Secretory proteins and virulence factors identified in the Blastocystis sp. subtype 7 potentially involved in host interaction. Blastocystis sp. may release cysteine proteases, which could be processed by legumain. These proteases may attack intestinal epithelium together with other hydrolases, such as glysoside hydrolases. Protease inhibitors, some of which have been predicted to be secreted, could act on host proteases (digestive enzymes or proteases involved in the immune response). Some as yet uncharacterized secondary metabolites produced by polyketide synthase (PKS) identified in the genome could also participate in host intestinal symptoms. Adhesive candidate proteins (proteins with an immunoglobulin Ig domain) have been found. Finally, drug-resistant isolates of the parasite could be explained by the presence of multidrug resitance (MDR) proteins. Lightning bolts indicate potential toxic effects.
Denoeud et al. Genome Biology 2011 12:R29 doi:10.1186/gb-2011-12-3-r29