Fungi generally activate the Toll signaling pathway of the Drosophila innate immune system via a specific set of PGRP detection peptides (Fig. 1C ). RNAi screens similar to those performed to identify host genes required for phagocytosis of bacteria have also been carried out to identify host factors involved in response to fungi such as Candida albicans (Stroschein-Stevenson et al., 2006; Stroschein-Stevenson et al., 2009) . Beyond identifying genes with broad expected functions, such as regulators of the actin cytoskeleton and vesicular trafficking, these studies also identified genes required for the uptake of specific fungal pathogens. One of these proteins, Macroglobulin complement related (Mcr), is a secreted protein that binds directly to C. albicans and promotes its internalization. Interestingly, Mcr is related to four other Drosophila thioester proteins (Teps), two of which are selectively required for phagocytosis of specific bacterial species (TepII for Escherichia coli and TepIII for Staphylococcus aureus), but not for phagocytosis of C. albicans (Stroschein-Stevenson et al., 2006) .