Regulation of HD-ZIPIII Activity by the START Lipid-binding Domain

Cold Spring Harbor Laboratory, Cold Spg Hbr NY

Investigators

Abstract

Marja Timmermans IOS-1022102 Regulation of HD-ZIPIII Activity by the START Lipid-binding Domain The START domain is a highly conserved protein motif associated with a number of diverse proteins, including key regulators of plant development. START domains are well known in animal systems where they regulate protein function through binding of specific lipids. The function of this domain in plant proteins is not well understood. Genetic analysis has shown that this motif is critical for function of the HD-ZIPIII proteins, which are required for normal embryonic, vegetative and floral development. The goal of this project is to elucidate the mechanism via which the START lipid-binding domain regulates activity of the HD-ZIPIII proteins. Genetic and biochemical approaches will be used to determine the effects of START domain mutations on the localization of HD-ZIPIII proteins within the cell, their ability to bind protein partners or DNA, and their ability to induce expression of target genes. A second aspect of this project is to identify lipids that bind the START domain to modulate HD-ZIPIII activity. A large library of distinct chemical compounds will be screened for substances that bind the HD-ZIPIII START domain and affect its ability to modulate target gene expression. Resolving the role of the START domain in HD-ZIPIII function will have wide-ranging implications for the large number of START domain-containing proteins in plants that contribute to diverse developmental processes, disease resistance and the regulation of flowering time. Likewise, identification of agonists / antagonists of the START domain will provide an entirely new toolkit to research START domain proteins and can reveal signals important for the fundamental developmental processes regulated by START domain factors. This project will also make significant educational contributions through the training of a Postdoctoral Fellow who is a member of a group underrepresented in science, and the training of undergraduate and high school students. In addition, participants in this project will lecture in the NSF-funded CSHL Plant Science Course and will teach in a summer training program for high school teachers at the CSHL Dolan DNA learning center.