A new regulatory switch in a JAK protein kinase

Proteins. 2011 Feb;79(2):393-401. doi: 10.1002/prot.22889.


Members of the JAK family of protein kinases mediate signal transduction from cytokine receptors to transcription factor activation. Over-stimulation of these pathways is causative in immune disorders like rheumatoid arthritis, psoriasis, lupus, and Crohn's disease. A search for selective inhibitors of a JAK kinase has led to our characterization of a previously unknown kinase conformation arising from presentation of Tyr962 of TYK2 to an inhibitory small molecule via an H-bonding interaction. A small minority of protein kinase domains has a Tyrosine residue in this position within the αC-β4 loop, and it is the only amino acid commonly seen here with H-bonding potential. These discoveries will aid design of inhibitors that discriminate among the JAK family and more widely among protein kinases.

Publication types

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

MeSH terms

  • Catalytic Domain
  • Crystallography, X-Ray
  • Drug Design
  • Humans
  • Isoquinolines / chemistry
  • Models, Molecular
  • Mutation
  • Protein Binding
  • Protein Kinase Inhibitors / chemistry
  • Protein Structure, Tertiary
  • Quinolines / chemistry
  • Recombinant Proteins / antagonists & inhibitors
  • Recombinant Proteins / chemistry
  • TYK2 Kinase / antagonists & inhibitors
  • TYK2 Kinase / chemistry*
  • Thiophenes / chemistry


  • Isoquinolines
  • Protein Kinase Inhibitors
  • Quinolines
  • Recombinant Proteins
  • Thiophenes
  • TYK2 Kinase
  • TYK2 protein, human