Microtubule associated motor proteins of Plasmodium falciparum merozoites

We have studied the occurrence, stage specificity and cellular location of key molecules associated with microtubules in Plasmodium falciparum merozoi tes. Antibodies to gamma tubulin. conventional kinesin and cytoplasmic dyne in were used to determine the polarity of merozoite microtubules (mt), the stage specificity of the motor proteins and their location during merozoite development. We conclude that the minus ends of the mts are located at the ir apical pole. Kinesin was present throughout the lifecycle, appearing as a distinct crescent at the apex of developing merozoites. The vast majority of cytoplasmic dynein reactivity occurred in late merogony, also appearing at the merozoite apex. Destruction of mt with dinitroanilines did not affe ct the cellular location of kinesin or dynein. In invasion assays, dynein i nhibitors reduced the number of ring stage parasites. Our results show that both conventional kinesin and cytoplasmic dynein are abundant, located at the negative pole of the merozoite mt and, intriguingly, appear there only in very late merogony, prior to merozoite release and invasion. (C) 2001 El sevier Science B.V. All rights reserved.