Abstract
MAP200 belongs to eukaryotic MAP215 family. The basic functions of MAP215 family in regulation of dynamic instability are conserved in plant and animal. Based on GTP cap model, the catastrophe frequency is suppressed when the growth rate is increased. However, MAP 215 family promotes both growth rate and catastrophe frequency. The MT regulation mechanism by MAP215 family is not elucidated yet.
MAP200 forms a complex with tubulin dimers. Cosedimentation assay and electron microscopy suggested that the MAP200-tubulin complexes polymerized and form tubulin protofilament-like structure in the presence of either GTP or taxol. GDP induced the catastrophe frequency and inhibited the growth rate. MAP200 suppressed these processes. Based on these results, I propose a novel hypothesis for mechanism of MT regulation by MAP215 family.
