The spatial and temporal organization of immune cell signaling molecules is becoming increasingly accepted as a crucial step in controlling immunity. Our research interest is focused on molecules underlying control devices in protein transport. In particular, our up-to-now data strongly indicate a regulatory function of the mannose 6-phosphate/insulin-like growth factor 2 receptor (CD222) in pericellular proteolysis, cell migration, signal transduction, angiogenesis, and endocytosis. Our major goal is to decipher the role of this endosomal transporter, and protein trafficking in general, in adaptive and innate immune signalling and effector functions, and to provide pharmacologic tools to modulate these functions.