Complex nature of malaria parasite hemoglobin degradation

Abstract

Hemoglobin degradation is a massive catabolic process that is essential for the intraerythrocytic development of malaria parasites (1, 2). This process takes place in an acidic food vacuole and is mediated by the concerted action of nearly a dozen proteases (3). The by-product of this degradation, free heme, is sequestered in a crystalline lattice called hemozoin (Fig. 1). The process of hemozoin formation has remained somewhat mysterious over the years. Under highly acidic conditions and high temperatures, hemozoin will form spontaneously (4). Using more physiological conditions, various proteins and lipids have been shown to accelerate the formation of hemozoin from heme (5⇓–7). Chugh et al. have now advanced our understanding by linking the degradation and biomineralization processes (8). The authors show that there is a complex comprising many of the proteases and heme detoxification protein (HDP), the most potent of the hemozoin-forming …