Protein Kinase A Associates with HA95 and Affects Transcriptional Coactivation by Epstein-Barr Virus Nuclear Proteins
- 1 April 2002
- journal article
- research article
- Published by Informa UK Limited in Molecular and Cellular Biology
- Vol. 22 (7), 2136-2146
- https://doi.org/10.1128/mcb.22.7.2136-2146.2002
Abstract
HA95, a nuclear protein homologous to AKAP95, has been identified in immune precipitates of the Epstein-Barr virus (EBV) coactivating nuclear protein EBNA-LP from EBV-transformed lymphoblastoid cells (LCLs). We now find that HA95 and EBNA-LP are highly associated in LCLs and in B-lymphoma cells where EBNA-LP is expressed by gene transfer. Binding was also evident in yeast two-hybrid assays. HA95 binds to the EBNA-LP repeat domain that is the principal coactivator of transcription. EBNA-LP localizes with HA95 and causes HA95 to partially relocalize with EBNA-LP in promyelocytic leukemia nuclear bodies. Protein kinase A catalytic subunit α (PKAcsα) is significantly associated with HA95 in the presence or absence of EBNA-LP. Although EBNA-LP is not a PKA substrate, HA95 or PKAcsα expression in B lymphoblasts specifically down-regulates the strong coactivating effects of EBNA-LP. The inhibitory effects of PKAcsα are reversed by coexpression of protein kinase inhibitor. PKAcsα also inhibits EBNA-LP coactivation with the EBNA-2 acidic domain fused to the Gal4 DNA binding domain. Furthermore, EBNA-LP- and EBNA-2-induced expression of the EBV oncogene, LMP1, is down-regulated by PKAcsα or HA95 expression in EBV-infected lymphoblasts. These experiments indicate that HA95 and EBNA-LP localize PKAcsα at nuclear sites where it can affect transcription from specific promoters. The role of HA95 as a scaffold for transcriptional regulation is discussed.Keywords
This publication has 56 references indexed in Scilit:
- Epstein–Barr virusVirus Research, 2001
- Mapping the Functional Domains of HAP95, a Protein That Binds RNA Helicase A and Activates the Constitutive Transport Element of Type D RetrovirusesPublished by Elsevier BV ,2001
- Identification of Major Phosphorylation Sites of Epstein-Barr Virus Nuclear Antigen Leader Protein (EBNA-LP): Ability of EBNA-LP To Induce Latent Membrane Protein 1 Cooperatively with EBNA-2 Is Regulated by PhosphorylationJournal of Virology, 2001
- EBNA-LP Associates with Cellular Proteins Including DNA-PK and HA95Journal of Virology, 2001
- Characterisation of Regulatory Sequences at the Epstein–Barr VirusBamHI W PromoterVirology, 1998
- Molecular Cloning, Chromosomal Localization, and Cell Cycle-Dependent Subcellular Distribution of the A-Kinase Anchoring Protein, AKAP95Experimental Cell Research, 1998
- Developments in expression cloningCurrent Opinion in Biotechnology, 1995
- Mediation of Epstein-Barr Virus EBNA2 Transactivation by Recombination Signal-Binding Protein J κScience, 1994
- Recombinant Fragment of Protein Kinase Inhibitor Blocks Cyclic AMP-Dependent Gene TranscriptionScience, 1987
- VIRUS PARTICLES IN CULTURED LYMPHOBLASTS FROM BURKITT'S LYMPHOMAThe Lancet, 1964