Binds to actin filaments (F-actin) and shows cross-linking activity. Binds along the sides of the F-actin. May be involved in neurite formation. Inhibits protein phosphatase 1-alpha activity. May play an important role in linking the actin cytoskeleton to the plasma membrane at the synaptic junction. Possibly exists as a homodimer, homotrimer or a homotetramer. Interacts with F-actin, protein phosphatase 1 (PP1), neurabin-2, TGN38 and p70-S6K. Brain, and widely expressed in neural tissue. Highly concentrated in synapses of developed neurons. In developing neurons, concentrated in the lamellipodia of the growth cone. Interacts with p70-S6K via its PDZ domain. The PP1 binding region is natively unstructured, upon PP1 binding, it acquires structure, blocks a substrate-binding site, and restricts PP1 phosphatase specificity to a subset of substrates.