Intriguing parasites and intramembrane proteases.

Rhomboid intramembrane proteases occur throughout the kingdoms of life. In this issue of Genes & Development, Baxt and colleagues (pp. 1636-1646) report that the single proteolytic rhomboid (EhROM1) from Entamoeba histolytica cleaves cell surface galactose-binding or N-acetylgalactosamine-binding (Gal/Gal-NAc) lectins. EhROM1 and lectins colocalize during phagocytosis and receptor capping. EhROM1 is found at the base of the cap rather than in the cap proper, suggesting a role in receptor shedding and implying that EhROM1 is crucial for amoebal infection.