Contents
Summary936I.Introduction936II.The quest for plant protease substrates – proteomics to the rescue?937III.Quantitative proteome comparison reveals candidate substrates938IV.Dynamic metabolic stable isotope labeling to measure protein turnover in vivo938V.Terminomics – large‐scale identification of protease cleavage sites939VI.Substrate or not substrate, that is the question940VII.Concluding remarks941Acknowledgements941References941
Summary
Proteolysis is a central regulatory mechanism of protein homeostasis and protein function that affects all aspects of plant life. Higher plants encode for hundreds of proteases, but their physiological substrates and hence their molecular functions remain mostly unknown. Current quantitative mass spectrometry‐based proteomics enables unbiased large‐scale interrogation of the proteome and its modifications. Here we provide an overview of proteomics techniques that allow profiling of changes in protein abundance, measurement of proteome turnover rates, identification of protease cleavage sites in vivo and in vitro and determination of protease sequence specificity. We discuss how these techniques can help to reveal protease substrates and determine plant protease function, illustrated by recent studies on selected plant proteases.