TY - JOUR
T1 - Engagement of the T lymphocyte antigen receptor regulates association of son-of-sevenless homologues with the SH3 domain of phospholipase Cγ1
AU - Papadopoulos, Elektra J.
AU - Fitzhugh, David J.
AU - Tkaczyk, Christine
AU - Gilfillan, Alasdair M.
AU - Sassetti, Christopher
AU - Metcalfe, Dean D.
AU - Hwang, Samuel T
PY - 2000
Y1 - 2000
N2 - One mechanism for transducing signals downstream of lymphocyte receptor activation involves the stable association between signaling proteins. To identify protein ligands of the signal activator phospholipase Cγ1 (PLCγ1), we screened T cell cDNA libraries with the PLCγ1-SH3 domain by the yeast two-hybrid assay. We observed association between the PLCγ1-SH3 domain and the human Ras guanine nucleotide exchange factor son-of-sevenless-2 (hSos2) through a proline-rich domain interaction. Stable and abundant hSos2/ PLCγ1 and hSosl/PLCγ1 complexes were observed in unstimulated T cells. The interaction between these enzymes was augmented following engagement of the T cell antigen receptor (TCR/CD3). The kinetics of protein complex enhancement correlated with TCR/CD3-induced tyrosine phosphorylation of PLCγ1; however; those PLCγ1 molecules in complex with hSos2 were non-phosphorylated after TCR/CD3 stimulation, in contrast to the phosphorylated PLCγ1 associated with the linker for activation of T cells, LAT. The Grb2 adapter protein was detected in complex with hSos/PLCγ1, suggesting a regulatory role for Grb2. SH3 domains from both Grb2 and PLCγ1, but not RasGAP, bound directly to hSos homologues. The SH2 domain from Grb2 formed an association with the hSos/PLCγ1 complex, which was enhanced following TCR/CD3 ligation. Together, the data suggest a mechanism for the son-of-sevenless and PLCγ1 signal transducing enzymes in recruitment to protein complexes with potentially differential signaling consequences in T lymphocytes.
AB - One mechanism for transducing signals downstream of lymphocyte receptor activation involves the stable association between signaling proteins. To identify protein ligands of the signal activator phospholipase Cγ1 (PLCγ1), we screened T cell cDNA libraries with the PLCγ1-SH3 domain by the yeast two-hybrid assay. We observed association between the PLCγ1-SH3 domain and the human Ras guanine nucleotide exchange factor son-of-sevenless-2 (hSos2) through a proline-rich domain interaction. Stable and abundant hSos2/ PLCγ1 and hSosl/PLCγ1 complexes were observed in unstimulated T cells. The interaction between these enzymes was augmented following engagement of the T cell antigen receptor (TCR/CD3). The kinetics of protein complex enhancement correlated with TCR/CD3-induced tyrosine phosphorylation of PLCγ1; however; those PLCγ1 molecules in complex with hSos2 were non-phosphorylated after TCR/CD3 stimulation, in contrast to the phosphorylated PLCγ1 associated with the linker for activation of T cells, LAT. The Grb2 adapter protein was detected in complex with hSos/PLCγ1, suggesting a regulatory role for Grb2. SH3 domains from both Grb2 and PLCγ1, but not RasGAP, bound directly to hSos homologues. The SH2 domain from Grb2 formed an association with the hSos/PLCγ1 complex, which was enhanced following TCR/CD3 ligation. Together, the data suggest a mechanism for the son-of-sevenless and PLCγ1 signal transducing enzymes in recruitment to protein complexes with potentially differential signaling consequences in T lymphocytes.
KW - Cellular activation
KW - Phospholipase Cγ1
KW - SH3
KW - Signal transduction
KW - T lymphocyte
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U2 - 10.1002/1521-4141(2000)30:8<2378::AID-IMMU2378>3.0.CO;2-E
DO - 10.1002/1521-4141(2000)30:8<2378::AID-IMMU2378>3.0.CO;2-E
M3 - Article
C2 - 10940929
AN - SCOPUS:0033843231
VL - 30
SP - 2378
EP - 2387
JO - European Journal of Immunology
JF - European Journal of Immunology
SN - 0014-2980
IS - 8
ER -