Modular complexes that regulate actin assembly in budding yeast

The actin cytoskeleton of budding yeast contains an extensive set of actin- associated proteins with conserved mammalian counterparts. For more than 20 years, yeast has been used as a model organism to dissect the in vivo func tions of these factors, revealing an intricate web of genetic interactions in the cell. Now, a surge of biochemical reports is defining the physical i nteractions and activities of these proteins and providing mechanistic insi ghts into their cellular roles. The emerging view is that most actin-associ ated proteins do not act alone but, rather, associate to form modular prote in complexes that regulate actin assembly and organization.