SP-RING finger found in zinc finger MIZ domain-containing protein 1 (Zmiz1) and similar proteins
Zmiz1, also known as PIAS-like protein Zimp10 (zinc finger-containing, Miz1, PIAS-like protein on chromosome 10) or retinoic acid-induced protein 17, is a novel PIAS-like protein that was initially identified as an androgen receptor (AR) interacting protein and functions as a transcriptional co-activator. It co-localizes with AR and small ubiquitin-like modifier SUMO-1, forms a protein complex at replication foci in the nucleus, and augments AR-mediated transcription. It also functions as a transcriptional co-activator of the p53 tumor suppressor that plays a critical role in the cell cycle progression, DNA repair, and apoptosis. Moreover, Zmiz1 associates with multiple autoimmune diseases and has been implicated in the development, function, and survival of melanocyte. Zmiz1 also interacts with Smad3/4 proteins and augments Smad-mediated transcription, suggesting it is important in the regulation of the transforming growth factor beta (TGF-beta)/Smad signaling pathway and may have an inhibitory effect on the immune system. Furthermore, Zmiz1 is overexpressed in a significant percentage of human cutaneous squamous cell carcinoma (SCC), breast, ovarian, and colon cancers, suggesting it may play a broader role in epithelial cancers. It functionally interacts with NOTCH1 to promote C-MYC transcription and activity, and thus is involved in a variety of C-MYC-driven cancers. Zmiz1 contains a PAT domain, a highly conserved Siz/PIAS (protein inhibitor of activated signal transducer and activator of transcription) RING (SP-RING) finger, also known as msx-interacting zinc finger (Miz domain), and a putative nuclear localization sequence (NLS), as well as a strong intrinsic transactivation domain within the C-terminus.