title: Distinct role for c-kit receptor tyrosine kinase and SgIGSF adhesion molecule in attachment of mast cells to fibroblasts.
abstract: Binding of stem cell factor (SCF) to c-kit receptor tyrosine kinase (KIT) transduces signals essential for mast cell development via several pathways including activation of phosphatidylinositol 3-kinase (PI3-K). When cultured mast cells (CMCs) are cocultured with fibroblasts expressing membrane-bound SCF, CMCs with normal KIT adhere to fibroblasts and proliferate, whereas CMCs lacking cell surface expression of KIT do neither. Spermatogenic immunoglobulin superfamily (SgIGSF) was identified as another molecule that participates in mast cell adhesion to fibroblasts. Since the IC-2 mast cell line expressed neither KIT nor SgIGSF, the effect of ectopic expression of KIT or SgIGSF on the adhesion of IC-2 cells was examined. Three forms of KIT with the normal ectodomain were used: wild-type (KIT-WT) and two mutant types with a phenylalanine substitution at the tyrosine residue 719 (KIT-Y719F) or 821 (KIT-Y821F). KIT-Y719F does not activate PI3-K, whereas KIT-Y821F does. Firstly, KIT or SgIGSF was expressed singly in IC-2 cells. All three forms of KIT increased the adhesion level of IC-2 cells, whereas SgIGSF did not. Secondly, SgIGSF was coexpressed with one of the three forms of KIT. Coexpression of SgIGSF with KIT-WT or KIT-Y821F increased the adhesion level more markedly than was achieved by KIT-WT or KIT-Y821F alone. The effect was abolished by an antibody that blocks SCF-KIT interaction. In contrast, coexpression of SgIGSF with KIT-Y719F did not increase the adhesion level induced by KIT-Y719F alone. In adhesion of mast cells to fibroblasts, KIT appeared to behave as an adhesion molecule and as an activator of other adhesion molecules through phosphorylating PI3-K.
authors.affiliation: Department of Pathology, Osaka University Medical School/Graduate School of Frontier Bioscience, Suita, Osaka, Japan.
authors.forename: Yu-ichiro
authors.initials: Y
authors.lastname: Koma
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ito
authors.forename: Kenji
authors.initials: K
authors.lastname: Watabe
authors.forename: Tatsumi
authors.initials: T
authors.lastname: Hirata
authors.forename: Masao
authors.initials: M
authors.lastname: Mizuki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokozaki
authors.forename: Toshio
authors.initials: T
authors.lastname: Kitamura
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Kanakura
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Kitamura
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000502:physiology*; D000075982:Cell Adhesion Molecule-1; D015815:Cell Adhesion Molecules; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018920:Coculture Techniques; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology*; D007136:Immunoglobulins / Q000378:metabolism*; D008407:Mast Cells / Q000166:cytology / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D009154:Mutation; D041681:NIH 3T3 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D019089:Stem Cell Factor / Q000378:metabolism
chemical_list: C498598:Cadm1 protein, mouse; D000075982:Cell Adhesion Molecule-1; D015815:Cell Adhesion Molecules; D007136:Immunoglobulins; D008565:Membrane Proteins; D019089:Stem Cell Factor; D019869:Phosphatidylinositol 3-Kinases; D019009:Proto-Oncogene Proteins c-kit