Phosphorylation of the pro-apoptotic protein Bim in lymphocytes is associated with protection from apoptosis.
Bim is a pro-apoptotic member of the Bcl-2 protein family. Bim has three isoforms, EL, L, and S, of which the EL form is the least cytotoxic. We show here that Bim is serine phosphorylated in lymphocytes, predominantly on the EL form. Withdrawal of IL-2 from IL-2-dependent T lymphocytes or culture of thymocytes leads to reduced Bim phosphorylation and apoptosis induction. This decrease in Bim phosphorylation occurs when most cells in culture are still viable, indicating that reduction of Bim phosphorylation may be an early event in apoptosis signaling of lymphocytes.
Department of Pathology, Tufts University School of Medicine, Jaharis 906, 150 Harrison Avenue, Boston, MA 02111, USA.
Robert J
RJ
Seward
Priska D
PD
von Haller
Ruedi
R
Aebersold
Brigitte T
BT
Huber
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D001402:B-Lymphocytes / Q000276:immunology*; D000072224:Bcl-2-Like Protein 11; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D019610:Cytoprotection; D029721:Drosophila Proteins; D004398:Dyneins; D007376:Interleukin-2 / Q000502:physiology; D007700:Kinetics; D008565:Membrane Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D019606:Phosphoamino Acids / Q000032:analysis; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology; D014407:Tumor Cells, Cultured
D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; D002352:Carrier Proteins; D029721:Drosophila Proteins; D007376:Interleukin-2; D008565:Membrane Proteins; D019606:Phosphoamino Acids; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012694:Serine; D004398:Dyneins