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Alteration of protein composition in mouse thymocytes by signals through T‐cell receptor
Author(s) -
Kawakami Takao,
Nagata Takuya,
Muraguchi Atsushi,
Nishimura Toshihide
Publication year - 2000
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/(sici)1522-2683(20000501)21:9<1846::aid-elps1846>3.0.co;2-i
Subject(s) - microbiology and biotechnology , chemistry , thymocyte , fragmentation (computing) , t cell receptor , cd3 , receptor , apoptosis , tandem mass spectrometry , t cell , biology , biochemistry , mass spectrometry , antigen , chromatography , immune system , ecology , genetics , cd8 , immunology
To avoid destructive autoimmunity, T‐cell precursors (thymocytes) expressing autoreactive T‐cell receptor are deleted in the thymus via an apoptotic process by the signals from the T‐cell receptor‐CD3 complexes. In order to analyze the apoptotic mechansism, we established a cell‐free system using the lysates from mouse thymocytes treated in vivo with anti‐CD3 monoclonal antibody (mAb). The soluble cytosolic high molecular mass protein fraction from the anti‐CD3‐treated thymocytes revealed an activity that directly induces nuclear apoptotic morphological changes and DNA fragmentation. This fragmentation activity was not observed in the fraction from the thymocytes without anti‐CD3 treatment. Proteins in both fractions were separated by two‐dimensional electrophoresis. The silver‐stained gels revealed differences in protein spots. These protein spots were identified by database searching of mass spectrometric (MS) and tandem mass spectrometric (MS/MS) data obtained from in‐gel tryptic digests of the spots, using an integrated system of liquid chromatography/electrospray ionization/ion‐trap mass spectrometry. In this study, the high mobility group protein HMG2 was identified as one of the cytosolic proteins that is increased by the signals from the T‐cell receptor, and heterogeneous nuclear ribonucleoprotein A2/B1 and glyceraldehyde 3‐phosphate dehydrogenase were found to be decreased by the signals.