Identification of an interferon-gamma receptor alpha chain sequence required for JAK-1 binding

J Biol Chem. 1996 Jan 5;271(1):9-12. doi: 10.1074/jbc.271.1.9.

Abstract

We have shown previously that a four-amino acid block residing at positions 266-269 (LPKS) in the intracellular domain of the human interferon-gamma (IFN-gamma) receptor alpha chain is critical for IFN-gamma-dependent tyrosine kinase activation and biologic response induction. Herein we show that this sequence is required for the constitutive attachment of the tyrosine kinase JAK-1. Using a vaccinia expression system, a receptor alpha chain-specific monoclonal antibody coprecipitated JAK-1 from cells coexpressing JAK-1 and either (a) wild type IFN-gamma receptor alpha chain, (b) a receptor alpha chain truncation mutant containing only the first 59 intracellular domain amino acids, or (c) a receptor mutant containing alanine substitutions for the functionally irrelevant residues 272-275. In contrast, JAK-1 was not coprecipitated when coexpressed with a receptor alpha chain mutant containing alanine substitutions for the functionally critical residues 266-269 (LPKS). Mutagenesis of the LPKS sequence revealed that Pro-267 is the only residue obligatorily required for receptor function. In addition, Pro-267 is required for JAK-1 binding. These results thus identify a site in the IFN-gamma receptor alpha chain required for constitutive JAK-1 association and establish that this association is critical for IFN-gamma signal transduction.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigens, CD / chemistry
  • Antigens, CD / metabolism*
  • Humans
  • Interferon gamma Receptor
  • Janus Kinase 1
  • Mice
  • Molecular Sequence Data
  • Proline / chemistry
  • Proline / metabolism
  • Protein Binding
  • Protein-Tyrosine Kinases / metabolism*
  • Receptors, Interferon / chemistry
  • Receptors, Interferon / metabolism*
  • Tumor Cells, Cultured

Substances

  • Antigens, CD
  • Receptors, Interferon
  • Proline
  • Protein-Tyrosine Kinases
  • JAK1 protein, human
  • Jak1 protein, mouse
  • Janus Kinase 1