Implication of the GRB2-associated phosphoprotein SLP-76 in T cell receptor-mediated interleukin 2 production.
Recently we described the molecular cloning of SLP-76, a hematopoietic cell-specific 76-kD protein that was first identified through its association with GST/Grb2 fusion proteins. The primary sequence of SLP-76 predicts a protein of 533 amino acids comprising an amino-terminal region with numerous potential tyrosine phosphorylation sites, a central region rich in proline residues, and a single carboxy-terminal SH2 domain. Here we demonstrate formally that Grb2 associates with unphosphorylated SLP-76 and map the Grb2 binding site on SLP-76 undergoes rapid tyrosine phosphorylation and associates with tyrosine phosphoproteins of 36, 62, and 130 kD. In vitro experiments show that the SH2 domain of SLP-76 associates with the 62- and 130-kD proteins and additionally with a serine/threonine kinase. Finally, we demonstrate that transient overexpression of SLP-76 results in dramatically enhanced TCR-mediated induction of nuclear factor of activated T cells (NFAT) and interleukin (IL) 2 promoter activity; and we provide evidence that a functional SLP-76 SH2 domain is required for this effect. Our data document the in vivo associations of SLP-76 with several proteins that potentially participate in T cell activation and implicate SLP-76 itself as an important molecule in TCR-mediated IL-2 production.
Motto
D G
DG
Department of Physiology, University of Iowa College of Medicine, Iowa City 52242, USA.
Ross
S E
SE
Wu
J
J
Hendricks-Taylor
L R
LR
Koretzky
G A
GA
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D051380:GRB2 Adaptor Protein; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000235:genetics; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D007376:Interleukin-2; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011506:Proteins; D011948:Receptors, Antigen, T-Cell; C092947:SLP-76 signal Transducing adaptor proteins; D014157:Transcription Factors