Plasmodium falciparum heme-associated proteins and heme-dependent protein targets (PfHAPs)

Plasmodium falciparum heme-associated proteins, such as the Heme Detoxification Protein (HDP) and Histidine-Rich Protein II (HRP2), are essential for the parasite's survival during its intraerythrocytic stage (Jani et al., 2008, PLoS Pathogens). As the parasite degrades host hemoglobin to obtain amino acids, it releases toxic free heme (ferriprotoporphyrin IX), which can cause oxidative stress and membrane damage (Sigala & Goldberg, 2014, Annual Review of Microbiology). These proteins facilitate the sequestration of free heme into an insoluble, non-toxic crystalline polymer called hemozoin, or malaria pigment (Sullivan, 2002, International Journal for Parasitology). This detoxification pathway is the primary target for several classes of antimalarial drugs, including quinolines like chloroquine and quinine, which inhibit the biocrystallization process (Egan, 2008, Journal of Chemical Biology). The accumulation of free heme resulting from this inhibition is lethal to the parasite, making these proteins critical focal points for drug discovery. Furthermore, PfHRP2 serves as a vital diagnostic biomarker for malaria infection in rapid diagnostic tests (Moody, 2002, Clinical Microbiology Reviews). Despite their importance, the emergence of drug resistance linked to transporters like PfCRT poses a significant challenge to therapies targeting these heme-associated processes (Fidock et al., 2000, Molecular Cell).

Other names

Heme detoxification protein (HDP)Histidine-rich protein II (HRP2)Heme-binding proteinsHemozoin formation machineryHeme-dependent enzymes

Inhibition of heme biocrystallization into hemozoin, resulting in the accumulation of toxic free ferriprotoporphyrin IX which causes parasite death through oxidative damage and membrane disruption.