To improve security and privacy, we are moving our web pages and services from HTTP to HTTPS.
To give users of web services time to transition to HTTPS, we will support separate HTTP and HTTPS services until the end of 2017.
From January 2018 most HTTP traffic will be automatically redirected to HTTPS. [more...]
View this page in https
PROSITE documentation PDOC51044 [for PROSITE entry PS51044]

Zinc finger SP-RING-type profile


SIZ1, SIZ2, and PIAS (protein inhibitor of activated STAT) proteins form a conserved family defined by an unusual RING-related domain, the Siz/PIAS RING finger (SP-RING) [1]. While RING fingers coordinate two Zn2+ ions, with a cross-brace architecture, the SP-RING finger contains only one Zn2+ ion in site B, which is coordinated in a tetrahedral configuration (see <PDB:3I2D>). Three of the four amino acid side chains that coordinate the Zn2+ ion at site A in RING proteins are lacking in Siz/PIAS proteins [2]. Like classical RING fingers SP-RINGs function as an E3 enzyme but specific for sumoylation (see <PDOC00449> for more details on the ubiquitination pathway). The SP-RING zinc finger has the capacity to interact with Ubc9 (the SUMO specific E2 enzyme) and the substrate and thus can increase the rate of substrate sumoylation [3,4].

Some proteins known to contain an SP-RING zinc finger are listed below:

  • Mammalian PIAS proteins (PIAS 1,3,x and y). They bind to STAT transcription factors and prevent STAT-activated transcription. The mouse PIAS3 protein has also been called Msx-interacting-zinc finger protein (Miz1) [5].
  • Drosophila Su(var)2-10. It is required for proper chromosome structure and chromosome inheritance [6].
  • Yeast SIZ1 and SIZ2. They are required for SUMO attachment to the cytoskeletal septin proteins.
  • Pli1, the unique fission yeast member of the SP-RING family. It is involved in centromeric function.

The profile we developed covers the whole SP-RING-type zinc finger.


The SP-RING-type zinc finger is also known as the MIZ-type zinc finger [5].

Last update:

October 2009 / Text revised.

Technical section

PROSITE method (with tools and information) covered by this documentation:

ZF_SP_RING, PS51044; Zinc finger SP-RING-type profile  (MATRIX)


1AuthorsHochstrasser M.
TitleSP-RING for SUMO: new functions bloom for a ubiquitin-like protein.
SourceCell 107:5-8(2001).
PubMed ID11595179

2AuthorsYunus A.A., Lima C.D.
TitleStructure of the Siz/PIAS SUMO E3 ligase Siz1 and determinants required for SUMO modification of PCNA.
SourceMol. Cell 35:669-682(2009).
PubMed ID19748360

3AuthorsJohnson E.S., Gupta A.A.
TitleAn E3-like factor that promotes SUMO conjugation to the yeast septins.
SourceCell 106:735-744(2001).
PubMed ID11572779

4AuthorsSeeler J.S., Dejean A.
TitleNuclear and unclear functions of SUMO.
SourceNat. Rev. Mol. Cell Biol. 4:690-699(2003).
PubMed ID14506472

5AuthorsWu L., Wu H., Ma L., Sangiorgi F., Wu N., Bell J.R., Lyons G.E., Maxson R.
TitleMiz1, a novel zinc finger transcription factor that interacts with Msx2 and enhances its affinity for DNA.
SourceMech. Dev. 65:3-17(1997).
PubMed ID9256341

6AuthorsHari K.L., Cook K.R., Karpen G.H.
TitleThe Drosophila Su(var)2-10 locus regulates chromosome structure and function and encodes a member of the PIAS protein family.
SourceGenes Dev. 15:1334-1348(2001).
PubMed ID11390354

PROSITE is copyright. It is produced by the SIB Swiss Institute Bioinformatics. There are no restrictions on its use by non-profit institutions as long as its content is in no way modified. Usage by and for commercial entities requires a license agreement. For information about the licensing scheme send an email to
Prosite License or see: prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)