title: Functional Selectivity in Cytokine Signaling Revealed Through a Pathogenic EPO Mutation.
abstract: Cytokines are classically thought to stimulate downstream signaling pathways through monotonic activation of receptors. We describe a severe anemia resulting from a homozygous mutation (R150Q) in the cytokine erythropoietin (EPO). Surprisingly, the EPO R150Q mutant shows only a mild reduction in affinity for its receptor but has altered binding kinetics. The EPO mutant is less effective at stimulating erythroid cell proliferation and differentiation, even at maximally potent concentrations. While the EPO mutant can stimulate effectors such as STAT5 to a similar extent as the wild-type ligand, there is reduced JAK2-mediated phosphorylation of select downstream targets. This impairment in downstream signaling mechanistically arises from altered receptor dimerization dynamics due to extracellular binding changes. These results demonstrate how variation in a single cytokine can lead to biased downstream signaling and can thereby cause human disease. Moreover, we have defined a distinct treatable form of anemia through mutation identification and functional studies.
authors.affiliation: Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
authors.forename: Ah Ram
authors.initials: AR
authors.lastname: Kim
authors.affiliation: Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
authors.forename: Jacob C
authors.initials: JC
authors.lastname: Ulirsch
authors.affiliation: Department of Biology, Division of Biophysics, University of Osnabrück, 49076 Osnabrück, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Wilmes
authors.affiliation: Department of Pediatrics, Division of Pediatric Hematology and Oncology, Faculty of Medicine, Erciyes University, Kayseri 38039, Turkey.
authors.forename: Ekrem
authors.initials: E
authors.lastname: Unal
authors.affiliation: Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Moraga
authors.affiliation: Department of Pediatrics, Division of Pediatric Hematology and Oncology, Faculty of Medicine, Erciyes University, Kayseri 38039, Turkey.
authors.forename: Musa
authors.initials: M
authors.lastname: Karakukcu
authors.affiliation: Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Yuan
authors.affiliation: Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Shideh
authors.initials: S
authors.lastname: Kazerounian
authors.affiliation: Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
authors.forename: Nour J
authors.initials: NJ
authors.lastname: Abdulhay
authors.affiliation: Howard Hughes Medical Institute Mass Spectrometry Laboratory, University of California Berkeley, Berkeley, CA 94720, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: King
authors.affiliation: Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
authors.forename: Namrata
authors.initials: N
authors.lastname: Gupta
authors.affiliation: Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
authors.forename: Stacey B
authors.initials: SB
authors.lastname: Gabriel
authors.affiliation: Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Lander
authors.affiliation: Department of Pediatrics, Division of Pediatric Hematology and Oncology, Faculty of Medicine, Erciyes University, Kayseri 38039, Turkey.
authors.forename: Turkan
authors.initials: T
authors.lastname: Patiroglu
authors.affiliation: Department of Pediatrics, Division of Pediatric Hematology and Oncology, Faculty of Medicine, Erciyes University, Kayseri 38039, Turkey.
authors.forename: Alper
authors.initials: A
authors.lastname: Ozcan
authors.affiliation: Department of Pediatrics, Division of Pediatric Hematology and Oncology, Faculty of Medicine, Erciyes University, Kayseri 38039, Turkey.
authors.forename: Mehmet Akif
authors.initials: MA
authors.lastname: Ozdemir
authors.affiliation: Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors.forename: K Christopher
authors.initials: KC
authors.lastname: Garcia
authors.affiliation: Department of Biology, Division of Biophysics, University of Osnabrück, 49076 Osnabrück, Germany.
authors.forename: Jacob
authors.initials: J
authors.lastname: Piehler
authors.affiliation: Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Hanna T
authors.initials: HT
authors.lastname: Gazda
authors.affiliation: Department of Pharmacology, Cancer Biology Institute, Yale University School of Medicine, West Haven, CT 06516, USA. Electronic address: daryl.klein@yale.edu.
authors.forename: Daryl E
authors.initials: DE
authors.lastname: Klein
authors.affiliation: Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA. Electronic address: sankaran@broadinstitute.org.
authors.forename: Vijay G
authors.initials: VG
authors.lastname: Sankaran
mesh_terms: D029503:Anemia, Diamond-Blackfan / Q000235:genetics* / Q000473:pathology* / Q000628:therapy; D002648:Child; D003241:Consanguinity; D004789:Enzyme Activation; D004920:Erythropoiesis; D004921:Erythropoietin / Q000737:chemistry / Q000235:genetics*; D005260:Female; D006801:Humans; D053614:Janus Kinase 2 / Q000378:metabolism; D007700:Kinetics; D008297:Male; D020125:Mutation, Missense; D017467:Receptors, Erythropoietin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: C554270:EPO protein, human; D017467:Receptors, Erythropoietin; D004921:Erythropoietin; C507924:JAK2 protein, human; D053614:Janus Kinase 2
keywords: JAK2; cytokine; erythropoiesis; erythropoietin; functional selectivity; hematopoiesis; receptor; signaling