LAT Is Required for TCR-Mediated Activation of PLC gamma 1 and the Ras Pathway

• Published in: Immunity (Cambridge, Mass.) Vol. 9; no. 5; pp. 617 - 626
• Main Authors: Finco, T S, Kadlecek, T, Zhang, W, Samelson, LE, Weiss, A
• Format: Journal Article
• Language: English
• Published: 01.11.1998
• ISSN: 1074-7613
• DOI: 10.1016/S1074-7613(00)80659-7

In this study, we present the further characterization of a mutant Jurkat T cell line, J.CaM2, that is defective in TCR-mediated signal transduction. Although initial TCR-mediated signaling events such as the inducible tyrosine phosphorylation of the TCR-\g?\ chain and ZAP-70 are intact in J.CaM2, subsequent events, including increases in intracellular calcium, Ras activation, and IL-2 gene expression are defective. Subsequent analysis of J.CaM2 demonstrated a severe deficiency in pp36/LAT expression, a recently cloned adaptor protein implicated in TCR signaling. Importantly, reexpression of LAT in J.CaM2 restored all aspects of TCR signaling. These results demonstrate a necessary and exclusive role for LAT in T cell activation.