title: Critical roles of c-Kit tyrosine residues 567 and 719 in stem cell factor-induced chemotaxis: contribution of src family kinase and PI3-kinase on calcium mobilization and cell migration.
abstract: Stem cell factor (SCF) has crucial roles in proliferation, survival, and differentiation of hematopoietic stem cells and mast cells through binding to c-Kit receptor (KIT). Chemotaxis is another unique function of SCF. However, little is known about the intracellular signaling pathway of SCF/KIT-mediated cell migration. To investigate the signaling cascade, we made a series of 22 KIT mutants, in which tyrosine (Y) residue was substituted for phenylalanine (F) in the cytoplasmic domain, and introduced into BAF3 cells or 293T cells. On stimulation with SCF, BAF3 expressing KIT(WT)(WT) showed cell migration and Ca(2+) mobilization. Among 22 YF mutants, Y567F, Y569F, and Y719F showed significantly reduced cell migration and Ca(2+) mobilization compared to WT. In Y567F, Lyn activation on SCF stimulation decreased and C-terminal Src kinase (Csk) suppressed KIT-mediated Ca(2+) influx and cell migration, suggesting that Y567-mediated Src family kinase (SFK) activation leads to Ca(2+) influx and migration. Furthermore, we found that p38 mitogen-activated protein kinase (p38 MAPK) and Erk1/2 were also regulated by Y567/SFK and involved in cell migration, and that p38 MAPK induced Ca(2+) influx, thereby leading to Erk1/2 activation. In Y719F, the binding of phosphatidylinositol 3'-kinase (PI3K) to KIT was lost and KIT-mediated cell migration and Ca(2+) mobilization were suppressed by PI3K chemical inhibitors or dominant-negative PI3K, suggesting the involvement of Y719-mediated PI3K pathway in cell migration. Combination of Csk and the PI3K inhibitor synergistically reduced cell migration, suggesting the cooperation of SFK and PI3K. Taken together, these results indicate that 2 major KIT signaling pathways lead to cell migration, one is Y567-SFK-p38 MAPK-Ca(2+) influx-Erk and the other is Y719-PI3K-Ca(2+) influx.
authors.affiliation: Department of Hematology and Oncology, and the Department of Microbiology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Ueda
authors.forename: Masao
authors.initials: M
authors.lastname: Mizuki
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Ikeda
authors.forename: Tohru
authors.initials: T
authors.lastname: Tsujimura
authors.forename: Itaru
authors.initials: I
authors.lastname: Matsumura
authors.forename: Kazushi
authors.initials: K
authors.lastname: Nakano
authors.forename: Hanako
authors.initials: H
authors.lastname: Daino
authors.forename: Zen-ichiro
authors.initials: Z
authors.lastname: Honda Zi
authors.forename: Junko
authors.initials: J
authors.lastname: Sonoyama
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Shibayama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sugahara
authors.forename: Takashi
authors.initials: T
authors.lastname: Machii
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Kanakura
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects*; D002460:Cell Line; D002633:Chemotaxis / Q000187:drug effects*; D006801:Humans; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D016297:Mutagenesis, Site-Directed; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D019009:Proto-Oncogene Proteins c-kit / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D019089:Stem Cell Factor / Q000494:pharmacology / Q000502:physiology*; D014443:Tyrosine; D048051:p38 Mitogen-Activated Protein Kinases; D019061:src-Family Kinases / Q000502:physiology
chemical_list: D019089:Stem Cell Factor; D014443:Tyrosine; D019869:Phosphatidylinositol 3-Kinases; D019009:Proto-Oncogene Proteins c-kit; D019061:src-Family Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases