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RBPJ (Recombination signal-binding protein for immunoglobulin kappa J region; also known as RBP-J, RBP-Jκ, CBF-1, or CSL) is the central DNA-binding transcription factor and nuclear effector of the canonical Notch signaling pathway in humans (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 1-3). The protein belongs to the conserved CSL family (CBF1/Suppressor of Hairless/LAG-1), which is found across metazoan species and serves as the universal transcriptional mediator of Notch signals (pan2021transcriptionfactorrbpjl pages 1-2).
RBPJ functions as a sequence-specific DNA-binding transcription factor that recognizes a consensus motif typically represented as 5'-CGTGGGAA-3' or 5'-TGTGGGAA-3' (giaimo2021transcriptionfactorrbpj pages 3-5, hoffmeister2024singlemoleculetracking pages 23-27, pan2021transcriptionfactorrbpjl pages 1-2). This DNA recognition is mediated through cooperative interactions between the N-terminal domain (NTD) and the beta-trefoil domain (BTD), which contact the major and minor grooves of DNA, respectively (hoffmeister2024singlemoleculetracking pages 23-27). The BTD contains critical residues including arginine 218 (R218), which is essential for DNA binding; mutation of R218 to histidine disrupts DNA association and dramatically shortens nuclear residence time (pan2021transcriptionfactorrbpjl pages 12-14).
While RBPJ exhibits sequence-specific DNA binding, genomic analysis reveals that only a subset of RBPJ binding sites contain the canonical motif, with cooperating transcription factors and chromatin context also influencing occupancy (friedrich2023decipheringthenotch pages 53-58, friedrich2023decipheringthenotch pages 49-53).
The hallmark feature of RBPJ is its ability to function as a molecular switch between transcriptional repression and activation, depending on the presence of Notch signaling (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 1-3). In the absence of Notch activation, DNA-bound RBPJ recruits corepressor complexes containing SHARP/SPEN, NCoR/SMRT, histone deacetylases (HDACs), and chromatin-modifying enzymes including KDM1A/LSD1 and L3MBTL3, thereby maintaining transcriptional repression of Notch target genes (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 5-8, sprinzak2021biophysicsofnotch pages 13-14). Following Notch receptor activation and proteolytic release of the Notch intracellular domain (NICD), NICD enters the nucleus and binds RBPJ, displacing corepressors and recruiting the coactivator Mastermind-like (MAML) to form a ternary transcriptional activation complex (giaimo2021transcriptionfactorrbpj pages 3-5, hoffmeister2024singlemoleculetracking pages 13-16, giaimo2021transcriptionfactorrbpj pages 1-3). This complex subsequently recruits histone acetyltransferases such as p300/EP300, PCAF, and GCN5, which promote chromatin accessibility and activate transcription (giaimo2021transcriptionfactorrbpj pages 3-5, hoffmeister2024singlemoleculetracking pages 13-16).
RBPJ exhibits a highly conserved modular architecture consisting of three principal domains integrated into a single structural unit. A detailed summary of the structural organization is provided below:
| Domain Name | Residues/Location | Molecular Function | Key Interactions |
|---|---|---|---|
| Conserved CSL structural core | Approximately 425-aa conserved core within the 500-aa human RBPJ protein; organized as NTD–BTD–CTD | Forms the integrated DNA-binding and transcriptional-coregulator scaffold characteristic of the CSL/Su(H) family; a β-strand spanning the domains helps unite them structurally | Supports assembly of mutually regulated corepressor and NICD–MAML coactivator complexes (hoffmeister2024singlemoleculetracking pages 23-27, hall2022thestructurebinding pages 1-2, oswald2018cslassociatedcorepressorand pages 3-5) |
| N-terminal domain (NTD) | N-terminal portion of the conserved core; immunoglobulin/Rel-homology-like fold | Contributes an electropositive surface for sequence-specific DNA recognition, primarily contacting the major groove; also participates in assembly of the Notch transcription complex | Contacts DNA, NICD ankyrin repeats, MAML, L3MBTL2, and portions of SHARP-containing complexes (hoffmeister2024singlemoleculetracking pages 23-27, yuan2019structuralandfunctional pages 1-3, oswald2018cslassociatedcorepressorand pages 3-5) |
| β-trefoil domain (BTD) | Central domain; includes the DNA-contact region around Arg218 and an exposed hydrophobic pocket | Cooperates with the NTD to recognize canonical RBPJ/CSL elements, typically containing the core GTGGGAA; a β-hairpin contacts the minor groove. Also serves as the principal docking site for short hydrophobic coregulator motifs | Binds the NICD RAM domain through its conserved ΦWΦP motif, with reported affinity of approximately 20 nM; also binds SHARP, FHL1/KyoT2, RITA1, EBNA2, and other regulators. R218H disrupts DNA binding (hoffmeister2024singlemoleculetracking pages 23-27, pan2021transcriptionfactorrbpjl pages 8-12, hall2022thestructurebinding pages 1-2, oswald2018cslassociatedcorepressorand pages 3-5) |
| C-terminal domain (CTD) | C-terminal portion of the conserved core; immunoglobulin/Rel-homology-like fold; includes functionally important Leu388 | Primarily provides protein-interaction surfaces that stabilize activating or repressing transcription complexes rather than serving as the main sequence-recognition module | Contacts NICD ankyrin repeats and contributes to the composite NICD–MAML interface; participates in bipartite SHARP binding and interactions with other corepressors (hoffmeister2024singlemoleculetracking pages 23-27, pan2021transcriptionfactorrbpjl pages 8-12, yuan2019structuralandfunctional pages 1-3) |
| Composite DNA-binding surface | Formed mainly by the NTD and BTD; includes BTD residues Arg218, Arg220, and Ser221 | Recognizes RBPJ/CSL response elements such as 5′-TGTGGGAA-3′ or the closely related 5′-CGTGGGAA-3′. The NTD and BTD contact major and minor grooves, respectively; intact DNA binding supports long-lived chromatin residence | Associates with promoters and enhancers of Notch-responsive genes; DNA-binding-defective R218H markedly shortens nuclear residence time (giaimo2021transcriptionfactorrbpj pages 3-5, hoffmeister2024singlemoleculetracking pages 23-27, pan2021transcriptionfactorrbpjl pages 12-14) |
| NICD/coactivator interaction surface | Composite surface across the BTD, CTD, and NTD | Converts DNA-bound RBPJ from a repressive platform into the Notch transcription complex: NICD RAM first engages the BTD, NICD ankyrin repeats contact NTD/CTD, and the resulting conformation permits MAML recruitment | NICD1–4, MAML proteins, and downstream coactivators including p300/EP300, PCAF, and GCN5 (giaimo2021transcriptionfactorrbpj pages 3-5, sprinzak2021biophysicsofnotch pages 13-14, hoffmeister2024singlemoleculetracking pages 23-27) |
| Corepressor interaction surface | Distributed principally across the BTD and CTD, with additional NTD contacts for selected repressors; F261 and L388 are important SHARP-interface residues | Recruits chromatin-repressive machinery in the Notch-OFF state; partner-binding surfaces partly overlap with NICD-binding surfaces, supporting mutually exclusive or competitive complex assembly | SHARP/SPEN, NCoR/SMRT–HDAC complexes, L3MBTL3–KDM1A/LSD1, FHL1/KyoT2, RITA1, and PRC1.6-associated L3MBTL2 (giaimo2021transcriptionfactorrbpj pages 5-8, sprinzak2021biophysicsofnotch pages 13-14, pan2021transcriptionfactorrbpjl pages 8-12, yuan2019structuralandfunctional pages 1-3) |
| SUMO-interaction motif (SIM) | NTD residues 187–191; hydrophobic residues Ile187 and Val189 are functionally important | Mediates non-covalent recognition of SUMO, preferentially SUMO2/3, helping recruit or stabilize RBPJ at SUMO-rich Notch regulatory elements; this is distinct from covalent SUMOylation of RBPJ | Engages SUMOylated PRC1.6 components, especially L3MBTL2; I187A/V189A reduces SUMO2 binding, and inhibition of SUMOylation decreases RBPJ chromatin occupancy (sotomska2021sumoylatednoncanonicalpolycomb pages 1-2, sotomska2021sumoylatednoncanonicalpolycomb pages 7-9, sotomska2021sumoylatednoncanonicalpolycomb pages 6-7) |
| Covalent SUMOylation sites | Lys110 and Lys195, identified in activated dendritic cells | Ubc9-dependent SUMOylation protects RBPJ from ubiquitin-mediated proteasomal degradation, increasing protein stability and transcriptional activity toward CIITA and MHC-II genes | Ubc9, SUMO machinery, ubiquitin–proteasome system, and CIITA promoter complexes; SUMOylation-defective RBPJ has reduced transcriptional activity (zhang2023ubc9regulatesthe pages 7-8, zhang2023ubc9regulatesthe pages 5-7) |
Table: This table maps RBPJ’s conserved domains, DNA- and cofactor-binding surfaces, SUMO-interaction motif, and experimentally identified SUMOylation sites to their molecular functions. It distinguishes structural docking elements from post-translational regulatory sites.
The NTD and BTD together form the DNA-binding interface, while the BTD serves as the primary protein-interaction hub for both activating (NICD, MAML) and repressing (SHARP, FHL1/KyoT2) cofactors (hoffmeister2024singlemoleculetracking pages 23-27, yuan2019structuralandfunctional pages 1-3, oswald2018cslassociatedcorepressorand pages 3-5). The BTD contains an exposed hydrophobic pocket that binds the conserved ΦWΦ P (phi-tryptophan-phi-proline) motif found in the RAM region of NICD, with an affinity of approximately 20 nM (hall2022thestructurebinding pages 1-2). The C-terminal domain contributes additional interaction surfaces for NICD ankyrin repeats and participates in bipartite binding with corepressors (hoffmeister2024singlemoleculetracking pages 23-27, yuan2019structuralandfunctional pages 1-3).
RBPJ is predominantly localized in the cell nucleus, where it carries out its transcriptional regulatory functions (hoffmeister2024singlemoleculetracking pages 23-27, hoffmeister2024singlemoleculetracking pages 13-16, giaimo2021transcriptionfactorrbpj pages 3-5, pan2021transcriptionfactorrbpjl pages 12-14). The protein undergoes dynamic nucleo-cytoplasmic shuttling regulated by binding to cofactors such as Hairless in Drosophila and potentially similar mechanisms in mammals (wolf2021nucleocytoplasmicshuttlingof pages 1-2, hoffmeister2024singlemoleculetracking pages 23-27). Nuclear localization is essential for RBPJ's ability to bind DNA at Notch target gene regulatory elements and assemble transcriptional complexes (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 1-3, friedrich2023decipheringthenotch pages 49-53). RITA (RBPJ-interacting and tubulin-associated protein) can facilitate nuclear export of RBPJ, providing an additional layer of regulatory control (hoffmeister2024singlemoleculetracking pages 23-27).
RBPJ serves as the central nuclear transcriptional mediator of canonical Notch signaling. The pathway's core mechanism and RBPJ's dual regulatory functions are summarized in the following table:
| Signaling State | RBPJ Complex Composition | Cofactors/Partners | Chromatin Modifications | Transcriptional Output |
|---|---|---|---|---|
| Notch OFF: basal repression | DNA-bound RBPJ assembles a corepressor complex at canonical RBPJ/CSL response elements and serves as the sequence-specific DNA-binding scaffold. (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 5-8) | SHARP/SPEN, NCoR/SMRT, HDAC-containing complexes, KyoT2/FHL1, L3MBTL3–KDM1A/LSD1, and PRC1.6-associated proteins. (giaimo2021transcriptionfactorrbpj pages 5-8, sprinzak2021biophysicsofnotch pages 13-14, yuan2019structuralandfunctional pages 1-3, hall2022thestructurebinding pages 1-2) | Histone deacetylation and repressive changes in histone methylation reduce promoter and enhancer activity. SUMOylated PRC1.6 components can stabilize RBPJ recruitment to chromatin. (hoffmeister2024singlemoleculetracking pages 13-16, sotomska2021sumoylatednoncanonicalpolycomb pages 1-2, sotomska2021sumoylatednoncanonicalpolycomb pages 6-7) | Basal expression of Notch-responsive genes is silenced or dampened. Repressed targets include HES1, HEY1, and context-dependent genes such as KCNN1 and LGMN. (friedrich2023decipheringthenotch pages 53-58, friedrich2023decipheringthenotch pages 58-62) |
| Notch ON: complex exchange | Ligand-induced receptor cleavage releases NICD, which enters the nucleus, binds DNA-associated RBPJ, and displaces or competes with corepressors. (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 1-3) | The NICD RAM region binds RBPJ's β-trefoil domain, while NICD ankyrin repeats contact RBPJ's N- and C-terminal domains; these interactions enable MAML1–3 recruitment. (sprinzak2021biophysicsofnotch pages 13-14, hoffmeister2024singlemoleculetracking pages 23-27, yuan2019structuralandfunctional pages 1-3) | Repressor-associated deacetylation is replaced by coactivator-driven chromatin opening. Recruitment of p300/EP300, PCAF, GCN5, and SETD1A promotes H3K27 acetylation and activating histone methylation. (giaimo2021transcriptionfactorrbpj pages 3-5, hoffmeister2024singlemoleculetracking pages 13-16, friedrich2023decipheringthenotch pages 113-116, hoffmeister2024singlemoleculetracking pages 16-20) | RBPJ is converted from a repressive scaffold into the DNA-targeting component of the Notch transcription complex; transcription begins at responsive promoters and enhancers. (sprinzak2021biophysicsofnotch pages 13-14, friedrich2023decipheringthenotch pages 113-116) |
| Notch ON: productive activation | The ternary RBPJ–NICD–MAML complex remains tethered to RBPJ response elements and recruits additional transcriptional and chromatin-remodeling machinery. (giaimo2021transcriptionfactorrbpj pages 3-5, hoffmeister2024singlemoleculetracking pages 13-16) | MAML proteins, p300/EP300, PCAF, GCN5, SETD1A, and context-specific transcription factors or coactivators. (giaimo2021transcriptionfactorrbpj pages 3-5, friedrich2023decipheringthenotch pages 23-27, hoffmeister2024singlemoleculetracking pages 16-20) | Increased chromatin accessibility and activating histone marks—especially H3K27ac—support enhancer activation and transcription. Dynamic distal RBPJ sites and super-enhancers are particularly Notch-responsive. (hoffmeister2024singlemoleculetracking pages 13-16, friedrich2023decipheringthenotch pages 113-116) | Canonical targets such as HES1, HEY1/HEY-family genes, MYC, NRARP, and DTX1/Deltex are activated, regulating cell fate, differentiation, proliferation, and feedback control. (pan2021transcriptionfactorrbpjl pages 1-2, giaimo2021transcriptionfactorrbpj pages 1-3) |
| Signal termination/reset | NICD turnover dismantles the activation complex, allowing RBPJ to reassociate with corepressors and restore the Notch-OFF state. (giaimo2021transcriptionfactorrbpj pages 3-5, hoffmeister2024singlemoleculetracking pages 13-16) | Loss of NICD/MAML is followed by renewed recruitment of SHARP/SPEN, NCoR/SMRT, HDACs, and other repressors; RITA-mediated export can also reduce nuclear RBPJ availability. (hoffmeister2024singlemoleculetracking pages 23-27, giaimo2021transcriptionfactorrbpj pages 5-8, sprinzak2021biophysicsofnotch pages 13-14) | Coactivator-dependent acetylation declines, while deacetylation and repressive chromatin regulation are restored. (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 5-8) | Notch-induced transcription is attenuated, limiting response amplitude and duration and re-establishing basal repression. (giaimo2021transcriptionfactorrbpj pages 3-5, pan2021transcriptionfactorrbpjl pages 1-2) |
Table: This table summarizes how RBPJ switches between corepressor and coactivator complexes during canonical Notch signaling. It links each pathway state to specific partners, chromatin effects, and representative transcriptional targets.
RBPJ regulates a well-characterized set of Notch target genes, including the basic helix-loop-helix transcription factors HES1 and HEY1/HEY family members, the proto-oncogene c-MYC, and feedback regulators such as NRARP and DTX1/Deltex (pan2021transcriptionfactorrbpjl pages 1-2, friedrich2023decipheringthenotch pages 53-58, friedrich2023decipheringthenotch pages 58-62, giaimo2021transcriptionfactorrbpj pages 1-3). Chromatin immunoprecipitation studies have also identified KCNN1, LGMN, IL2RA, and CIITA as direct RBPJ targets in specific cellular contexts (friedrich2023decipheringthenotch pages 53-58, friedrich2023decipheringthenotch pages 58-62, zhang2023ubc9regulatesthe pages 7-8).
Beyond canonical Notch signaling, RBPJ regulates diverse biological processes:
Immune Cell Development and Function: RBPJ is essential for T-cell development, hematopoietic homeostasis, and lymphocyte differentiation (giaimo2021transcriptionfactorrbpj pages 1-3, chen2024theexpressionof pages 9-11). It regulates dendritic cell antigen presentation through control of CIITA and MHC class II expression (zhang2023ubc9regulatesthe pages 7-8, zhang2023ubc9regulatesthe pages 1-2).
Inflammatory Signaling: RBPJ modulates macrophage inflammatory responses by suppressing TGFβ receptor expression and thereby amplifying TNF-driven inflammation (xia2024reciprocalsuppressionbetween pages 9-11). It also regulates Jagged1 expression to create negative feedback on TNF-mediated osteoclastogenesis (ng2023jagged1actsas pages 1-3, ng2023jagged1actsas pages 4-6).
Cancer Biology: RBPJ has context-dependent roles in cancer, functioning as both a tumor suppressor and oncogenic factor depending on tissue type (giaimo2021transcriptionfactorrbpj pages 1-3, pan2021transcriptionfactorrbpjl pages 1-2, hoffmeister2024singlemoleculetracking pages 23-27, borggrefe2016settingthestage pages 7-8).
Recent research has revealed novel regulatory mechanisms and therapeutic implications for RBPJ:
| Study/Year | Main Finding | Biological Context | Clinical Relevance | Key Mechanism |
|---|---|---|---|---|
| Pan et al., 2023 | High RBPJ was associated with PD-1⁺, TIM-3⁺, granzyme-B-low exhausted CD8⁺ T cells in hepatocellular carcinoma (HCC). RBPJ knockdown or inhibition of the RBPJ transcriptional complex with RIN1 reduced exhaustion markers and improved antitumor activity. (pan2023targetedinhibitionof pages 2-5, pan2023targetedinhibitionof pages 1-2) | Tumor-infiltrating CD8⁺ T cells and HCC cells; patient datasets, mouse models, and cell-based experiments | Supports RBPJ-complex inhibition as a candidate strategy to reduce immune exhaustion and enhance anti-PD-1/PD-L1 therapy; RIN1 also suppressed tumor-cell PD-L1, L-kynurenine production, and mTOR signaling. Evidence remains preclinical. | RBPJ-associated transcription promotes inhibitory-receptor expression and an exhausted T-cell state; RIN1 disrupts this program, while RBPJ knockdown lowers PD-1 and TIM-3. (pan2023targetedinhibitionof pages 2-5, pan2023targetedinhibitionof pages 1-2) |
| Zhang et al., 2023 | Ubc9-dependent SUMOylation of RBPJ at K110 and K195 stabilized the protein, enhanced its transcriptional activity, and increased CIITA and MHC class II expression in dendritic cells. (zhang2023ubc9regulatesthe pages 7-8, zhang2023ubc9regulatesthe pages 5-7) | LPS-activated dendritic cells and a mouse DSS-induced colitis model | Identifies the Ubc9–RBPJ–CIITA axis as a potential inflammatory-disease target. Dendritic-cell Ubc9 deficiency impaired antigen presentation and CD4⁺ T-cell priming and reduced colitis severity. | SUMOylation protects RBPJ from ubiquitin-mediated proteasomal degradation; stabilized RBPJ binds the CIITA promoter and promotes the MHC-II antigen-presentation program. (zhang2023ubc9regulatesthe pages 7-8, zhang2023ubc9regulatesthe pages 1-2) |
| Ng et al., 2023 | Jagged1 was identified as a direct RBPJ target that feeds back to suppress TNF-driven inflammatory osteoclastogenesis. Recombinant Jagged1 inhibited human inflammatory osteoclast formation without broadly suppressing TNF-induced inflammatory genes. (ng2023jagged1actsas pages 1-3, ng2023jagged1actsas pages 4-6) | Macrophages and osteoclast precursors exposed to TNF; mouse and human cultures, with comparison of rheumatoid arthritis and systemic lupus erythematosus samples | Suggests that restoring Jagged1 signaling could limit inflammatory bone loss, including rheumatoid-arthritis-associated erosion, while potentially preserving broader immune responses. | TNF induces RBPJ-dependent JAG1 transcription; Jagged1 then establishes negative feedback that restrains TNF-mediated—but not RANKL-mediated—osteoclast differentiation. (ng2023jagged1actsas pages 1-3, ng2023jagged1actsas pages 4-6) |
| Xia et al., 2024 | RBPJ amplified TNF-driven macrophage inflammation by suppressing homeostatic TGFβ signaling. RBPJ loss reduced TNF-induced cytokines and interferon-stimulated genes and lowered circulating inflammatory mediators in mice. (xia2024reciprocalsuppressionbetween pages 9-11) | Macrophage inflammatory responses and a TNF-induced chronic-inflammation mouse model | Positions RBPJ-mediated repression of TGFβ signaling as a possible intervention point in TNF-dependent inflammatory disease; therapeutic translation has not yet been established. | RBPJ binds the TGFBR1 and TGFBR2 promoters and represses receptor expression, weakening TGFβ-mediated restraint of TNF responses; RBPJ may also directly regulate inflammatory genes. (xia2024reciprocalsuppressionbetween pages 9-11) |
| Chen et al., 2024 | RBPJ mRNA was lower in PBMCs from 83 newly diagnosed rheumatoid arthritis patients than in 70 healthy controls and correlated inversely with DAS28, CRP, and ESR. Synovial analysis identified 562 genes differing between RBPJ-low and RBPJ-high groups. (chen2024theexpressionof pages 9-11, chen2024theexpressionof pages 1-2) | Human rheumatoid arthritis PBMCs and the GSE89408 synovial-tissue transcriptomic dataset | Suggests RBPJ as a candidate disease-activity biomarker and mechanistic link to immune dysregulation and bone destruction, but the observational design does not establish causality or clinical utility. | RBPJ-associated genes were enriched in T-cell-receptor signaling, Th1/Th2 and Th17 differentiation, PI3K–AKT and cytokine signaling, lymphocyte differentiation, and osteoclastogenesis. (chen2024theexpressionof pages 9-11, chen2024theexpressionof pages 1-2) |
Table: Summary of major 2023–2024 studies linking RBPJ to tumor immunity, post-translational regulation, antigen presentation, inflammatory signaling, rheumatoid arthritis, and osteoclastogenesis. The table distinguishes mechanistic findings from still-preclinical or associative clinical implications.
A major 2023 discovery identified Ubc9-mediated SUMOylation of RBPJ at lysines K110 and K195 as a critical regulatory mechanism (zhang2023ubc9regulatesthe pages 7-8, zhang2023ubc9regulatesthe pages 1-2, zhang2023ubc9regulatesthe pages 5-7). SUMOylation protects RBPJ from ubiquitin-mediated proteasomal degradation, thereby stabilizing the protein and enhancing its transcriptional activity (zhang2023ubc9regulatesthe pages 7-8, zhang2023ubc9regulatesthe pages 5-7). This modification is particularly important in dendritic cells, where it sustains CIITA expression and MHC class II antigen presentation (zhang2023ubc9regulatesthe pages 1-2, zhang2023ubc9regulatesthe pages 2-3).
Additionally, RBPJ contains a SUMO-interaction motif (SIM) at residues 187-191 in the N-terminal domain that enables non-covalent recognition of SUMOylated PRC1.6 complex components, particularly L3MBTL2, facilitating RBPJ recruitment to chromatin (sotomska2021sumoylatednoncanonicalpolycomb pages 1-2, sotomska2021sumoylatednoncanonicalpolycomb pages 7-9, sotomska2021sumoylatednoncanonicalpolycomb pages 6-7). Phosphorylation of RBPJ-associated corepressors, particularly casein kinase II (CKII)-dependent phosphorylation of NCoR, regulates the balance between repressive and activating complexes (giaimo2021transcriptionfactorrbpj pages 5-8).
In 2023, Pan and colleagues identified RBPJ as a driver of CD8+ T-cell exhaustion in hepatocellular carcinoma, with high RBPJ expression correlating with increased PD-1, TIM-3, and reduced granzyme B (pan2023targetedinhibitionof pages 2-5, pan2023targetedinhibitionof pages 1-2). Pharmacological inhibition of the RBPJ transcriptional complex using the small molecule RIN1 reduced T-cell exhaustion markers, inhibited tumor growth through dual effects on mTOR signaling and PD-L1 expression, and synergized with anti-PD-1/PD-L1 checkpoint blockade (pan2023targetedinhibitionof pages 2-5, pan2023targetedinhibitionof pages 1-2). These findings position RBPJ as a potential immunotherapy target for overcoming resistance in HCC.
A 2024 study demonstrated that RBPJ expression is significantly reduced in peripheral blood mononuclear cells from rheumatoid arthritis patients and inversely correlates with disease activity scores (DAS28), C-reactive protein, and erythrocyte sedimentation rate (chen2024theexpressionof pages 9-11, chen2024theexpressionof pages 1-2). Differential gene expression analysis linked RBPJ to T-cell activation, Th17 differentiation, osteoclastogenesis, and inflammatory signaling pathways, suggesting that diminished RBPJ may contribute to immune dysregulation and joint destruction in RA (chen2024theexpressionof pages 9-11, chen2024theexpressionof pages 1-2, chen2024theexpressionof pages 11-12).
RBPJ dysfunction has been implicated in multiple human diseases:
Developmental Disorders: Heterozygous RBPJ mutations cause Adams-Oliver syndrome, characterized by limb defects, aplasia cutis, and vascular abnormalities (hoffmeister2024singlemoleculetracking pages 20-23).
Hematologic Malignancies: Aberrant RBPJ-corepressor activity may contribute to leukemogenesis, particularly in T-cell acute lymphoblastic leukemia (T-ALL), where Notch1 mutations are frequent (giaimo2021transcriptionfactorrbpj pages 1-3, borggrefe2016settingthestage pages 7-8).
Solid Tumors: RBPJ has been implicated in pancreatic cancer, breast cancer, and other malignancies, with context-dependent tumor-suppressive or oncogenic roles (pan2021transcriptionfactorrbpjl pages 1-2, hoffmeister2024singlemoleculetracking pages 23-27, pan2021transcriptionfactorrbpjl pages 8-12).
Inflammatory Bowel Disease: The Ubc9-RBPJ-CIITA axis in dendritic cells promotes DSS-induced colitis, suggesting potential therapeutic targeting for inflammatory bowel diseases (zhang2023ubc9regulatesthe pages 1-2, zhang2023ubc9regulatesthe pages 2-3).
Bone Diseases: RBPJ regulates osteoclastogenesis and inflammatory bone loss, with relevance to rheumatoid arthritis and metabolic bone disease (ng2023jagged1actsas pages 1-3, ng2023jagged1actsas pages 4-6).
RBPJ is a highly conserved, sequence-specific DNA-binding transcription factor that serves as the obligate nuclear mediator of canonical Notch signaling. Its unique ability to switch between transcriptional repression and activation, mediated through dynamic assembly of distinct corepressor and coactivator complexes, positions it as a central regulator of cell fate, differentiation, and immune function. Recent discoveries have expanded our understanding of RBPJ regulation through post-translational modifications, particularly SUMOylation, and identified novel therapeutic opportunities in cancer immunotherapy and inflammatory disease. The protein's nuclear localization, well-defined domain architecture, and precisely characterized DNA-binding specificity make it an excellent model system for understanding context-dependent transcriptional control and a promising target for therapeutic intervention in Notch-dependent diseases.
Key authoritative reviews and primary research cited in this report include:
Giaimo et al. (2021). "Transcription Factor RBPJ as a Molecular Switch in Regulating the Notch Response." Advances in Experimental Medicine and Biology, 1287:9-30. doi:10.1007/978-3-030-55031-8_2 (giaimo2021transcriptionfactorrbpj pages 3-5, giaimo2021transcriptionfactorrbpj pages 5-8, giaimo2021transcriptionfactorrbpj pages 1-3)
Sprinzak & Blacklow (2021). "Biophysics of Notch Signaling." Annual Review of Biophysics, 50:157-189. doi:10.1146/annurev-biophys-101920-082204 (sprinzak2021biophysicsofnotch pages 13-14)
Pan et al. (2023). "Targeted inhibition of RBPJ transcription complex alleviates the exhaustion of CD8+ T cells in hepatocellular carcinoma." Communications Biology, 6. doi:10.1038/s42003-023-04521-x (pan2023targetedinhibitionof pages 2-5, pan2023targetedinhibitionof pages 1-2)
Zhang et al. (2023). "Ubc9 regulates the expression of MHC II in dendritic cells to enhance DSS-induced colitis by mediating RBPJ SUMOylation." Cell Death & Disease, 14. doi:10.1038/s41419-023-06266-1 (zhang2023ubc9regulatesthe pages 7-8, zhang2023ubc9regulatesthe pages 1-2, zhang2023ubc9regulatesthe pages 5-7)
Chen et al. (2024). "The expression of RBPJ and its potential role in rheumatoid arthritis." BMC Genomics, 25. doi:10.1186/s12864-024-10804-2 (chen2024theexpressionof pages 9-11, chen2024theexpressionof pages 1-2)
Xia et al. (2024). "Reciprocal suppression between TGFβ signaling and TNF stimulation finetunes the macrophage inflammatory response." The FASEB Journal, 38. doi:10.1096/fj.202302230r (xia2024reciprocalsuppressionbetween pages 9-11)
Additional structural and mechanistic studies:
Yuan et al. (2019). "Structural and Functional Studies of the RBPJ-SHARP Complex Reveal a Conserved Corepressor Binding Site." Cell Reports, 26:845-854. doi:10.1016/j.celrep.2018.12.097 (yuan2019structuralandfunctional pages 1-3)
Hall et al. (2022). "The structure, binding and function of a Notch transcription complex involving RBPJ and the epigenetic reader protein L3MBTL3." Nucleic Acids Research, 50:13083-13099. doi:10.1093/nar/gkac1137 (hall2022thestructurebinding pages 1-2)
Sotomska et al. (2021). "SUMOylated non-canonical polycomb PRC1.6 complex as a prerequisite for recruitment of transcription factor RBPJ." Epigenetics & Chromatin, 14. doi:10.1186/s13072-021-00412-9 (sotomska2021sumoylatednoncanonicalpolycomb pages 1-2, sotomska2021sumoylatednoncanonicalpolycomb pages 7-9, sotomska2021sumoylatednoncanonicalpolycomb pages 6-7)
References
(giaimo2021transcriptionfactorrbpj pages 3-5): Benedetto Daniele Giaimo, Ellen K. Gagliani, Rhett A. Kovall, and Tilman Borggrefe. Transcription factor rbpj as a molecular switch in regulating the notch response. Advances in experimental medicine and biology, 1287:9-30, Oct 2021. URL: https://doi.org/10.1007/978-3-030-55031-8_2, doi:10.1007/978-3-030-55031-8_2. This article has 56 citations and is from a peer-reviewed journal.
(giaimo2021transcriptionfactorrbpj pages 1-3): Benedetto Daniele Giaimo, Ellen K. Gagliani, Rhett A. Kovall, and Tilman Borggrefe. Transcription factor rbpj as a molecular switch in regulating the notch response. Advances in experimental medicine and biology, 1287:9-30, Oct 2021. URL: https://doi.org/10.1007/978-3-030-55031-8_2, doi:10.1007/978-3-030-55031-8_2. This article has 56 citations and is from a peer-reviewed journal.
(pan2021transcriptionfactorrbpjl pages 1-2): Leiling Pan, Philipp Hoffmeister, Aleksandra Turkiewicz, N. N. Duyen Huynh, Andreas Große-Berkenbusch, Uwe Knippschild, J. Christof M. Gebhardt, Bernd Baumann, Tilman Borggrefe, and Franz Oswald. Transcription factor rbpjl is able to repress notch target gene expression but is non-responsive to notch activation. Oct 2021. URL: https://doi.org/10.18725/oparu-46089, doi:10.18725/oparu-46089. This article has 21 citations.
(hoffmeister2024singlemoleculetracking pages 23-27): Single molecule tracking analysis of Notch transcription factors RBPJ and RBPL, and establishment of the iNotch system This article has 0 citations.
(pan2021transcriptionfactorrbpjl pages 12-14): Leiling Pan, Philipp Hoffmeister, Aleksandra Turkiewicz, N. N. Duyen Huynh, Andreas Große-Berkenbusch, Uwe Knippschild, J. Christof M. Gebhardt, Bernd Baumann, Tilman Borggrefe, and Franz Oswald. Transcription factor rbpjl is able to repress notch target gene expression but is non-responsive to notch activation. Oct 2021. URL: https://doi.org/10.18725/oparu-46089, doi:10.18725/oparu-46089. This article has 21 citations.
(friedrich2023decipheringthenotch pages 53-58): Deciphering the Notch Pathway: A Bioinformatics Analysis of the RBPJ/Notch Axis This article has 0 citations.
(friedrich2023decipheringthenotch pages 49-53): Deciphering the Notch Pathway: A Bioinformatics Analysis of the RBPJ/Notch Axis This article has 0 citations.
(giaimo2021transcriptionfactorrbpj pages 5-8): Benedetto Daniele Giaimo, Ellen K. Gagliani, Rhett A. Kovall, and Tilman Borggrefe. Transcription factor rbpj as a molecular switch in regulating the notch response. Advances in experimental medicine and biology, 1287:9-30, Oct 2021. URL: https://doi.org/10.1007/978-3-030-55031-8_2, doi:10.1007/978-3-030-55031-8_2. This article has 56 citations and is from a peer-reviewed journal.
(sprinzak2021biophysicsofnotch pages 13-14): David Sprinzak and Stephen C. Blacklow. Biophysics of notch signaling. Annual Review of Biophysics, 50:157-189, May 2021. URL: https://doi.org/10.1146/annurev-biophys-101920-082204, doi:10.1146/annurev-biophys-101920-082204. This article has 280 citations and is from a domain leading peer-reviewed journal.
(hoffmeister2024singlemoleculetracking pages 13-16): Single molecule tracking analysis of Notch transcription factors RBPJ and RBPL, and establishment of the iNotch system This article has 0 citations.
(hall2022thestructurebinding pages 1-2): Daniel Hall, Benedetto Daniele Giaimo, Sung-Soo Park, Wiebke Hemmer, Tobias Friedrich, Francesca Ferrante, Marek Bartkuhn, Zhenyu Yuan, Franz Oswald, Tilman Borggrefe, Jean-François Rual, and Rhett A. Kovall. The structure, binding and function of a notch transcription complex involving rbpj and the epigenetic reader protein l3mbtl3. Nucleic Acids Research, 50:13083-13099, Feb 2022. URL: https://doi.org/10.1093/nar/gkac1137, doi:10.1093/nar/gkac1137. This article has 10 citations and is from a highest quality peer-reviewed journal.
(oswald2018cslassociatedcorepressorand pages 3-5): Franz Oswald and Rhett A. Kovall. Csl-associated corepressor and coactivator complexes. Advances in experimental medicine and biology, 1066:279-295, Jan 2018. URL: https://doi.org/10.1007/978-3-319-89512-3_14, doi:10.1007/978-3-319-89512-3_14. This article has 53 citations and is from a peer-reviewed journal.
(yuan2019structuralandfunctional pages 1-3): Zhenyu Yuan, Bradley D. VanderWielen, Benedetto Daniele Giaimo, Leiling Pan, Courtney E. Collins, Aleksandra Turkiewicz, Kerstin Hein, Franz Oswald, Tilman Borggrefe, and Rhett A. Kovall. Structural and functional studies of the rbpj-sharp complex reveal a conserved corepressor binding site. Jan 2019. URL: https://doi.org/10.1016/j.celrep.2018.12.097, doi:10.1016/j.celrep.2018.12.097. This article has 56 citations and is from a highest quality peer-reviewed journal.
(pan2021transcriptionfactorrbpjl pages 8-12): Leiling Pan, Philipp Hoffmeister, Aleksandra Turkiewicz, N. N. Duyen Huynh, Andreas Große-Berkenbusch, Uwe Knippschild, J. Christof M. Gebhardt, Bernd Baumann, Tilman Borggrefe, and Franz Oswald. Transcription factor rbpjl is able to repress notch target gene expression but is non-responsive to notch activation. Oct 2021. URL: https://doi.org/10.18725/oparu-46089, doi:10.18725/oparu-46089. This article has 21 citations.
(sotomska2021sumoylatednoncanonicalpolycomb pages 1-2): Małgorzata Sotomska, Robert Liefke, Francesca Ferrante, Heiko Schwederski, Franz Oswald, and Tilman Borggrefe. Sumoylated non-canonical polycomb prc1.6 complex as a prerequisite for recruitment of transcription factor rbpj. Epigenetics & Chromatin, Jul 2021. URL: https://doi.org/10.1186/s13072-021-00412-9, doi:10.1186/s13072-021-00412-9. This article has 4 citations and is from a peer-reviewed journal.
(sotomska2021sumoylatednoncanonicalpolycomb pages 7-9): Małgorzata Sotomska, Robert Liefke, Francesca Ferrante, Heiko Schwederski, Franz Oswald, and Tilman Borggrefe. Sumoylated non-canonical polycomb prc1.6 complex as a prerequisite for recruitment of transcription factor rbpj. Epigenetics & Chromatin, Jul 2021. URL: https://doi.org/10.1186/s13072-021-00412-9, doi:10.1186/s13072-021-00412-9. This article has 4 citations and is from a peer-reviewed journal.
(sotomska2021sumoylatednoncanonicalpolycomb pages 6-7): Małgorzata Sotomska, Robert Liefke, Francesca Ferrante, Heiko Schwederski, Franz Oswald, and Tilman Borggrefe. Sumoylated non-canonical polycomb prc1.6 complex as a prerequisite for recruitment of transcription factor rbpj. Epigenetics & Chromatin, Jul 2021. URL: https://doi.org/10.1186/s13072-021-00412-9, doi:10.1186/s13072-021-00412-9. This article has 4 citations and is from a peer-reviewed journal.
(zhang2023ubc9regulatesthe pages 7-8): Jing Zhang, Longmin Chen, Qianqian Xu, Yuan Zou, Fei Sun, Qing Zhou, Xi Luo, Yang Li, Cai Chen, Shu Zhang, Fei Xiong, Ping Yang, Shiwei Liu, and Cong-Yi Wang. Ubc9 regulates the expression of mhc ii in dendritic cells to enhance dss-induced colitis by mediating rbpj sumoylation. Cell Death & Disease, Nov 2023. URL: https://doi.org/10.1038/s41419-023-06266-1, doi:10.1038/s41419-023-06266-1. This article has 10 citations and is from a peer-reviewed journal.
(zhang2023ubc9regulatesthe pages 5-7): Jing Zhang, Longmin Chen, Qianqian Xu, Yuan Zou, Fei Sun, Qing Zhou, Xi Luo, Yang Li, Cai Chen, Shu Zhang, Fei Xiong, Ping Yang, Shiwei Liu, and Cong-Yi Wang. Ubc9 regulates the expression of mhc ii in dendritic cells to enhance dss-induced colitis by mediating rbpj sumoylation. Cell Death & Disease, Nov 2023. URL: https://doi.org/10.1038/s41419-023-06266-1, doi:10.1038/s41419-023-06266-1. This article has 10 citations and is from a peer-reviewed journal.
(wolf2021nucleocytoplasmicshuttlingof pages 1-2): Dorina B. Wolf, Dieter Maier, and Anja C. Nagel. Nucleo-cytoplasmic shuttling of murine rbpj by hairless protein matches that of su(h) protein in the model system drosophila melanogaster. Hereditas, Mar 2021. URL: https://doi.org/10.1186/s41065-021-00175-z, doi:10.1186/s41065-021-00175-z. This article has 4 citations and is from a peer-reviewed journal.
(friedrich2023decipheringthenotch pages 58-62): Deciphering the Notch Pathway: A Bioinformatics Analysis of the RBPJ/Notch Axis This article has 0 citations.
(friedrich2023decipheringthenotch pages 113-116): Deciphering the Notch Pathway: A Bioinformatics Analysis of the RBPJ/Notch Axis This article has 0 citations.
(hoffmeister2024singlemoleculetracking pages 16-20): Single molecule tracking analysis of Notch transcription factors RBPJ and RBPL, and establishment of the iNotch system This article has 0 citations.
(friedrich2023decipheringthenotch pages 23-27): Deciphering the Notch Pathway: A Bioinformatics Analysis of the RBPJ/Notch Axis This article has 0 citations.
(chen2024theexpressionof pages 9-11): Shuaishuai Chen, Weibo Zhao, Juping Du, Suyun Chen, Jun Li, Bo Shen, Yuanlin Zhou, and Shiyong Chen. The expression of rbpj and its potential role in rheumatoid arthritis. BMC Genomics, Sep 2024. URL: https://doi.org/10.1186/s12864-024-10804-2, doi:10.1186/s12864-024-10804-2. This article has 3 citations and is from a peer-reviewed journal.
(zhang2023ubc9regulatesthe pages 1-2): Jing Zhang, Longmin Chen, Qianqian Xu, Yuan Zou, Fei Sun, Qing Zhou, Xi Luo, Yang Li, Cai Chen, Shu Zhang, Fei Xiong, Ping Yang, Shiwei Liu, and Cong-Yi Wang. Ubc9 regulates the expression of mhc ii in dendritic cells to enhance dss-induced colitis by mediating rbpj sumoylation. Cell Death & Disease, Nov 2023. URL: https://doi.org/10.1038/s41419-023-06266-1, doi:10.1038/s41419-023-06266-1. This article has 10 citations and is from a peer-reviewed journal.
(xia2024reciprocalsuppressionbetween pages 9-11): Yuhan Xia, Kazuki Inoue, Ting Zheng, Yongli Qin, and Baohong Zhao. Reciprocal suppression between tgfβ signaling and tnf stimulation finetunes the macrophage inflammatory response. The FASEB Journal, Jun 2024. URL: https://doi.org/10.1096/fj.202302230r, doi:10.1096/fj.202302230r. This article has 10 citations.
(ng2023jagged1actsas pages 1-3): Courtney Ng, Yongli Qin, Yuhan Xia, Xiaoyu Hu, and Baohong Zhao. Jagged1 acts as an rbp-j target and feedback suppresses tnf-mediated inflammatory osteoclastogenesis. Journal of immunology, 211:1340-1347, Sep 2023. URL: https://doi.org/10.4049/jimmunol.2300317, doi:10.4049/jimmunol.2300317. This article has 11 citations and is from a domain leading peer-reviewed journal.
(ng2023jagged1actsas pages 4-6): Courtney Ng, Yongli Qin, Yuhan Xia, Xiaoyu Hu, and Baohong Zhao. Jagged1 acts as an rbp-j target and feedback suppresses tnf-mediated inflammatory osteoclastogenesis. Journal of immunology, 211:1340-1347, Sep 2023. URL: https://doi.org/10.4049/jimmunol.2300317, doi:10.4049/jimmunol.2300317. This article has 11 citations and is from a domain leading peer-reviewed journal.
(borggrefe2016settingthestage pages 7-8): Tilman Borggrefe and Franz Oswald. Setting the stage for notch: the drosophila su(h)-hairless repressor complex. PLOS Biology, 14:e1002524, Jul 2016. URL: https://doi.org/10.1371/journal.pbio.1002524, doi:10.1371/journal.pbio.1002524. This article has 37 citations and is from a highest quality peer-reviewed journal.
(pan2023targetedinhibitionof pages 2-5): Banglun Pan, Zengbin Wang, Xiaoxia Zhang, Shuling Shen, Xiaoling Ke, Jiacheng Qiu, Yuxin Yao, Xiaoxuan Wu, Xiaoqian Wang, and Nanhong Tang. Targeted inhibition of rbpj transcription complex alleviates the exhaustion of cd8+ t cells in hepatocellular carcinoma. Communications Biology, Jan 2023. URL: https://doi.org/10.1038/s42003-023-04521-x, doi:10.1038/s42003-023-04521-x. This article has 23 citations and is from a peer-reviewed journal.
(pan2023targetedinhibitionof pages 1-2): Banglun Pan, Zengbin Wang, Xiaoxia Zhang, Shuling Shen, Xiaoling Ke, Jiacheng Qiu, Yuxin Yao, Xiaoxuan Wu, Xiaoqian Wang, and Nanhong Tang. Targeted inhibition of rbpj transcription complex alleviates the exhaustion of cd8+ t cells in hepatocellular carcinoma. Communications Biology, Jan 2023. URL: https://doi.org/10.1038/s42003-023-04521-x, doi:10.1038/s42003-023-04521-x. This article has 23 citations and is from a peer-reviewed journal.
(chen2024theexpressionof pages 1-2): Shuaishuai Chen, Weibo Zhao, Juping Du, Suyun Chen, Jun Li, Bo Shen, Yuanlin Zhou, and Shiyong Chen. The expression of rbpj and its potential role in rheumatoid arthritis. BMC Genomics, Sep 2024. URL: https://doi.org/10.1186/s12864-024-10804-2, doi:10.1186/s12864-024-10804-2. This article has 3 citations and is from a peer-reviewed journal.
(zhang2023ubc9regulatesthe pages 2-3): Jing Zhang, Longmin Chen, Qianqian Xu, Yuan Zou, Fei Sun, Qing Zhou, Xi Luo, Yang Li, Cai Chen, Shu Zhang, Fei Xiong, Ping Yang, Shiwei Liu, and Cong-Yi Wang. Ubc9 regulates the expression of mhc ii in dendritic cells to enhance dss-induced colitis by mediating rbpj sumoylation. Cell Death & Disease, Nov 2023. URL: https://doi.org/10.1038/s41419-023-06266-1, doi:10.1038/s41419-023-06266-1. This article has 10 citations and is from a peer-reviewed journal.
(chen2024theexpressionof pages 11-12): Shuaishuai Chen, Weibo Zhao, Juping Du, Suyun Chen, Jun Li, Bo Shen, Yuanlin Zhou, and Shiyong Chen. The expression of rbpj and its potential role in rheumatoid arthritis. BMC Genomics, Sep 2024. URL: https://doi.org/10.1186/s12864-024-10804-2, doi:10.1186/s12864-024-10804-2. This article has 3 citations and is from a peer-reviewed journal.
(hoffmeister2024singlemoleculetracking pages 20-23): Single molecule tracking analysis of Notch transcription factors RBPJ and RBPL, and establishment of the iNotch system This article has 0 citations.