TY - JOUR
T1 - DNA-dependent protein kinase is activated by nicks and larger single- stranded gaps
AU - Morozov, V. E.
AU - Falzon, M.
AU - Anderson, C. W.
AU - Kuff, E. L.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1994
Y1 - 1994
N2 - DNA-PK is a DNA-activated serine/threonine protein kinase capable of phosphorylating a number of nuclear DNA-binding proteins. Purified human DNA- PK has two subunits, a 350-kDa polypeptide, Prkdc, which binds ATP and is presumed to contain the catalytic site, and the Ku autoantigen which mediates DNA binding and activation. Previous studies have shown that DNA-PK is activated in vitro by linear double-stranded DNA fragments; however, the Ku subunit binds a broader range of DNA structures. Here we show that EBP-80, a protein originally isolated as a transcription factor for a retroviral long terminal repeat element and subsequently found to be similar to if not identical with Ku, also mediates kinase activation. The EBP-80-Prkde complex is activated by nanomolar concentrations of DNA constructs containing single- to-double strand transitions, including a closed stem-loop structure and single strand gaps of 0 (nick), 6, and 30 nucleotides. Kinase activation parallels the ability of EBP-80 to bind these and other constructs. Our results extend the range of DNA configurations known to activate DNA-PK and are consistent with the participation of this enzyme complex in several nuclear functions.
AB - DNA-PK is a DNA-activated serine/threonine protein kinase capable of phosphorylating a number of nuclear DNA-binding proteins. Purified human DNA- PK has two subunits, a 350-kDa polypeptide, Prkdc, which binds ATP and is presumed to contain the catalytic site, and the Ku autoantigen which mediates DNA binding and activation. Previous studies have shown that DNA-PK is activated in vitro by linear double-stranded DNA fragments; however, the Ku subunit binds a broader range of DNA structures. Here we show that EBP-80, a protein originally isolated as a transcription factor for a retroviral long terminal repeat element and subsequently found to be similar to if not identical with Ku, also mediates kinase activation. The EBP-80-Prkde complex is activated by nanomolar concentrations of DNA constructs containing single- to-double strand transitions, including a closed stem-loop structure and single strand gaps of 0 (nick), 6, and 30 nucleotides. Kinase activation parallels the ability of EBP-80 to bind these and other constructs. Our results extend the range of DNA configurations known to activate DNA-PK and are consistent with the participation of this enzyme complex in several nuclear functions.
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M3 - Article
C2 - 8206988
AN - SCOPUS:0028286463
SN - 0021-9258
VL - 269
SP - 16684
EP - 16688
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 24
ER -