%0 Journal Article
%T Approaches and Guidelines for the Identification of Novel Substrates of Protein Lysine Methyltransferases.
%A Kudithipudi S
%A Jeltsch A
%J Cell Chem Biol
%V 23
%N 9
%D Sep 2016 22
%M 27569752
%F 9.039
%R 10.1016/j.chembiol.2016.07.013
%X Protein lysine methylation is emerging as a general post-translational modification (PTM) with essential functions regulating protein stability, activity, and protein-protein interactions. One of the outstanding challenges in this field is linking protein lysine methyltransferases (PKMTs) with specific substrates and lysine methylation events in a systematic manner. Inability to validate reported PKMT substrates delayed progress in the field and cast unnecessary doubt about protein lysine methylation as a truly general PTM. Here, we aim to provide a concise guide to help avoid some of the most common pitfalls in studies searching for new PKMT substrates and propose a set of seven basic biochemical rules: (1) include positive controls; (2) use target lysine mutations of substrate proteins as negative controls; (3) use inactive enzyme variants as negative controls; (4) report quantitative methylation data; (5) consider PKMT specificity; (6) validate methyl lysine antibodies; and (7) connect cellular and in vitro results. We explain the logic behind them and discuss how they should be implemented in the experimental work.