PROSITE documentation PDOC51081
Zinc finger SIAH-type profile


SINA/Siah family proteins represent mammalian homologs of the Drosophila SINA (seven in absentia) protein. SINA is required for R7 photoreceptor cell differentiation within the sevenless pathway [1]. Members of this family are E3 ubiquitin ligases that regulate ubiquitination and protein degradation. Siahs are known to recognize several target proteins including Deleted in Colorectal Cancer (DCC), synaptophysin and Numb and promote their degradation [2,3].

SINA/Siah sequences are highly conserved from plants to mammals. Whereas the N terminus and RING domain of Siah bind E2 proteins, the C terminus can be considered as a substrate- and cofactor-interaction domain (substrate-binding domain, SBD) that interacts with a number of proteins, some of which are degraded [4]. The SBD domain displays some sequence similarities with the C-terminal region of TRAF proteins. It contains a cysteine-rich region, the SIAH-type zinc finger, with eight totally conserved Cys and His residues that coordinate two zinc atoms [5].

The crystal structure of SIAH-type zinc finger has been solved (see <PDB:1K2F>) [5]. It folds in two subdomains, each one binding one zinc atom and consisting of two β-strands and an α helice.

The profile we developed covers the entire SIAH-type zinc finger.

Last update:

February 2005 / First entry.


Technical section

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

ZF_SIAH, PS51081; Zinc finger SIAH-type profile  (MATRIX)


1AuthorsCarthew R.W. Rubin G.M.
Titleseven in absentia, a gene required for specification of R7 cell fate in the Drosophila eye.
SourceCell 63:561-577(1990).
PubMed ID2146028

2AuthorsHu G. Zhang S. Vidal M. Baer J.L. Xu T. Fearon E.R.
TitleMammalian homologs of seven in absentia regulate DCC via the ubiquitin-proteasome pathway.
SourceGenes Dev. 11:2701-2714(1997).
PubMed ID9334332

3AuthorsSusini L. Passer B.J. Amzallag-Elbaz N. Juven-Gershon T. Prieur S. Privat N. Tuynder M. Gendron M.C. Israel A. Amson R. Oren M. Telerman A.
TitleSiah-1 binds and regulates the function of Numb.
SourceProc. Natl. Acad. Sci. U.S.A. 98:15067-15072(2001).
PubMed ID11752454

4AuthorsHu G. Fearon E.R.
TitleSiah-1 N-terminal RING domain is required for proteolysis function, and C-terminal sequences regulate oligomerization and binding to target proteins.
SourceMol. Cell. Biol. 19:724-732(1999).
PubMed ID9858595

5AuthorsPolekhina G. House C.M. Traficante N. Mackay J.P. Relaix F. Sassoon D.A. Parker M.W. Bowtell D.D.
TitleSiah ubiquitin ligase is structurally related to TRAF and modulates TNF-alpha signaling.
SourceNat. Struct. Biol. 9:68-75(2002).
PubMed ID11742346

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