Endocytosis, initially thought to be a relatively simple process for transporting molecules across the cell plasma membrane, is now appreciated to be intricately linked to almost all aspects of cellular signaling. Endosome signaling stations determine the localization

and intensity of a signaling process and are key in maintaining cell surface-derived signals away from the plasma membrane in a process termed signaling from endosomes.

Here, we will describe the general principles and highlight several examples of endosome signaling including propagation of growth factor signals and how these are regulated at different levels of endocytosis.