Jasja Wolthoorn

Learn More
Glycosphingolipids, a family of heterogeneous lipids with biophysical properties conserved from fungi to mammals, are key components of cellular membranes. Because of their tightly packed backbone, they have the ability to associate with other sphingolipids and cholesterol to form microdomains called lipid rafts, with which a variety of proteins associate.(More)
The use of recombinant human proteins for the treatment of several diseases has increased considerably during the last decades. A major safety and efficacy issue of biopharmaceuticals is their potential immunogenicity. To prevent immunogenicity, biotechnology-derived proteins are engineered to be as human-like as possible. Immunogenicity is mainly(More)
In higher eukaryotes, glucosylceramide is the simplest member and precursor of a fascinating class of membrane lipids, the glycosphingolipids. These lipids display an astounding variation in their carbohydrate head groups, suggesting that glycosphingolipids serve specialized functions in recognition processes. It is now realized that they are organized in(More)
Melanosomes are lysosome-related organelles that coexist with lysosomes in mammalian pigment cells. Melanosomal and lysosomal membrane proteins share similar sorting signals in their cytoplasmic tail, raising the question how they are segregated. We show that in control melanocytes, the melanosomal enzymes tyrosinase-related protein 1 (Tyrp1) and tyrosinase(More)
Sphingolipids are considered to play a key role in protein sorting and membrane trafficking. In melanocytic cells, sorting of lysosomal and melanosomal proteins requires the sphingolipid glucosylceramide (GlcCer). This sorting information is located in the lumenal domain of melanosomal proteins. We found that two processes dependent on lumenal pH, protein(More)
Glycosphingolipids are controlled by the spatial organization of their metabolism and by transport specificity. Using immunoelectron microscopy, we localize to the Golgi stack the glycosyltransferases that produce glucosylceramide (GlcCer), lactosylceramide (LacCer), and GM3. GlcCer is synthesized on the cytosolic side and must translocate across to the(More)
  • 1