Active and inactive orientations of the transmembrane and cytosolic domains of the erythropoietin receptor dimer

Mol Cell. 2003 Nov;12(5):1239-50. doi: 10.1016/s1097-2765(03)00389-7.

Abstract

Binding of erythropoietin to the erythropoietin receptor (EpoR) extracellular domain orients the transmembrane (TM) and cytosolic regions of the receptor dimer into an unknown activated conformation. By replacing the EpoR extracellular domain with a dimeric coiled coil, we engineered TM EpoR fusion proteins where the helical TM domains were constrained into seven possible relative orientations. We identify one dimeric TM conformation that imparts full activity to the cytosolic domain of the receptor and signals via JAK2, STAT proteins, and MAP kinase, one partially active orientation that preferentially activates MAP kinase, and one conformation corresponding to the inactive receptor. The active and inactive conformations were independently identified by computational searches for low-energy TM dimeric structures. We propose a specific EpoR-activated interface and suggest its use for structural and signaling studies.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Line
  • DNA-Binding Proteins / metabolism
  • Dimerization
  • Enzyme Activation
  • Erythroid Precursor Cells / metabolism
  • Erythropoietin / metabolism
  • Janus Kinase 2
  • Mice
  • Milk Proteins*
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Structure, Quaternary*
  • Protein Structure, Secondary
  • Protein Structure, Tertiary*
  • Protein-Tyrosine Kinases / metabolism
  • Proto-Oncogene Proteins*
  • Receptors, Erythropoietin / chemistry*
  • Receptors, Erythropoietin / genetics
  • Receptors, Erythropoietin / metabolism*
  • Recombinant Fusion Proteins / chemistry*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • STAT3 Transcription Factor
  • STAT5 Transcription Factor
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Sequence Alignment
  • Signal Transduction / physiology
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • Transcription Factors
  • Transcription, Genetic
  • Viral Envelope Proteins / metabolism

Substances

  • DNA-Binding Proteins
  • Milk Proteins
  • PUT3 protein, S cerevisiae
  • Proto-Oncogene Proteins
  • Receptors, Erythropoietin
  • Recombinant Fusion Proteins
  • STAT3 Transcription Factor
  • STAT5 Transcription Factor
  • Saccharomyces cerevisiae Proteins
  • Stat3 protein, mouse
  • Trans-Activators
  • Transcription Factors
  • Viral Envelope Proteins
  • Erythropoietin
  • Protein-Tyrosine Kinases
  • Jak2 protein, mouse
  • Janus Kinase 2