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Gene Review

RAD23A  -  RAD23 homolog A (S. cerevisiae)

Homo sapiens

Synonyms: HHR23A, HR23A, MGC111083, UV excision repair protein RAD23 homolog A, hHR23A
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Disease relevance of RAD23A

  • We also determined that hHR23A and hHR23B could be co-purified with unique proteolytic and stress-responsive factors from human breast cancer tissues, indicating that they have unique functions in vivo [1].
  • Analysis of apoptosis induced by HIV-1 Vpr and examination of the possible role of the hHR23A protein [2].
  • Yeast two-hybrid selection of proteins interacting with human immunodeficiency virus type 1 Vpr identified HHR23A, a human homologue of the yeast DNA repair protein RAD23, as a specific interactor [3].
  • The two human homologs of Rad23, hHR23A and B, are functionally redundant in NER and interact with xeroderma pigmentosum complementation group C (XPC) protein [4].

High impact information on RAD23A


Biological context of RAD23A


Anatomical context of RAD23A


Associations of RAD23A with chemical compounds

  • Threonine-79 contributed to the weak proteasome-binding property of hHR23A, and its conversion to proline (T79P), which is the residue present in hHR23B, increased proteasome interaction [1].
  • We present evidence that the UBL domain of HHR23A negatively regulates polyubiquitin/UBA interactions and identify leucine 8 of ubiquitin as an important determinant of chain recognition [13].

Physical interactions of RAD23A

  • Consistent with this hypothesis, an MDM2 mutant that demonstrated increased binding in vivo to hHR23A was able to ubiquitinate, but not degrade p53 [14].
  • Structure of the XPC binding domain of hHR23A reveals hydrophobic patches for protein interaction [4].
  • However, the interaction is dissimilar to the molecular models proposed for the hHR23A UBA domains bound to either monoubiquitin or Lys48-linked diubiquitin [15].

Other interactions of RAD23A

  • The hHR23A knock-down (KD) construct diminished the RNA level of hHR23A protein by approximately 60%, and it did not interfere with expression of the hHR23B gene [10].
  • Moreover, the defective phenotype of this MDM2 mutant was rescued by siRNA knockdown of hHR23A [14].
  • Although HHR23A is a stable protein in non-synchronized cells, its levels are regulated in a cell cycle-dependent manner, with specific degradation occurring during S phase [9].

Analytical, diagnostic and therapeutic context of RAD23A


  1. Evidence for distinct functions for human DNA repair factors hHR23A and hHR23B. Chen, L., Madura, K. FEBS Lett. (2006) [Pubmed]
  2. Analysis of apoptosis induced by HIV-1 Vpr and examination of the possible role of the hHR23A protein. Gaynor, E.M., Chen, I.S. Exp. Cell Res. (2001) [Pubmed]
  3. HHR23A, the human homologue of the yeast repair protein RAD23, interacts specifically with Vpr protein and prevents cell cycle arrest but not the transcriptional effects of Vpr. Gragerov, A., Kino, T., Ilyina-Gragerova, G., Chrousos, G.P., Pavlakis, G.N. Virology (1998) [Pubmed]
  4. Structure of the XPC binding domain of hHR23A reveals hydrophobic patches for protein interaction. Kamionka, M., Feigon, J. Protein Sci. (2004) [Pubmed]
  5. Structural determinants for selective recognition of a Lys48-linked polyubiquitin chain by a UBA domain. Varadan, R., Assfalg, M., Raasi, S., Pickart, C., Fushman, D. Mol. Cell (2005) [Pubmed]
  6. Structural determinants for the binding of ubiquitin-like domains to the proteasome. Mueller, T.D., Feigon, J. EMBO J. (2003) [Pubmed]
  7. Ataxin-3, the MJD1 gene product, interacts with the two human homologs of yeast DNA repair protein RAD23, HHR23A and HHR23B. Wang, G., Sawai, N., Kotliarova, S., Kanazawa, I., Nukina, N. Hum. Mol. Genet. (2000) [Pubmed]
  8. 3-Methyladenine-DNA glycosylase (MPG protein) interacts with human RAD23 proteins. Miao, F., Bouziane, M., Dammann, R., Masutani, C., Hanaoka, F., Pfeifer, G., O'Connor, T.R. J. Biol. Chem. (2000) [Pubmed]
  9. Identification of HHR23A as a substrate for E6-associated protein-mediated ubiquitination. Kumar, S., Talis, A.L., Howley, P.M. J. Biol. Chem. (1999) [Pubmed]
  10. HHR23A, a human homolog of Saccharomyces cerevisiae Rad23, regulates xeroderma pigmentosum C protein and is required for nucleotide excision repair. Hsieh, H.C., Hsieh, Y.H., Huang, Y.H., Shen, F.C., Tsai, H.N., Tsai, J.H., Lai, Y.T., Wang, Y.T., Chuang, W.J., Huang, W. Biochem. Biophys. Res. Commun. (2005) [Pubmed]
  11. Chromosomal localization of three repair genes: the xeroderma pigmentosum group C gene and two human homologs of yeast RAD23. van der Spek, P.J., Smit, E.M., Beverloo, H.B., Sugasawa, K., Masutani, C., Hanaoka, F., Hoeijmakers, J.H., Hagemeijer, A. Genomics (1994) [Pubmed]
  12. Human immunodeficiency virus type 1 Vpr interacts with HHR23A, a cellular protein implicated in nucleotide excision DNA repair. Withers-Ward, E.S., Jowett, J.B., Stewart, S.A., Xie, Y.M., Garfinkel, A., Shibagaki, Y., Chow, S.A., Shah, N., Hanaoka, F., Sawitz, D.G., Armstrong, R.W., Souza, L.M., Chen, I.S. J. Virol. (1997) [Pubmed]
  13. Binding of polyubiquitin chains to ubiquitin-associated (UBA) domains of HHR23A. Raasi, S., Orlov, I., Fleming, K.G., Pickart, C.M. J. Mol. Biol. (2004) [Pubmed]
  14. A post-ubiquitination role for MDM2 and hHR23A in the p53 degradation pathway. Brignone, C., Bradley, K.E., Kisselev, A.F., Grossman, S.R. Oncogene (2004) [Pubmed]
  15. Structural basis for monoubiquitin recognition by the Ede1 UBA domain. Swanson, K.A., Hicke, L., Radhakrishnan, I. J. Mol. Biol. (2006) [Pubmed]
  16. XPC and human homologs of RAD23: intracellular localization and relationship to other nucleotide excision repair complexes. van der Spek, P.J., Eker, A., Rademakers, S., Visser, C., Sugasawa, K., Masutani, C., Hanaoka, F., Bootsma, D., Hoeijmakers, J.H. Nucleic Acids Res. (1996) [Pubmed]
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