Cross-linking of FcεRI causes Ca2+ mobilization via a sphingosine kinase pathway in a clathrin-dependent manner

Seung Duk Ryu, Hyun Sil Lee, Ho Young Suk, Chang Shin Park, Oksoon Hong Choi

Research output: Contribution to journalArticle

Abstract

Clathrin-coated pits are now recognized to be involved in cell signaling in addition to receptor down-regulation. Here we tried to identify signaling pathways that might be dependent on clathrin. Our initial data with pharmacological inhibitors of formation of clathrin-coated pits or lipid-rafts indicated that Ca2+ response evoked by cross-linking of the high affinity receptors for IgE (FcεRI) was dependent on clathrin. To confirm this finding, we created clathrin-knockdown cells by transfecting the mast cell line RBL-2H3 with a shRNA-clathrin heavy chain construct. In these cells, the FcεRI-mediated Ca2+ response was almost completely abolished, which was accompanied by the inhibition of sphingosine 1-phosphate (S1P) production with no changes in inositol 1,4,5-trisphosphate (IP3) production. This suggests that the Ca2+ signaling pathway via a sphingosine kinase (SK) is dependent on clathrin. Furthermore, antigen-induced tyrosine phosphorylation of p85 and p110 subunits of PI3K was almost completely inhibited in clathrin-knockdown cells. In contrast, antigen-induced tyrosine phosphorylation of phospholipase Cγ was not affected by clathrin-knockdown and tyrosine phosphorylation of Syk and degranulation were partially inhibited in clathrin-knockdown cells. The present study identifies the SK/Ca2+ pathway to be dependent on clathrin.

Original languageEnglish (US)
Pages (from-to)99-108
Number of pages10
JournalCell Calcium
Volume45
Issue number2
DOIs
StatePublished - Feb 2009

Keywords

  • Ca signaling
  • Clathrin
  • FcεRI
  • Mast cell
  • Sphingosine kinase

ASJC Scopus subject areas

  • Physiology
  • Molecular Biology
  • Cell Biology

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