Identification of arginylated N-termini with specific reagents

N-terminal arginylation is a posttranslational modification of proteins that may determine their fate with respect to their stability and half-life and timing of their physiological and molecular function. Arginylated N-termini are in some documented cases N-degrons leading to degradation through the proteasome or autophagic-lysosomal system (ALS) regulating cellular homeostasis and global physiological alterations. Proteins that are targets of arginyl-transferases (Ates) capable of ligating arginine (Arg) residues to N-terminal amino groups and internal side chains show therefore high importance for manipulation in therapeutic and research contexts. Because of that, identifying those substrates is of high interest for all organisms from human to plant research. This chapter will shed some light onto methods for identification of arginylated N-termini with focus on specific antibodies targeting the N-terminally modified proteins.