Competition between SLP76 and LAT for PLCγ1 binding in resting T cells.
The constitutive interaction between the P1 domain (a 67-amino-acid functional domain within the proline-rich region) of SLP76 and the SH3 domain of phospholipase Cγ1 (PLCγ1) has been shown. To determine the significance of the interaction between SLP76 and PLCγ1 in resting T cells, we examined molecules associated with PLCγ1 in the absence of both SLP76 and, more specifically, the P1 domain of SLP76. Using a mutant Jurkat T-cell line, we showed that PLCγ1 associated with LAT when the constitutive association with SLP76 was blocked. We also found that the PLCγ1 association with LAT occurred in the membranes of resting T cells. Further experiments demonstrated that LAT competed with SLP76 for PLCγ1 binding and that the LAT interaction with PLCγ1 was mediated by the SH3 domain of PLCγ1. Collectively, these results suggest that the constitutive association of SLP76 with PLCγ1 is required to prevent the association with LAT as well as the premature recruitment of PLCγ1 to the cell membrane.
Jung
Seung Hee
SH
Division of Life and Pharmaceutical Sciences, Ewha Womans University, Seoul, Korea.
Jeong
Ji Hye
JH
Seul
Hee Jung
HJ
Lee
Jong Ran
JR
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D001667:Binding, Competitive / Q000235:genetics; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D051966:Phospholipase C gamma / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015202:Protein Engineering; D021381:Protein Transport / Q000235:genetics / Q000276:immunology; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D018909:src Homology Domains / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; C110810:LAT protein, human; D008565:Membrane Proteins; D010750:Phosphoproteins; C092947:SLP-76 signal Transducing adaptor proteins; C522157:PLCG1 protein, human; D051966:Phospholipase C gamma