The abscisic acid receptor PYR1 in complex with abscisic acid.
The plant hormone abscisic acid (ABA) has a central role in coordinating the adaptive response in situations of decreased water availability as well as the regulation of plant growth and development. Recently, a 14-member family of intracellular ABA receptors, named PYR/PYL/RCAR, has been identified. These proteins inhibit in an ABA-dependent manner the activity of a family of key negative regulators of the ABA signalling pathway: the group-A protein phosphatases type 2C (PP2Cs). Here we present the crystal structure of Arabidopsis thaliana PYR1, which consists of a dimer in which one of the subunits is bound to ABA. In the ligand-bound subunit, the loops surrounding the entry to the binding cavity fold over the ABA molecule, enclosing it inside, whereas in the empty subunit they form a channel leaving an open access to the cavity, indicating that conformational changes in these loops have a critical role in the stabilization of the hormone-receptor complex. By providing structural details on the ABA-binding pocket, this work paves the way for the development of new small molecules able to activate the plant stress response.
Santiago
Julia
J
Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, ES-46022 Valencia, Spain.
Dupeux
Florine
F
Round
Adam
A
Antoni
Regina
R
Park
Sang-Youl
SY
Jamin
Marc
M
Cutler
Sean R
SR
Rodriguez
Pedro Luis
PL
Márquez
José Antonio
JA
D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary
D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; C540976:AT4G17870 protein, Arabidopsis; D000040:Abscisic Acid