Download MendeleyMolecular structure of the GARP family of plant Myb-related DNA binding motifs of the Arabidopsis response regulators
Hosoda, K., Imamura, A., Katoh, E., Hatta, T., Tachiki, M., Yamada, H., Mizuno, T., Yamazaki, T.(2003) Plant Cell 14: 2015-2029
- PubMed: 12215502
- DOI: https://doi.org/10.1105/tpc.002733
- Primary Citation of Related Structures:
1IRZ - PubMed Abstract:
The B motif is a signature of type-B response regulators (ARRs) involved in His-to-Asp phosphorelay signal transduction systems in Arabidopsis. Homologous motifs occur widely in the GARP family of plant transcription factors. To gain general insight into the structure and function of B motifs (or GARP motifs), we characterized the B motif derived from a representative ARR, ARR10, which led to a number of intriguing findings. First, the B motif of ARR10 (named ARR10-B and extending from Thr-179 to Ser-242) possesses a nuclear localization signal, as indicated by the intracellular localization of a green fluorescent protein-ARR10-B fusion protein in onion epidermal cells. Second, the purified ARR10-B molecule binds specifically in vitro to DNA with the core sequence AGATT. This was demonstrated by several in vitro approaches, including PCR-assisted DNA binding site selection, gel retardation assays, and surface plasmon resonance analysis. Finally, the three-dimensional structure of ARR10-B in solution was determined by NMR spectroscopy, showing that it contains a helix-turn-helix structure. Furthermore, the mode of interaction between ARR10-B and the target DNA was assessed extensively by NMR spectroscopy. Together, these results lead us to propose that the mechanism of DNA recognition by ARR10-B is essentially the same as that of homeodomains. We conclude that the B motif is a multifunctional domain responsible for both nuclear localization and DNA binding and suggest that these insights could be applicable generally to the large GARP family of plant transcription factors.
Organizational Affiliation:
Biochemistry Department, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.
