The SERK1 protein complexes

Cell fate in plant cells is highly flexible and even differentiated cells can change fate back to the totipotent state. In this study we show that plant steroid hormones are required for this cell fate change. Brassinosteroids are perceived by receptors of the BRI1 and SERK type present in the plasma membrane of plant cells. SERK1 phosphorilation status in vivo is enhanced by brassinosteroid perception and in vitro SERK1 appears to be the most active kinase compared with the other members of the family. Using a combination of biochemical, molecular and cell biological tools the work presented in this thesis shows that the BRI1 and SERK1 receptors transduce the signal from the membrane directly to the nucleus via a transcription factor, AGL15. This is a novel finding in plants where it was not shown that such short signaling transduction pathways are operational.