Abstract
Microtubule, a polarized hollow tube having plus and minus ends, is highly dynamic structure repeating growth and shortening, especially at its plus end. In cells, the parameters of microtubule dynamics are spatio-temporally regulated by a number of microtubule-binding proteins that stabilize or destabilize microtubules, and thereby asymmetrical microtubule networks are generated. The generation of a polarized microtubule organization is critically important for proper cellular functions, such as cell division and migration. To explain how microtubules set up and make contacts with cellular structures, a "search-and-capture" mechanism has been proposed, in which the microtubule plus ends dynamically search for and capture specific sites, such as mitotic kinetochores and cell cortex. To date, several classes of proteins called "microtubule plus-end-tracking proteins" or "+TIPs" have been shown to be associated with "growing" microtubule plus ends in a wide range of organisms from fungi to humans to play critical roles in the "search-and-capture" mechanism. Some of +TIPs highlight every growing microtubule plus ends, while some of them accumulate at the microtubule-capturing structure created at the specialized sites, and the complex formation of these molecules serves a link between the microtubule plus end and variety of cellular structures. In this talk, I will introduce the tools to visualize microtubule dynamics in living cells and overview our current understanding of the +TIPs. [J Physiol Sci. 2006;56 Suppl:S59]
