It is thus important to study their entry into cells, in order to increase the efficacy of the conjugates. A novel assay for studying the entry of the plant toxin ricin has been developed, and this assay is used to study the intracellular route taken by ricin before it transfers its enzymatic moiety to the cytosol. Diphtheria toxin as a vector to translocate exogenous peptides into the cytosol. At present, this translocation system is used to investigate the ubiquitin dependent degradation of cytosolic proteins. Mechanisms of endocytosis.
Cells internalize molecules from the exterior by at least two distinct pathways of endocytosis.
While the clathrin dependent pathway of endocytosis is best characterized so far, this group also studies the alternative mechanism of clathrin independent endocytosis. Retrograde transport of protein toxins. After being endocytosed, certain protein toxins, such as Shiga toxin, are transported in a retrograde manner through the Golgi stack before they translocate their enzymatic moiety to the cytosol. The mechanisms of retrograde transport are being studied. Endocytosis in polarized epithelial cells.