title: Two Plasmodium falciparum merozoite proteins binding to erythrocyte band 3 form a direct complex.
abstract: Erythrocyte invasion by malaria parasites requires multiple protein interactions. Our earlier studies showed that erythrocyte band 3 is an invasion receptor binding Plasmodium falciparum merozoite surface protein 1 and 9 (MSP1, MSP9) existing as a co-ligand complex. In this study, we have used biochemical approaches to identify the binding sites within MSP1 and MSP9 involved in the co-ligand complex formation. A major MSP9-binding site is located within the 19kDa C-terminal domain of MSP1 (MSP1(19)). Two specific regions of MSP9 defined as Delta1a and Delta2 interacted with native MSP1(19). The 42 kDa domain of MSP1 (MSP1(42)) bearing MSP1(19) in the C-terminus bound directly to both MSP9/Delta1a and Delta2. Thus, the regions of MSP1 and MSP9 interacting with the erythrocyte band 3 receptor are also responsible for assembling the co-ligand complex. Our evidence suggests a ternary complex is formed between MSP1, MSP9, and band 3 during erythrocyte invasion by P. falciparum.
authors.affiliation: Division of Cell Biology, Caritas St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA, USA.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Kariuki
authors.forename: Xuerong
authors.initials: X
authors.lastname: Li
authors.forename: Innocent
authors.initials: I
authors.lastname: Yamodo
authors.forename: Athar H
authors.initials: AH
authors.lastname: Chishti
authors.forename: Steven S
authors.initials: SS
authors.lastname: Oh
mesh_terms: D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte / Q000378:metabolism*; D015153:Blotting, Western; D006801:Humans; D008024:Ligands; D008565:Membrane Proteins / Q000378:metabolism*; D020066:Merozoite Surface Protein 1 / Q000378:metabolism*; D008956:Models, Chemical; D010963:Plasmodium falciparum / Q000502:physiology*; D015800:Protozoan Proteins / Q000378:metabolism*
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte; D008024:Ligands; D008565:Membrane Proteins; D020066:Merozoite Surface Protein 1; D015800:Protozoan Proteins; C455300:merozoite surface protein 9, Plasmodium