdc123 alone and in complex with domain III of S. cerevisiae eIF2γ shows Cdc123 is an ATP-grasp enzyme; it binds ATP-Mg²⁺ via conserved residues, and mutagenesis of those residues abolishes eIF2 assembly and cell viability, demonstrating that ATP binding is required for Cdc123 function. Domain III of eIF2γ binds domain I of Cdc123. X-ray crystallography (structures of apo and eIF2γD3-bound Cdc123), site-directed mutagenesis of ATP-contact residues, yeast viability assays, biochemical binding assays Structure High 26211610
2015 Computational and phylogenetic analysis classifies CDC123 as a novel clade (R2K) of ATP-grasp enzymes distinguished by a RAGNYA domain with two conserved lysines; the enzymatic classification predicts CDC123 may function as an ATP-dependent protein-peptide ligase that modifies substrates by oligopeptide tagging. Bioinformatic sequence/structure analysis integrated with published biochemical data Biology direct Low 25976611
2023 Crystal structure of human CDC123 bound to domain 3 of human eIF2γ shows that eIF2γD3 contacts domain 1 of Cdc123, and the long C-terminal region of human Cdc123 links the ATP-binding site to the eIF2γ-binding site. Thermal shift assay shows ATP binds Cdc123 tightly whereas ADP affinity is much lower. Yeast viability experiments, western blot, and two-hybrid assays confirm that ATP binding is required for human CDC123 function in eIF2 assembly. X-ray crystallography of human CDC123–eIF2γD3 complex, thermal shift assay, yeast complementation viability assay, western blot, yeast two-hybrid Journal of structural biology High 37507029
2023 In plants, CDC123 is required for ETI (effector-triggered immunity)-associated global translational induction; an increase in cellular ATP concentration during ETI facilitates CDC123-mediated eIF2 complex assembly, linking NLR-dependent ATP elevation to translational reprogramming in defense. Genetic screen with translational reporter, CDC123 loss-of-function phenotyping, ATP measurement, eIF2 assembly assays Cell host & microbe Medium 36801014
2025 Human CDC123 acts as an ATPase (not merely an ATP-binding scaffold) to drive eIF2 heterotrimer assembly; impaired CDC123 activity reduces eIF2 complex assembly and activates the integrated stress response (ISR) through a noncanonical mechanism, altering global and mRNA-specific translation. Pharmacological or genetic rescue strategies can correct the translational defects caused by impaired CDC123. ATPase activity assays, eIF2 complex assembly measurements, translational assays (polysome profiling or reporters), ISR marker readouts, pharmacological and genetic rescue The Journal of biological chemistry High 41461316
2026 Cannabidiol (CBD) was identified as an inhibitor of the CDC123–eIF2γ protein-protein interaction; disruption of the CDC123–eIF2γ complex by CBD leads to sustained activation of the integrated stress response and apoptosis in colorectal cancer cells, validating the CDC123–eIF2γ interface as a druggable target. Stability- and degradation-based proteome profiling (SDPP) for target ID, biochemical PPI inhibition assays, ISR activation assays, cell viability/apoptosis assays in CRC cell lines Journal of the American Chemical Society Medium 41518300
2014 A type 2 diabetes-associated SNP (rs11257655) in the CDC123/CAMK1D locus shows allele-specific enhancer activity in insulinoma and hepatocellular carcinoma cells; the risk allele T binds FOXA1 and FOXA2 with higher affinity than the non-risk allele C, as shown by EMSA, supershift, and allele-specific ChIP in human islets, suggesting that altered FOXA1/FOXA2 binding at this locus modulates CDC123 transcription. Luciferase reporter enhancer assays, EMSA, supershift assays, allele-specific ChIP in human islets PLoS genetics Medium 25211022

Source papers

Stage 0 corpus · 20 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2008 Association testing of novel type 2 diabetes risk alleles in the JAZF1, CDC123/CAMK1D, TSPAN8, THADA, ADAMTS9, and NOTCH2 loci with insulin release, insulin sensitivity, and obesity in a population-based sample of 4,516 glucose-tolerant middle-aged Danes. Diabetes 121 18567820
2009 Gene variants in the novel type 2 diabetes loci CDC123/CAMK1D, THADA, ADAMTS9, BCL11A, and MTNR1B affect different aspects of pancreatic beta-cell function. Diabetes 106 19833888
2000 Mutation of a conserved residue (D123) required for oligomerization of human immunodeficiency virus type 1 Nef protein abolishes interaction with human thioesterase and results in impairment of Nef biological functions. Journal of virology 90 10799608
2014 Identification of a regulatory variant that binds FOXA1 and FOXA2 at the CDC123/CAMK1D type 2 diabetes GWAS locus. PLoS genetics 74 25211022
2004 Cdc123 and checkpoint forkhead associated with RING proteins control the cell cycle by controlling eIF2gamma abundance. The Journal of biological chemistry 44 15319434
2023 Global translational induction during NLR-mediated immunity in plants is dynamically regulated by CDC123, an ATP-sensitive protein. Cell host & microbe 32 36801014
2013 Translation initiation requires cell division cycle 123 (Cdc123) to facilitate biogenesis of the eukaryotic initiation factor 2 (eIF2). The Journal of biological chemistry 32 23775072
2011 Genetic variants at CDC123/CAMK1D and SPRY2 are associated with susceptibility to type 2 diabetes in the Japanese population. Diabetologia 27 21909839
2015 Cdc123, a Cell Cycle Regulator Needed for eIF2 Assembly, Is an ATP-Grasp Protein with Unique Features. Structure (London, England : 1993) 24 26211610
2017 CDC123/CAMK1D gene rs12779790 polymorphism and rs10811661 polymorphism upstream of the CDKN2A/2B gene in women with gestational diabetes. Journal of perinatology : official journal of the California Perinatal Association 17 28079868
1996 An amino acid change in novel protein D123 is responsible for temperature-sensitive G1-phase arrest in a mutant of rat fibroblast line 3Y1. Experimental cell research 16 8601400
2015 The effect of D123 wheat as a companion crop on soil enzyme activities, microbial biomass and microbial communities in the rhizosphere of watermelon. Frontiers in microbiology 14 26388851
2015 The eukaryotic translation initiation regulator CDC123 defines a divergent clade of ATP-grasp enzymes with a predicted role in novel protein modifications. Biology direct 12 25976611
1999 Extensive degradation of mutant-type D123 protein is responsible for temperature-sensitive proliferation inhibition in 3Y1tsD123 cells. Cell structure and function 5 10698258
2001 Reversion of temperature-sensitive mutation by inhibition of proteasome-mediated degradation of mutated D123 protein. Cell structure and function 4 11699637
2023 Binding of human Cdc123 to eIF2γ. Journal of structural biology 2 37507029
1998 Expression study on D123 gene product: evidence for high positivity in testis. Experimental cell research 2 9683532
2023 CDC123 promotes Hepatocellular Carcinoma malignant progression by regulating CDKAL1. Pathology, research and practice 1 38237400
2026 Stability and Degradation-based Proteome Profiling Reveals Cannabidiol as a Promising CDC123-eIF2γ Inhibitor for Colorectal Cancer Therapy. Journal of the American Chemical Society 0 41518300
2025 CDC123 is an ATPase that modulates mRNA translation and the integrated stress response by regulating eIF2 complex assembly. The Journal of biological chemistry 0 41461316

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