Microtubule Nucleation Pathways

Abstract

α- and β-tubulins polymerize to form polarized filaments called microtubules, which are critical for a variety of cellular activities, such as cell division, morphology, and intracellular transport. The initiation of microtubule formation in cells requires the nucleation process, which largely relies on another protein from the tubulin family, γ-tubulin. Since γ-tubulin is enriched at the centrosome in animal cells, microtubules in the textbooks are usually shown to be exclusively nucleated at the centrosome. However, in reality, cellular microtubules are nucleated at other places as well, and these are important for various cellular activities. This article describes several microtubule nucleation pathways that are operational in animal and plant cells.