title: Novel role of WD40 and SOCS box protein-2 in steady-state distribution of granulocyte colony-stimulating factor receptor and G-CSF-controlled proliferation and differentiation signaling.
abstract: Signals induced by granulocyte colony-stimulating factor (G-CSF), the major cytokine involved in neutrophil development, are tightly controlled by ligand-induced receptor internalization. Truncated G-CSF receptors (G-CSF-Rs) that fail to internalize show sustained proliferation and defective differentiation signaling. Steady-state forward routing also determines cell surface levels of cytokine receptors, but mechanisms controlling this are poorly understood. Here, we show that WD40 and suppressor of cytokine signaling (SOCS) box protein-2 (Wsb-2), an SOCS box-containing WD40 protein with currently unknown function, binds to the COOH-terminal region of G-CSF-R. Removal of this region did not affect internalization, yet resulted in increased membrane expression of G-CSF-R and enhanced proliferation signaling at the expense of differentiation induction. Conversely, Wsb-2 binding to the G-CSF-R reduced its cell surface expression and inhibited proliferation signaling. These effects depended on the SOCS box involved in ubiquitylation and on cytosolic lysines of G-CSF-R and imply a major role for ubiquitylation through the G-CSF-R C-terminus in forward routing of the receptor. Importantly, the Wsb-2 gene is commonly disrupted by virus integrations in mouse leukemia. We conclude that control of forward routing of G-CSF-R is essential for a balanced response of myeloid progenitors to G-CSF and suggest that disturbance of this balance may contribute to myeloid leukemia.
authors.affiliation: Department of Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: S J
authors.initials: SJ
authors.lastname: Erkeland
authors.forename: L H
authors.initials: LH
authors.lastname: Aarts
authors.forename: M
authors.initials: M
authors.lastname: Irandoust
authors.forename: O
authors.initials: O
authors.lastname: Roovers
authors.forename: A
authors.initials: A
authors.lastname: Klomp
authors.forename: M
authors.initials: M
authors.lastname: Valkhof
authors.forename: J
authors.initials: J
authors.lastname: Gits
authors.forename: S
authors.initials: S
authors.lastname: Eyckerman
authors.forename: J
authors.initials: J
authors.lastname: Tavernier
authors.forename: I P
authors.initials: IP
authors.lastname: Touw
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D049109:Cell Proliferation; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism*; D006801:Humans; D007951:Leukemia, Myeloid / Q000209:etiology* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D025941:Protein Interaction Mapping; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000032:analysis / Q000378:metabolism*; D015398:Signal Transduction; D050826:Suppressor of Cytokine Signaling Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D016188:Receptors, Granulocyte Colony-Stimulating Factor; D050826:Suppressor of Cytokine Signaling Proteins; D025801:Ubiquitin; C519735:Wsb-2 protein, mouse; D016179:Granulocyte Colony-Stimulating Factor