Title

Zeta Phosphorylation without ZAP-70 Activation Induced by TCR Antagonists or Partial Agonists

Document Type

Article

Publication Date

1-27-1995

Journal

Science

Volume

267

Issue

5197

First Page

515

Last Page

518

URL with Digital Object Identifier

http://dx.doi.org/10.1126/science.7824949

Abstract

Small changes in the peptide-major histocompatibility complex (MHC) molecule ligands recognized by antigen-specific T cell receptors (TCRs) can convert fully activating complexes into partially activating or even inhibitory ones. This study examined early TCR-dependent signals induced by such partial agonists or antagonists. In contrast to typical agonist ligands, both an antagonist and several partial agonists stimulated a distinct pattern of zeta chain phosphorylation and failed to activate associated ZAP-70 kinase. These results identify a specific step in the early tyrosine phosphorylation cascade that is altered after TCR engagement with modified peptide-MHC molecule complexes. This finding may explain the different biological responses to TCR occupancy by these variant ligands.

Notes

Dr. Joaquin Madrenas is currently a faculty member at The University of Western Ontario.