Functional association between SLAP-130 and SLP-76 in Jurkat T cells.
T cell antigen receptor (TCR) engagement results in protein-tyrosine kinase activation which initiates signaling cascades leading to induction of the interleukin-2 gene. Previous studies identified two substrates of the TCR-induced protein-tyrosine kinases, SH2 domain-containing leukocyte specific protein of 76 kDa (SLP-76) and SLP-76-associated phosphoprotein of 130 kDa (SLAP-130). While SLP-76 appears to couple the TCR with downstream signals, SLAP-130 may play a negative regulatory role in T cell activation. In this study, we demonstrate that consistent with its ability to abrogate the SLP-76 augmentation of TCR-induced activation of the NFAT/AP1 region of the interleukin-2 promoter, overexpression of SLAP-130 also interferes with the rescue of signaling in SLP-76-deficient Jurkat cells in co-transfection experiments. The effect of SLAP-130 on SLP-76 function is specific for regulating TCR-induced ERK activation, but not phospholipase Cgamma 1 phosphorylation. By generating both deletion and point mutants of SLAP-130, we identified tyrosine 559 as critical for the interaction between SLP-76 and SLAP-130. We show that mutation of this residue in context of full-length SLAP-130 diminishes the ability of SLAP-130 to abrogate SLP-76 function. These data suggest that the SLAP-130/SLP-76 association is important for the negative regulatory role that SLAP-130 appears to play in T cell signaling.
Boerth
N J
NJ
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
Judd
B A
BA
Koretzky
G A
GA
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000378:metabolism* / Q000502:physiology; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D019169:Jurkat Cells; D008969:Molecular Sequence Data; D009154:Mutation; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010750:Phosphoproteins / Q000378:metabolism* / Q000502:physiology; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014443:Tyrosine / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; C106957:FYB1 protein, human; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011948:Receptors, Antigen, T-Cell; C092947:SLP-76 signal Transducing adaptor proteins; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D014443:Tyrosine