Shibagaki, Nakako , Grossman, Arthur .
Functions of the STAS domain in the Arabidopsis sulfate transporter, Sultr1;2.
The SLC26A family of transporters, including the Arabidopsis sulfate transporters, have a conserved structure comprised of catalytic trans-membrane domains and a C-terminal STAS domain. The latter domain, which extends into the cytosol, has similarity with bacterial anti-sigma-factor antagonists such as SpoIIAA of Bacillus subtilis. Recent studies suggest that the STAS domain influences the biogenesis and activity of sulfate transporters, although the mechanisms associated with these processes have not been determined. To explore how STAS domain structure affects sulfate transport function, we introduced random mutations in the STAS domain of the Arabidopsis sulfate transporter, designated Sultr1;2, and evaluated the consequences of the lesions on sulfate transport in a heterologous yeast system (the host yeast strain is null for the endogenous sulfate transporters). We identified distinct subdomains in the STAS domain that affect protein stability or transport activity. We also used the yeast two hybrid system to screen for proteins that interact with the Sultr1;2 STAS domain. Interestingly, the STAS domain appears to associate with a cytosolic isoform of cysteine synthase (O-acetyl serine (thiol) lyase or OASTL) that is expressed in cells of the root cortex. The interaction was confirmed both in vitro and in vivo. The potential functional relevance of this interaction is currently under investigation, and will be discussed.
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1 - Carnegie Institution, Plant Biology, 260 Panama St., Stanford, CA, 94305, USA
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM