PROSITE documentation PDOC50801
STAS domain profile


The STAS domain is found in the C-terminal cytoplasmic part of anion transporters from eukaryotes and many bacteria, as well as in the bacterial anti-sigma-factor antagonists (ASAs). It was named STAS after sulfate transporters and anti-sigma-factor antagonist [1].

Malfunctions in members of the SLC26A family of anion transporters are involved in three human diseases: diastrophic dysplasia/achondrogenesis type 1B (DTDST), Pendred's syndrome (PDS) and congenital chloride diarrhea (CLD). These proteins contain 12 transmembrane helices followed by a cytoplasmic STAS domain at the C-terminus. The importance of the STAS domain in these transporters is illustrated by the fact that a number of mutations in PDS and DTDST map to it [1].

The activity of bacterial sigma transcription factors is controlled by a regulatory cascade involving an anti-sigma-factor, the ASA and a phosphatase. The antisigma-factor binds to sigma and holds it in an inactive complex. The ASA can also interact with the anti-sigma-factor, allowing the release of the active sigma factor. As the anti-sigma-factor is a protein kinase, it can phosphorylate the anti-sigma antagonist on a conserved serine residue of the STAS domain. This phosphorylation inactivates the ASA that can be reactivated through dephosphorylation by a phosphatase [1,2]. The STAS domain of the ASA SpoIIAA binds GTP and ATP and possesses a weak NTPase activity. Strong sequence conservation suggests that the STAS domain could possess general NTP-binding activity and it has been proposed that the NTPs are likely to elicit specific conformational changes in the STAS domain through binding and/or hydrolysis [1].

Resolution of the solution structure of the ASA SpoIIAA from Bacillus subtilis (see <PDB:1AUZ>) has shown that the STAS domain consists of a four-stranded β-sheet and four α helices. The STAS domain forms a characteristic α-helical handle-like structure [1,3].

Some proteins known to contain a STAS domain are listed below:

  • Members of the SLC26 family of anion transporters.
  • Anti-sigma-factor antagonists such as Bacillus subtilis SpoIIAA [2].
  • Blue-light photoreceptor (Phototropin homolog) from Bacillus subtilis.
  • Hypothetical protein K12G11.1 from Caenorhabditis elegans.
  • Hypothetical protein SPCC320.05 from fission yeast.

The profile we developed covers the entire STAS domain.

Last update:

April 2002 / First entry.


Technical section

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

STAS, PS50801; STAS domain profile  (MATRIX)


1AuthorsAravind L. Koonin E.V.
TitleThe STAS domain - a link between anion transporters and antisigma-factor antagonists.
SourceCurr. Biol. 10:R53-R55(2000).
PubMed ID10662676

2AuthorsFeucht A. Daniel R.A. Errington J.
TitleCharacterization of a morphological checkpoint coupling cell-specific transcription to septation in Bacillus subtilis.
SourceMol. Microbiol. 33:1015-1026(1999).
PubMed ID10476035

3AuthorsKovacs H. Comfort D. Lord M. Campbell I.D. Yudkin M.D.
TitleSolution structure of SpoIIAA, a phosphorylatable component of the system that regulates transcription factor sigmaF of Bacillus subtilis.
SourceProc. Natl. Acad. Sci. U.S.A. 95:5067-5071(1998).
PubMed ID9560229

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