Research in conjunction with Melanie Rug, Walter & Eliza Hall Institute, Australia.

Malaria KAHRP knobs on the surface of red blood cells

Knobs appear on Plasmodium falciparum-infected erythrocytes in early trophozoite stages of the asexual life cycle of the parasite. They are protuberances of the red blood cell membrane that contain various malarial proteins, with the structural component being the knob-associated histidine rich protein (KAHRP). Knobs provide an elevation for the major variant protein family P. falciparum erythrocyte membrane protein (PfEMP1) which confers adherence to endothelia in the deep vasculature of various organs, e.g. the brain, often leading to fatal complications of the disease. In order to determine the domains of KAHRP necessary for knob formation we used targeted gene truncation in 3D7 parasites. The resulting 7 mutant cell lines express gradual truncations of the full length protein. Using atomic force, scanning and transmission electron microscopy we were able to decipher the elements for knob formation [1].

SEM and AFM images of KAHRP knobs on malaria-infected red blood cells.


  1. The role of KAHRP domains in knob formation and cytoadherence of P. falciparum-infected human erythrocytes. M Rug, SW Prescott, KM Fernandez, BM Cooke and AF Cowman. Blood, 108(1), 370–378, 2006.

Last edited: Tuesday September 9, 2008

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