Evidence for distinct functions for human DNA repair factors hHR23A and hHR23B.
Rad23 proteins bind ubiquitinated substrates and the proteasome, consistent with an important role in protein degradation. Although human Rad23 proteins (hHR23A and hHR23B) have redundant roles in DNA repair, we determined they formed distinct interactions with proteasomes and multiubiquitinated proteins, but similar binding to Ataxin-3. 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. 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.
Chen
Li
L
Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
Madura
Kiran
K
D000595:Amino Acid Sequence; D000067699:Ataxin-3; D002460:Cell Line; D004260:DNA Repair; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000502:physiology*; D006801:Humans; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms / Q000502:physiology*; D012097:Repressor Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013912:Threonine / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism
D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; C513287:RAD23B protein, human; D012097:Repressor Proteins; D025801:Ubiquitin; C086985:RAD23A protein, human; D013912:Threonine; C092341:ATXN3 protein, human; D000067699:Ataxin-3; D046988:Proteasome Endopeptidase Complex; D045643:DNA Repair Enzymes