Post translational modifications of proteins are important events that influence protein function, interaction and localization [ 1], making those key elements in cellular processes and systemic reactions of organisms.
Advances in DNA sequencing technologies have enhanced our understanding of the functional roles of epigenetic modifications in fundamental cellular processes, including DNA repair and replication, nucleosome assembly, gene transcription, and pre-mRNA splicing.
Protein sumoylation, an important post-translational modification in various cellular processes, involves the covalent attachment of the SUMO polypeptide to specific lysine residues of target proteins [ 27].
SUMOylation, covalent modification of a protein by a small ubiquitin-related modifier (SUMO) peptide on a lysine residue, has emerged as an important posttranslational modification in regulating cellular processes.
Since first identification of the first UBLp (the interferon stimulated gene 15, ISG15) in 1979 additional UBLps (at least 10 to date) have been described with an escalating frequency and evidence of UBLps ever-widening role in the modification of cellular processes [17], [23].
In addition to cytosine demethylation, TET proteins are involved in chromatin modifications and other cellular processes through the interaction with O-linked β- N-acetylglucosamine transferase.
SUMOylation is a reversible post-translational modification involved in various cellular processes, such as nucleo-cytoplasmic shuttling and transcriptional regulation [ 25- 27].
Ubiquitination, just like phosphorylation, is a dynamic modification engaged in diverse cellular processes including cell growth and proliferation, apoptosis, DNA damage response, inflammation, cancer and neurodegenerative diseases [ 50– 50].
Lysine acetylation is a reversible posttranslational modification involved in multiple cellular processes, where an acetyl group is transferred to the epsilon-amino group of an internal lysine residue of a protein.
Assays originally developed for drug discovery can be used, directly or with modification, to evaluate cellular processes potentially involved in toxicity responses.
