Welcome to KMetHub, the database of non-histone lysine methylation!

Lysine methylation is one of the several post-translational modifications that regulate protein function. It's most well-known and studied version is the methylation of lysine residues in histone tails, where it orchestrates complex gene regulatory programs through the interaction with different effectors. The human proteome contains over 50 identified lysine methyltransferases that carry out different lysine methylation events in histone tails. However, lysine methylation is not limited to histones, it occurs throughout the whole proteome, influencing a multitude of different molecular pathways.

Even so, technical limitations have hindered the large-scale identification of methylated lysines until the last few years. The development of pan-methyl-lysine antibodies and advances in mass spectrometry and proteomics have now begun to overcome these limitations, leading to a rapid expansion in our understanding of lysine methylation beyond chromatin. As a result, an increasing number of non-histone proteins have been identified as targets of lysine methyltransferases, revealing diverse roles for this modification across cellular processes.

The KMetHub database collects and organises the information about the identified lysine methylation sites scattered throughout the scientific literature to provide a curated resource of experimentally identified lysine methylation sites in human non-histone proteins. Individual methylated lysines are presented as single entries, complete with information on the modified protein, the degree of methylation (mono-, di-, or tri-methylation) and the sequential context of the methylation site. Entries also contain information on the cellular context where the methylation was identified, the methyltransferase enzyme where available, and the gene ontology categories for the modified proteins.