Consequences of Altering Tubulin Levels in Yeast

Abstract

Microtubules are the central component of the mitotic and meiotic spindles, and their proper assembly and function is vital to the fidelity of chromosome segregation. Twenty-five years of microtubule research has provided the fundamentals for understanding microtubule function. All microtubules are composed primarily of two different kinds of proteins, alpha tubulin and beta tubulin. The genes for these proteins have been isolated and sequenced from a wide variety of organisms. Alpha and beta tubulin form a heterodimer, which serves as the subunit of the microtubule polymer. The properties of the heterodimer are fairly well understood, and in vitro assembly experiments have defined parameters and factors that control the intrinsic ability of tubulin to self-assemble. Nontubulin proteins that bind to microtubules have been identified, and are candidates for elements that may control microtubule assembly, organization, and function in the cell. Biochemical approaches have been complemented by genetic analyses of microtubule function, demonstrating the essentiality of the tubulin proteins and dissecting their functional properties.