Merozoite surface protein 1 42 kDa fragment (MSP1-42)

Merozoite surface protein 1 (MSP1) is the most abundant protein on the surface of Plasmodium falciparum merozoites and is essential for the parasite's blood-stage life cycle [2, 4]. It is synthesized as a ~190 kDa precursor that undergoes primary proteolytic cleavage into four fragments (p83, p30, p38, and p42), which remain non-covalently associated on the merozoite surface [2, 10]. The C-terminal 42 kDa fragment (MSP1-42) is anchored to the parasite membrane via a glycosylphosphatidylinositol (GPI) moiety and plays a critical role in erythrocyte invasion [2, 9]. During invasion, MSP1-42 undergoes a secondary cleavage into a 33 kDa fragment (MSP1-33), which is shed, and a 19 kDa fragment (MSP1-19), which is carried into the host cell [4, 21]. MSP1-42 is a leading malaria vaccine candidate, with several formulations (e.g., FMP1/AS02) tested in clinical trials to induce antibodies that block invasion or processing [1, 14, 16]. These antibodies act by inhibiting the secondary cleavage of MSP1-42 or by agglutinating merozoites to prevent their entry into red blood cells [5, 21]. However, significant genetic polymorphism in the MSP1-42 region, particularly in the MSP1-33 domain, poses a major challenge for developing a broadly effective vaccine [3, 6, 8]. Recent research also suggests that MSP1 may be involved in the egress of merozoites from infected erythrocytes, adding another layer to its functional importance [15]. Small molecule inhibitors like NIC have been identified that bind to the MSP1-19 domain and inhibit invasion across divergent Plasmodium species [19]. Despite its promise, the high degree of allelic diversity remains the primary hurdle for MSP1-based therapeutic strategies [6, 18].

Other names

MSP1-42p42MSP-1 p42Merozoite surface protein 1 C-terminal 42 kDa fragmentFMP1Merozoite surface protein 1

Inhibition of erythrocyte invasion, prevention of secondary proteolytic processing, and merozoite agglutination