title: Contributions of F-BAR and SH2 domains of Fes protein tyrosine kinase for coupling to the FcepsilonRI pathway in mast cells.
abstract: This study investigates the roles of Fer-CIP4 homology (FCH)-Bin/amphiphysin/Rvs (F-BAR) and SH2 domains of Fes protein tyrosine kinase in regulating its activation and signaling downstream of the high-affinity immunoglobulin G (IgE) receptor (FcepsilonRI) in mast cells. Homology modeling of the Fes F-BAR domain revealed conservation of some basic residues implicated in phosphoinositide binding (R113/K114). The Fes F-BAR can bind phosphoinositides and induce tubulation of liposomes in vitro. Mutation of R113/K114 to uncharged residues (RK/QQ) caused a significant reduction in phosphoinositide binding in vitro and a more diffuse cytoplasmic localization in transfected COS-7 cells. RBL-2H3 mast cells expressing full-length Fes carrying the RK/QQ mutation show defects in FcepsilonRI-induced Fes tyrosine phosphorylation and degranulation compared to cells expressing wild-type Fes. This correlated with reduced localization to Lyn kinase-containing membrane fractions for the RK/QQ mutant compared to wild-type Fes in mast cells. The Fes SH2 domain also contributes to Fes signaling in mast cells, via interactions with the phosphorylated FcepsilonRI beta chain and the actin regulatory protein HS1. We show that Fes phosphorylates C-terminal tyrosine residues in HS1 implicated in actin stabilization. Thus, coordinated actions of the F-BAR and SH2 domains of Fes allow for coupling to FcepsilonRI signaling and potential regulation the actin reorganization in mast cells.
authors.affiliation: Department of Biochemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada.
authors.forename: Victor A
authors.initials: VA
authors.lastname: McPherson
authors.forename: Stephanie
authors.initials: S
authors.lastname: Everingham
authors.forename: Robert
authors.initials: R
authors.lastname: Karisch
authors.forename: Julie A
authors.initials: JA
authors.lastname: Smith
authors.forename: Christian M
authors.initials: CM
authors.lastname: Udell
authors.forename: Jimin
authors.initials: J
authors.lastname: Zheng
authors.forename: Zongchao
authors.initials: Z
authors.lastname: Jia
authors.forename: Andrew W B
authors.initials: AW
authors.lastname: Craig
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D001798:Blood Proteins / Q000378:metabolism; D015550:Cell Degranulation / Q000502:physiology; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D008407:Mast Cells / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010716:Phosphatidylinositols / Q000378:metabolism; D010766:Phosphorylation; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs / Q000235:genetics / Q000502:physiology*; D051578:Proto-Oncogene Proteins c-fes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017455:Receptors, IgE / Q000378:metabolism*; D018909:src Homology Domains / Q000235:genetics / Q000502:physiology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D001798:Blood Proteins; C061909:HCLS1 protein, human; D010716:Phosphatidylinositols; D017455:Receptors, IgE; C496645:FES protein, human; D051578:Proto-Oncogene Proteins c-fes