Tuning ITAM multiplicity on T cell receptors can control potency and selectivity to ligand density

Sci Signal. 2018 May 22;11(531):eaan1088. doi: 10.1126/scisignal.aan1088.


The T cell antigen receptor (TCR) recognizes peptides from pathogenic proteins bound in the major histocompatibility complex (MHC). To convert this binding event into downstream signaling, the TCR complex contains immunoreceptor tyrosine-based activation motifs (ITAMs) that act as docking sites for the cytoplasmic tyrosine kinase ZAP-70. Unique among antigen receptors, the TCR complex uses 10 ITAMs to transduce peptide-MHC binding to the cell interior. Using synthetic, drug-inducible receptor-ligand pairs, it was found that greater ITAM multiplicity primarily enhanced the efficiency with which ligand binding was converted into an intracellular signal. This manifested as an increase in the fraction of cells that became activated in response to antigen, and a more synchronous initiation of TCR-proximal signaling, rather than direct amplification of the intracellular signals. Exploiting these findings, the potency and selectivity of chimeric antigen receptors targeted against cancer were substantially enhanced by modulating the number of encoded ITAMs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs*
  • HEK293 Cells
  • Humans
  • Jurkat Cells
  • Ligands*
  • Lymphocyte Activation
  • Phosphorylation
  • Receptors, Antigen, T-Cell / chemistry
  • Receptors, Antigen, T-Cell / metabolism*
  • Receptors, Chimeric Antigen / metabolism
  • Signal Transduction
  • Tacrolimus Binding Proteins / metabolism
  • Tyrosine / metabolism
  • ZAP-70 Protein-Tyrosine Kinase / metabolism


  • Ligands
  • Receptors, Antigen, T-Cell
  • Receptors, Chimeric Antigen
  • Tyrosine
  • ZAP-70 Protein-Tyrosine Kinase
  • ZAP70 protein, human
  • Tacrolimus Binding Proteins