Phosphorylation of human replication protein A by the DNA-dependent protein kinase is involved in the modulation of DNA replication.
AUTOR(ES)
Henricksen, L A
RESUMO
The single-stranded DNA-binding protein, Replication Protein A (RPA), is a heterotrimeric complex with subunits of 70, 32 and 14 kDa involved in DNA metabolism. RPA may be a target for cellular regulation; the 32 kDa subunit (RPA32) is phosphorylated by several cellular kinases including the DNA-dependent protein kinase (DNA-PK). We have purified a mutant hRPA complex lacking amino acids 1-33 of RPA32 (rhRPA x 32delta1-33). This mutant bound ssDNA and supported DNA replication; however, rhRPA x 32delta1-33 was not phosphorylated under replication conditions or directly by DNA-PK. Proteolytic mapping revealed that all the sites phosphorylated by DNA-PK are contained on residues 1-33 of RPA32. When wild-type RPA was treated with DNA-PK and the mixture added to SV40 replication assays, DNA replication was supported. In contrast, when rhRPA x 32delta1-33 was treated with DNA-PK, DNA replication was strongly inhibited. Because untreated rhRPA x 32delta1-33 is fully functional, this suggests that the N-terminus of RPA is needed to overcome inhibitory effects of DNA-PK on other components of the DNA replication system. Thus, phosphorylation of RPA may modulate DNA replication indirectly, through interactions with other proteins whose activity is modulated by phosphorylation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=146026Documentos Relacionados
- scid cells are deficient in Ku and replication protein A phosphorylation by the DNA-dependent protein kinase.
- Synapsis of DNA ends by DNA-dependent protein kinase
- DNA looping by Ku and the DNA-dependent protein kinase
- Phosphorylation of linker histones by DNA-dependent protein kinase is required for DNA ligase IV-dependent ligation in the presence of histone H1
- Single-stranded-DNA binding alters human replication protein A structure and facilitates interaction with DNA-dependent protein kinase.