Genetic ablation of a Maurer's cleft protein prevents assembly of the Plasmodium falciparum virulence complex

Mol Microbiol. 2011 Aug;81(4):982-93. doi: 10.1111/j.1365-2958.2011.07740.x. Epub 2011 Jul 7.


The malaria parasite Plasmodium falciparum assembles knob structures underneath the erythrocyte membrane that help present the major virulence protein, P. falciparum erythrocyte membrane protein-1 (PfEMP1). Membranous structures called Maurer's clefts are established in the erythrocyte cytoplasm and function as sorting compartments for proteins en route to the RBC membrane, including the knob-associated histidine-rich protein (KAHRP), and PfEMP1. We have generated mutants in which the Maurer's cleft protein, the ring exported protein-1 (REX1) is truncated or deleted. Removal of the C-terminal domain of REX1 compromises Maurer's cleft architecture and PfEMP1-mediated cytoadherance but permits some trafficking of PfEMP1 to the erythrocyte surface. Deletion of the coiled-coil region of REX1 ablates PfEMP1 surface display, trapping PfEMP1 at the Maurer's clefts. Complementation of mutants with REX1 partly restores PfEMP1-mediated binding to the endothelial cell ligand, CD36. Deletion of the coiled-coil region or complete deletion of REX1 is tightly associated with the loss of a subtelomeric region of chromosome 2, encoding KAHRP and other proteins. A KAHRP-green fluorescent protein (GFP) fusion expressed in the REX1-deletion parasites shows defective trafficking. Thus, loss of functional REX1 directly or indirectly ablates the assembly of the P. falciparum virulence complex at the surface of host erythrocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD36 Antigens / metabolism
  • Cell Adhesion
  • Endothelial Cells / metabolism
  • Erythrocytes / parasitology
  • Genetic Complementation Test
  • Humans
  • Membrane Proteins / metabolism*
  • Peptides / metabolism*
  • Plasmodium falciparum / genetics*
  • Plasmodium falciparum / metabolism*
  • Protein Transport
  • Protozoan Proteins / genetics*
  • Protozoan Proteins / metabolism*
  • Sequence Deletion
  • Virulence Factors / metabolism*


  • CD36 Antigens
  • Membrane Proteins
  • Peptides
  • Protozoan Proteins
  • REX1 protein, Plasmodium falciparum
  • Virulence Factors
  • erythrocyte membrane protein 1, Plasmodium falciparum
  • knob protein, Plasmodium falciparum