Cell cycle stage-specific phosphorylation of the Epstein-Barr virus immortalization protein EBNA-LP.
AUTOR(ES)
Kitay, M K
RESUMO
EBNA-LP is a viral nuclear oncoprotein implicated in the immortalization of B lymphocytes by Epstein-Barr virus. An analysis of EBNA-LP migration on polyacrylamide gels was performed with protein derived from the X50-7 lymphoblastoid cell line blocked by hydroxyurea or aphidicolin at the G1/S phase of the cell cycle or by nocodazole at the G2/M phase. More slowly migrating species of EBNA-LP were detected in G2/M phase-arrested cell extracts. Release from nocodazole G2/M block or treatment with phosphatase caused the more slowly migrating species of EBNA-LP to disappear. Analyses of 32PO(4)(3-)-labeled EBNA-LP protein immunoprecipitated from the drug-synchronized cells showed that phosphorylated EBNA-LP was present throughout the cell cycle but that phosphorylation increased in G2 and was maximal at G2/M. Phosphoamino acid analysis revealed that all phosphorylation was on serine residues only. The ability of EBNA-LP to be phosphorylated by p34(cdc2) kinase and casein kinase II exclusively on serines implicates these enzymes as being potentially involved in EBNA-LP phosphorylation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=190860Documentos Relacionados
- 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 Phosphorylation†
- Interaction of Epstein-Barr Virus Nuclear Antigen Leader Protein (EBNA-LP) with HS1-Associated Protein X-1: Implication of Cytoplasmic Function of EBNA-LP
- EBNA-2 and EBNA-LP cooperate to cause G0 to G1 transition during immortalization of resting human B lymphocytes by Epstein-Barr virus.
- Epstein-Barr virus nuclear protein LP stimulates EBNA-2 acidic domain-mediated transcriptional activation.
- Phosphorylation sites of Epstein–Barr virus EBNA1 regulate its function