PAK1 and infection: Here we describe the important roles that host PAK1 (and PAK2, see BOX 2) plays during infection by viruses, bacteria, and parasitic protists, examining how pathogens target PAK1 signalling to interact with their host cell at several stages of their infectious cycle to promote entry into, survival and replication within, and egress from their host cell (see Figure 2 and Table 1 for a summary).