Controls cell shape changes in the neuroepithelium during neural tube closure (PubMed:10589677, PubMed:14680628). Induces apical constriction in epithelial cells by promoting the apical accumulation of F-actin and myosin II, and probably by bundling stress fibers (PubMed:14680628, PubMed:16249236, PubMed:16684770, PubMed:22493320). Induces apicobasal cell elongation by redistributing gamma-tubulin and directing the assembly of robust apicobasal microtubule arrays (By similarity). Interacts with F-actin (PubMed:10589677). Interacts with ROCK1 (PubMed:22493320). Colocalizes with F-actin in stress fibers and adherens junctions. At 8.75 dpc, strongly expressed in the cranial neuroepithelium, and also expressed in neural tube, paraxial mesoderm and gut. At 10.5 dpc, expressed in neural tube, forebrain, somites, ventral body wall, heart and gut. At 14.5 dpc, expression is restricted to skeletal muscle, tips of the digits and forebrain. The ASD1 domain mediates F-actin binding. The ASD2 domain mediates the interaction with ROCK1 and is required for apical constriction induction. Death at birth due to defects in neural tube closure causing exencephaly, acrania, facial clefting and spina bifida. Belongs to the shroom family.