title: Tryptophan residue of Trp-Ser-X-Trp-Ser motif in extracellular domains of erythropoietin receptor is essential for signal transduction.
abstract: The Trp-Ser-X-Trp-Ser motif commonly exists just outside the transmembrane domains of all cytokine receptors so far isolated. The role of this conserved motif in erythropoietin receptor was examined by assessing a series of mutant receptors on erythropoietin-induced signal transduction. Replacement of one of the two conserved Trp residues in the motif to Gly was found to completely abolish the binding of erythropoietin to the receptor and also to lose the ability to transduce the factor-dependent growth signal. While the mutants with one Ser residue converted to Gly or Ala retained full biological activities, the replacement of both conserved Ser residues diminished the functions of the receptor. Furthermore, the receptors lacking a part or all of the Trp-Ser-X-Trp-Ser motif did not respond to erythropoietin. The Trp-Ser-X-Trp-Ser motif, especially Trp residue, located in extracellular domains of the erythropoietin receptor thus appears to play a critical role in receptor-mediated signal transduction.
authors.affiliation: Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Chiba
authors.forename: H
authors.initials: H
authors.lastname: Amanuma
authors.forename: K
authors.initials: K
authors.lastname: Todokoro
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004921:Erythropoietin / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D007377:Interleukin-3 / Q000235:genetics / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017467:Receptors, Erythropoietin; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D015183:Restriction Mapping; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D014364:Tryptophan
chemical_list: D007377:Interleukin-3; D009838:Oligodeoxyribonucleotides; D011956:Receptors, Cell Surface; D017467:Receptors, Erythropoietin; D011994:Recombinant Proteins; D004921:Erythropoietin; D014364:Tryptophan