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Identification of a type 6 protein Ser/Thr phosphatase regulated by interleukin‐2 stimulation
Author(s) -
Filali Mohammed,
Li Shiyong,
Kim Ha Won,
Wadzinski Brian,
Kamoun Malek
Publication year - 1999
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19990501)73:2<153::aid-jcb2>3.0.co;2-7
Subject(s) - stimulation , phosphatase , identification (biology) , chemistry , microbiology and biotechnology , biology , endocrinology , phosphorylation , botany
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. J. Cell. Biochem. 73:153–163, 1999. © 1999 Wiley‐Liss, Inc.