The GRAS Protein SCL14

To gain insight in how clade II TGA factors mediate different responses, we isolated interacting proteins using a protein interaction screen in yeast. This screen yielded the glutaredoxin ROXY19 and the GRAS protein SCL14.

GRAS proteins, which are unique to plants, are typically composed of 400–770 amino acid residues and exhibit considerable sequence homology to each other in their respective C-termini, the GRAS domain (Bolle, 2004). Arabidopsis has 33 members which play important roles in diverse functions ranging from gibberellic acid signaling to root pattern formation and light responses.

We have shown that SCL14 is permanently recruited to target promoters through its interaction with as-1-bound TGA factors and that this recruitment is essential for the transcriptional activation of detoxification genes. SCL14 is found both in the nucleus and the cytosol. Blocking the nuclear export leads to its accumulation in the nucleus indicating a constant shuttling between both compartments (Fode et al., 2008)

• Post-translational modifications and novel protein-protein interactions leading to the activation of the SCL14 protein.
• Importance of the nuclear export for SLC14 function.
• Functional analysis of transcription factor NAC032, a direct target gene of the SCL14/TGA complex.