Polyglutamine binding protein 1, also known as PQBP1, is a transcription repressor that associates with polyglutamine tract-containing transcription regulators and causative genes for neurodegenerative disorders. PQBP-1 localizes to the nucleus and is present in neurons throughout the brain, with abundant levels in hippocampus, cerebellar cortex and olfactory bulb. PQBP-1 contains a WWP/WW domain that binds proline-rich motifs and a C2 domain that can influence Ca2+-dependent phospholipid signaling.