The actin cytoskeleton is ubiquitous among eukaryotes, and is involved in numerous cellular processes. Even within a single cell, it can have structural as well as motile functions, and each of these can take many different forms. Important issues are (i) the proteins that regulate actin assembly and function, and (ii) the cellular processes that are mediated by the actin cytoskeleton.

In order to study the cytoskeleton in vivo, we have chosen to use yeast because of its simplicity as a single-celled organism (e.g., just single genes encoding actin and most of the actin-binding proteins); the fact that most basic cell biological mechanisms are conserved between yeast and more complex cells; and because of the extremely powerful genetics possible with this organism.

We have taken two general approaches to an analysis of the actin cytoskeleton. First, we have studied the interactions between various proteins of the cytoskeleton, with a view to understanding the molecular organization and regulation of the cytoskeleton. This analysis has led to important insights into the biochemical and functional interactions of cytoskeletal components. Second, we have used a large collection of cytoskeletal mutants to identify the roles of the actin cytoskeleton in various cellular functions. These studies have led to novel insights into the roles of the actin cytoskeleton in yeast, and will likely improve our understanding of cytoskeletal function in higher cells.