Critical Glycosylated Residues in Exon Three of Erythrocyte Glycophorin A Engage <named-content content-type="genus-species">Plasmodium falciparum</named-content> EBA-175 and Define Receptor Specificity

ABSTRACT Erythrocyte invasion is an essential step in the pathogenesis of malaria. The erythrocyte binding-like (EBL) family of Plasmodium falciparum proteins recognizes glycophorins (Gp) on erythrocytes and plays a critical role in attachment during invasion. However, the molecular basis for specif...

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Autores principales:	Nichole D. Salinas, May M. Paing, Niraj H. Tolia
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2014
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/534f5dd47de748d88cb9780689234d2d
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spelling	oai:doaj.org-article:534f5dd47de748d88cb9780689234d2d2021-11-15T15:45:54ZCritical Glycosylated Residues in Exon Three of Erythrocyte Glycophorin A Engage <named-content content-type="genus-species">Plasmodium falciparum</named-content> EBA-175 and Define Receptor Specificity10.1128/mBio.01606-142150-7511https://doaj.org/article/534f5dd47de748d88cb9780689234d2d2014-10-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01606-14https://doaj.org/toc/2150-7511ABSTRACT Erythrocyte invasion is an essential step in the pathogenesis of malaria. The erythrocyte binding-like (EBL) family of Plasmodium falciparum proteins recognizes glycophorins (Gp) on erythrocytes and plays a critical role in attachment during invasion. However, the molecular basis for specific receptor recognition by each parasite ligand has remained elusive, as is the case with the ligand/receptor pair P. falciparum EBA-175 (PfEBA-175)/GpA. This is due largely to difficulties in producing properly glycosylated and functional receptors. Here, we developed an expression system to produce recombinant glycosylated and functional GpA, as well as mutations and truncations. We identified the essential binding region and determinants for PfEBA-175 engagement, demonstrated that these determinants are required for the inhibition of parasite growth, and identified the glycans important in mediating the PfEBA-175–GpA interaction. The results suggest that PfEBA-175 engages multiple glycans of GpA encoded by exon 3 and that the presentation of glycans is likely required for high-avidity binding. The absence of exon 3 in GpB and GpE due to a splice site mutation confers specific recognition of GpA by PfEBA-175. We speculate that GpB and GpE may have arisen due to selective pressure to lose the PfEBA-175 binding site in GpA. The expression system described here has wider application for examining other EBL members important in parasite invasion, as well as additional pathogens that recognize glycophorins. The ability to define critical binding determinants in receptor-ligand interactions, as well as a system to genetically manipulate glycosylated receptors, opens new avenues for the design of interventions that disrupt parasite invasion. IMPORTANCE Plasmodium falciparum uses distinct ligands that bind host cell receptors for invasion of red blood cells (RBCs) during malaria infection. A key entry pathway involves P. falciparum EBA-175 (PfEBA-175) recognizing glycophorin A (GpA) on RBCs. Despite knowledge of this protein-protein interaction, the complete mechanism for specific receptor engagement is not known. PfEBA-175 recognizes GpA but is unable to engage the related RBC receptor GpB or GpE. Understanding the necessary elements that enable PfEBA-175 to specifically recognize GpA is critical in developing specific and potent inhibitors of PfEBA-175 that disrupt host cell invasion and aid in malaria control. Here, we describe a novel system to produce and manipulate the host receptor GpA. Using this system, we probed the elements in GpA necessary for engagement and thus for host cell invasion. These studies have important implications for understanding how ligands and receptors interact and for the future development of malaria interventions.Nichole D. SalinasMay M. PaingNiraj H. ToliaAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 5, Iss 5 (2014)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Nichole D. Salinas May M. Paing Niraj H. Tolia Critical Glycosylated Residues in Exon Three of Erythrocyte Glycophorin A Engage <named-content content-type="genus-species">Plasmodium falciparum</named-content> EBA-175 and Define Receptor Specificity
description	ABSTRACT Erythrocyte invasion is an essential step in the pathogenesis of malaria. The erythrocyte binding-like (EBL) family of Plasmodium falciparum proteins recognizes glycophorins (Gp) on erythrocytes and plays a critical role in attachment during invasion. However, the molecular basis for specific receptor recognition by each parasite ligand has remained elusive, as is the case with the ligand/receptor pair P. falciparum EBA-175 (PfEBA-175)/GpA. This is due largely to difficulties in producing properly glycosylated and functional receptors. Here, we developed an expression system to produce recombinant glycosylated and functional GpA, as well as mutations and truncations. We identified the essential binding region and determinants for PfEBA-175 engagement, demonstrated that these determinants are required for the inhibition of parasite growth, and identified the glycans important in mediating the PfEBA-175–GpA interaction. The results suggest that PfEBA-175 engages multiple glycans of GpA encoded by exon 3 and that the presentation of glycans is likely required for high-avidity binding. The absence of exon 3 in GpB and GpE due to a splice site mutation confers specific recognition of GpA by PfEBA-175. We speculate that GpB and GpE may have arisen due to selective pressure to lose the PfEBA-175 binding site in GpA. The expression system described here has wider application for examining other EBL members important in parasite invasion, as well as additional pathogens that recognize glycophorins. The ability to define critical binding determinants in receptor-ligand interactions, as well as a system to genetically manipulate glycosylated receptors, opens new avenues for the design of interventions that disrupt parasite invasion. IMPORTANCE Plasmodium falciparum uses distinct ligands that bind host cell receptors for invasion of red blood cells (RBCs) during malaria infection. A key entry pathway involves P. falciparum EBA-175 (PfEBA-175) recognizing glycophorin A (GpA) on RBCs. Despite knowledge of this protein-protein interaction, the complete mechanism for specific receptor engagement is not known. PfEBA-175 recognizes GpA but is unable to engage the related RBC receptor GpB or GpE. Understanding the necessary elements that enable PfEBA-175 to specifically recognize GpA is critical in developing specific and potent inhibitors of PfEBA-175 that disrupt host cell invasion and aid in malaria control. Here, we describe a novel system to produce and manipulate the host receptor GpA. Using this system, we probed the elements in GpA necessary for engagement and thus for host cell invasion. These studies have important implications for understanding how ligands and receptors interact and for the future development of malaria interventions.
format	article
author	Nichole D. Salinas May M. Paing Niraj H. Tolia
author_facet	Nichole D. Salinas May M. Paing Niraj H. Tolia
author_sort	Nichole D. Salinas
title	Critical Glycosylated Residues in Exon Three of Erythrocyte Glycophorin A Engage <named-content content-type="genus-species">Plasmodium falciparum</named-content> EBA-175 and Define Receptor Specificity
title_short	Critical Glycosylated Residues in Exon Three of Erythrocyte Glycophorin A Engage <named-content content-type="genus-species">Plasmodium falciparum</named-content> EBA-175 and Define Receptor Specificity
title_full	Critical Glycosylated Residues in Exon Three of Erythrocyte Glycophorin A Engage <named-content content-type="genus-species">Plasmodium falciparum</named-content> EBA-175 and Define Receptor Specificity
title_fullStr	Critical Glycosylated Residues in Exon Three of Erythrocyte Glycophorin A Engage <named-content content-type="genus-species">Plasmodium falciparum</named-content> EBA-175 and Define Receptor Specificity
title_full_unstemmed	Critical Glycosylated Residues in Exon Three of Erythrocyte Glycophorin A Engage <named-content content-type="genus-species">Plasmodium falciparum</named-content> EBA-175 and Define Receptor Specificity
title_sort	critical glycosylated residues in exon three of erythrocyte glycophorin a engage <named-content content-type="genus-species">plasmodium falciparum</named-content> eba-175 and define receptor specificity
publisher	American Society for Microbiology
publishDate	2014
url	https://doaj.org/article/534f5dd47de748d88cb9780689234d2d
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Critical Glycosylated Residues in Exon Three of Erythrocyte Glycophorin A Engage <named-content content-type="genus-species">Plasmodium falciparum</named-content> EBA-175 and Define Receptor Specificity

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