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XPB
from Wikipedia
ERCC3
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesERCC3, excision repair cross-complementation group 3, BTF2, GTF2H, RAD25, TFIIH, XPB, TTD2, ERCC excision repair 3, TFIIH core complex helicase subunit, Ssl2
External IDsOMIM: 133510; MGI: 95414; HomoloGene: 96; GeneCards: ERCC3; OMA:ERCC3 - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_000122
NM_001303416
NM_001303418

NM_133658

RefSeq (protein)

NP_000113
NP_001290345
NP_001290347

NP_598419

Location (UCSC)Chr 2: 127.26 – 127.29 MbChr 18: 32.37 – 32.4 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

XPB (xeroderma pigmentosum type B) is an ATP-dependent DNA helicase in humans that is a part of the TFIIH transcription factor complex.

Structure

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The 3D-structure of the archaeal homolog of XPB has been solved by X-ray crystallography by Dr. John Tainer and his group at The Scripps Research Institute.[5]

Function

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XPB plays a significant role in normal basal transcription, transcription coupled repair (TCR), and nucleotide excision repair (NER). Purified XPB has been shown to unwind DNA with 3’-5’ polarity.

The function of the XPB(ERCC3) protein in NER is to assist in unwinding the DNA double helix after damage is initially recognized. NER is a multi-step pathway that removes a wide range of different DNA damages that distort normal base pairing. Such damages include bulky chemical adducts, UV-induced pyrimidine dimers, and several forms of oxidative damage. Mutations in the XPB(ERCC3) gene can lead, in humans, to xeroderma pigmentosum (XP) or XP combined with Cockayne syndrome (XPCS).[6] Mutant XPB cells from individuals with the XPCS phenotype are sensitive to UV irradiation and acute oxidative stress.[7]

XPB helicase is also a component of the p53-mediated programmed cell death (apoptosis) pathway.[8]

Disorders

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Mutations in XPB and other related complementation groups, XPA-XPG, leads to a number of genetic disorders such as Xeroderma pigmentosum, Cockayne's syndrome, and trichothiodystrophy.

Interactions

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XPB has been shown to interact with:

Small molecule inhibitors

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Potent, bioactive natural products like triptolide that inhibit mammalian transcription via inhibition of the XPB subunit of the general transcription factor TFIIH has been recently reported as a glucose conjugate for targeting hypoxic cancer cells with increased glucose transporter expression.[19]

See also

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References

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Further reading

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