Protein / target

E3 ubiquitin-protein ligase RBX1

RBX1P62877Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
3
Approved medicines
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Ubiquitin-protein transferase activity

Primary system

Immune system

Strongest disease association

plasma cell myeloma

Clinical evidence · score 0.62

Therapeutic maturity

Clinically validated target

3 approved medicines against this target

Druggability

Small molecule

Open Targets tractability · Approved Drug

Clinical development

3 approved · 1 in clinical development

30 linked trials

Derived from structured UniProt, Open Targets and literature data on this page.

Protein profile

UniProt 2026_02

Canonical identity and biological annotation from UniProt.

Function

E3 ubiquitin ligase component of multiple cullin-RING-based E3 ubiquitin-protein ligase (CRLs) complexes which mediate the ubiquitination and subsequent proteasomal degradation of target proteins, including proteins involved in cell cycle progression, signal transduction, transcription and transcription-coupled nucleotide excision repair (PubMed:10230407, PubMed:10579999, PubMed:11961546, PubMed:15983046, PubMed:16678110, PubMed:19112177, PubMed:19679664, PubMed:22748924, PubMed:23455478, PubMed:27565346, PubMed:29769719, PubMed:32355176, PubMed:33417871, PubMed:37844242, PubMed:38326650, PubMed:39504960, PubMed:39667934, PubMed:38316879). CRLs complexes and ARIH1 collaborate in tandem to mediate ubiquitination of target proteins, ARIH1 mediating addition of the first ubiquitin on CRLs targets (PubMed:27565346). The functional specificity of the E3 ubiquitin-protein ligase complexes depends on the variable substrate recognition components. As a component of the CSA complex mediates ubiquitination of Pol II subunit POLR2A at 'Lys-1268', a critical TC-NER checkpoint (PubMed:32355176, PubMed:34526721). Core component of the Cul7-RING(FBXW8) ubiquitin ligase complex, which mediates the ubiquitination and subsequent proteasomal degradation of target proteins (PubMed:35982156). Core component of a Cul9-RING ubiquitin ligase complex composed of CUL9 and RBX1, which mediates mono-ubiquitination of p53/TP53 (PubMed:38605244). Recruits the E2 ubiquitin-conjugating enzyme CDC34 to the complex and brings it into close proximity to the substrate. Probably also stimulates CDC34 autoubiquitination. May be required for histone H3 and histone H4 ubiquitination in response to ultraviolet and for subsequent DNA repair. Promotes the neddylation of CUL1, CUL2, CUL4 and CUL4 via its interaction with UBE2M. Involved in the ubiquitination of KEAP1, ENC1 and KLHL41. In concert with ATF2 and CUL3, promotes degradation of KAT5 thereby attenuating its ability to acetylate and activate ATM. As part of a multisubunit complex composed of elongin BC complex (ELOB and ELOC), elongin A/ELOA, RBX1 and CUL5; polyubiquitinates monoubiquitinated POLR2A (PubMed:19920177)

Subcellular location

CytoplasmNucleus
Domains and Gene Ontology detail (100)

Gene Ontology

  • Ccentrosome
  • CCul2-RING ubiquitin ligase complex
  • CCul3-RING ubiquitin ligase complex
  • CCul4-RING E3 ubiquitin ligase complex
  • CCul4A-RING E3 ubiquitin ligase complex
  • CCul4B-RING E3 ubiquitin ligase complex
  • CCul5-RING ubiquitin ligase complex
  • CCul7-RING ubiquitin ligase complex
  • Ccullin-RING ubiquitin ligase complex
  • Ccytoplasm
  • Ccytosol
  • CGolgi apparatus

108 aa · 12 kDa

Biological roles

Reactome v97

What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.

Transcriptional regulationUniProt · GO · ReactomeImmune signallingGOMetabolic enzyme activityGOApoptosis & cell deathGO
View supporting evidence

Transcriptional regulation

  • ·E3 ubiquitin ligase component of multiple cullin-RING-based E3 ubiquitin-protein ligase…
  • ·RNA polymerase II-specific DNA-binding transcription factor binding
  • ·epigenetic regulation of gene expression
  • ·negative regulation of transcription by RNA polymerase II

Immune signalling

  • ·negative regulation of beige fat cell differentiation
  • ·neural crest cell differentiation
  • ·regulation of inflammatory response
  • ·regulation of mitotic cytokinesis

Metabolic enzyme activity

  • ·NEDD8 transferase activity
  • ·ubiquitin-protein transferase activity

Apoptosis & cell death

  • ·regulation of apoptotic process
View underlying pathways (25)

Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.

Interaction neighbourhood

STRING v12.0

Proteins with the strongest functional or physical association. Node size and line weight reflect STRING confidence; hover or select a partner to inspect one association.

UBE2D2SKP1CUL7CAND1CUL4AGLMNUBE2D1FBXW8SKP2NEDD8RBX1

10 strongest partners — larger node and heavier line mean higher confidence

Functional and physical associations from STRING v12.0. Only associations with this protein are drawn — partner-to-partner links are not part of this evidence.

Drugs targeting this protein

2

Whether each drug engages this protein directly or through a complex, and how many other targets are recorded for it. Direct binders with few recorded targets are listed first.

Thalidomide
ApprovedInhibitor

CRL4(CRBN) E3 ubiquitin ligase inhibitor

Appears in clinical studies involving plasma cell myeloma, immune system disorder, prostate cancer, non-small cell lung carcinoma

Acts on a complex — shared with CRBN, DDB1, CUL4A · 1 of 4 recorded protein targets

lenalidomide
ApprovedInhibitor

CRL4(CRBN) E3 ubiquitin ligase inhibitor

Appears in clinical studies involving anemia, mantle cell lymphoma, myelodysplastic syndrome, plasma cell myeloma

Acts on a complex — shared with CRBN, DDB1, CUL4A · 1 of 4 recorded protein targets

ChEMBL mechanism, action type and target identity. Open Targets clinical status and indications.

Translational evidence

Open Targets 26

Why this target matters therapeutically — disease associations, drugs in development, tractability and safety, from Open Targets.

Highest-confidence therapeutic associations

Diseases where a drug acting on this target has already reached clinical development.

plasma cell myeloma0.99

Clinical · overall 0.62

follicular lymphoma0.93

Clinical · overall 0.57

myelodysplastic syndrome0.93

Clinical · overall 0.56

mantle cell lymphoma0.90

Clinical · overall 0.55

immune system disorder0.83

Clinical · overall 0.50

Highest overall evidence

Remaining associations by Open Targets' aggregated evidence score.

cancer0.54

Pathway

HIV infectious disease0.50

Pathway

anemia0.49

Clinical

diffuse large B-cell lymphoma0.41

Clinical

marginal zone lymphoma0.40

Clinical

Show all associations
plasma cell myeloma0.62
follicular lymphoma0.57
myelodysplastic syndrome0.56
mantle cell lymphoma0.55
cancer0.54
HIV infectious disease0.50
immune system disorder0.50
anemia0.49
diffuse large B-cell lymphoma0.41
marginal zone lymphoma0.40

Open Targets ranks 364 associations for this target and we store the top 10 by aggregated score. The long tail is largely literature co-mention and RNA-expression evidence, not evidence that this target drives those diseases.

Known drugs · 4 total

IBERDOMIDEPhase 3

plasma cell myeloma · sarcoidosis · systemic lupus erythematosus

THALIDOMIDEApproval

plasma cell myeloma · immune system disorder · prostate cancer

LENALIDOMIDEApproval

anemia · mantle cell lymphoma · myelodysplastic syndrome

POMALIDOMIDEApproval

plasma cell myeloma · systemic sclerosis · immune system disorder

Tractability

SM · Approved DrugSM · Structure with LigandSM · High-Quality PocketPR · Database UbiquitinationPR · Half-life Data

Safety liabilities

neutropenia

Clinical trials

30

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein.

Show remaining trials (24)

UNKNOWN · via lenalidomide · NCT04025593

ClinicalTrials.gov via the drug-target graph.

Forefront confidence

Synthesis

Our own weighting of the evidence behind each disease association. Human genetics and clinical evidence count for most; literature co-mention counts for little, because two entities sharing an abstract is not evidence that one drives the other.

plasma cell myelomaWell supported
0.77
agreement 0.610.92
Clinical90%Literature10%

Open Targets aggregate 0.62 · 2 independent evidence families

follicular lymphomaModerately supported
0.70
agreement 0.530.86
Clinical100%

Open Targets aggregate 0.57 · 1 independent evidence family

myelodysplastic syndromeModerately supported
0.69
agreement 0.540.85
Clinical100%Literature0%

Open Targets aggregate 0.56 · 2 independent evidence families

mantle cell lymphomaModerately supported
0.68
agreement 0.510.84
Clinical100%

Open Targets aggregate 0.55 · 1 independent evidence family

immune system disorderModerately supported
0.62
agreement 0.460.79
Clinical100%

Open Targets aggregate 0.50 · 1 independent evidence family

The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the underlying per-type scores are shown above so the calculation can be checked.

What's happening now

60

Recent activity around this target, drawn from one canonical event stream. Every item is reached through 2 drugs that target this protein, so each event is news about that drug rather than about the protein directly.

  1. Label change2026-07-22

    Label change: LENALIDOMIDE (NDA021880)

    fda · regulatory · fda · via lenalidomide

  2. Industry development2026-06-29
    Advanced hierarchical ZnFe-LDH@MnO₂ nanostructures for sensitive voltammetric determination of lenalidomide

    Nature — Environmental Sciences · news · via lenalidomide

  3. Label change2026-06-15

    Label change: LENALIDOMIDE (ANDA201452)

    fda · regulatory · fda · via lenalidomide

  4. Label change2026-06-15

    Label change: LENALIDOMIDE (ANDA201452)

    fda · regulatory · fda · via lenalidomide

  5. Supplemental approval2026-04-27

    Supplemental approval: LENALIDOMIDE (ANDA201452)

    fda · regulatory · fda · via lenalidomide

  6. Supplemental approval2026-04-27

    Supplemental approval: LENALIDOMIDE (NDA021880)

    fda · regulatory · fda · via lenalidomide

  7. Supplemental approval2023-03-24

    Supplemental approval: LENALIDOMIDE (ANDA201452)

    fda · regulatory · fda · via lenalidomide

  8. Supplemental approval2023-03-24

    Supplemental approval: LENALIDOMIDE (NDA021880)

    fda · regulatory · fda · via lenalidomide

  9. Regulatory approval2023-03-06

    Approval: LENALIDOMIDE (ANDA201452)

    fda · regulatory · fda · via lenalidomide

  10. Regulatory approval2022-09-19

    Approval: Thalidomide Lipomed (EMA)

    ema · regulatory · ema · via Thalidomide

  11. Label change2022-05-24

    Label change: LENALIDOMIDE (NDA021880)

    fda · regulatory · fda · via lenalidomide

  12. Label change2021-08-31

    Label change: LENALIDOMIDE (NDA021880)

    fda · regulatory · fda · via lenalidomide

Objective event titles are shown unmodified; the event kind and significance line are derived from structured fields. Forefront AttentionEvent stream aggregating Europe PMC Regulatory filings ClinicalTrials.gov.