Malaria held captive

Malaria sporozoites that lack a certain protease get trapped in their cyst-like breeding ground (the oocyst), as shown by Aly and Matuschewski (page 225). Unable to break free, these captive parasites turn in helpless circles inside the oocyst and their life cycle halts.

Malaria-causing parasites (Plasmodium species) have a complex life cycle that includes several distinct stages of intracellular growth in vertebrate and mosquito hosts. Movement from one stage to the next requires exit from one host cell and entry into another. Invasion of target cells has been shown to require parasite-encoded proteases that, by poorly defined mechanisms, allow the bug to penetrate cell membranes. Parasite exit from target cells has been even less well-studied.Aly and Matuschewski now identify a cysteine protease that is...