CD28 ligation induces rapid tyrosine phosphorylation of the linker molecule LAT in the absence of Syk and ZAP-70 tyrosine phosphorylation.

Journal Article (Journal Article)

CD28 is a T cell surface molecule that is important for T cell activation. CD28-triggered T cell stimulation involves protein tyrosine phosphorylation, a process that is critical for CD28 function. Recently, a linker molecule has been identified as LAT (Linker for Activation of T cells). Studies involving LAT mutants and reconstitution experiments strongly implicate LAT in playing a critical role in T cell activation. We show in the present report that CD28 ligation induces tyrosine phosphorylation of LAT. CD28-induced tyrosine phosphorylation of LAT was rapid, as it was apparent within 1 min of CD28 ligation, reached a peak by 5 min, and declined thereafter. Previous studies implicated the protein tyrosine kinases ZAP-70 and Syk in the TCR-induced tyrosine phosphorylation of LAT. Here, tyrosine phosphorylation of Syk and ZAP-70 was detected after TCR but not after CD28 ligation. Thus, CD28 ligation appears to induce tyrosine phosphorylation of LAT by mechanisms that are independent of ZAP-70 and Syk. The concurrent ligation of CD28 and TCR increased tyrosine phosphorylation of LAT. These results implicate LAT in CD28 signal transduction pathways and in the co-stimulatory process in T cells.

Full Text

Duke Authors

Cited Authors

  • Tsuchida, M; Manthei, ER; Knechtle, SJ; Hamawy, MM

Published Date

  • July 1999

Published In

Volume / Issue

  • 29 / 7

Start / End Page

  • 2354 - 2359

PubMed ID

  • 10427998

International Standard Serial Number (ISSN)

  • 0014-2980

Digital Object Identifier (DOI)

  • 10.1002/(SICI)1521-4141(199907)29:07<2354::AID-IMMU2354>3.0.CO;2-P


  • eng

Conference Location

  • Germany