Figure 1: Structural components in tumor suppressor RIZ1 and its alternatively transcribed proto-oncoprotein RIZ2. Except the PR domain located at the N-terminus of RIZ1, both RIZ isoforms containing a retinoblastoma-binding (Rb) domain, eight zinc finger motifs (shown in pink), a SH3 domain, a putative GTPase domain, a proline-rich region and a PR domain-binding motif (PRB).