Human ku autoantigen binds cisplatin damaged dna but fails to stimulate dna-activated protein kinase

John J. Turchi, Karen Henkels

Research output: Contribution to journalArticle

Abstract

We have identified a series of proteins based on an affinity for cisplatin damaged DNA. One protein termed DRP-1 has been purified to homogeneity and was isolated as two distinct complexes. The first complex is a heterodimer of 83 and 68 kDa subunits, while the second complex is a heterotrimer of 350, 83 and 68 kDa subunits in a 1:1:1 ratio. The 83 and 68 kDa subunits in each complex are identical. The 83 kDa subunit of DRP-1 was identified as the p80 subunit of Ku autoantigen by N-terminal protein sequence and western blot analysis. The 68 kDa subunit of DRP-1 cross reacted with monoclonal antisera raised against the Ku autoantigen p70 subunit. The 350 kDa subunit was identified as Prkdc, the catalytic subunit of the human DNA-activated protein kinase, DNA-PK. DRP-1 DNA binding was assessed in mobility shift assays and results indicate that DNA binding was essentially unaffected by cisplatin-DNA adducts in the presence or absence of Prkdc. DNA-PK activity was only stimulated with undamaged DNA, despite the ability of Ku to bind to cisplatin damaged DNA. The lack of DNA-PK stimulation by cisplatin damaged DNA correlated with the extent of cisplatin-DNA adduct formation. These results are discussed with respect to the repair of cisplatin-DNA adducts and the role of DNA-PK in coordinating DNA repair processes.

Original languageEnglish (US)
Pages (from-to)A967
JournalFASEB Journal
Volume10
Issue number6
StatePublished - Dec 1 1996
Externally publishedYes

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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