Identification of a type 6 protein ser/thr phosphatase regulated by interleukin-2 stimulation

Mohammed Filali, Shiyong Li, Ha Won Kim, Brian Wadzinski, Malek Kamoun

Research output: Contribution to journalArticle

13 Scopus citations


We have identified a 36 kD phosphoprotein that forms a complex with spliceosomal small nuclear ribonucleoproteins in lymphocyte extracts. This 36 kD protein is differentially phosphorylated in transformed human lymphoid cell lines and is regulated by IL-2 in peripheral blood T cells. We purified the 36 kD protein from human lymphocytes by employing a combination of immuno-affinity chromatography and preparative two-dimensional gel electrophoresis. Internal amino acid sequence analysis of the purified protein yielded two peptides that had perfect matches with sequences in the human protein serine/threonine phosphatase 6 (PP6). Using degenerate primers corresponding to the peptides, we obtained from a human T lymphocyte cDNA library a DNA fragment whose sequence is homologous to an EST cDNA clone (R05547). The predicted amino acid sequence of this clone showed over 98% sequence identity to human PP6. The identification of an IL-2 regulated type 6 protein serine/threonine phosphatase in lymphocytes was further substantiated by immunoblotting with anti-peptide antibodies. These findings suggest that PP6 is a component of a signaling pathway regulating cell cycle progression in response to IL-2 receptor stimulation.

Original languageEnglish (US)
Pages (from-to)153-163
Number of pages11
JournalJournal of cellular biochemistry
Issue number2
StatePublished - May 1 1999
Externally publishedYes


  • Cell cycle regulation
  • Cellular activation
  • IL2 receptor
  • Protein ser/thr phosphatase

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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