HeLa nuclear protein recognizing DNA termini and translocating on DNA forming a regular DNA-multimeric protein complex

Devries, Ege; Vandriel, W; Bergsma, Wg; Arnberg, Annika C.; Vandervliet, Pc

doi:10.1016/0022-2836(89)90088-0

Cited by 244 publications

(217 citation statements)

References 32 publications

Supporting

Mentioning

194

Contrasting

Unclassified

Order By: Relevance

“…As shown in Figure 1, in the human cell lines AHH1 and HeLa, at least three complexes of di erent mobility were observed (A, A' and A''). Ku has the ability to translocate internally on DNA allowing another Ku heterodimer to bind to free DNA ends (deVries et al, 1989). Thus, the increase in complex A' and A'' formation in association with increased protein concentration is likely to correspond to the binding of multiple Ku heterodimers to the same DNA-probe as previously described (Zhang and Yaneva, 1992).…”

Section: Detection Of An Altered Form Of the Ku Heterdomer In Periphesupporting

confidence: 51%

Human normal peripheral blood B-lymphocytes are deficient in DNA-dependent protein kinase activity due to the expression of a variant form of the Ku86 protein

et al. 1998

View full text Add to dashboard Cite

The heterodimeric Ku protein, which comprises a 86 kDa (Ku86) amd a 70 kDa (Ku70) subunits, is an abundant nuclear DNA-binding protein which binds in vitro to DNA termini without sequence speci®city. Ku is the DNA-targeting component of the large catalytic sub-unit of the DNA-dependent protein kinase complex (DNA-PK CS ), that plays a critical role in mammalian doublestrand break repair and lymphoid V(D)J recombination. By using electrophoretic mobility shift assays, we demonstrated that in addition to the major Ku⋅DNA complex usually detected in cell line extracts, a second complex with faster electrophoretic mobility was observed in normal peripheral blood lymphocytes (PBL) extracts. The presence of this faster migrating complex was restricted to B cells among the circulating lymphocyte population. Western blot analysis revealed that B cells express a variant form of the Ku86 protein with an apparent molecular weight of 69 kDa, and not the 86 kDa-full-length protein. Although the heterodimer Ku70/variant-Ku86 binds to DNA-ends, this altered form of the Ku heterodimer has a decreased ability to recruit the catalytic component of the complex, DNA-PK CS , which contributes to an absence of detectable DNA-PK activity in B cells. These data provide a molecular basis for the increased sensitivity of B cells to ionizing radiation and identify a new mechanism of regulation of DNA-PK activity that operates in vivo.

show abstract

Section: Detection Of An Altered Form Of the Ku Heterdomer In Periphesupporting

confidence: 51%

Human normal peripheral blood B-lymphocytes are deficient in DNA-dependent protein kinase activity due to the expression of a variant form of the Ku86 protein

et al. 1998

View full text Add to dashboard Cite

show abstract

“…Previous reports have found Ku capable of binding to linear DNA ends and translocating to internal positions with little or no sequence specificity (53). Ku is capable of binding to hairpin structures, single-stranded nicks, and gaps in an apparently sequence-independent manner (44)(45)(46)61).…”

Section: Discussionmentioning

confidence: 99%

DNA looping by Ku and the DNA-dependent protein kinase

Cary

Peterson

Wang

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

227

138

View full text Add to dashboard Cite

The DNA-dependent protein kinase (DNA-PK) is required for DNA double-strand break (DSB) repair and immunoglobulin gene rearrangement and may play a role in the regulation of transcription. The DNA-PK holoenzyme is composed of three polypeptide subunits: the DNA binding Ku70͞86 heterodimer and an Ϸ460-kDa catalytic subunit (DNA-PKcs). DNA-PK has been hypothesized to assemble at DNA DSBs and play structural as well as signal transduction roles in DSB repair. Recent advances in atomic force microscopy (AFM) have resulted in a technology capable of producing high resolution images of native protein and proteinnucleic acid complexes without staining or metal coating. The AFM provides a rapid and direct means of probing the protein-nucleic acid interactions responsible for DNA repair and genetic regulation. Here we have employed AFM as well as electron microscopy to visualize Ku and DNA-PK in association with DNA. A significant number of DNA molecules formed loops in the presence of Ku. DNA looping appeared to be sequence-independent and unaffected by the presence of DNA-PKcs. Gel filtration of Ku in the absence and the presence of DNA indicates that Ku does not form nonspecific aggregates. We conclude that, when bound to DNA, Ku is capable of self-association. These findings suggest that Ku binding at DNA DSBs will result in Ku self-association and a physical tethering of the broken DNA strands.

show abstract

“…In the NHEJ pathway, the Ku70/Ku86 (Ku86 is also known as Ku80) heterodimer is the first protein to bind to the broken DNA ends at the site of DSBs (Mimori and Hardin, 1986;de Vries et al, 1989;Falzon et al, 1993). Binding of Ku to broken DNA termini recruits another PIKK family member, known as the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) (Chiu et al, 1998;Hammarsten and Chu, 1998;West et al, 1998).…”

Section: Mechanisms Of Hdac Inhibitor-mediated Enhanced Radiation Senmentioning

confidence: 99%

Modulation of cellular radiation responses by histone deacetylase inhibitors

Karagiannis

El‐Osta

2006

Oncogene

View full text Add to dashboard Cite

Histone deacetylase (HDAC) inhibitors are emerging as a new class of targeted cancer chemotherapeutics. Several HDAC inhibitors are currently in clinical trials and promising anticancer effects at well-tolerated doses have been observed for both hematologic and solid cancers. HDAC inhibitors have been shown to induce cell-cycle and growth arrest, differentiation and in certain cases apoptosis in cell cultures and in vivo. However, it is known that these compounds induce varying responses in different cells and biological settings, and identifying their precise mechanisms of action is an area of great interest. Important findings are continually expanding our understanding of the cellular effects of HDAC inhibitors and recent studies will be briefly outlined in this review. In addition to their intrinsic anticancer properties, numerous studies have demonstrated that HDAC inhibitors can modulate cellular responses to other cytotoxic modalities including ionizing radiation, ultraviolet radiation and chemotherapeutic drugs. Hence, there is a growing interest in potential clinical use of HDAC inhibitors in combination with conventional cancer therapies. In this review, the interaction of HDAC inhibitors with other anticancer agents is discussed. The focus of the article is on the different mechanisms by which HDAC inhibitors enhance the sensitivity of cells to the effects of ionizing radiation.

show abstract

HeLa nuclear protein recognizing DNA termini and translocating on DNA forming a regular DNA-multimeric protein complex

Cited by 244 publications

References 32 publications

Human normal peripheral blood B-lymphocytes are deficient in DNA-dependent protein kinase activity due to the expression of a variant form of the Ku86 protein

Human normal peripheral blood B-lymphocytes are deficient in DNA-dependent protein kinase activity due to the expression of a variant form of the Ku86 protein

DNA looping by Ku and the DNA-dependent protein kinase

Modulation of cellular radiation responses by histone deacetylase inhibitors

Contact Info

Product

Resources

About