title: Involvement of class II phosphoinositide 3-kinase α-isoform in antigen-induced degranulation in RBL-2H3 cells.
abstract: In this study, we present findings that suggest that PI3K-C2α, a member of the class II phosphoinositide 3-kinase (PI3K) subfamily, regulates the process of FcεRI-triggered degranulation. RBL-2H3 cells were transfected with shRNA targeting PI3K-C2α. The knockdown impaired the FcεRI-induced release of a lysosome enzyme, β-hexosaminidase, without affecting the intracellular Ca2+ mobilization. The release of mRFP-tagged neuropeptide-Y, a reporter for the regulated exocytosis, was also decreased in the PI3K-C2α-deficient cells. The release was increased significantly by the expression of the siRNA-resistant version of PI3K-C2α. In wild-type cells, FcεRI stimulation induced the formation of large vesicles, which were associated with CD63, a marker protein of secretory granules. On the vesicles, the existence of PI3K-C2α and PtdIns(3,4)P2 was observed. These results indicated that PI3K-C2α and its product PtdIns(3,4)P2 may play roles in the secretory process.
authors.affiliation: Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Nigorikawa
authors.affiliation: Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Hazeki
authors.affiliation: Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Ying
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Hazeki
mesh_terms: D000818:Animals; D000941:Antigens / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D015550:Cell Degranulation / Q000187:drug effects*; D045744:Cell Line, Tumor; D058541:Class II Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009478:Neuropeptide Y / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D000067996:RAW 264.7 Cells; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017455:Receptors, IgE / Q000378:metabolism; D014162:Transfection; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism
chemical_list: D000941:Antigens; D007527:Isoenzymes; D009478:Neuropeptide Y; D018129:Phosphatidylinositol Phosphates; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017455:Receptors, IgE; C060980:phosphatidylinositol 3,4-diphosphate; D058541:Class II Phosphatidylinositol 3-Kinases; D001619:beta-N-Acetylhexosaminidases; D002118:Calcium