Suppresses MEK1 null cell polarity, chemotaxis, and gene expression defects. Required for proper cytokinesis during vegetative growth, timely exit from the mound stage during development, and myosin II assembly. May be a regulatory subunit of serine/threonine-protein phosphatase 4 (PP4) and may control localization of PP4 to the nucleus. Involved in the regulation of some ppp4c functions, such as developmental progression, chemotaxis, expression of stress response genes and cell movement. Interacts with ppp4c. Localizes to the cell cortex in vegetative cells but translocates to the nucleus during starvation and development (PubMed:16107728). Levels are constant throughout development. The EVH1/WH1 domain is necessary for cortical localization. Belongs to the SMEK family.