RRC ID 67686
Author Sasaki H, Toyomura K, Matsuzaki W, Okamoto A, Yamaguchi N, Nakamura H, Murayama T.
Title Regulation of alkaline ceramidase activity by the c-Src-mediated pathway.
Journal Arch Biochem Biophys
Abstract Ceramidase hydrolyzes ceramide to fatty acids and sphingosine, and sphingosine is then converted to sphingosine-1-phosphate. Ceramide and sphingosine-1-phosphate act as signaling molecules. Although stimuli coupling to protein kinases-dependent systems have been shown to regulate ceramidase activity, the exact role of c-Src-mediated signal has not been elucidated. We examined the effects of the downregulation of c-Src activity and c-Src overexpression on ceramidase activity in cells. In A549, CHO, and HeLa cells labeled with a fluorescent ceramide, 4-nitrobenzo-2-oxa-1,3-diazole-labeled C6-ceramide (NBD-ceramide), the downregulation of c-Src by c-Src-shRNA and pharmacological inhibitors including SU6656 decreased levels of NBD-caproic acid. The overexpression of c-Src increased NBD-caproic acid levels in CHO and HeLa cells. Similar results were obtained in Na3VO4-treated cells having higher NBD-caproic acid levels. The downregulation and overexpression of c-Src decreased and increased ceramidase activity, respectively, in the lysates of A549 cells at pH 8.8. The ceramidase sensitivity to substrates, pH, and Ca(2+) suggest that the c-Src- and SU6656-sensitive ceramidase is alkaline ceramidase (ACER), possibly Ca(2+)-activated ACER2. Serum starvation increased both ceramidase activity at pH 8.8 and expression of ACER2. Our data suggest that c-Src-mediated signal positively regulates ACER activity in a Ca(2+)-independent manner.
Volume 550-551
Pages 12-9
Published 2014-5-15
DOI 10.1016/j.abb.2014.03.012
PII S0003-9861(14)00121-0
PMID 24708996
MeSH 4-Chloro-7-nitrobenzofurazan / analogs & derivatives* 4-Chloro-7-nitrobenzofurazan / metabolism Alkaline Ceramidase / antagonists & inhibitors Alkaline Ceramidase / genetics Alkaline Ceramidase / metabolism* Animals CHO Cells CSK Tyrosine-Protein Kinase Calcium / metabolism Caproates / metabolism Cell Line, Tumor Ceramides / metabolism* Cricetulus Enzyme Inhibitors / pharmacology Gene Expression Regulation Humans Hydrogen-Ion Concentration Indoles / pharmacology Lysophospholipids / metabolism Membrane Transport Modulators / pharmacology RNA, Small Interfering / genetics RNA, Small Interfering / metabolism Signal Transduction / drug effects* Sphingosine / analogs & derivatives Sphingosine / metabolism Staining and Labeling Sulfonamides / pharmacology Vanadates / pharmacology src-Family Kinases / genetics src-Family Kinases / metabolism*
IF 3.391
DNA material pENTR4-H1 (RDB04395)