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Ceramide kinase, ceramide‐1‐phosphate: Roles and implication in phagocytosis and phagolysosomal fusion
Author(s) -
HinkovskaGalcheva Vania T,
Kindzelski Andrei L,
Huang Jibiao,
Clark Andrea,
Shanley Thomas,
Shayman James,
Petty Howard,
Boxer Laurence
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a484-a
Subject(s) - ceramide , phagocytosis , microbiology and biotechnology , kinase , lipid signaling , chemistry , biochemistry , biology , enzyme , apoptosis
Ceramide‐1‐phosphate (C1P) is derived by phosphorylation of ceramide by Ca 2+ ‐dependent ceramide kinase (CERK). In order to determine the role of CIP in phagocytosis and phagolysosomal fusion, COS‐1 cells carrying Fcγ RIIA were stably transfected with vector, hCERK, or G198DhCERK. Using high‐speed fluorescence microscopy, we found that hCERK transfected cells displayed clockwise and counterclockwise Ca 2+ waves whereas cell expressing either vector, Fcγ RIIA, or G198DhCERK displayed only a counterclockwise Ca 2+ wave under identical conditions. This was accompanied by enhanced phagolysosomal formation. Store operated channel inhibitors blocked the clockwise propagating wave and reduced the phagocytic index in hCERK transfectants. Kinase activity of hCERK is required for the generation of the second wave. Cell fractionation and immunohistochemistry studies showed that hCERK and the protein transient potential channel (TRP‐1) were enriched in caveolae fractions in the plasma membrane. Our results show that introduction of the hCERK gene in cells alters the dynamic behavior of intracellular signals as well as downstream cell functions with implications affecting immunity. (Supported by NIH AI20065 and NIAID DK41487 grants)