Distribution of Clathrin During Electron Dense Granule Secretion of Entamoeba histolytica Trophozoites

摘要

In vitro interaction of Entamoeba histolytica with collagen type I and Ca~(2+) induces intracellular formation and release of electron-dense granules (EDG) and stimulation of collagenolytic activity. Because EDG contain collagenase activity, we have postulated that EDG participates in tissue destruction during invasive amebiasis. Clathrin mediates cargo selection and vesicle fusion at the TGN, in the endosomal, lysosomal, and regulated secretory pathways as well as endo-cytosis at the plasma membrane of eukaryote cells. More recently it has been also demonstrated that reassembly of the Golgi apparatus required the presence of clathrin heavy chain. Because the role of clathrin in EDG secretion is unknown the main aim of our study is to determine the role of this protein in EDG formation and release. Electron and confocal microscopy using specific antibodies showed that clathrin participates in E. histolytica EDG secretion. E. histolytica is a human pathogen that has the potential to destroy any host tissue. Previously, we demonstrated an increased expression and secretion of EDG containing collagenase activity when trophozoites interact with collagen type I and Ca~(2+) (1). This induction is achieved through an increase of adhesion, tyrosine phosphorylation and activation of pp125~(FAK) and p42~(MAPK), which results in cytoskeleton organization (2).