Affinage

INTS8

Integrator complex subunit 8 · UniProt Q75QN2

Round 2 corrected
Length
995 aa
Mass
113.1 kDa
Annotated
2026-04-28
60 papers in source corpus 11 papers cited in narrative 12 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

INTS8 is a scaffolding subunit of the Integrator complex that is essential for snRNA 3′-end processing, transcriptional pausing enforcement, and neurodevelopmental gene regulation. Within Integrator, INTS8 forms a discrete module with INTS5 and is required for recruiting PP2A into the INTAC (Integrator–PP2A) assembly, which dephosphorylates RNA Pol II CTD at Ser2/5/7 and the elongation factor Spt5 to oppose CDK9-driven pause release (PMID:32966759, PMID:33243860, PMID:33548203). Loss of INTS8 causes genome-wide Pol II hyperphosphorylation, premature entry into productive elongation, and uncontrolled release of transcriptionally incompetent Pol II into gene bodies, functioning in parallel with CRL3-ARMC5 as a quality-control checkpoint before elongation licensing (PMID:37831607, PMID:39667934). Biallelic INTS8 mutations in humans cause a neurodevelopmental syndrome with severe developmental delay and periventricular nodular heterotopia, linked to impaired snRNA processing and widespread transcriptional dysregulation (PMID:28542170).

Mechanistic history

Synthesis pass · year-by-year structured walk · 8 steps
  1. 2005 High

    Identifying INTS8 as a subunit of the Integrator complex established the first molecular framework for how snRNA 3′-end processing is coupled to the Pol II CTD.

    Evidence Affinity purification and mass spectrometry of CTD-associated complexes in human cells with in vitro snRNA processing assay

    PMID:16239144

    Open questions at the time
    • Specific contribution of INTS8 versus other subunits to snRNA processing not resolved
    • No structural information on subunit arrangement
  2. 2017 High

    Discovery that biallelic INTS8 mutations cause a human neurodevelopmental disorder demonstrated that INTS8 is essential for complex stability, snRNA maturation, and neural development in vivo.

    Evidence Patient genetics with CRISPR modeling of mutations in P19 cells, RT-PCR for unprocessed snRNAs, transcriptome analysis

    PMID:28542170

    Open questions at the time
    • Mechanism by which INTS8 loss leads to neuronal migration defects (heterotopia) not defined
    • Whether transcriptional versus snRNA processing defects drive the phenotype unclear
  3. 2019 High

    Drosophila genetic studies revealed that INTS8 maintains neural progenitor identity by preventing dedifferentiation of intermediate progenitors into stem cells, linking Integrator function to a specific cell-fate decision during neurogenesis.

    Evidence Loss-of-function mutants, INP-specific RNAi knockdown, DamID for INTS5 binding sites, genetic epistasis with earmuff

    PMID:31018143

    Open questions at the time
    • Whether the progenitor-maintenance role is conserved in mammals not tested
    • Direct transcriptional targets of INTS8 in INPs beyond erm unknown
  4. 2020 High

    Two landmark studies established the phosphatase function of Integrator: INTS8 is required for PP2A recruitment into the INTAC assembly, which dephosphorylates Pol II CTD and Spt5 to enforce transcriptional pausing, and the 3.5-Å cryo-EM structure revealed a cruciform architecture with phosphatase and endonuclease modules on opposite sides.

    Evidence siRNA knockdown with Co-IP/ChIP-seq/GRO-seq (functional); cryo-EM at 3.5 Å with in vitro phosphatase assays (structural)

    PMID:32966759 PMID:33243860

    Open questions at the time
    • How INTS8 physically bridges PP2A to the complex at the residue level not fully resolved
    • Whether phosphatase and endonuclease activities are always coordinated or separable in vivo unclear
  5. 2021 High

    Biochemical and structural dissection showed that INTS5 and INTS8 form a distinct modular unit, and cryo-EM of the pretermination complex on paused Pol II revealed how Integrator excludes elongation factors SPT6 and PAF1C while positioning PP2A for CTD dephosphorylation.

    Evidence Cryo-EM, co-expression pulldowns for INTS5/8 module; cryo-EM of Integrator–PP2A–Pol II–DSIF–NELF complex

    PMID:33548203 PMID:34762484

    Open questions at the time
    • Dynamic transitions between paused and terminated states not captured
    • Stoichiometry and stability of INTS5/8 module relative to full complex in vivo not quantified
  6. 2023 Medium

    Domain-truncation rescue experiments using dTAG-mediated INTS8 degradation confirmed that the N-terminal domain of INTS8 is specifically required for INTAC phosphatase function, as its removal causes genome-wide Pol II hyperphosphorylation.

    Evidence dTAG degradation with ectopic INTS8-ΔN rescue in DLD-1 cells, ChIP and phospho-western blot

    PMID:37831607

    Open questions at the time
    • Structural basis of N-terminal domain interaction with PP2A not resolved at atomic level
    • Whether N-terminal truncation also impairs endonuclease activity not addressed
  7. 2024 High

    Multi-state cryo-EM structures captured INTAC in free-inactive, pre-termination, and post-termination conformations, revealing autoinhibition (INTS6 blocks PP2A active site in the free state) and post-termination mechanisms (INTS3–SOSS prevent Pol II rebinding), contextualizing INTS8's scaffolding role across the entire termination cycle.

    Evidence Cryo-EM of three distinct INTAC functional states with biochemical reconstitution

    PMID:38570683

    Open questions at the time
    • How the transition between inactive and active conformations is triggered in vivo remains unclear
    • Role of INTS8 in conformational switching not individually delineated
  8. 2024 High

    Genetic epistasis showed that INTS8 and CRL3-ARMC5 operate as parallel quality-control pathways preventing release of excess or incompetent Pol II into gene bodies, with combined loss being synthetically detrimental to cell growth.

    Evidence CRISPR knockout and degron-based depletion with RNA-seq, ChIP-seq, and growth assays

    PMID:39667934

    Open questions at the time
    • Whether INTS8 and ARMC5 converge on the same Pol II population or act on distinct subsets unknown
    • Downstream consequences for mRNA quality and translation fidelity not explored

Open questions

Synthesis pass · forward-looking unresolved questions
  • It remains unresolved how the INTS5/INTS8 module structurally bridges PP2A recruitment, whether the phosphatase and endonuclease activities of Integrator are independently regulated at specific gene classes, and what the precise molecular pathomechanism is that connects INTS8 loss to neuronal migration defects in human cortical development.
  • Atomic-resolution contacts between INTS8 N-terminal domain and PP2A-AC not mapped
  • In vivo dissection of phosphatase vs endonuclease contributions to neurodevelopmental phenotype lacking
  • Whether INTS8 has Integrator-independent functions not explored

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 4 GO:0098772 molecular function regulator activity 3
Localization
GO:0005654 nucleoplasm 3 GO:0005634 nucleus 2
Pathway
R-HSA-74160 Gene expression (Transcription) 4 R-HSA-1266738 Developmental Biology 2 R-HSA-8953854 Metabolism of RNA 2
Partners
INTS11INTS4INTS5INTS6INTS9PPP2CAPPP2R1A
Complex memberships
INTAC (Integrator-PP2A)INTS5/INTS8 moduleIntegrator complex

Evidence

Reading pass · 12 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2005 INTS8 (Integrator subunit 8) is a component of the Integrator complex, a multiprotein assembly that associates with the C-terminal repeat domain (CTD) of RNA polymerase II and mediates 3'-end processing of small nuclear RNAs (snRNAs). The complex was identified by biochemical purification and contains at least 12 novel subunits. Affinity purification, mass spectrometry, Co-IP, in vitro snRNA 3'-end processing assay Cell High 16239144
2017 Biallelic INTS8 mutations in humans cause a neurodevelopmental syndrome featuring severe developmental delay and neuronal migration defects (periventricular nodular heterotopia). A 9-bp deletion mutation disrupts Integrator complex stability, while a missense mutation creates an alternative splice site producing an unstable mRNA. Patient cells show increased levels of unprocessed snRNA, confirming INTS8's role in snRNA 3'-end maturation, and display widespread disruptions in gene expression and RNA processing. Introduction of the deletion mutation in P19 cells via genome editing alters gene expression during retinoic acid-induced neural differentiation. Patient genetics, genome editing (CRISPR), RT-PCR for unprocessed snRNA, transcriptome analysis, western blot for complex stability PLoS genetics High 28542170
2019 In Drosophila, loss of intS8 (along with intS5 and intS1) causes dedifferentiation of intermediate neural progenitors (INPs) back into type II neuroblasts (neural stem cells). INP-specific knockdown of intS8 produces excess type II neuroblasts. Cell-type-specific DamID identified IntS5-binding sites in INPs including the zinc-finger transcription factor earmuff (erm); erm expression is lost in intS5 and intS8 mutant neuroblast lineages, and intS8 genetically interacts with erm to suppress ectopic neuroblast formation. Drosophila genetics (loss-of-function mutants, RNAi knockdown), cell-type-specific DamID, immunostaining, genetic epistasis Cell reports High 31018143
2020 Integrator subunit 8 (INTS8) is critical for transcription repression and is required for association of the Integrator complex with protein phosphatase 2A (PP2A). Integrator-bound PP2A dephosphorylates the RNA Pol II CTD and Spt5, preventing the transition to productive elongation. Blocking PP2A association with Integrator (via INTS8 perturbation) stimulates pause release and increases gene activity, revealing a phosphatase catalytic function in Integrator-mediated premature transcription termination. siRNA knockdown, Co-IP, ChIP-seq, GRO-seq, phospho-western blot, mass spectrometry Molecular cell High 32966759
2020 INTS8 is part of the INTAC complex (Integrator-PP2A), whose 3.5-Å cryo-EM structure reveals nine Integrator subunits and the PP2A core enzyme (PP2A-AC) assembling into a cruciform-shaped scaffold with phosphatase and endonuclease modules on opposite sides. INTAC dephosphorylates the RNA Pol II CTD at serine-2, -5, and -7, regulating transcription. Cryo-EM structure determination (3.5 Å), biochemical reconstitution, in vitro phosphatase assay Science (New York, N.Y.) High 33243860
2021 INTS5 and INTS8 form a separable subcomplex within Integrator. Biochemical characterization demonstrates that INTS5/8 constitutes a distinct structural module of the Integrator complex, separate from the catalytic core (INTS4/9/11) and the INTS10/13/14 module. Cryo-EM, biochemical fractionation, co-expression and pulldown assays Molecular cell High 33548203
2021 Cryo-EM structure of the Integrator-PP2A pretermination complex bound to paused Pol II shows that Integrator binds Pol II and pausing factors DSIF and NELF, excludes elongation factors SPT6 and PAF1C, and positions PP2A to counteract Pol II phosphorylation. INTS8 participates in the central scaffold assembly that organizes these functional interactions. Cryo-EM structure determination, biochemical reconstitution Science (New York, N.Y.) High 34762484
2019 INTS8 knockdown in hepatocellular carcinoma (HCC) cell lines reduces invasion and migration, decreases metastatic nodules in a lung metastasis in vivo model, increases epithelial markers (E-cadherin), and decreases mesenchymal markers (N-cadherin, vimentin) with concomitant downregulation of SMAD4. Pretreatment with TGF-β1 partially prevents these effects, placing INTS8 upstream of the TGF-β/SMAD4 axis in regulating EMT. siRNA knockdown, migration/invasion assays, in vivo lung metastasis model, western blot, RT-qPCR, TGF-β1 rescue experiment Cancer management and research Medium 30881114
2023 A protocol using INTS8 degradation-tag (dTAG) combined with ectopic expression of N-terminally truncated INTS8 (INTS8-ΔN) demonstrates that disruption of INTS8 phosphatase module activity induces genome-wide RNA Pol II hyperphosphorylation, confirming that the N-terminal domain of INTS8 is essential for INTAC phosphatase function at Pol II. dTAG degradation system, ectopic truncation rescue, ChIP and phospho-western validation in DLD-1 cells STAR protocols Medium 37831607
2024 INTS8 acts as a gatekeeper preventing release of excess RNA Pol II molecules into gene bodies. Combined loss of ARMC5 (the CRL3 ubiquitin ligase substrate receptor) and INTS8 causes uncontrolled release of transcriptionally incompetent RNA Pol II into early elongation, with detrimental effects on cell growth. This places INTS8/Integrator and CRL3ARMC5 as two parallel pathways that together monitor quantity and quality of transcription complexes before elongation licensing. CRISPR knockout, degron-based depletion, RNA-seq, ChIP-seq, cell growth assays, genetic epistasis Molecular cell High 39667934
2024 Three cryo-EM structures of the complete Integrator-PP2A complex in pre-termination, post-termination, and free inactive states reveal that INTS8 contributes to the central scaffold. The free complex adopts an inactive closed conformation in which INTS6 blocks the PP2A active site. INTS3 and SOSS factors (visible in the post-termination state) prevent Pol II rebinding after termination. The scorpion-tail INTS10-INTS13-INTS14-INTS15 module may use its 'sting' to open the DSIF DNA clamp to facilitate termination. Cryo-EM (multiple states), biochemical reconstitution Nature High 38570683
2024 A patient-specific in-frame deletion in INTS8 that prevents its association with the Integrator complex causes a global increase in nascent transcription and precocious expression of neuronal genes in neural progenitor cells, leading to premature differentiation and failure to sustain a progenitor pool during cortical development. Targeted BRD4 degradation (to attenuate Pol II pause-release) reverts neuronal gene activation and prevents premature progenitor loss, genetically placing INTS8 upstream of BRD4-mediated pause-release control. Patient-derived cell model, genome editing to introduce patient mutation, nascent transcription sequencing, BRD4 degrader rescue, cortical organoid/differentiation assays bioRxivpreprint Medium

Source papers

Stage 0 corpus · 60 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2006 Global, in vivo, and site-specific phosphorylation dynamics in signaling networks. Cell 2861 17081983
2002 Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences. Proceedings of the National Academy of Sciences of the United States of America 1479 12477932
2017 Architecture of the human interactome defines protein communities and disease networks. Nature 1085 28514442
2015 A human interactome in three quantitative dimensions organized by stoichiometries and abundances. Cell 1015 26496610
2003 Complete sequencing and characterization of 21,243 full-length human cDNAs. Nature genetics 754 14702039
2021 Dual proteome-scale networks reveal cell-specific remodeling of the human interactome. Cell 705 33961781
2012 A census of human soluble protein complexes. Cell 689 22939629
2011 Phylogenetic-based propagation of functional annotations within the Gene Ontology consortium. Briefings in bioinformatics 656 21873635
2021 Multilevel proteomics reveals host perturbations by SARS-CoV-2 and SARS-CoV. Nature 532 33845483
1994 Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides. Gene 492 8125298
2005 Integrator, a multiprotein mediator of small nuclear RNA processing, associates with the C-terminal repeat of RNA polymerase II. Cell 443 16239144
2004 The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). Genome research 438 15489334
2022 OpenCell: Endogenous tagging for the cartography of human cellular organization. Science (New York, N.Y.) 432 35271311
2005 Diversification of transcriptional modulation: large-scale identification and characterization of putative alternative promoters of human genes. Genome research 409 16344560
2015 Panorama of ancient metazoan macromolecular complexes. Nature 407 26344197
1996 Generation and analysis of 280,000 human expressed sequence tags. Genome research 376 8889549
2017 Genome-wide CRISPR screen identifies HNRNPL as a prostate cancer dependency regulating RNA splicing. Proceedings of the National Academy of Sciences of the United States of America 282 28611215
2014 Meta-analysis of genome-wide association studies in African Americans provides insights into the genetic architecture of type 2 diabetes. PLoS genetics 167 25102180
2021 The PP2A-Integrator-CDK9 axis fine-tunes transcription and can be targeted therapeutically in cancer. Cell 152 34004147
2020 Identification of Integrator-PP2A complex (INTAC), an RNA polymerase II phosphatase. Science (New York, N.Y.) 151 33243860
2020 Integrator Recruits Protein Phosphatase 2A to Prevent Pause Release and Facilitate Transcription Termination. Molecular cell 139 32966759
2006 A dopamine transporter gene functional variant associated with cocaine abuse in a Brazilian sample. Proceedings of the National Academy of Sciences of the United States of America 125 16537431
2021 Structural basis of Integrator-mediated transcription regulation. Science (New York, N.Y.) 112 34762484
2010 Personalized smoking cessation: interactions between nicotine dose, dependence and quit-success genotype score. Molecular medicine (Cambridge, Mass.) 108 20379614
2010 Streamlined analysis schema for high-throughput identification of endogenous protein complexes. Proceedings of the National Academy of Sciences of the United States of America 102 20133760
2020 The Human Integrator Complex Facilitates Transcriptional Elongation by Endonucleolytic Cleavage of Nascent Transcripts. Cell reports 94 32697989
2017 Human mutations in integrator complex subunits link transcriptome integrity to brain development. PLoS genetics 91 28542170
2017 The STUbL RNF4 regulates protein group SUMOylation by targeting the SUMO conjugation machinery. Nature communications 86 29180619
2007 Relationship between VNTR polymorphisms of the human dopamine transporter gene and expression in post-mortem midbrain tissue. American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics 76 17579365
2017 Systematic Analysis of Human Protein Phosphatase Interactions and Dynamics. Cell systems 65 28330616
2010 Direct interaction between hnRNP-M and CDC5L/PLRG1 proteins affects alternative splice site choice. EMBO reports 59 20467437
2021 Structure of the catalytic core of the Integrator complex. Molecular cell 54 33548203
2000 Aspartic proteases from the nematode Caenorhabditis elegans. Structural organization and developmental and cell-specific expression of asp-1. The Journal of biological chemistry 54 10854422
2024 Structural basis of Integrator-dependent RNA polymerase II termination. Nature 52 38570683
2020 INTS10-INTS13-INTS14 form a functional module of Integrator that binds nucleic acids and the cleavage module. Nature communications 52 32647223
2017 Pan-Cancer Mutational and Transcriptional Analysis of the Integrator Complex. International journal of molecular sciences 48 28468258
2013 A 4-gene panel as a marker at chromosome 8q in Asian gastric cancer patients. Genomics 28 23722107
2014 Further evidence for the association between a polymorphism in the promoter region of SLC6A3/DAT1 and ADHD: findings from a sample of adults. European archives of psychiatry and clinical neuroscience 27 24487615
2010 Association study between the DAT1, DBH and DRD2 genes and cocaine dependence in a Spanish sample. Psychiatric genetics 27 20505554
2019 The Integrator Complex Prevents Dedifferentiation of Intermediate Neural Progenitors back into Neural Stem Cells. Cell reports 24 31018143
2015 Concurrent Mutations in ATM and Genes Associated with Common γ Chain Signaling in Peripheral T Cell Lymphoma. PloS one 23 26536348
2010 Response to methylphenidate is not influenced by DAT1 polymorphisms in a sample of Brazilian adult patients with ADHD. Journal of neural transmission (Vienna, Austria : 1996) 21 20049490
2018 A pan-cancer study of copy number gain and up-regulation in human oncogenes. Life sciences 19 30243646
1995 Four mutations in the porphobilinogen deaminase gene in patients with acute intermittent porphyria. Journal of medical genetics 19 8825929
2019 Biallelic INTS1 Mutations Cause a Rare Neurodevelopmental Disorder in Two Chinese Siblings. Journal of molecular neuroscience : MN 17 31428919
2020 Genome-wide DNA methylation analysis of cognitive function in middle and old-aged Chinese monozygotic twins. Journal of psychiatric research 16 33131831
2024 CRL3ARMC5 ubiquitin ligase and Integrator phosphatase form parallel mechanisms to control early stages of RNA Pol II transcription. Molecular cell 15 39667934
2019 INTS8 accelerates the epithelial-to-mesenchymal transition in hepatocellular carcinoma by upregulating the TGF-β signaling pathway. Cancer management and research 12 30881114
2013 Genetic variants associated with addictive behavior in Colombian addicted and non-addicted to heroin or cocaine. Colombia medica (Cali, Colombia) 10 24892317
2001 Novel compound heterozygous mutations for lipoprotein lipase deficiency. A G-to-T transversion at the first position of exon 5 causing G154V missense mutation and a 5' splice site mutation of intron 8. Journal of lipid research 10 11441134
2007 Association study of a functional variant in intron 8 of the dopamine transporter gene and migraine susceptibility. European journal of neurology 9 17539957
2010 Influence of genotype on dopamine transporter availability in human striatum and sleep architecture. Psychiatry research 7 20493539
2023 Protocol for rapidly inducing genome-wide RNA Pol II hyperphosphorylation by selectively disrupting INTAC phosphatase activity. STAR protocols 5 37831607
2021 Mining Complex Genetic Patterns Conferring Multiple Sclerosis Risk. International journal of environmental research and public health 4 33802599
2005 Coordinates, DNA content and heterogeneity of cell nuclei and segments of the Caenorhabditis elegans intestine. Histochemistry and cell biology 4 16158289
2022 Intron-Encoded Domain of Herstatin, An Autoinhibitor of Human Epidermal Growth Factor Receptors, Is Intrinsically Disordered. Frontiers in molecular biosciences 3 35573740
2022 FEEDNet: a feature enhanced encoder-decoder LSTM network for nuclei instance segmentation for histopathological diagnosis. Physics in medicine and biology 3 35905732
2021 Antisense oligonucleotide repress telomerase activity via manipulating alternative splicing or translation. Biochemical and biophysical research communications 3 34710826
2024 Integrative analysis of miRNA-mRNA expression in the brain during high temperature-induced masculinization of female Nile tilapia (Oreochromis niloticus). Genomics 2 38734154
2002 A family-based study of hyperinsulinemia and hypertriglyceridemia in heterozygous lipoprotein lipase deficiency. Clinica chimica acta; international journal of clinical chemistry 2 11750290