Characterization of the phosphorylation status of the hepatitis b virus x-associated protein 2

Angie B. Dull, David B. Carlson, John R. Petrulis, Gary H. Perdew

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The cytosolic Ah receptor (AhR) heterocomplex consists of one molecule of the AhR, a 90-kDa heat shock protein (Hsp90) dimer, and one molecule of the hepatitis B virus X-associated protein 2 (XAP2). Serine residues 43,53,131-2, and 329 on XAP2-FLAG were identified as putative phosphorylation sites using site-directed mutagenesis followed by two-dimensional phosphopeptide mapping analysis. Protein kinase CK2 (CK2) was identified as the 45-kDa kinase from COS 1 cell or liver extracts that was responsible for phosphorylation of serine 43 in the XAP2 peptide 39-57. Loss of phosphorylation at any or all of the serine residues did not significantly affect the ability of XAP2-FLAG to bind to the murine AhR in rabbit reticulocyte lysate or Hsp90 in COS-1 cells. Furthermore, all of these serine mutants were able to sequester murine AhR-YFP into the cytoplasm as well as wild-type XAP2. YFP-XAP2 S53A was unable to enter the nucleus, indicating a potential role of phosphorylation in nuclear translocation of XAP2.

Original languageEnglish (US)
Pages (from-to)209-221
Number of pages13
JournalArchives of Biochemistry and Biophysics
Issue number2
StatePublished - 2002

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology


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