Neurabin-II, also called spinophilin, interacts with actin and PP-1 in dendritic spines of the central nervous system (1,2). The gene encoding human neurabin-II maps to chromosome 17q21-q22 (2). The structural characteristics of neurabin-II include one F-actin binding domain at the N-terminal region, a predicted coiled-coil struture at the C-terminal, one PDZ domain at the middle region, and a domain known to interact with transmembrane proteins (1). Neurabin-II bundles actin fliaments in vitro (1). In vivo, spinophilin localizes to the cortical sites of actin filaments and to the sites of active membrane remodelling (4). Neurabin-II also forms a complex with the catalytic subunit of PP1 and modulates PP1 enzymatic activity in vitro (2). Neurabin-II localizes to the head of dendritic spines (2) and aids in the ability of PP-1 to regulate the activity of a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-asparate (NMDA) receptors (3). In this manner, neurabin-II modulates both glutamatergic synaptic transmission and dendritic morphology (3). Synergistic interactions between spinophilin and human tumor supressor ARF suggest a role for neurabin-II in cell growth (5).