Ceramide kinase promotes Ca2+ signaling near IgG-opsonized targets and enhances phagolysosomal fusion in COS-1 cells

Vania Hinkovska-Galcheva, Andrea Clark, Susan VanWay, Ji Biao Huang, Miki Hiraoka, Akira Abe, Michael Borofsky, Robin G. Kunkel, Thomas Shanley, James A. Shayman, Frederick Lanni, Howard R. Petty, Laurence A. Boxer

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Ceramide-1-phosphate (C1P) is a novel bioactive sphingolipid formed by the phosphorylation of ceramide catalyzed by ceramide kinase (CERK). In this study, we evaluated the mechanism by which increased C1P during phagocytosis enhances phagocytosis and phagolysosome formation in COS-1 cells expressing hCERK. Stable transfectants of COS-1 cells expressing FcγRIIA or both FcγRIIA/hCERK expression vectors were created. Cell fractionation studies demonstrated that hCERK and the transient receptor potential channel (TRPC-1) were enriched in caveolae fractions. Our data establish that both CERK and TRPC-1 localize to the caveolar microdomains during phagocytosis and that CERK also colocalizes with EIgG in FcγRIIA/hCERK-bearing COS-1 cells. Using high-speed fluorescence microscopy, FcγRIIA/hCERK transfected cells displayed Ca2+ sparks around the phagosome. In contrast, cells expressing FcγRIIA under identical conditions displayed little periphagosomal Ca2+ signaling. The enhanced Ca2+ signals were accompanied by enhanced phagolysosome formation. However, the addition of pharmacological reagents that inhibit store-operated channels (SOCs) reduced the phagocytic index and phagolysosomal fusion in hCERK transfected cells. The higher Ca2+ signal observed in hCERK transfected cells as well as the fact that CERK colocalized with EIgG during phagocytosis support our hypothesis that Ca2+ signaling is an important factor for increasing phagocytosis and is regulated by CERK in a manner that involves SOCs/TRPCs.

Original languageEnglish (US)
Pages (from-to)531-542
Number of pages12
JournalJournal of Lipid Research
Volume49
Issue number3
DOIs
StatePublished - Mar 1 2008

Keywords

  • Ceramide-1-phosphate
  • Immunoglobulin G
  • Phagocytosis
  • Store operated channels
  • Transient potential channel

Fingerprint Dive into the research topics of 'Ceramide kinase promotes Ca<sup>2+</sup> signaling near IgG-opsonized targets and enhances phagolysosomal fusion in COS-1 cells'. Together they form a unique fingerprint.

Cite this