Structural and functional studies of interaction between Plasmodium falciparum knob-associated histidine-rich protein (KAHRP) and erythrocyte spectrin

J Biol Chem. 2005 Sep 2;280(35):31166-71. doi: 10.1074/jbc.M505298200. Epub 2005 Jul 8.


Plasmodium falciparum dramatically modifies the structure and function of the membrane of the parasitized host erythrocyte. Altered membrane properties are the consequence of the interaction of a group of exported malaria proteins with host cell membrane proteins. KAHRP (the knob-associated histidine-rich protein), a member of this group, has been shown to interact with erythrocyte membrane skeletal protein spectrin. However, the molecular basis for this interaction has yet to be defined. In the present study, we defined the binding motifs in both KAHRP and spectrin and identified a functional role for this interaction. We showed that spectrin bound to a 72-amino-acid KAHRP fragment (residues 370-441). Among nine-spectrin fragments, which encompass the entire alpha and beta spectrin molecules (four alpha spectrin and five beta spectrin fragments), KAHRP bound only to one, the alpha N-5 fragment. The KAHRP-binding site within the alpha N-5 fragment was localized uniquely to repeat 4. The interaction of full-length spectrin dimer to KAHRP was inhibited by repeat 4 of alpha spectrin. Importantly, resealing of this repeat peptide into erythrocytes mislocalized KAHRP in the parasitized cells. We concluded that the interaction of KAHRP with spectrin is critical for appropriate membrane localization of KAHRP in parasitized erythrocytes. As the presence of KAHRP at the erythrocyte membrane is necessary for cytoadherence in vivo, our findings have implications for the development of new therapies for mitigating the severity of malaria infection.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Membrane / chemistry
  • Cell Membrane / metabolism
  • Erythrocytes / cytology
  • Erythrocytes / metabolism*
  • Erythrocytes / parasitology
  • Humans
  • Membrane Proteins* / genetics
  • Membrane Proteins* / metabolism
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • Peptides* / genetics
  • Peptides* / metabolism
  • Plasmodium falciparum / metabolism*
  • Protozoan Proteins* / genetics
  • Protozoan Proteins* / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Spectrin* / genetics
  • Spectrin* / metabolism
  • Surface Plasmon Resonance


  • Membrane Proteins
  • Peptide Fragments
  • Peptides
  • Protozoan Proteins
  • Recombinant Fusion Proteins
  • knob protein, Plasmodium falciparum
  • Spectrin