The two SH2-domain-containing inositol 5-phosphatases SHIP1 and SHIP2 are coexpressed in human T lymphocytes.
The activation of many hematopoietic cells via cytokine receptors, as well as B and T cell receptors, leads to the tyrosine phosphorylation of Shc and its association with both Grb2-Sos1 complexes and with a 145 kDa protein referred to as the SH2 containing inositol 5-phosphatase (SHIP1). In a search of putative 5-phosphatase isoenzymes, we have isolated a second SH2 domain containing inositol 5-phosphatase, referred to as (SHIP2). Both SHIP1 and SHIP2 are coexpressed in human T lymphocytes. This was shown at the protein level by Western blot analysis in transformed T cell lines and in peripheral blood T lymphocytes either unstimulated or after in vitro activation through TCR-CD3 complex. SHIP1 protein level was not modulated after activation of T lymphocytes, in contrast to SHIP2, which was increased after long-term stimulation. SHIP1 was tyrosine phosphorylated in resting naive T cells. This was not observed in the transformed T cell lines. T lymphocyte is therefore a model of coexpression of the two SH2-containing inositol 5-phosphatases SHIP1 and SHIP2.
Bruyns
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C
Interdisciplinary Research Institute (IRIBHN), Université Libre de Bruxelles, Brussels, Belgium.
Pesesse
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X
Moreau
C
C
Blero
D
D
Erneux
C
C
D000595:Amino Acid Sequence; D002461:Cell Line, Transformed; D006801:Humans; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D010766:Phosphorylation; D013601:T-Lymphocytes / Q000201:enzymology*; D014443:Tyrosine / Q000378:metabolism; D018909:src Homology Domains
D014443:Tyrosine; D010744:Phosphoric Monoester Hydrolases; C098706:INPPL1 protein, human; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases