A Pipeline to Monitor Proteasome Homeostasis in Plants

The proteasome is a key component for regulation of protein turnover across kingdoms. The proteasome has been shown to be involved in or affected by various stress conditions in multiple model organisms in plants. As such, studying proteasome homeostasis is crucial to understand its participation in different cellular conditions. However, the involvement of the proteasome in many cellular processes and its interplay with other degradation pathways hamper the interpretation of experiments based on a single approach. Thus, it is crucial to formulate a framework to investigate proteasome dynamics in different model organisms including plants. Here, we describe a pipeline to monitor proteasome homeostasis using four different methods including (i) luminescent-based proteasome activity measurement, (ii) immunoblot analysis of ubiquitinated proteins, (iii) evaluation of proteasome subunit protein levels, and (iv) monitoring of the proteasome stress regulon on mRNA levels using quantitative real-time PCR (polymerase chain reaction).