Phosphorylated T cell receptor zeta-chain and ZAP70 tandem SH2 domains form a 1:3 complex in vitro

Eur J Biochem. 1996 Jun 1;238(2):440-5. doi: 10.1111/j.1432-1033.1996.0440z.x.

Abstract

The zeta polypeptide is part of the T cell antigen receptor (TCR). The zeta-chain contributes to efficient cell-surface expression of the TCR and accounts for part of its signal transduction capability. TCR recognition triggers a complex set of events that result in cellular activation. The protein tyrosine kinase (PTK) Lck phosphorylates the zeta-chain, which in turn associates with another PTK, ZAP70, and stimulates its phosphorylation activity. Here we report the expression of the intracellular part of the zeta-chain and its biochemical characterization. The recombinant protein does not dimerize by itself in solution. Circular-dichroic analysis reveals a random coil conformation. zeta, phosphorylated using recombinant Lck, associates with recombinant ZAP70 tandem-SH2 domains. All three T cell activation motifs in zeta bind ZAP70 tandem-SH2 domains in vitro, forming a 1:3 complex. This result extends the picture, derived from earlier studies, of a mechanism for signal amplification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Chromatography, Gel
  • Circular Dichroism
  • Cloning, Molecular
  • Cross-Linking Reagents / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli / genetics
  • Gene Expression
  • Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism*
  • Phosphorylation
  • Protein Binding
  • Protein-Tyrosine Kinases / chemistry
  • Protein-Tyrosine Kinases / metabolism*
  • Receptors, Antigen, T-Cell / chemistry
  • Receptors, Antigen, T-Cell / metabolism*
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • T-Lymphocytes / metabolism*
  • ZAP-70 Protein-Tyrosine Kinase
  • src Homology Domains*
  • src-Family Kinases / metabolism

Substances

  • Cross-Linking Reagents
  • Membrane Proteins
  • Receptors, Antigen, T-Cell
  • Recombinant Proteins
  • antigen T cell receptor, zeta chain
  • Protein-Tyrosine Kinases
  • Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
  • ZAP-70 Protein-Tyrosine Kinase
  • src-Family Kinases