Abstract

Plants sense changing light patterns within their environment, which allows them to adapt their growth patterns in response to different light conditions. Phytochromes (Phys) are proteins that perceive red and far-red light using two photo-interchangeable states. Light response BTB (LRB) E3 ligases act within the Phy signaling pathway and may function to target specific proteins within the plant for degradation via the 26s proteasome. The LRB proteins are part of a larger complex that together tag proteins for degradation, and an interaction between the LRB and Cullin subunits are required for E3 ligase activity. Previous studies in Arabidopsis thaliana have established that this Cullin-LRB interaction is present in red light but not in darkness. This study aims to identify if far-red light can reverse the affects of red light and disassociate LRB from Cullin, thus inactivating the complex in a Phy dependent way. Currently, we are undertaking an immunoprecipitation approach using GFP-tagged LRB proteins in Arabidopsis seedlings to assess E3 complex assembly in dark, red and far-red light treatments.