Abstract
The ceramide (Cer) and sphingomyelin (SM) species of cultured differentiated rat cerebellar granule cells and human fibroblasts were characterized by electrospray ionization-mass spectrometry. We identified 35 different species of Cer and 18 species of SM in human fibroblasts, and 35 different species of Cer and 9 species of SM were characterized in rat neurons. The main Cer species of rat cerebellar granule cells contained d18:1 sphingosine linked with palmitic, stearic, or nervonic fatty acid, and the two main SM species were d18:1,16:0 and d18:1,18:0. Both sphingolipids were enriched in detergent-resistant membranes (DRMs; or lipid rafts), and significant differences were found in the sphingolipid patterns of DRMs and of detergent-soluble fractions (DSF) from these cells. In human fibroblasts, the main Cer species were d18:1,16:0, d18:2,16:0, d18:1,24:0, d18:2,24:0, d18:1,24:1, and d18:2,24:1; the most represented species of SM were d18:1,16:0, d18:1,24:0, and d18:1,24:1. In these cells, SM was highly enriched in DRMs and Cer was mainly associated with DSF, and the species found in DRMs were markedly different from those found in DSF.
Highlights
The ceramide (Cer) and sphingomyelin (SM) species of cultured differentiated rat cerebellar granule cells and human fibroblasts were characterized by electrospray ionization-mass spectrometry
We report on the Cer and SM species patterns of human fibroblasts and differentiated rat cerebellum granule cells in culture
We compare data obtained from detergent-resistant membrane (DRM) and detergentsoluble fractions (DSF) prepared by ultracentrifugation on sucrose gradients, as described in Materials and Methods
Summary
The ceramide (Cer) and sphingomyelin (SM) species of cultured differentiated rat cerebellar granule cells and human fibroblasts were characterized by electrospray ionization-mass spectrometry. The main Cer species of rat cerebellar granule cells contained d18:1 sphingosine linked with palmitic, stearic, or nervonic fatty acid, and the two main SM species were d18:1,16:0 and d18:1,18:0 Both sphingolipids were enriched in detergent-resistant membranes (DRMs; or lipid rafts), and significant differences were found in the sphingolipid patterns of DRMs and of detergentsoluble fractions (DSF) from these cells. Recent findings indicated that a particular set of lipids and proteins are segregated together within the plasma membrane, forming functional domains that are involved in signal transduction processes [9, 10] These domains, highly enriched in sphingolipids and cholesterol, have been found within the plasma membrane as well as in intracellular membranes, and for their physicochemical characteristics they are resistant to detergent solubilization [from this property derives the term detergent-resistant membranes (DRMs)] [9, 11,12,13]. Cer is a component of DRMs, and it has been suggested that its production and its functional properties are strictly connected to domain organization [14]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
