This family, the N-terminal segment, is the most variable part of the variant surface antigen family of Plasmodium falciparum, the erythrocyte membrane protein-1 (PfEMP1) proteins. PfEMP1 is an important target for protective immunity and is implicated in the pathology of malaria through its ability to adhere to host endothelial receptors [1]. A structural and functional study of the N-terminal domain of PfEMP1 from the VarO variant comprising the N-terminal segment (NTS) and the first DBL domain (DBL1alpha1), shows this region is directly implicated in rosetting. NTS, previously thought to be a structurally independent component of PfEMP1, forms an integral part of the DBL1alpha domain that is found to be the important heparin-binding site [2]. This family is closely associated with PFEMP, Pfam:PF03011, and Duffy_binding, Pfam:PF05424.

1: Sub-grouping of Plasmodium falciparum 3D7 var genes based on sequence analysis of coding and non-coding regions. Lavstsen T, Salanti A, Jensen AT, Arnot DE, Theander TG; Malar J. 2003;2:27. PMID:14565852

2: Structure of a Plasmodium falciparum PfEMP1 rosetting domain reveals a role for the N-terminal segment in heparin-mediated rosette inhibition. Juillerat A, Lewit-Bentley A, Guillotte M, Gangnard S, Hessel A, Baron B, Vigan-Womas I, England P, Mercereau-Puijalon O, Bentley GA; Proc Natl Acad Sci U S A. 2011;108:5243-5248. PMID:21402930