Endocytic transit in Dictyostelium discoideum

The cells of Dictyostelium discoideum are soil amoebae with a simple endocytic pathway: Particles or fluid are taken up at the plasma membrane in a process dependent on the actin cytoskeleton. After rapid acidification and subsequent neutralisation of the food vacuoles during which breakdown of the contents occurs, indigestible remnants are exocytosed. This tight coupling between endocytosis and exocytosis is thought to maintain membrane homeostasis. In spite of the apparent overall difference between the endocytic pathways of mammalian cells and D. discoideum, conserved proteins an involved in individual steps of endocytic transport, possibly indicating that in mammalian cells it is only the routing of marker that has evolved from a simple transit to a complex, branched pathway.