Bethyl Laboratories, Inc.

Antibodies Against Ku70 and Ku80

May 4, 2010

Overview

The Ku protein was originally identified as an antigen recognized by antibodies present in the serum of patients with autoimmune disease. The designation of this antigen as �Ku� is reported to be derived from the surname of a Japanese patient. The Ku antigen is made up of a heterodimer of two subunits of approximately 70 kDa and 80 kDa. Biochemical characterization of the Ku antigen, along with studies of the DNA-dependent serine/threonine protein kinase, DNA-PK, revealed that Ku protein associates with the ends of linear duplex DNA and is the regulatory component of DNA-PK (DNA protein kinase). Later it was established that Ku protein plays a central role in DNA double-strand break repair and transposition. In the presence of DSBs, Ku binds DNA ends and recruits the DNA-protein kinase catalytic subunit (DNA-PKcs) leading to phosphorylation events and further recruitment of DNA repair enzymes to the break site. Ku not only localizes to the nucleus as first described, but it is also found in the cytosol and on the cell surface. This discovery has broadened the probable functions of Ku antigen. In the cytosol, Ku plays a role in cell-survival; and on the cell surface, it is suspected to play a role in cell adhesion. The discovery of Ku as a cell surface protein has lead to the investigation of alternate roles of Ku in transformation and metastasis.

Selected Reviews
1. W. S. Dynan and S. Yoo, "Interaction of Ku Protein and DNA-Dependent Protein Kinase Catalytic Subunit With Nucleic Acids," Nucleic Acids Res. 26, no. 7 (1998): 1551-1559.
2. C. Muller et al., "The Double Life of the Ku Protein: Facing the DNA Breaks and the Extracellular Environment," Cell Cycle. 4, no. 3 (2005): 438-441.

Bethyl Laboratories' Portfolio
Ku70 Ku80	Detection of Human Ku70 by WB and IP. Samples: Whole cell lysate from HeLa (5, 15 and 50 mcg for WB; 1 mg for IP, 20% of IP loaded) and 293T (T; 50 mcg) cells. Antibodies: Ku70 antibody A302-625A used for WB at 0.04 mcg/ml (A) and 1 mcg/ml (B) and used for IP at 3 mcg/mg lysate. Ku70 was also immunoprecipitated by Ku70 antibodies A302-623A and A302-624A, which recognize upstream epitopes. For blotting immunoprecipitated Ku70, the ReliaBLOT Reagents and Procedures (Cat. No. WB120) were used. Detection: Chemiluminescence with exposure times of 3 seconds (A) and 1 second (B).	Detection of Human Ku80 by WB and IP. Samples: Whole cell lysate from HeLa (5, 15 and 50 mcg for WB; 1 mg for IP, 20% of IP loaded) and 293T (T; 50 mcg) cells. Antibodies: Ku80 antibody A302-627A used for WB at 0.04 mcg/ml (A) and 0.4 mcg/ml (B) and used for IP at 3 mcg/mg lysate. Ku80 was also immunoprecipitated by Ku80 antibody A302-626A, which recognizes an upstream epitope. For blotting immunoprecipitated Ku80, the ReliaBLOT Reagents and Procedures (Cat. No. WB120) were used. Detection: Chemiluminescence with exposure times of 3 minutes (A) and 30 seconds (B).

Search for Antibodies by Research Area
Bethyl Laboratories' portfolio of polyclonal antibodies commercially available includes over 5000 polyclonal antibodies to over 1500 proteins. We test our antibodies in a wide range of applications including ELISA, western blot, immunoprecipitation, immunohistochemistry, and immunocytochemistry. We have recently validated many of our antibodies for flow cytometry and ChIP. Our antibody range also includes secondary antibodies, loading controls and antibodies to epitope tags.

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