“Kruppel-associated box-associated protein 1 (KAP1) is thought to act mainly as a scaffold for protein complexes, which together BTSA1 silence transcription by triggering the formation of heterochromatin. Using small interfering RNA-mediated KAP1 knockdown, we found that endogenous KAP1 negatively regulated TNF-alpha-induced IL-6 production in HeLa cells. KAP1 is likely to modulate the binding of NF-kappa B to the IL-6 promoter because KAP1 knockdown enhanced TNF-a-induced
NF-kappa B-luciferase activity, but not Ik kappa B alpha degradation. Of importance, we found negative regulatory effects of KAP1 on the serine phosphorylation of STAT3, the acetylation of NF-kappa B/p65 by p300, and the nuclear localization of NF-kappa B/p65. In addition, KAP1 associated with NF-kappa B/p65 and inhibited the binding between NF-kappa B/p65 and p300. Thus, KAP1 is likely to
negatively control the acetylation of NF-kappa B/p65, which is critical for its nuclear retention. Taken together, KAP1 modulated the acetylation of NF-kappa B/p65 by interfering with the interactions among STAT3, p300, and NF-kappa B/p65, resulting in reduced IL-6 production after TNF-alpha stimulation. Our findings that KAP1 directly interacts with transcriptional factors are new, and will inform further research to elucidate KAP1 function. The Journal of Immunology, 2011, 187: 2476-2483.”
“Lysine acetylation is a reversible posttranslational modification of proteins and plays a key role in regulating gene expression. Technological limitations R788 concentration have so far prevented a global analysis of lysine acetylation’s cellular roles. We used high-resolution find more mass spectrometry to identify 3600 lysine acetylation sites on 1750 proteins and quantified acetylation changes in response to the deacetylase inhibitors suberoylanilide hydroxamic acid and MS-275. Lysine acetylation preferentially targets large macromolecular complexes involved in diverse cellular processes, such as chromatin remodeling, cell cycle, splicing,
nuclear transport, and actin nucleation. Acetylation impaired phosphorylation-dependent interactions of 14-3-3 and regulated the yeast cyclin-dependent kinase Cdc28. Our data demonstrate that the regulatory scope of lysine acetylation is broad and comparable with that of other major posttranslational modifications.”
“Apart from alcohol, there are other factors that may induce complications, which resemble alcohol-related liver disorders. In particular, obesity has been brought into focus as a risk factor for fatty liver disease. The term “non-alcoholic” fatty liver disease is commonly used to distinguish between obesity-related and alcohol-related hepatic steatosis. This review uses the epidemiological perspective to critically assess whether it is necessary and useful to differentiate between alcoholic and “non-alcoholic” fatty liver disease.