The Polycomb-group protein ENX-2 interacts with ZAP-70

Motoyuki Ogawa, Yoshiki Hiraoka, Sadakazu Aiso

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Human ENX-2 is a homologue of Drosophila Enhancer of zeste, which is a member of Polycomb-group proteins regulating the expression of homeotic genes as chromatin-associated proteins. In this study, we demonstrate that ENX-2 plays an important role as a signaling molecule involved in T cell receptor-mediated signaling pathway. In immunoprecipitation experiments, ENX-2 and zeta associated protein-70 (ZAP-70) were co-precipitated from T cell lysate. When probed with an anti-phospho-tyrosine antibody, ENX-2 was found to be phosphorylated on tyrosine. On the other hand, ENX-2 was not phosphorylated on tyrosine in the mutant Jurkat cell, J.Cam1.6 lacking the activity of lymphocyte protein tyrosine kinase p56lck. The interaction between ENX-2 and ZAP-70 was abolished in the mutant cell. Furthermore, in-vitro kinase assay using purified p56lck demonstrated that ENX-2 became tyrosine phosphorylated by this kinase. These findings show that the phosphorylation of ENX-2 is responsible for the interaction between ENX-2 and ZAP-70.

Original languageEnglish
Pages (from-to)57-61
Number of pages5
JournalImmunology Letters
Issue number1
Publication statusPublished - 2003 Mar 3
Externally publishedYes


  • Polycomb group protein
  • Signal transduction
  • T cell receptors
  • T lymphocytes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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