EAPSI: Investigating the regulatory Mechanisms of Plant Thimet Oligopeptidases

Westlake Timothy J, Cortland NY

Investigators

Abstract

Plant diseases result in multi-billion dollar crop loss worldwide. Salicylic acid (SA) is a vital plant hormone that plays a central role in immune signaling and activation of defense responses. The hormone elicits a cascade of effects that regulates gene expression and protein activity. The project explores the means in which the activity and protein-interactions of two salicylic acid binding proteins, thimet oligopeptidase 1 and 2 (TOP1 & TOP2) are regulated. The research project will be conducted at RIKEN institute in Yohokama, Japan. The project will be a collaborative effort with Dr. Ken Shirasu, who is at the forefront of research pertaining to plant immunity and salicylic acid. Dr. Shirasu belongs to the renowned RIKEN research institute which houses a state-of-the-art research center with all the equipment and facilities needed to conduct the research project. The project will investigate the enzymatic activity and multimer formation of TOP1 and TOP2. Evidence suggests that TOP activity is governed by redox-sensitive bonds; however, the extent and dynamics of the redox-regulated and hormone-regulated peptide processing of TOP1 and TOP2 have yet to be determined. The objective of the project is to investigate the key components of the proteins that dictate the perceptivity of the peptidases towards SA and the cellular redox state. In order to do this, the activities and oligomerization of TOPs and various TOP deletion/substitution mutants will be assessed under different SA concentrations and reducing/oxidizing environments. The findings will further our understanding of a potential hub of hormone-controlled and redox-regulated peptidase processing in plants. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science (JSPS).