Characterization of the role of AMBRA1 protein in light-mediated development in Physcomitrium patens

Light is a critical environmental cue for plant signaling and development, especially given their sessile nature. The integration of light signals into signaling networks in plants involves both light perception and signal transduction, regulated by wide range of proteins. Plants have evolved unique mechanisms to negatively regulate light signaling, repressing light-responsive processes in the absence of light, using ubiquitin-proteasome system for regulation of signaling components abundance. E3 ubiquitin ligases play key roles in regulating various signaling pathways, including those related to light response. The Cullin4-DDB1 RING ubiquitin ligase complex (CRL4) interacts with DDB1-Cullin4-associated factors (DCAFs), such as COP1-SPA and DET1, which play crucial role in photomorphogenesis - a light-dependent developmental program. AMBRA1 is a DCAF protein previously characterized in animals, where it is involved in development, autophagy, and the cell cycle. Here, I present the most complete functional characterization to date of the role of AMBRA1 protein in the model nonvascular plant Physcomitrium patens, highlighting its potential role in light-mediated development of plants.