Sphingolipids affected

Kobayashi, T., Shimizugawa, T., Osakabe, T., Watanabe, S., Okuyama, H. 1997. A long-term feeding of sphingolipids affected the levels of plasma cholesterol and hepatic triacylglycerol but not tissue phospholipids and sphingolipids. Nutr. Res. 17, 111-114. 

Sphingolipid metabolism is also affected by cytokines and other signaling molecules. Tumor necrosis factor a (TNFa) is a cytokine that... 

Lipid raft domains of plasma membranes are enriched in cholesterol and sphingolipids. As a consequence, compounds that extract or sequester cholesterol, such as fS-cyclodextrins, nystatin, and filipin, can block selectively endocytosis of cholera toxin, GPI-linked proteins, and other receptors that associate with lipid rafts and caveolae. However, cholesterol is also critical for CME, secretion of proteins, and the actin network. Therefore, conditions designed to affect selectively raft-mediated endocytosis by perturbing cholesterol levels must be carefully controlled to avoid disrupting other mechanisms of endocytosis (40). 

Novel Proteins That Regulate Sphingolipid Synthesis Could Affect the Regulation of Lipid Metabolism... 

Colsch et al., 2007). Because the diagnosis may be complicated in cases of arylsulfatase A pseudodeficiency and sphingolipid activator protein deficiency, this measurement of sulfatide in the urinary sediment of affected individuals by a rapid, sensitive, and specific mass spectrometric method has been long wanted (Whitfield et al., 2001). Urinary sulfatides are now commonly detected using electrospray ionization-tandem mass spectrometry by means of the precursor ion scan 97. Levels are considerably increased to X20-30 folds as compared to controls which allows the rapid screening of a large number of samples. 

Fig. 12. Some signaling targets and pathways affected by sphingolipid backbones that are metabolically interrelated. PKA, protein kinase A PDKl, 3-phosphoinositide-dependent kinase 1 SDKl, sphingosine-dependent kinase 1 PKC, protein kinase C PPl, protein phosphatase 1 PP2A, protein phosphatase 2A aSMase, acid sphingomyelinase PLA, phospholipase Aj SIP, sphingosine-l-phosphase MATIA, methionine adenosyl-transferase (liver specific) SFl, steroidogenic factor 1. The biophysical properties of ceramides and ceramide 1-phosphates may play important roles in membrane structure, including tendencies to form rafts, membrane curvature, and leakiness.

A typical feature of caveola-mediated endocytosis is the formation of non-coated invaginations composed of detergent-resistant membrane components rich in cholesterol and sphingolipids, known as lipid rafts [56]. The importance of the caveola-mediated mechanism in the PTD-mediated internalization was confirmed in an experiment where the cellular uptake of Tat peptide was affected by drugs that either disrupt lipid rafts or alter caveolar trafficking [57]. Moreover, Tat-PTD-fused protein showed colocalization with a marker of caveolar uptake, caveolin, further strengthening the importance of the mechanism in the PTD-mediated internalization [57]. 

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