9601064 Crowell In plants, the mevalonate pathway leads to the synthesis of cytokinins, abscisic acid, gibberellins, ubiquinones, plastoquinones, dolichols, sterols, carotenoids, chlorophylls, and numerous other isoprenoids. Derivatives of mevalonate have also been found to be incorporated into a variety of plant cell proteins, but little is currently known about the function of these isoprenylated plant proteins. Since isoprenylated proteins are involved in a number of fundamental process in mammalian and yeast cells, including signal transduction, cell cycle regulation, cytoskeletal organization, and vesicular transport, it is likely that they serve important roles in plants. Preliminary data indicate that plants contain both known and novel isoprenylated proteins with probable functions ranging from regulation of actin polymerization to mediation of vesicle fusion. The objective of this project is to demonstrate the isoprenylation of these proteins in plant cells, to elucidate the role of isoprenylation in protein targeting and function, and to characterize the developmental regulation of the corresponding plant genes. This research will further our understanding of this important class of proteins and provide critical insights into their roles in plant growth and development. %%% Plants are the 'producers' of the biological world. Because of their ability to utilize sunlight and inorganic carbon in the production of energy-rich organic compounds, they constitute the biological foundation upon which all animal life depends. Accordingly, it is essential that we understand plant growth and development (cell cycle regulation, cytoskeletal organization, and vesicular transport) and the mechanisms by which plants interact with their environment (signal transduction). Plant responses to environmental or developmental stimuli result in remarkable changes in plant growth, habit, and ultimate biomass production. In this project, the role of several isoprenylated proteins, likely to be i nvolved in these processes will be characterized. By characterizing in detail the molecular events that influence these processes, we will be able to maximize the efficiency and utility of this natural process. ***
