TY - JOUR
T1 - Plasmodium falciparum Clag9-Associated PfRhopH Complex Is Involved in Merozoite Binding to Human Erythrocytes
AU - Chourasia, Bishwanath Kumar
AU - Deshmukh, Arunaditya
AU - Kaur, Inderjeet
AU - Paul, Gourab
AU - Panda, Ashutosh
AU - Rathore, Sumit
AU - Singh, Susheel K
AU - Theisen, Michael
AU - Mohmmed, Asif
AU - Malhotra, Pawan
N1 - Copyright © 2020 American Society for Microbiology.
PY - 2020/1/22
Y1 - 2020/1/22
N2 - Cytoadherence-linked asexual gene 9 (Clag9), a conserved Plasmodium protein expressed during the asexual blood stages, is involved in the cytoadherence of infected red blood cells (RBCs) to the endothelial lining of blood vessels. Here, we show that Plasmodium falciparum Clag9 (PfClag9) is a component of the PfClag9-RhopH complex that is involved in merozoite binding to human erythrocytes. To characterize PfClag9, we expressed four fragments of PfClag9, encompassing the entire protein. Immunostaining analysis using anti-PfClag9 antibodies showed expression and localization of PfClag9 at the apical end of the merozoites. Mass spectrometric analysis of merozoite extracts after immunoprecipitation using anti-PfClag9 antibody identified P. falciparum rhoptry-associated protein 1 (PfRAP1), PfRAP2, PfRAP3, PfRhopH2, and PfRhopH3 as associated proteins. The identified rhoptry proteins were expressed, and their association with PfClag9 domains was assessed by using protein-protein interaction tools. We further showed that PfClag9 binds human RBCs by interacting with the glycophorin A-band 3 receptor-coreceptor complex. In agreement with its cellular localization, PfClag9 was strongly recognized by antibodies generated during natural infection. Mice immunized with the C-terminal domain of PfClag9 were partially protected against a subsequent challenge infection with Plasmodium berghei, further supporting a biological role of PfClag9 during natural infection. Taken together, these results provide direct evidence for the existence of a PfRhopH-Clag9 complex on the Plasmodium merozoite surface that binds to human RBCs.
AB - Cytoadherence-linked asexual gene 9 (Clag9), a conserved Plasmodium protein expressed during the asexual blood stages, is involved in the cytoadherence of infected red blood cells (RBCs) to the endothelial lining of blood vessels. Here, we show that Plasmodium falciparum Clag9 (PfClag9) is a component of the PfClag9-RhopH complex that is involved in merozoite binding to human erythrocytes. To characterize PfClag9, we expressed four fragments of PfClag9, encompassing the entire protein. Immunostaining analysis using anti-PfClag9 antibodies showed expression and localization of PfClag9 at the apical end of the merozoites. Mass spectrometric analysis of merozoite extracts after immunoprecipitation using anti-PfClag9 antibody identified P. falciparum rhoptry-associated protein 1 (PfRAP1), PfRAP2, PfRAP3, PfRhopH2, and PfRhopH3 as associated proteins. The identified rhoptry proteins were expressed, and their association with PfClag9 domains was assessed by using protein-protein interaction tools. We further showed that PfClag9 binds human RBCs by interacting with the glycophorin A-band 3 receptor-coreceptor complex. In agreement with its cellular localization, PfClag9 was strongly recognized by antibodies generated during natural infection. Mice immunized with the C-terminal domain of PfClag9 were partially protected against a subsequent challenge infection with Plasmodium berghei, further supporting a biological role of PfClag9 during natural infection. Taken together, these results provide direct evidence for the existence of a PfRhopH-Clag9 complex on the Plasmodium merozoite surface that binds to human RBCs.
KW - Animals
KW - Antibodies, Protozoan/immunology
KW - Antigens, Protozoan/immunology
KW - Cell Adhesion Molecules/immunology
KW - Erythrocytes/immunology
KW - Humans
KW - Malaria, Falciparum/immunology
KW - Merozoites/immunology
KW - Mice
KW - Mice, Inbred BALB C
KW - Plasmodium berghei/immunology
KW - Plasmodium falciparum/immunology
KW - Protein Interaction Maps/immunology
KW - Protozoan Proteins/immunology
U2 - 10.1128/IAI.00504-19
DO - 10.1128/IAI.00504-19
M3 - Journal article
C2 - 31712270
SN - 0019-9567
VL - 88
JO - Infection and Immunity
JF - Infection and Immunity
IS - 2
ER -