Contribution of the Box 1 and Box 2 motifs of cytokine receptors to Jak1 association and activation

J Biol Chem. 2002 Dec 13;277(50):48220-6. doi: 10.1074/jbc.M205757200. Epub 2002 Oct 8.


Kinases of the Jak family (Jak1/2/3 and Tyk2) interact with the membrane proximal domain of different cytokine receptors and play a critical role in the activation of cytokine and growth factor signaling pathways. In this report we demonstrate that both the Box 1 and Box 2 motif collaborate in the association and activation of Jak1 by type I interferons. Mutational analysis of the beta chain of type I interferon receptor (IFNalphaRbetaL/IFNAR2) revealed that Box 1 plays a more significant role in activation than in the association with Jak1. On the contrary, the Box 2 motif contributes more to the association with Jak1 than to kinase activation. Additionally, the study of the Jak1 binding sites on the IL2 receptor beta (IL2Rbeta), IFNgammaRalpha/IFNGR1, and IL10Ralpha/IL10R1 chains suggests that cytokine receptors have two different kinds of interaction with Jak1. One form of interaction involves the Box 1 and the previously described Box 2 motif, which we now designate as Box 2A, characterized by the VEVI and LEVL sequences present in IFNalphaRbetaL/IFNAR2 and IL2Rbeta subunits, respectively. The second form of interaction requires a motif termed Box 2B, which is present in the IFNgammaRalpha/IFNGR1 (SILLPKS) and IL10Ralpha/IL10R1 (SVLLFKK) chains. Interestingly, Box 2B localizes close to the membrane region (8-10 amino acids from the membrane) similar to Box 1, whereas Box 2A is more distal (38-58 amino acids from the membrane).

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Humans
  • Janus Kinase 1
  • Mutagenesis
  • Protein-Tyrosine Kinases / metabolism*
  • Receptors, Interferon / chemistry
  • Receptors, Interferon / genetics
  • Receptors, Interferon / metabolism*
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Homology, Amino Acid


  • Receptors, Interferon
  • Recombinant Fusion Proteins
  • Protein-Tyrosine Kinases
  • JAK1 protein, human
  • Janus Kinase 1