Publication details

Auxin-binding pocket of ABP1 is crucial for its gain-of-function cellular and developmental roles

Authors

GRONES Peter CHEN Xu SIMON Sibu KAUFMANN Walter A. DE RYCKE Riet NODZYNSKI Tomasz ZAŽÍMALOVÁ Eva FRIML Jiří

Year of publication 2015
Type Article in Periodical
Magazine / Source Journal of Experimental Botany
MU Faculty or unit

Central European Institute of Technology

Citation
Web http://jxb.oxfordjournals.org/content/66/16/5055.abstract
Doi http://dx.doi.org/10.1093/jxb/erv177
Field Botany
Keywords Auxin; ABP1; Auxin binding; Site-directed mutagenesis; PIN proteins
Description The plant hormone auxin is a key regulator of plant growth and development. Auxin levels are sensed and interpreted by distinct receptor systems that activate a broad range of cellular responses. The Auxin-Binding Protein1 (ABP1) that has been identified based on its ability to bind auxin with high affinity is a prime candidate for the extracellular receptor responsible for mediating a range of auxin effects, in particular, the fast non-transcriptional ones. Contradictory genetic studies suggested prominent or no importance of ABP1 in many developmental processes. However, how crucial the role of auxin binding to ABP1 is for its functions has not been addressed. Here, we show that the auxinbinding pocket of ABP1 is essential for its gain-of-function cellular and developmental roles. In total, 16 different abp1 mutants were prepared that possessed substitutions in the metal core or in the hydrophobic amino acids of the auxin-binding pocket as well as neutral mutations. Their analysis revealed that an intact auxin-binding pocket is a prerequisite for ABP1 to activate downstream components of the ABP1 signalling pathway, such as Rho of Plants (ROPs) and to mediate the clathrin association with membranes for endocytosis regulation. In planta analyses demonstrated the importance of the auxin binding pocket for all known ABP1-mediated postembryonic developmental processes, including morphology of leaf epidermal cells, root growth and root meristem activity, and vascular tissue differentiation. Taken together, these findings suggest that auxin binding to ABP1 is central to its function, supporting the role of ABP1 as auxin receptor.
Related projects:

You are running an old browser version. We recommend updating your browser to its latest version.

More info