Ubiquitin-based proteolysis is a modification and degradation system that is essential to proper functioning of all eukaryotes. Of the cullin ubiquitin ligases, the SCF class is the most diverse, with nearly 700 F-box proteins identified. ZEITLUPE (ZTL) is a key F-box protein involved in regulating the plant circadian clock. The recent identification of a proteolytic target of ZTL (TOC1), will now allow focus on the functional dissection of ZTL, its intracellular site of action, and identify additional biochemical interactors. Using deletion constructs of ZTL, and newly identified point mutations, the domains and residues necessary for in planta TOC1/ZTL interactions will be identified. The spatial and temporal ZTL/TOC interaction will also be identified, by experimentally controlling and monitoring their compartmentation. Furthermore direct targets of ZTL-mediated degradation will be determined. The specific ASK family member(s) that participate in the native SCFZTL complex and other additional interacting partners will also be studied. This work will provide an opportunity for the graduate student and postdoctoral researchers involved to learn contemporary molecular biology and plant molecular genetic techniques in an interactive environment. Additionally, the more experienced lab workers will mentor undergraduates, so they will learn technical and molecular skills that they could use later in their career. Additional impacts include the development and instruction of a Circadian Biology course designed to survey and synthesize current topics in all circadian systems. The research experiences of the personnel in this project will broaden their scientific expertise, and contribute to their development as future PI's, post-docs and teachers.
