title: Enhancement of nuclear factor-kappa B acetylation by coactivator p300 and HIV-1 Tat proteins.
abstract: Nuclear factor (NF)-kappaB transcription factors are involved in the control of a large number of normal cellular and organismal processes, such as immune and inflammatory responses, developmental processes, cellular growth, and apoptosis. Transcription of the human immunodeficiency virus type 1 (HIV-1) genome depends on the intracellular environment where the integrate viral DNA is regulated by a complex interplay among viral regulatory proteins, such as Tat, and host cellular transcription factors, such as NF-kappaB, interacting with the viral long terminal repeat region. CBP (CREB-binding protein) and p300, containing an intrinsic histone acetyltransferase (HAT) activity, have emerged as coactivators for various DNA-binding transcription factors. Here, we show that the p50 subunit as well as the p50/p65 of NF-kappaB, and not other factors such as SP1, TFIIB, polymerase II, TFIIA, or p65, can be acetylated by CBP/p300 HAT domain. Acetylation of p50 was completely dependent on the presence of both HAT domain and Tat proteins, implying that Tat influences the transcription machinery by aiding CBP/p300 to acquire new partners and increase its functional repertoire. Three lysines, Lys-431, Lys-440, and Lys-441 in p50 were all acetylated in vitro, and a sequence similarity among p50, p53, Tat, and activin receptor type I on these particular lysines was observed. All proteins have been shown to be acetylated by the CBP/p300 HAT domain. Acetylated p50 increases its DNA binding properties, as evident by streptavidin/biotin pull-down assays when using labeled NF-kappaB oligonucleotides. Increased DNA binding on HIV-1 long terminal repeat coincided with increases in the rate of transcription. Therefore, we propose that acetylation of the DNA binding domain of NF-kappaB aids in nuclear translocation and enhanced transcription and also suggest that the substrate specificity of CBP/p300 can be altered by small peptide molecules, such as HIV-encoded Tat.
authors.affiliation: Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103, USA.
authors.forename: Bansri
authors.initials: B
authors.lastname: Furia
authors.forename: Longwen
authors.initials: L
authors.lastname: Deng
authors.forename: Kaili
authors.initials: K
authors.lastname: Wu
authors.forename: Shanese
authors.initials: S
authors.lastname: Baylor
authors.forename: Kylene
authors.initials: K
authors.lastname: Kehn
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Robert
authors.initials: R
authors.lastname: Donnelly
authors.forename: Tim
authors.initials: T
authors.lastname: Coleman
authors.forename: Fatah
authors.initials: F
authors.lastname: Kashanchi
mesh_terms: D000107:Acetylation; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D015696:Gene Products, tat / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D007313:Insecta; D008239:Lysine / Q000737:chemistry; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D052002:NF-kappa B p50 Subunit; D009687:Nuclear Proteins / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000378:metabolism*; D051996:Transcription Factor RelA; D014158:Transcription, Genetic; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D015696:Gene Products, tat; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D051996:Transcription Factor RelA; D054322:tat Gene Products, Human Immunodeficiency Virus; D004247:DNA; D005982:Glutathione Transferase; D008239:Lysine