SP-RING finger found in zinc finger MIZ domain-containing protein 2 (Zmiz2) and similar proteins
Zmiz2, also known as PIAS-like protein Zimp7 (zinc finger-containing, Miz1, PIAS-like protein on chromosome 7), 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 interacts with beta-catenin and enhances Wnt/beta-catenin-mediated transcription. It also associates with BRG1 and BAF57, components of the ATP-dependent mammalian SWI/SNF-like BAF chromatin-remodeling complexes, and thus plays a potential role in modulation of AR and/or other nuclear receptor-mediated transcription. For instance, it can increase the effects of BRG1 on AR-mediated transcriptional activity. Moreover, Zmiz2 physically interacts with PIAS proteins, especially PIAS3. Through this interaction, PIAS3 augments Zmiz2-mediated transcription, suggesting PIAS proteins may play a regulatory role in Zmiz-mediated transcription. Furthermore, Zmiz2 is involved in transcriptional regulation of factors essential for patterning in the dorsoventral axis. It is required for the restriction of the zebrafish organizer and mesoderm development. Zmiz2 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 strong intrinsic transactivation domain within the C-terminus. The SP-RING finger is a variant of RING finger, which lacks the second, fifth, and sixth zinc-binding residues of the consensus C3H2C3-/C3HC4-type RING fingers. It binds a single Zn ion, instead of two ions bound by typical RING fingers.
Comment:based on the structures of human Sumo ligases Pias2 and Pias3 with bound Zn2+ ion through their SP-RING fingers
Comment:The SP-RING finger is a variant of RING finger; it binds a single Zn ion and lacks the second, fifth, and sixth zinc-binding residues of the consensus C3H2C3-/C3HC4-type RING fingers.
Jiyao W et al.(2023). "The conserved domain database in 2023.",