Transcription intermediary factor 1-beta (UniProt Q13263; also known as E3 SUMO-protein ligase TRIM28, KAP-1, KRAB-associated protein 1, KRAB-interacting protein 1, KRIP-1, Nuclear corepressor KAP-1, Protein phosphatase 1 regulatory subunit 157, RING finger protein 96, TIF1-beta, Transcriptional intermediary factor 1-beta, Tripartite motif-containing 28, Tripartite motif-containing protein 28) is encoded by the TRIM28 (also known as KAP1, PPP1R157, RNF96, TF1B, TIF1B) gene (Gene ID 10155) in human. Kruppel-associated box-/KRAB-associated protein 1 (KAP-1) is a transcriptional co-repressor that selectively targets the KRAB domain of zinc finger protein-based transcription factors with its N-terminal tripartite RBCC (RING, b-box, coiled-coil) domain. KAP-1 uses its C-terminal PxVxL motif and the PHD-Bromo domain to recruit chromatin modifiers, such as heterochromatin protein 1 (HP-1), Histone-lysine N-methyltransferase SETDB1, nucleosome remodeling and deacetylation (NuRD) complex, and histone deacetylases (HDACs), for transcriptional repression. KAP-1 also plays an essential role in the DNA damage response (DDR). Upon DNA damage, KAP-1 is rapidly phosphorylated by Ataxia telangiectasia mutated (ATM) on Ser824, causing chromatin relaxation to facilitate DNA repair. In addition, SIRT1-mediated KAP-1 deacetylation is reported to stabilize KAP1 and 53BP1 interaction, resulting in an enhancement of NHEJ-mediated repair efficiency in a KAP-1 pSer824-independent manner.
Synonyms: Transcription intermediary factor 1-beta, TIF1-beta, E3 SUMO-protein ligase TRIM28, KRAB-associated protein 1, KAP-1, KRAB-interacting protein 1, KRIP-1, Nuclear corepressor KAP-1, RING finger protein 96, Tripartite motif-containing protein 28, KAP-1/TRI
Application: Western Blotting Analysis: A representative lot detected the endogenous KAP-1/Trim28 only in the immunoprecipitats of exogenously expressed FLAG-SirT1 constructs that contain the KAP-1/Trim28-binding domain (a.a. 143-213) using various transfected HEK293T cells (Lin, Y.H., et al. (2015). PLoS One. 10(4):e0123935).Western Blotting Analysis: A representative lot detected similar level of endogenous KAP-1/Trim28 in HEK293T cells regardless of ionizing radiation treatment or shRNA-mediated SirT1 downregulation (Lin, Y.H., et al. (2015). PLoS One. 10(4):e0123935).Western Blotting Analysis: A representative lot detected KAP-1/Trim28 in whole cell lysates, but not in BAP1, FoxK1, or FoxK2 immunoprecipitate (Okino, Y., et al. (2015). J. Biol. Chem. 16;290(3):1580-1591).Immunoprecipitation Analysis: 10 µL from a representative lot immunoprecipitated KAP-1/Trim28 from HEK293T cell lysates (Courtesy of Dr. Zhenkun Lou, Mayo clinic, Rochester, MN).Immunocytochemistry Analysis: An 1:1000 dilution from a representative lot detected KAP-1/Trim28 nuclear localization in U2OS cells (Courtesy of Dr. Zhenkun Lou, Mayo clinic, Rochester, MN).Immunoprecipitation Analysis: A representative lot co-immunoprecipitated SirT1 with KAP-1/Trim28 from HEK293T cell lysates (Lin, Y.H., et al. (2015). PLoS One. 10(4):e0123935).Western Blotting Analysis: An 1:1000 dilution from a representative lot detected KAP-1/Trim28 in mouse embryonic fibroblast (MEF) lysate, as well as downregulated KAP-1/Trim28 in lysates from KAP1 siRNA-treated HEK293T cells (Courtesy of Dr. Zhenkun Lou, Mayo clinic, Rochester, MN).
Other Notes: Concentration: Please refer to lot specific datasheet.