Summary
We have isolated and characterized heteromeric membrane receptor complexes of the SERK family involved in a variety of developmental processes such as gametogenenesis (Albrecht et al. 2005), brassinosteroid signaling (Karlova et al. 2006) and plant cell immunity (Albrecht et al. 2008, Kemmerling et al. 2007). One of the proteins interacting with SERK1 was found to be a transcription factor of the MADS box class, AGL15 (Karlova et al. 2006). Genetic, molecular and cell biological evidence proposes that AGL15 has multiple functions of which one is the BL-mediated induction of embryogenic competence in vascular stem cells in tissue culture (Thakare et al. 2008, Karlova and de Vries 2008 and Kwaaitaal and de Vries 2007). In our part of the project we will focus on the signaling pathways upstream and downstream of the activation of AGL15. This will involve a proteomics-based analysis of the BL-induced BRI1/SERK1-mediated pathway leading to the activation of AGL15 in vascular stem cells as well as visualization of the various protein interactions and relocalizations by fluorescence spectroscopy.