Domain

STAS domain (IPR002645)

Short name: STAS_dom

Domain relationships

None.

Description

The STAS (Sulphate Transporter and AntiSigma factor antagonist) domain is found in the C-terminal region of sulphate transporters and bacterial anti-sigma factor antagonists. It has been suggested that this domain may have a general NTP binding function.

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 [PMID: 10662676].

The activity of bacterial sigma transcription factors is controlled by a regulatory cascade involving an antisigma-factor, the antisigma-factor antagonist (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 antisigma-factor is a protein kinase, it can phosphorylate the antisigma antagonist on a conserved serine residue of the STAS domain. This phosphorylation inactivates the ASA that can be reactivated through dephosphorylation by a phosphatase [PMID: 10662676, PMID: 10476035]. 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 [PMID: 10662676].

Resolution of the solution structure of the ASA SpoIIAA from Bacillus subtilis has shown that the STAS domain consists of a four-stranded beta-sheet and four alpha helices. The STAS domain forms a characteristic alpha-helical handle-like structure [PMID: 10662676, PMID: 9560229].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
GENE3D
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SUPERFAMILY
PROSITE profiles