Identification of a Ets1 variant protein unaffected in its chromatin and in vitro DNA binding capacities by T cell antigen receptor triggering and intracellular calcium rises.
We previously showed that thymocytes express high levels of c-ets-1 protein (Ets1) that can be rapidly phosphorylated following mitogenic stimulation using lectins. We demonstrate here that T cell receptor (TCR) specific stimulation with monoclonal antibodies of mature CD8+ or CD4+ T cells also results in the rapid phosphorylation of Ets1, reinforcing the hypothesis of a possible role for Ets1 in T cell activation. In addition to the major Ets1 product (mu-p63c-ets-1), we identify in mouse thymocytes and mature T cells a distinct 52 Kd Ets1 related protein (mu-p52c-ets-1). In contrast to the major Ets1 protein, mu-p52c-ets-1 is poorly phosphorylated in unstimulated cells. Furthermore, mitogenic stimulation of thymocytes and T cells failed to induce in mu-p52c-ets-1 the Ca2(+)-dependent phosphorylation events which are known to drastically affect the migration of the major Ets1 protein in SDS polyacrylamide gels. Mu-p52c-ets-1, like mu-p63c-ets-1, is a nuclear-chromatin associated protein which exhibits DNA binding activity in vitro. However, in contrast to the major Ets1 protein, the association of mu-p53c-ets-1 with chromatin and its ability to bind to DNA in vitro are unaffected by activation stimuli resulting in an increase in [Ca2+]i. Finally, we present indications suggesting that mu-p52c-ets-1 might be the murine equivalent of the translation product of an alternatively c-ets-1 spliced mRNA described in human cells by others.
Pognonec
P
P
INSERM U 186, CNRS UA 041160, Institut Pasteur, Lille, France.
Boulukos
K E
KE
Bosselut
R
R
Boyer
C
C
Schmitt-Verhulst
A M
AM
Ghysdael
J
J
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism*; D002846:Chromatography, Affinity; D004268:DNA-Binding Proteins / Q000235:genetics*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D050783:Proto-Oncogene Proteins c-ets; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D013601:T-Lymphocytes / Q000201:enzymology* / Q000276:immunology; D014157:Transcription Factors
D002843:Chromatin; D004268:DNA-Binding Proteins; C494041:ETS1 protein, human; C494042:Ets1 protein, mouse; D008565:Membrane Proteins; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D011948:Receptors, Antigen, T-Cell; D014157:Transcription Factors; D011505:Protein-Tyrosine Kinases; D002118:Calcium