Biological function of ROS-dependent CRKs modifications

Background

Under various biotic and abiotic stress conditions Reactive Oxygen Species (ROS) are produced in the plant cell as a universal stress response. They play an important role in intra- and extra-cellular signaling essential for proper growth and immunity processes. However, it is not yet known what are the ROS sensors in extracellular space (apoplast) and how it facilitates downstream signaling.

Among different subfamilies of plant Receptor Kinases (RK)s, Cysteine Rich Receptor Kinases (CRKs) is the second largest subfamily with 44 members. They are single pass transmembrane proteins with extracellular domain and cytoplasmic kinase domain. The ExtraCellular Domain (ECD) consists of two Domains of Unknown Function 26, with a conserved cysteine motif (C - 8X - C - 2X - C) at the core they are the most suitable candidates for elusive ROS sensors. The free thiols on these cysteines are highly susceptible to oxidation and it makes CRKs potential redox regulators.

Aim of the project

Fluctuating levels of ROS can cause different types of the oxidative modifications on the thiol group of cysteines in ECDs of Cysteine Rich Receptors. We aim to analyse the presence of these oxidative modifications of CRKs using redox mass spectrometry approaches. Knowing exactly which cysteine modifications in CRK’s ECD we will be able to assess which CRK interactions are modulated by changed redox conditions. This will contribute towards our understanding of the relation between ROS and CRK signaling. In this project we are also aiming to establish a reliable methodology to identify oxidative cysteine modifications.