Structural Basis of the Strigolactone Signaling through Plant SCF E3 complex

Abstract

Strigolactones (SL) are plant hormones that play an essential role in the control of plant branching, and act as rhizospheric signals for communication with symbiotic fungi and parasitic plants. MORE AXILLARY GROWTH2 (MAX2/D3) and DWARF14 (D14), are crucial signalling components that regulate SL‐repressed plant branching. D14 is a α/β hydrolase that hydrolyses SL into an inactive intermediate. MAX2/D3 is an ubiquitin ligase that has a leucine‐rich (LRR) F‐box region, which interacts with D14 in a SL‐dependent fashion. Once formed the D14‐D3 complex can bind to the repressor DWARF53 (D53) for subsequent ubiquitination and proteasomal degradation. The D3‐D14‐D53 complex is proposed to be involved in SL signaling. However, the recruitment of D53 by the D3‐D14 complex and the role of SL perception and hydrolysis remains largely unclear. In this study, we determine the structures of rice MAX2/D3 and D14‐SL complexes. In addition we measure the hydrolytic activity of D14 with and with out its binding partners D3 and D53. We also measured the binding of these three components using ALPHA technology. Our structural and biochemical studies shed light on SL sensing mechanism that is largely regulated by MAX2/D3 ubiquitin ligase.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.