Toxoplasma

Toxoplasma gondii is an obligate intracellular apicomplexan parasite that actively invades host cells, builds a replication-permissive vacuole, and serves as a model for related parasites including Plasmodium and Cryptosporidium[1]. Mechanistically, Ca2+-dependent microneme exocytosis drives motility, invasion, and egress, with TgCDPK1 acting downstream of calcium to regulate these essential steps[2]. In disease models, tachyzoites support acute expansion, whereas bradyzoites within tissue cysts mediate chronic infection and can reconvert to tachyzoites during immunosuppression[3][4]. Compared with mammalian kinases, TgCDPKs provide parasite-selective targets because they are absent in mammals[5]. For experimental applications, bumped kinase inhibitors inhibit TgCDPK1 at low nanomolar levels and exploit a glycine gatekeeper residue in the ATP-binding site[5].