Molecular Architecture and Function of the Cytoskeleton

点击翻译按钮获取中文摘要

(1) We purified the microtubule associated protein 2C, which specifically expressed in juvenile brains, and characterized them biochemically and ultrastructurally. The MAP2C CDNA was cloned from rat brain CDNA library and was sequenced. To analyze functions of MAP2 in vivo, we carried out transfection experiments. A. fibroblast cell line which was transfected with the CDNA expressed MAP2C and formed thick bundles of 'microtubules. Ineterestingly intermediate filaments also changed their organization and colocalized with microtubule bundles.(2) To elucidate the mechamism which control bidirectional transport of membranous organelle we examined the effect of phosphorylation of kinesin on their binding to the membranes ; We found phosphorylation of kinesin by A-kinase considerably decreased the binding. Thus A-kinase probably play an important role on the dissociation of kinesin from the membranous, organelles in the. axon.(3) To study the dynamics of tubulin in axons we microinjected caged fluorescein labeled tubulin into cultured neurons and subsequently analysed its turnover by UV photoactivation method. The results suggested that most of the polymers in the axon are stationary and the free oligomers could be the form to be transported.(4) We established a method to purify 10OKD microtubule Associated idrotein (dynamin) from mammalian brains. Dynamin revealed a potent GTPase activity activated by microtubules. CDNA of dynamin was cloned and sequenced. Dynaim was proved to be a new GTP binding protein which specifically expressed in mature nerve cells.