The moving junction, a key portal to host cell invasion by apicomplexan parasites

One defining feature of apicomplexan parasites is their special ability to actively invade host cells. Although rapid, invasion is a complicated process that requires coordinated activities of host cell attachment, protein secretion, and motility by the parasite. Central to this process is the establishment of a structure called moving junction (MJ), which forms a tight connection between invading parasite and host cell membranes through which the parasite passes to enter into the host. Although recognized microscopically for decades, molecular characterization of the MJ was only enabled by the recent discovery of components that make up this multi-protein complex. Exciting progress made during the past few years on both the structure and function of the components of the MJ is reviewed here.