Binds actin monomers (G actin) and plays a role in multiple processes including the regulation of actin cytoskeleton dynamics, actin stress fibers formation, cell motility and survival, formation of tubules by endothelial cells, and regulation of PPP1CA activity (By similarity). Involved in the regulation of cortical neuron migration and dendrite arborization (By similarity). Interacts (via RPEL repeats) with ACTA1 and PPP1CA; ACTA1 and PPP1CA compete for the same binding site. Cytoplasmic in resting cells, and is imported into the nucleus upon serum stimulation. Interaction with actin prevents nuclear import (By similarity). Enriched at synapses. Selectively expressed in brain. High levels are found in the olfactory tubercle, nucleus accumbens core and shell, caudate-putamen, cerebral cortex, hippocampus and piriform cortex. Moderate to high levels in the olfactory bulb, arcuate and ventromedial hypothalamus, subthalamic nucleus, amygdala, lateral septum, habenula and thalamus. Low expression, if any, in substantia nigra pars compacta/pars reticula and globus pallidus (at protein level). Binds three actin monomers via the three C-terminal RPEL repeats. Belongs to the phosphatase and actin regulator family.