THE ATP-BINDING CASSETTE (ABC) GENE FAMILY OF PLASMODIUM-FALCIPARUM

Multidrug resistance (MDX) in mammalian tumour cells is mediated by P- glycoproteins. The apparent similarities between MDX and the chloroqui ne-resistance phenotype (CQR) in Plasmodium falciparum suggests that h omologous proteins may be involved. In mammals, P-glycoproteins are en coded by mdr genes that are a subset of a superfamily characterized by ATP-binding cassettes (ABC). Three genes, pfmdr1, pfmdr2 and pfef3-r1 , have been identified in P. falciparum that have homology to the ABC transporter gene family. Each protein encoded by these genes has a dis tinct structure, suggesting functional differences between the three. Justin Rubio and Alan Cowman here discuss the structure and possible f unction of the ABC proteins from P. falciparum and evidence that the p rotein encoded by the pfmdr1 gene can influence quinoline-containing a ntimalarial drug-resistance phenotypes.