 Details of the SIZ1 structure were published by Ali A. Yunus and Christopher D. Lima in 2009.Four PIAS domains and two PIAS motifs have been identified.They include the N-terminal scaffold attachment factor-A/B, acinus and PIAS (SAP) domain, the Pro-Ile-Asn-Ile-Thr (PINIT) motif, the RING-finger-like zinc-binding domain (RLD), the highly acidic domain (AD), the SUMO-interacting motif (SIM), and the serine/threonine-rich C-terminal region (S/T).