@article{AvotaSchneiderSchaulies2014, author = {Avota, Elita and Schneider-Schaulies, Sibylle}, title = {The Role of Sphingomyelin Breakdown in Measles Virus Immunmodulation}, series = {Cellular Physiology and Biochemistry}, volume = {34}, journal = {Cellular Physiology and Biochemistry}, number = {1}, issn = {1015-8987}, doi = {10.1159/000362981}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120004}, pages = {20-26}, year = {2014}, abstract = {Measles virus (MV) efficiently causes generalized immunosuppression which accounts to a major extent for cases of measles-asscociated severe morbidity and mortality. MV infections alter many functions of antigen presenting cells (APC) (dendritic cells (DCs)) and lymphocytes, yet many molecular targets of the virus remain poorly defined. Cellular interactions and effector functions of DCs and lymphocytes are regulated by surface receptors. Associating with other proteins involved in cell signaling, receptors form part of receptosomes that respond to and transmit external signals through dynamic interctions with the cytoskeleton. Alterations in the composition and metabolism of membrane sphingolipids have a substantial impact on both processes. In this review we focus on the regulation of sphingomyelinase activity and ceramide release in cells exposed to MV and discuss the immunosuppressive role of sphingomyelin breakdown induced by MV.}, language = {en} } @article{SchneiderSchauliesMuellerAvotaetal.2014, author = {Schneider-Schaulies, Sibylle and Mueller, Nora and Avota, Elita and Collenburg, Lena and Grassm{\´e}, Heike}, title = {Neutral Sphingomyelinase in Physiological and Measles Virus Induced T Cell Suppression}, doi = {10.1371/journal.ppat.1004574}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-111038}, year = {2014}, abstract = {T cell paralysis is a main feature of measles virus (MV) induced immunosuppression. MV contact mediated activation of sphingomyelinases was found to contribute to MV interference with T cell actin reorganization. The role of these enzymes in MV-induced inhibition of T cell activation remained equally undefined as their general role in regulating immune synapse (IS) activity which relies on spatiotemporal membrane patterning. Our study for the first time reveals that transient activation of the neutral sphingomyelinase 2 (NSM2) occurs in physiological co-stimulation of primary T cells where ceramide accumulation is confined to the lamellum (where also NSM2 can be detected) and excluded from IS areas of high actin turnover. Genetic ablation of the enzyme is associated with T cell hyper-responsiveness as revealed by actin dynamics, tyrosine phosphorylation, Ca2+-mobilization and expansion indicating that NSM2 acts to suppress overshooting T cell responses. In line with its suppressive activity, exaggerated, prolonged NSM2 activation as occurring in co-stimulated T cells following MV exposure was associated with aberrant compartmentalization of ceramides, loss of spreading responses, interference with accumulation of tyrosine phosphorylated protein species and expansion. Altogether, this study for the first time reveals a role of NSM2 in physiological T cell stimulation which is dampening and can be abused by a virus, which promotes enhanced and prolonged NSM2 activation to cause pathological T cell suppression.}, language = {en} }