Protein Phosphatase 1, Regulatory Subunit 9 (PPP1R9)

Spinophilin is a regulatory subunit of protein phosphatase-1 catalytic subunit (PP1) and is highly enriched in dendritic spines, specialized protrusions from dendritic shafts that receive most of the excitatory input in the central nervous system.To identify proteins that interact with the ARF protein encoded by the CDKN2A gene, Vivo et al. (2001) used a yeast 2-hybrid screen of a human brain cDNA library with an ARF fusion construct as bait. By database searching with the identified clones, they reconstructed a full-length cDNA of human spinophilin. The deduced 813-amino acid protein shares 95% sequence identity with the rat homolog and contains an F-actin binding domain, a PP1C binding site, a PDZ domain, and a myosin-like left-handed alpha helix.