Saccharomyces cerevisiae as a model system.
Research involves a combination of molecular genetic, biochemical and cell biological approaches.
Cells contain multiple MAPK cascades that can use subsets of the same kinases yet activate different effector proteins in response to different stimuli. Our model pathway is the mating MAP kinase cascade that promotes cell cycle arrest and polarized growth in response to an antimitogenic differentiation factor. Regulated membrane recruitment of cytosolic scaffold and polarized localization of a signaling apparatus. The Ste5 scaffold localizes the mating MAPK cascade enzymes to a plasma membrane-associated Gb protein in response to signal. This localization event is essential for pathway activation and involves a novel localization pathway that shuttles the cytoplasmic scaffold through the nucleus prior to targeting it to the plasma membrane.