RNF20

Overview

RNF20 (Ring Finger Protein 20) is an E3 ubiquitin-protein ligase encoded by the RNF20 gene located on chromosome 9q34.3^{1RNF20 and H2B ubiquitination2009 · Mol Cell · PMID 19324053Open reference}. This enzyme catalyzes the monoubiquitination of histone H2B at Lys120 (H2B-K120ub1), an epigenetic modification with profound implications for transcription regulation, DNA repair, and chromosome dynamics^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}. RNF20-mediated H2B ubiquitination is a key driver of transcriptional elongation and has been implicated in various cancers including colon, breast, gastric, and prostate cancers.

The loss of RNF20 expression has been observed in multiple tumor types, suggesting a tumor suppressor function. RNF20-mediated H2B ubiquitination facilitates the recruitment of elongation factors and promotes productive transcription. Additionally, this modification plays roles in DNA damage response and checkpoint activation, making it an important regulator of genomic stability^{3H2B ubiquitination and Pol II2006 · Cell · PMID 16682354Open reference}.

Function

Function

RNF20 is an E3 ubiquitin-protein ligase that catalyzes monoubiquitination of histone H2B at Lys120 (H2B-K120ub1)^{1RNF20 and H2B ubiquitination2009 · Mol Cell · PMID 19324053Open reference}. This epigenetic modification plays crucial roles in transcription regulation, DNA repair, and chromosome dynamics.

Key Molecular Functions

• H2B ubiquitination: Catalyzes H2B K120ub1, a modification associated with active transcription^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}

• Transcriptional elongation: H2B-K120ub1 facilitates RNA Pol II passage through chromatin^{3H2B ubiquitination and Pol II2006 · Cell · PMID 16682354Open reference}

• DNA damage response: H2B ubiquitination promotes homologous recombination repair^{4H2B ubiquitination in DNA repair2011 · Nat Cell Biol · PMID 21502818Open reference}

• p53 regulation: RNF20 modulates p53 activity through H2B ubiquitination^{5RNF20-p53 pathway2008 · Mol Cell · PMID 18948756Open reference}

The protein functions as a scaffold, recruiting additional factors including:

• BRE1A/B (RNF40), the E3 ligase partner

• WAC, a cofactor that stimulates RNF20 activity^{6WAC and RNF20 cooperation2009 · Genes Dev · PMID 19270696Open reference}

• PAF1 complex, linking ubiquitination to transcriptional elongation^{7PAF1 complex and H2Bub12010 · Mol Cell · PMID 20400964Open reference}

Disease Associations

Cancer

• Colorectal cancer: RNF20 frequently downregulated; tumor suppressor function^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}0

• Breast cancer: RNF20 expression correlates with prognosis; loss promotes metastasis^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}1

• Gastric cancer: RNF20 reduced in aggressive subtypes^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}2

• Prostate cancer: Androgen receptor-mediated repression of RNF20 promotes progression^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}3

Neurodegeneration

• Alzheimer’s disease: RNF20/H2B-K120ub1 axis dysregulated in AD; affects neuronal gene expression^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}4

• Huntington’s disease: RNF20-mediated chromatin changes in HD models^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}5

• Parkinson’s disease: Transcriptional dysregulation involves altered H2B ubiquitination^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}6

Expression

RNF20 is ubiquitously expressed with tissue-specific variations^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}7:

• High expression: Testis, bone marrow, brain

• Moderate expression: Liver, kidney, lung

In the brain:

• Neurons throughout cortex and hippocampus

• Glial cells

• Expression regulated during neural development and aging

Therapeutic Implications

• Epigenetic therapy: RNF20 modulators may restore H2B-K120ub1 balance in cancer^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}8

• Combination therapy: RNF20-targeting with BET inhibitors shows synergy^{2H2B-K120ub1 and transcription2008 · Nature · PMID 18698038Open reference}9

• Neuroprotection: Understanding RNF20’s role may lead to AD/HD therapeutics^{3H2B ubiquitination and Pol II2006 · Cell · PMID 16682354Open reference}0

Pathway & Interaction Diagram

Interactive diagram showing RNF20’s key relationships in the SciDEX knowledge graph (8 connections shown).

flowchart TD
    RNF20(["RNF20"])
    Als["Als"]
    UBIQUITIN(["UBIQUITIN"])
    T_Cell["T Cell"]
    PPAR(["PPAR"])
    NCOR1(["NCOR1"])
    neurodegeneration["neurodegeneration"]

    RNF20 -->|"activates"| Als
    RNF20 -->|"regulates"| Als
    RNF20 -->|"associated with"| UBIQUITIN
    RNF20 -->|"activates"| T_Cell
    RNF20 -->|"regulates"| UBIQUITIN
    PPAR -->|"activates"| RNF20
    NCOR1 -->|"activates"| RNF20
    RNF20 -->|"implicated in"| neurodegeneration

    style RNF20 fill:#1a237e,stroke:#4fc3f7,stroke-width:3px,color:#fff

See Also

• RNF40 - Partner E3 ligase

• H2B - Substrate

• Epigenetic Regulation - Pathway

• Transcription - Related mechanism

External Links

• NCBI Gene: RNF20

• UniProt: Q5VTL2

• OMIM: 607683