Autoantibodies to DNA-dependent protein kinase probes for the catalytic subunit

Akira Suwa, Michito Hirakata, Yoshihiko Takeda, Yutaka Okano, Tsuneyo Mimori, Shinichi Inada, Fumiaki Watanabe, Hirobumi Teraoka, William S. Dynan, John A. Hardin

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


DNA-dependent protein kinase (DNA-PK) is an important nuclear enzyme which consists of a catalytic subunit known as DNA-PKcs and a regulatory component identified as the Ku autoantigen. In the present study, we surveyed 312 patients in a search for this specificity. 10 sera immunoprecipitated a large polypeptide which exactly comigrated with DNA-PKcs in SDS-PAGE. Immunoblot analysis demonstrated that this polypeptide was recognizable by a rabbit antiserum specific for DNA-PKcs. Although the patient sera did not bind to biochemically purified DNA-PKcs in immunoblots or ELISA, they were able to deplete DNA-PK catalytic activity from extracts of HeLa cells in a dose-dependent manner. We conclude that these antibodies should be useful probes for studies which aim to define the role of DNA-PK in cells. Since six sera simultaneously contained antibodies to the Ku protein, these studies suggest that relatively intact forms of DNA-PK complex act as autoantigenic particles in selected patients.

Original languageEnglish
Pages (from-to)1417-1421
Number of pages5
JournalJournal of Clinical Investigation
Issue number6
Publication statusPublished - 1996 Mar 15


  • Antinuclear antibodies
  • Autoantibodies
  • Autoimmunity
  • DNA-dependent protein kinase
  • Ku protein

ASJC Scopus subject areas

  • Medicine(all)


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