J. Neurochem. (2011) 117, 589–602. Abstract Brain tissue is characterized by its high glycosphingolipid content, particularly those containing sialic acid (gangliosides). As a result of this observation, brain tissue was a focus for studies leading to the characterization of the enzymes participating in ganglioside biosynthesis, and their participation in driving the compositional changes that occur in glycolipid expression during brain development. Later on, this focus shifted to the study of cellular aspects of the synthesis, which lead to the identification of the site of synthesis in the neuronal soma and their axonal transport toward the periphery. In this review article, we will focus in subcellular aspects of the biosynthesis of glycosphingolipid oligosaccharides, particularly the mechanisms underlying the trafficking of glycosphingolipid glycosyltransferases from the endoplasmic reticulum to the Golgi, those that promote their retention in the Golgi and those that participate in their topological organization as part of the complex membrane bound machinery for the synthesis of glycosphingolipids.

Pathogenic enterobacteria face various oxygen (O 2 ) levels during intestinal colonization from the O 2 -deprived lumen to oxygenated tissues. Using Shigella flexneri as a model, we had previously demonstrated that epithelium invasion is promoted by O 2 in a Type III secretion system (T3SS)dependent manner 1 . However, subsequent pathogen adaptation to tissue oxygenation modulation remained unknown. Assessing single-cell distribution, together with tissue oxygenation, we demonstrate here that the colonic mucosa O 2 is actively depleted by Shigella flexneri aerobic respiration, not host neutrophils, during infection, leading to the formation of hypoxic foci of infection. This process is promoted by T3SS inactivation in infected tissues, favoring colonizers over explorers. We identify the molecular mechanisms supporting infectious hypoxia induction, Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: