Involvement of class II phosphoinositide 3-kinase α-isoform in antigen-induced degranulation in RBL-2H3 cells

PLoS One. 2014 Oct 30;9(10):e111698. doi: 10.1371/journal.pone.0111698. eCollection 2014.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens / pharmacology*
  • Calcium / pharmacology
  • Cell Degranulation / drug effects*
  • Cell Line, Tumor
  • Class II Phosphatidylinositol 3-Kinases / genetics
  • Class II Phosphatidylinositol 3-Kinases / metabolism*
  • Gene Knockdown Techniques
  • Humans
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Mice
  • Neuropeptide Y / metabolism
  • Phosphatidylinositol Phosphates / metabolism
  • RAW 264.7 Cells
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / metabolism
  • Rats
  • Receptors, IgE / metabolism
  • Transfection
  • beta-N-Acetylhexosaminidases / metabolism

Substances

  • Antigens
  • Isoenzymes
  • Neuropeptide Y
  • Phosphatidylinositol Phosphates
  • RNA, Messenger
  • RNA, Small Interfering
  • Receptors, IgE
  • phosphatidylinositol 3,4-diphosphate
  • Class II Phosphatidylinositol 3-Kinases
  • beta-N-Acetylhexosaminidases
  • Calcium

Grants and funding

This work was supported by a Grant-in-Aid (Kakenhi) from the Japan Society for the Promotion of Science (grant number 23590078 to OH and 22590065 to KH). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.