Exported protein 1 (EXP1) (EXP1)

Plasmodium falciparum exported protein 1 (EXP1) is an essential membrane-bound protein situated on the parasitophorous vacuole membrane (PVM), which encapsulates the malaria parasite during its growth within human red blood cells [1, 4]. Long recognized as a major parasite antigen, recent functional studies have characterized EXP1 as a membrane glutathione S-transferase (mGST) belonging to the MAPEG superfamily [1, 2, 14]. Its primary biological role is the detoxification of cytotoxic hematin, a lethal byproduct generated during the parasite's digestion of host hemoglobin, thereby protecting the parasite from oxidative damage [1, 6, 11]. Additionally, EXP1 is critical for maintaining the structural integrity of the PVM, and its depletion leads to vacuolar collapse and parasite death [6, 10, 13]. EXP1 has emerged as a significant therapeutic target due to its essentiality and the discovery that frontline antimalarial drugs like artesunate and potentially chloroquine act as potent inhibitors of its enzymatic activity [1, 5, 8]. The inhibition of EXP1 results in the accumulation of toxic heme and disrupts the metabolic environment of the parasite [1, 2]. Furthermore, variations in EXP1 activity have been linked to artemisinin susceptibility and resistance in clinical malaria strains, making it a key focus for monitoring drug efficacy [1, 2, 8]. Given its surface accessibility on the PVM and lack of close human homologs, EXP1 is also a prominent candidate for vaccine development and the design of next-generation small-molecule inhibitors [10, 13, 16].

Other names

PfEXP1Circumsporozoite-related antigenCRAAntigen 5.1Ag5.1Q27Ag 5.1

Inhibition of membrane-bound glutathione S-transferase (mGST) activity, leading to the failure of cytotoxic hematin detoxification and disruption of the parasitophorous vacuole membrane (PVM) structural integrity.