Search results for " ceramidase"
showing 5 items of 5 documents
A case of lipogranulomatosis Farber: some clinical and ultrastructural aspects
1985
A 20-month-old girl showed typical clinical signs of Farber disease: hoarseness since birth, and periarticular subcutaneous painful nodules. Complete deficiency of acid ceramidase activity was found in cultured skin fibroblasts. An electron microscopic examination of a dermal nodule disclosed pathognomonic tubular inclusions in histiocytes. In epidermal cells zebra-body-like and needle-like lysosomal inclusions were found. Their ultrastructure is different from that of the intrahistiocytic lysosomal inclusions. Probably three clinical types of Farber disease may be distinguished according to the symptomatology and the course of the disease: a severe type, an intermediate type and a relative…
An active form of sphingosine kinase-1 is released in the extracellular medium as component of membrane vesicles shed by two human tumor cell line.
2010
Expression of sphingosine kinase-1 (SphK-1) correlates with a poor survival rate of tumor patients. This effect is probably due to the ability of SphK-1 to be released into the extracellular medium where it catalyzes the biosynthesis of sphingosine-1-phosphate (S1P), a signaling molecule endowed with profound proangiogenic effects. SphK-1 is a leaderless protein which is secreted by an unconventional mechanism. In this paper, we will show that in human hepatocarcinoma Sk-Hep1 cells, extracellular signaling is followed by targeting the enzyme to the cell surface and parallels targeting of FGF-2 to the budding vesicles. We will also show that SphK-1 is present in a catalitycally active form i…
High Levels of Exogenous C2-Ceramide Promote Morphological and Biochemical Evidences of Necrotic Features in Thyroid Follicular Cells
2002
CD95 and ceramide are known to be involved in the apoptotic mechanism. The triggering of CD95 induces a cascade of metabolic events that progressively and dramatically modifies the cell shape by intense membrane blebbing, leading to apoptotic bodies production. Although the CD95 pathway has been abundantly described in normal thyrocytes, the effects of cell permeable synthetic ceramide at morphological and biochemical levels are not fully known. In the present study, we show that thyroid follicular cells (TFC) exposed to 20 μM of C2-ceramide for 4 h are characterized by morphological features of necrosis, such as electron-lucent cytoplasm, mitochondrial swelling, and loss of plasma membrane…
nCDase and SphK-1 localization in vesicles shed by tumour cells and their biological roles.
2007
Sphingolipid metabolism is a dynamic process resulting in the formation of a number of bioactive metabolites including ceramide, ceramide-1-phosphate, sphingosine e sphingosine-1-phosphate (S1P). (Pyne and Pyne; Biochem. J. 2000; 349:385-402). Following sphingomyelinase activation, sphingomyelin is hydrolyzed to ceramide, which is considered to be an inducer of cell growth arrest, differentiation and apoptosis. (Hannun et. al 1996; Science: 274:1855-1859). Ceramidase catalyzes the deacylation of ceramide to produce a free fatty acid and sphingosine. The enzyme sphingosine kinase (SphK) catalyzes the formation of S1P from sphingosine and ATP (Olivera et al. J.Biol.Chem. 1998; 273:12576- 1258…