title: New Regulatory Roles of Galectin-3 in High-Affinity IgE Receptor Signaling.
abstract: Aggregation of the high-affinity receptor for IgE (FcεRI) in mast cells initiates activation events that lead to degranulation and release of inflammatory mediators. To better understand the signaling pathways and genes involved in mast cell activation, we developed a high-throughput mast cell degranulation assay suitable for RNA interference experiments using lentivirus-based short hairpin RNA (shRNA) delivery. We tested 432 shRNAs specific for 144 selected genes for effects on FcεRI-mediated mast cell degranulation and identified 15 potential regulators. In further studies, we focused on galectin-3 (Gal3), identified in this study as a negative regulator of mast cell degranulation. FcεRI-activated cells with Gal3 knockdown exhibited upregulated tyrosine phosphorylation of spleen tyrosine kinase and several other signal transduction molecules and enhanced calcium response. We show that Gal3 promotes internalization of IgE-FcεRI complexes; this may be related to our finding that Gal3 is a positive regulator of FcεRI ubiquitination. Furthermore, we found that Gal3 facilitates mast cell adhesion and motility on fibronectin but negatively regulates antigen-induced chemotaxis. The combined data indicate that Gal3 is involved in both positive and negative regulation of FcεRI-mediated signaling events in mast cells.
authors.affiliation: Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Monika
authors.initials: M
authors.lastname: Bambouskova
authors.affiliation: Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Iva
authors.initials: I
authors.lastname: Polakovicova
authors.affiliation: Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Ivana
authors.initials: I
authors.lastname: Halova
authors.affiliation: Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA Broad Institute of Harvard University and Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
authors.forename: Gautam
authors.initials: G
authors.lastname: Goel
authors.affiliation: Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Lubica
authors.initials: L
authors.lastname: Draberova
authors.affiliation: Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Viktor
authors.initials: V
authors.lastname: Bugajev
authors.affiliation: Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA Broad Institute of Harvard University and Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
authors.forename: Aivi
authors.initials: A
authors.lastname: Doan
authors.affiliation: Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Pavol
authors.initials: P
authors.lastname: Utekal
authors.affiliation: Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA Broad Institute of Harvard University and Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
authors.forename: Agnes
authors.initials: A
authors.lastname: Gardet
authors.affiliation: Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA Broad Institute of Harvard University and Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
authors.forename: Ramnik J
authors.initials: RJ
authors.lastname: Xavier
authors.affiliation: Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic draberpe@img.cas.cz.
authors.forename: Petr
authors.initials: P
authors.lastname: Draber
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion; D002633:Chemotaxis; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D037502:Galectin 3 / Q000235:genetics / Q000378:metabolism*; D059014:High-Throughput Nucleotide Sequencing; D008247:Lysosomes / Q000378:metabolism; D008407:Mast Cells / Q000166:cytology / Q000502:physiology*; D008807:Mice, Inbred BALB C; D010766:Phosphorylation; D015230:Prostaglandin D2 / Q000378:metabolism; D034741:RNA, Small Interfering; D017455:Receptors, IgE / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D054875:Ubiquitination
chemical_list: D000199:Actins; D016207:Cytokines; D037502:Galectin 3; C485095:Lgals3 protein, mouse; D034741:RNA, Small Interfering; D017455:Receptors, IgE; D015230:Prostaglandin D2; D002118:Calcium