Role of a major autoepitope in forming the DNA binding site of the p70 (Ku) antigen

doi:10.1084/jem.175.6.1677

This Article

	Full Text (PDF, 980K)
	Alert me when this article is cited
	Citation Map

Services

	Email this article
	Similar articles in this journal
	Similar articles in PubMed
	Alert me to new content in the JEM
	Download to citation manager

Citing Articles

	Citing Articles via HighWire
	Citing Articles via CrossRef
	Citing Articles via Google Scholar

Google Scholar

	Articles by Chou, C. H.
	Articles by Reeves, W. H.
	Search for Related Content

PubMed

	PubMed Citation
	Articles by Chou, C. H.
	Articles by Reeves, W. H.


Social Bookmarking

	What's this?

ARTICLES

Role of a major autoepitope in forming the DNA binding site of the p70 (Ku) antigen

CH Chou, J Wang, MW Knuth and WH Reeves
Division of Rheumatology and Immunology, University of North Carolina School of Medicine, Chapel Hill 27599.

The Ku antigen is a heterodimer consisting of 70- and 80-kD protein subunits that binds to termini of double-stranded DNA. DNA binding appears to be mediated partly by the 70-kD (p70) subunit, but the precise mechanism of its association with DNA is unclear. High-titer autoantibodies in sera from certain patients with systemic lupus erythematosus recognize at least eight distinct epitopes of Ku, and inhibit DNA binding. In the present studies, the binding of DNA to truncated p70 fusion proteins was determined in Southwestern blots and DNA immunoprecipitation assays. Appropriate folding of the p70 protein was crucial for efficient DNA binding. The minimal DNA binding site, amino acids 536-609, contains a major conformational autoepitope of p70 (amino acids 560-609). Deletion of amino acids 601-609, or substitution of ala-ala-ala for lys-ser-gly at positions 591-593, eliminated DNA binding as well as autoantibody binding, suggesting that the same secondary or supersecondary structure is involved in both DNA binding and autoantibody recognition. Residues within the DNA binding site/autoepitope closely resemble the helix-turn-helix motif in bacteriophage lambda Cro protein and certain other DNA binding proteins, and mutations predicted to destabilize this structure eliminated DNA binding. Adjacent to the helix-turn-helix is a highly basic domain (positions 539-559) that was also required for DNA binding. The findings suggest that the DNA binding site of p70 consists of a basic domain adjacent to a helix-turn-helix structure that also forms a major autoepitope.
Add to CiteULike CiteULike Add to Complore Complore Add to Connotea Connotea Add to Del.icio.us Del.icio.us Add to Digg Digg Facebook Add to Reddit Reddit Add to Technorati Technorati Twitter What's this?

This article has been cited by other articles:

Postow, L., Ghenoiu, C., Woo, E. M., Krutchinsky, A. N., Chait, B. T., Funabiki, H. (2008). Ku80 removal from DNA through double strand break-induced ubiquitylation. JCB 182: 467-479 [Abstract] [Full Text]
Chen, C.-S., Wang, Y.-C., Yang, H.-C., Huang, P.-H., Kulp, S. K., Yang, C.-C., Lu, Y.-S., Matsuyama, S., Chen, C.-Y., Chen, C.-S. (2007). Histone Deacetylase Inhibitors Sensitize Prostate Cancer Cells to Agents that Produce DNA Double-Strand Breaks by Targeting Ku70 Acetylation. Cancer Res. 67: 5318-5327 [Abstract] [Full Text]
Ahn, J. S., Whitby, M. C. (2003). The Role of the SAP Motif in Promoting Holliday Junction Binding and Resolution by SpCCE1. J. Biol. Chem. 278: 29121-29129 [Abstract] [Full Text]
Novac, O., Matheos, D., Araujo, F. D., Price, G. B., Zannis-Hadjopoulos, M. (2001). In Vivo Association of Ku with Mammalian Origins of DNA Replication. Mol. Biol. Cell 12: 3386-3401 [Abstract] [Full Text]
Satoh, M., Shaheen, V. M., Kao, P. N., Okano, T., Shaw, M., Yoshida, H., Richards, H. B., Reeves, W. H. (1999). Autoantibodies Define a Family of Proteins with Conserved Double-stranded RNA-binding Domains as Well as DNA Binding Activity. J. Biol. Chem. 274: 34598-34604 [Abstract] [Full Text]
Wang, J., Dong, X., Reeves, W. H. (1998). A Model for Ku Heterodimer Assembly and Interaction with DNA. IMPLICATIONS FOR THE FUNCTION OF Ku ANTIGEN. J. Biol. Chem. 273: 31068-31074 [Abstract] [Full Text]
Wang, J., Dong, X., Myung, K., Hendrickson, E. A., Reeves, W. H. (1998). Identification of Two Domains of the p70 Ku Protein Mediating Dimerization with p80 and DNA Binding. J. Biol. Chem. 273: 842-848 [Abstract] [Full Text]
Ochem, A. E., Skopac, D., Costa, M., Rabilloud, T., Vuillard, L., Simoncsits, A., Giacca, M., Falaschi, A. (1997). Functional Properties of the Separate Subunits of Human DNA Helicase II/Ku Autoantigen. J. Biol. Chem. 272: 29919-29926 [Abstract] [Full Text]
Osipovich, O., Durum, S. K., Muegge, K. (1997). Defining the Minimal Domain of Ku80 for Interaction with Ku70. J. Biol. Chem. 272: 27259-27265 [Abstract] [Full Text]
Ouyang, H., Nussenzweig, A., Kurimasa, A., Soares, V. d. C., Li, X., Cordon-Cardo, C., Li, W.-h., Cheong, N., Nussenzweig, M., Iliakis, G., Chen, D. J., Li, G. C. (1997). Ku70 Is Required for DNA Repair but Not for T Cell Antigen Receptor Gene Recombination In Vivo. JEM 186: 921-929 [Abstract] [Full Text]
Han, Z., Johnston, C., Reeves, W. H., Carter, T., Wyche, J. H., Hendrickson, E. A. (1996). Characterization of a Ku86 Variant Protein That Results in Altered DNA Binding and Diminished DNA-dependent Protein Kinase Activity. J. Biol. Chem. 271: 14098-14104 [Abstract] [Full Text]
Fewell, J., Kuff, E. (1996). Intracellular redistribution of Ku immunoreactivity in response to cell-cell contact and growth modulating components in the medium. J. Cell Sci. 109: 1937-1946 [Abstract]
Wang, J, Satoh, M, Pierani, A, Schmitt, J, Chou, C., Stunnenberg, H., Roeder, R., Reeves, W. (1994). Assembly and DNA binding of recombinant Ku (p70/p80) autoantigen defined by a novel monoclonal antibody specific for p70/p80 heterodimers. J. Cell Sci. 107: 3223-3233 [Abstract]
Zhang, Z., Zhu, L., Lin, D., Chen, F., Chen, D. J., Chen, Y. (2001). The Three-dimensional Structure of the C-terminal DNA-binding Domain of Human Ku70. J. Biol. Chem. 276: 38231-38236 [Abstract] [Full Text]